It’s been over two years since the release of Raspbian Jessie. As of August 17th, 2017, the Raspberry Pi foundation has officially released the successor to Raspbian Jessie — Raspbian Stretch.
Just as I have done in previous blog posts, I’ll be demonstrating how to install OpenCV 3 with Python bindings on Raspbian Stretch.
If you are looking for previous installation instructions for different platforms, please consult this list:
- Install guide: Raspberry Pi 3 + Raspbian Jessie + OpenCV 3
- How to install OpenCV 3.0 on Raspbian Jessie.
- Installing OpenCV on your Raspberry Pi Zero running Raspbian Jessie.
- Installing OpenCV 3.0 for both Python 2.7 and Python 3+ on Raspbian Wheezy.
- Install OpenCV 2.4 for Python 2.7 on Raspbian Wheezy.
Otherwise, let’s proceed with getting OpenCV 3 with Python bindings installed on Raspian Stretch!
The quick start video tutorial
If this is your first time installing OpenCV or you are just getting started with Linux I highly suggest that you watch the video below and follow along with me as you guide you step-by-step on how to install OpenCV 3 on your Raspberry Pi running Raspbian Stretch:
Otherwise, if you feel comfortable using the command line or if you have previous experience with Linux environments, feel free to use the text-based version of this guide below.
Assumptions
In this tutorial, I am going to assume that you already own a Raspberry Pi 3 with Raspbian Stretch installed.
If you don’t already have the Raspbian Stretch OS, you’ll need to upgrade your OS to take advantage of Raspbian Stretch’s new features.
To upgrade your Raspberry Pi 3 to Raspbian Stretch, you may download it here and follow these upgrade instructions (or these for the NOOBS route which is recommended for beginners). The former instructions take approximately 10 minutes to download via a torrent client and about 10 minutes to flash the SD card at which point you can power up and proceed to the next section.
Note: If you are upgrading your Raspberry Pi 3 from Raspbian Jessie to Raspbian Stretch, there is the potential for problems. Proceed at your own risk, and consult the Raspberry Pi forums for help.
Important: It is my recommendation that you proceed with a fresh install of Raspbian Stretch! Upgrading from Raspbian Jessie is not recommended.
Assuming that your OS is up to date, you’ll need one of the following for the remainder of this post:
- Physical access to your Raspberry Pi 3 so that you can open up a terminal and execute commands
- Remote access via SSH or VNC.
I’ll be doing the majority of this tutorial via SSH, but as long as you have access to a terminal, you can easily follow along.
Can’t SSH? If you see your Pi on your network, but can’t ssh to it, you may need to enable SSH. This can easily be done via the Raspberry Pi desktop preferences menu (you’ll need an HDMI cable and a keyboard/mouse) or running sudo service ssh start from the command line of your Pi.
After you’ve changed the setting and rebooted, you can test SSH directly on the Pi with the localhost address. Open a terminal and type ssh pi@127.0.0.1 to see if it is working.
Keyboard layout giving you problems? Change your keyboard layout by going to the Raspberry Pi desktop preferences menu. I use the standard US Keyboard layout, but you’ll want to select the one appropriate for your keyboard or desire (any Dvorkac users out there?).
Installing OpenCV 3 on a Raspberry Pi 3 running Raspbian Stretch
If you’ve ever installed OpenCV on a Raspberry Pi (or any other platform before), you know that the process can be quite time consuming with many dependencies and pre-requisites that have to be installed. The goal of this tutorial is to thus guide you step-by-step through the compile and installation process.
In order to make the installation process go more smoothly, I’ve included timings for each step so you know when to take a break, grab a cup of coffee, and checkup on email while the Pi compiles OpenCV.
Let’s go ahead and get started installing OpenCV 3 on your Raspberry Pi 3 running Raspbian Stretch.
Step #1: Expand filesystem
Are you using a brand new install of Raspbian Stretch?
If so, the first thing you should do is expand your filesystem to include all available space on your micro-SD card:
$ sudo raspi-config
And then select the “Advanced Options” menu item:
Followed by selecting “Expand filesystem”:
Once prompted, you should select the first option, “A1. Expand File System”, hit Enter on your keyboard, arrow down to the “<Finish>” button, and then reboot your Pi — you may be prompted to reboot, but if you aren’t you can execute:
$ sudo reboot
After rebooting, your file system should have been expanded to include all available space on your micro-SD card. You can verify that the disk has been expanded by executing df -h and examining the output:
$ df -h Filesystem Size Used Avail Use% Mounted on /dev/root 30G 4.2G 24G 15% / devtmpfs 434M 0 434M 0% /dev tmpfs 438M 0 438M 0% /dev/shm tmpfs 438M 12M 427M 3% /run tmpfs 5.0M 4.0K 5.0M 1% /run/lock tmpfs 438M 0 438M 0% /sys/fs/cgroup /dev/mmcblk0p1 42M 21M 21M 51% /boot tmpfs 88M 0 88M 0% /run/user/1000
As you can see, my Raspbian filesystem has been expanded to include all 32GB of the micro-SD card.
However, even with my filesystem expanded, I have already used 15% of my 32GB card.
If you are using an 8GB card you may be using close to 50% of the available space, so one simple thing to do is to delete both LibreOffice and Wolfram engine to free up some space on your Pi:
$ sudo apt-get purge wolfram-engine $ sudo apt-get purge libreoffice* $ sudo apt-get clean $ sudo apt-get autoremove
After removing the Wolfram Engine and LibreOffice, you can reclaim almost 1GB!
Step #2: Install dependencies
This isn’t the first time I’ve discussed how to install OpenCV on the Raspberry Pi, so I’ll keep these instructions on the brief side, allowing you to work through the installation process: I’ve also included the amount of time it takes to execute each command (some depend on your Internet speed) so you can plan your OpenCV + Raspberry Pi 3 install accordingly (OpenCV itself takes approximately 4 hours to compile — more on this later).
The first step is to update and upgrade any existing packages:
$ sudo apt-get update && sudo apt-get upgrade
Timing: 2m 14s
We then need to install some developer tools, including CMake, which helps us configure the OpenCV build process:
$ sudo apt-get install build-essential cmake pkg-config
Timing: 19s
Next, we need to install some image I/O packages that allow us to load various image file formats from disk. Examples of such file formats include JPEG, PNG, TIFF, etc.:
$ sudo apt-get install libjpeg-dev libtiff5-dev libjasper-dev libpng12-dev
Timing: 21s
Just as we need image I/O packages, we also need video I/O packages. These libraries allow us to read various video file formats from disk as well as work directly with video streams:
$ sudo apt-get install libavcodec-dev libavformat-dev libswscale-dev libv4l-dev $ sudo apt-get install libxvidcore-dev libx264-dev
Timing: 32s
The OpenCV library comes with a sub-module named highgui which is used to display images to our screen and build basic GUIs. In order to compile the highgui module, we need to install the GTK development library:
$ sudo apt-get install libgtk2.0-dev libgtk-3-dev
Timing: 1m 36s
Many operations inside of OpenCV (namely matrix operations) can be optimized further by installing a few extra dependencies:
$ sudo apt-get install libatlas-base-dev gfortran
Timing: 23s
These optimization libraries are especially important for resource constrained devices such as the Raspberry Pi.
Lastly, let’s install both the Python 2.7 and Python 3 header files so we can compile OpenCV with Python bindings:
$ sudo apt-get install python2.7-dev python3-dev
Timing: 45s
If you’re working with a fresh install of the OS, it is possible that these versions of Python are already at the newest version (you’ll see a terminal message stating this).
If you skip this step, you may notice an error related to the Python.h header file not being found when running make to compile OpenCV.
Step #3: Download the OpenCV source code
Now that we have our dependencies installed, let’s grab the 3.3.0 archive of OpenCV from the official OpenCV repository. This version includes the dnn module which we discussed in a previous post where we did Deep Learning with OpenCV (Note: As future versions of openCV are released, you can replace 3.3.0 with the latest version number):
$ cd ~ $ wget -O opencv.zip https://github.com/Itseez/opencv/archive/3.3.0.zip $ unzip opencv.zip
Timing: 41s
We’ll want the full install of OpenCV 3 (to have access to features such as SIFT and SURF, for instance), so we also need to grab the opencv_contrib repository as well:
$ wget -O opencv_contrib.zip https://github.com/Itseez/opencv_contrib/archive/3.3.0.zip $ unzip opencv_contrib.zip
Timing: 37s
You might need to expand the command above using the “<=>” button during your copy and paste. The .zip in the 3.3.0.zip may appear to be cutoff in some browsers. The full URL of the OpenCV 3.3.0 archive is:
https://github.com/Itseez/opencv_contrib/archive/3.3.0.zip
Note: Make sure your opencv and opencv_contrib versions are the same (in this case, 3.3.0). If the versions numbers do not match up, then you’ll likely run into either compile-time or runtime errors.
Step #4: Python 2.7 or Python 3?
Before we can start compiling OpenCV on our Raspberry Pi 3, we first need to install pip , a Python package manager:
$ wget https://bootstrap.pypa.io/get-pip.py $ sudo python get-pip.py $ sudo python3 get-pip.py
Timing: 33s
You may get a message that pip is already up to date when issuing these commands, but it is best not to skip this step.
If you’re a longtime PyImageSearch reader, then you’ll know that I’m a huge fan of both virtualenv and virtualenvwrapper. Installing these packages is not a requirement and you can absolutely get OpenCV installed without them, but that said, I highly recommend you install them as other existing PyImageSearch tutorials (as well as future tutorials) also leverage Python virtual environments. I’ll also be assuming that you have both virtualenv and virtualenvwrapper installed throughout the remainder of this guide.
So, given that, what’s the point of using virtualenv and virtualenvwrapper ?
First, it’s important to understand that a virtual environment is a special tool used to keep the dependencies required by different projects in separate places by creating isolated, independent Python environments for each of them.
In short, it solves the “Project X depends on version 1.x, but Project Y needs 4.x” dilemma. It also keeps your global site-packages neat, tidy, and free from clutter.
If you would like a full explanation on why Python virtual environments are good practice, absolutely give this excellent blog post on RealPython a read.
It’s standard practice in the Python community to be using virtual environments of some sort, so I highly recommend that you do the same:
$ sudo pip install virtualenv virtualenvwrapper $ sudo rm -rf ~/.cache/pip
Timing: 35s
Now that both virtualenv and virtualenvwrapper have been installed, we need to update our ~/.profile file to include the following lines at the bottom of the file:
# virtualenv and virtualenvwrapper export WORKON_HOME=$HOME/.virtualenvs export VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3 source /usr/local/bin/virtualenvwrapper.sh
In previous tutorials, I’ve recommended using your favorite terminal-based text editor such as vim , emacs , or nano to update the ~/.profile file. If you’re comfortable with these editors, go ahead and update the file to reflect the changes mentioned above.
Otherwise, you should simply use cat and output redirection to handle updating ~/.profile :
$ echo -e "\n# virtualenv and virtualenvwrapper" >> ~/.profile $ echo "export WORKON_HOME=$HOME/.virtualenvs" >> ~/.profile $ echo "export VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3" >> ~/.profile $ echo "source /usr/local/bin/virtualenvwrapper.sh" >> ~/.profile
Now that we have our ~/.profile updated, we need to reload it to make sure the changes take affect. You can force a reload of your ~/.profile file by:
- Logging out and then logging back in.
- Closing a terminal instance and opening up a new one
- Or my personal favorite, just use the
sourcecommand:
$ source ~/.profile
Note: I recommend running the source ~/.profile file each time you open up a new terminal to ensure your system variables have been setup correctly.
Creating your Python virtual environment
Next, let’s create the Python virtual environment that we’ll use for computer vision development:
$ mkvirtualenv cv -p python2
This command will create a new Python virtual environment named cv using Python 2.7.
If you instead want to use Python 3, you’ll want to use this command instead:
$ mkvirtualenv cv -p python3
Timing: 24s
Again, I can’t stress this point enough: the cv Python virtual environment is entirely independent and sequestered from the default Python version included in the download of Raspbian Stretch. Any Python packages in the global site-packages directory will not be available to the cv virtual environment. Similarly, any Python packages installed in site-packages of cv will not be available to the global install of Python. Keep this in mind when you’re working in your Python virtual environment and it will help avoid a lot of confusion and headaches.
How to check if you’re in the “cv” virtual environment
If you ever reboot your Raspberry Pi; log out and log back in; or open up a new terminal, you’ll need to use the workon command to re-access the cv virtual environment. In previous blog posts, I’ve seen readers use the mkvirtualenv command — this is entirely unneeded! The mkvirtualenv command is meant to be executed only once: to actually create the virtual environment.
After that, you can use workon and you’ll be dropped down into your virtual environment:
$ source ~/.profile $ workon cv
To validate and ensure you are in the cv virtual environment, examine your command line — if you see the text (cv) preceding your prompt, then you are in the cv virtual environment:
Otherwise, if you do not see the (cv) text, then you are not in the cv virtual environment:
To fix this, simply execute the source and workon commands mentioned above.
Installing NumPy on your Raspberry Pi
Assuming you’ve made it this far, you should now be in the cv virtual environment (which you should stay in for the rest of this tutorial). Our only Python dependency is NumPy, a Python package used for numerical processing:
$ pip install numpy
Timing: 11m 12s
Be sure to grab a cup of coffee or go for a nice walk, the NumPy installation can take a bit of time.
Note: A question I’ve often seen is “Help, my NumPy installation has hung and it’s not installing!” Actually, it is installing, it just takes time to pull down the sources and compile. You can verify that NumPy is compiling and installing by running top . Here you’ll see that your CPU cycles are being used compiling NumPy. Be patient. The Raspberry Pi isn’t as fast as your laptop/desktop.
Step #5: Compile and Install OpenCV
We are now ready to compile and install OpenCV! Double-check that you are in the cv virtual environment by examining your prompt (you should see the (cv) text preceding it), and if not, simply execute workon :
$ workon cv
Once you have ensured you are in the cv virtual environment, we can setup our build using CMake:
$ cd ~/opencv-3.3.0/
$ mkdir build
$ cd build
$ cmake -D CMAKE_BUILD_TYPE=RELEASE \
-D CMAKE_INSTALL_PREFIX=/usr/local \
-D INSTALL_PYTHON_EXAMPLES=ON \
-D OPENCV_EXTRA_MODULES_PATH=~/opencv_contrib-3.3.0/modules \
-D BUILD_EXAMPLES=ON ..
Timing: 2m 56s
Now, before we move on to the actual compilation step, make sure you examine the output of CMake!
Start by scrolling down the section titled Python 2 and Python 3 .
If you are compiling OpenCV 3 for Python 2.7, then make sure your Python 2 section includes valid paths to the Interpreter , Libraries , numpy and packages path , similar to my screenshot below:
Notice how the Interpreter points to our python2.7 binary located in the cv virtual environment. The numpy variable also points to the NumPy installation in the cv environment.
Similarly, if you’re compiling OpenCV for Python 3, make sure the Python 3 section looks like the figure below:
Again, the Interpreter points to our python3.5 binary located in the cv virtual environment while numpy points to our NumPy install.
In either case, if you do not see the cv virtual environment in these variables paths, it’s almost certainly because you are NOT in the cv virtual environment prior to running CMake!
If this is the case, access the cv virtual environment using workon cv and re-run the cmake command outlined above.
Configure your swap space size before compiling
Before you start the compile process, you should increase your swap space size. This enables OpenCV to compile with all four cores of the Raspberry PI without the compile hanging due to memory problems.
Open your /etc/dphys-swapfile and then edit the CONF_SWAPSIZE variable:
# set size to absolute value, leaving empty (default) then uses computed value # you most likely don't want this, unless you have an special disk situation # CONF_SWAPSIZE=100 CONF_SWAPSIZE=1024
Notice that I’ve commented out the 100MB line and added a 1024MB line. This is the secret to getting compiling with multiple cores on the Raspbian Stretch.
If you skip this step, OpenCV might not compile.
To activate the new swap space, restart the swap service:
$ sudo /etc/init.d/dphys-swapfile stop $ sudo /etc/init.d/dphys-swapfile start
Note: It is possible to burn out the Raspberry Pi microSD card because flash memory has a limited number of writes until the card won’t work. It is highly recommended that you change this setting back to the default when you are done compiling and testing the install (see below). To read more about swap sizes corrupting memory, see this page.
Finally, we are now ready to compile OpenCV:
$ make -j4
Timing: 1h 30m
Once OpenCV 3 has finished compiling, your output should look similar to mine below:
From there, all you need to do is install OpenCV 3 on your Raspberry Pi 3:
$ sudo make install $ sudo ldconfig
Timing: 52s
Step #6: Finish installing OpenCV on your Pi
We’re almost done — just a few more steps to go and you’ll be ready to use your Raspberry Pi 3 with OpenCV 3 on Raspbian Stretch.
For Python 2.7:
Provided your Step #5 finished without error, OpenCV should now be installed in /usr/local/lib/python2.7/site-pacakges . You can verify this using the ls command:
$ ls -l /usr/local/lib/python2.7/site-packages/ total 1852 -rw-r--r-- 1 root staff 1895772 Mar 20 20:00 cv2.so
Note: In some cases, OpenCV can be installed in /usr/local/lib/python2.7/dist-packages (note the dist-packages rather than site-packages ). If you do not find the cv2.so bindings in site-packages , we be sure to check dist-packages .
Our final step is to sym-link the OpenCV bindings into our cv virtual environment for Python 2.7:
$ cd ~/.virtualenvs/cv/lib/python2.7/site-packages/ $ ln -s /usr/local/lib/python2.7/site-packages/cv2.so cv2.so
For Python 3:
After running make install , your OpenCV + Python bindings should be installed in /usr/local/lib/python3.5/site-packages . Again, you can verify this with the ls command:
$ ls -l /usr/local/lib/python3.5/site-packages/ total 1852 -rw-r--r-- 1 root staff 1895932 Mar 20 21:51 cv2.cpython-34m.so
I honestly don’t know why, perhaps it’s a bug in the CMake script, but when compiling OpenCV 3 bindings for Python 3+, the output .so file is named cv2.cpython-35m-arm-linux-gnueabihf.so (or some variant of) rather than simply cv2.so (like in the Python 2.7 bindings).
Again, I’m not sure exactly why this happens, but it’s an easy fix. All we need to do is rename the file:
$ cd /usr/local/lib/python3.5/site-packages/ $ sudo mv cv2.cpython-35m-arm-linux-gnueabihf.so cv2.so
After renaming to cv2.so , we can sym-link our OpenCV bindings into the cv virtual environment for Python 3.5:
$ cd ~/.virtualenvs/cv/lib/python3.5/site-packages/ $ ln -s /usr/local/lib/python3.5/site-packages/cv2.so cv2.so
Step #7: Testing your OpenCV 3 install
Congratulations, you now have OpenCV 3 installed on your Raspberry Pi 3 running Raspbian Stretch!
But before we pop the champagne and get drunk on our victory, let’s first verify that your OpenCV installation is working properly.
Open up a new terminal, execute the source and workon commands, and then finally attempt to import the Python + OpenCV bindings:
$ source ~/.profile $ workon cv $ python >>> import cv2 >>> cv2.__version__ '3.3.0' >>>
As you can see from the screenshot of my own terminal, OpenCV 3 has been successfully installed on my Raspberry Pi 3 + Python 3.5 environment:
Once OpenCV has been installed, you can remove both the opencv-3.3.0 and opencv_contrib-3.3.0 directories to free up a bunch of space on your disk:
$ rm -rf opencv-3.3.0 opencv_contrib-3.3.0
However, be cautious with this command! Make sure OpenCV has been properly installed on your system before blowing away these directories. A mistake here could cost you hours in compile time.
Don’t forget to change your swap size back!
Open your /etc/dphys-swapfile and then edit the CONF_SWAPSIZE variable:
# set size to absolute value, leaving empty (default) then uses computed value # you most likely don't want this, unless you have an special disk situation CONF_SWAPSIZE=100 # CONF_SWAPSIZE=1024
Notice that I’ve commented out the 1024MB line and uncommented the 100MB line.
If you skip this step, your memory card won’t last as long. As stated above, larger swap spaces may lead to memory corruption, so I recommend setting it back to 100MB.
To revert to the smaller swap space, restart the swap service:
$ sudo /etc/init.d/dphys-swapfile stop $ sudo /etc/init.d/dphys-swapfile start
Troubleshooting and FAQ
Q. When I try to execute mkvirtualenv and workon , I get a “command not found error”.
A. There are three reasons why this could be happening, all of them related to Step #4:
- Make certain that you have installed
virtualenvandvirtualenvwrapperviapip. You can check this by runningpip freezeand then examining the output, ensuring you see occurrences of bothvirtualenvandvirtualenvwrapper. - You might not have updated your
~/.profilecorrectly. Use a text editor such asnanoto view your~/.profilefile and ensure that the properexportandsourcecommands are present (again, check Step #4 for the contents that should be appended to~/.profile. - You did not
sourceyour~/.profileafter editing it, rebooting, opening a new terminal, etc. Any time you open a new terminal and want to use a virtual environment, make sure you executesource ~/.profileto load the contents — this will give you access to themkvirtualenvandworkoncommands.
Q. After I open a new terminal, logout, or reboot my Pi, I cannot execute mkvirtualenv or workon .
A. See reason #3 from the previous question.
Q. When I (1) open up a Python shell that imports OpenCV or (2) execute a Python script that calls OpenCV, I get an error: ImportError: No module named cv2 .
A. Unfortunately, this error is extremely hard to diagnose, mainly because there are multiple issues that could be causing the problem. To start, make sure you are in the cv virtual environment by using workon cv . If the workon command fails, then see the first question in this FAQ. If you’re still getting an error, investigate the contents of the site-packages directory for your cv virtual environment. You can find the site-packages directory in ~/.virtualenvs/cv/lib/python2.7/site-packages/ or ~/.virtualenvs/cv/lib/python3.5/site-packages/ (depending on which Python version you used for the install). Make sure that your sym-link to the cv2.so file is valid and points to an existing file.
Q. I’m running into other errors.
A. Feel free to leave a comment and I’ll try to provide guidance; however, please understand that without physical access to your Pi it can often be hard to diagnose compile/install errors. If you’re in a rush to get OpenCV up and running on your Raspberry Pi be sure to take a look at the Quickstart Bundle and Hardcopy Bundle of my book, Practical Python and OpenCV. Both of these bundles include a Raspbian .img file with OpenCV pre-configured and pre-installed. Simply download the .img file, flash it to your Raspberry Pi, and boot! This method is by far the easiest, hassle free method to getting started with OpenCV on your Raspberry Pi.
So, what’s next?
Congrats! You have a brand new, fresh install of OpenCV on your Raspberry Pi — and I’m sure you’re just itching to leverage your Raspberry Pi to build some awesome computer vision apps.
But I’m also willing to bet that you’re just getting started learning computer vision and OpenCV, and you’re probably feeling a bit confused and overwhelmed on where exactly to start.
Personally, I’m a big fan of learning by example, so a good first step would be to read this blog post on accessing your Raspberry Pi Camera with the picamera module. This tutorial details the exact steps you need to take to (1) capture photos from the camera module and (2) access the raw video stream.
And if you’re really interested in leveling-up your computer vision skills, you should definitely check out my book, Practical Python and OpenCV + Case Studies. My book not only covers the basics of computer vision and image processing, but also teaches you how to solve real world computer vision problems including face detection in images and video streams, object tracking in video, and handwriting recognition.
All code examples covered in the book are guaranteed to run on the Raspberry Pi 2 and Pi 3 as well! Most programs will also run on the B+ and Zero models, but might be a bit slow due to the limited computing power of the B+ and Zero.
So let’s put your fresh install of OpenCV on your Raspberry Pi to good use — just click here to learn more about the real-world projects you can solve using your Raspberry Pi + Practical Python and OpenCV .
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Summary
In this blog post, we learned how to upgrade your Raspberry Pi 3‘s OS to Raspbian Stretch and to install OpenCV 3 with either Python 2.7 or Python 3 bindings.
If you are running a different version of Raspbian (such as Raspbian Wheezy) or want to install a different version of OpenCV (such as OpenCV 2.4), please consult the following tutorials:
- Install guide: Raspberry Pi 3 + Raspbian Jessie + OpenCV 3
- How to install OpenCV 3.0 on Raspbian Jessie.
- Installing OpenCV on your Raspberry Pi Zero running Raspbian Jessie.
- Installing OpenCV 3.0 for both Python 2.7 and Python 3+ on Raspbian Wheezy.
- Install OpenCV 2.4 for Python 2.7 on Raspbian Wheezy.
Are you looking for a project to work on with your new install of OpenCV on Raspbian Stretch? Readers have been big fans of this post on Home surveillance and motion detection with the Raspberry Pi, Python, OpenCV, and Dropbox.
But before you go…
I tend to utilize the Raspberry Pi quite a bit on this blog, so if you’re interested in learning more about the Raspberry Pi + computer vision, enter your email address in the form below to be notified when these posts go live!
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Adrian. I want to ask something.
I have the Raspberry Pi 2 (and its camera module), but I just don’t know what kind of project I can do with it.
Since I am busy, if possible, I want to make a project that can contribute the most to what I am learning right now (mainly machine learning). Do you have any idea?
I were thinking of using it for scrapping data, but do not know where to begin. I would be very happy if you could recommend some suggestions.
Thanks!
Hi Hilman — the Raspberry Pi 2 is a bit underpowered so I wouldn’t recommend training a machine learning classifier on your Pi, but I could see deploying one. Have you considered training an image classifier to recognize a particular object on your laptop/desktop and then actually running it on your Raspberry Pi?
Also, keep in mind that all chapters inside Practical Python and OpenCV will run on the Raspberry Pi. Go through any of those chapters and you can execute the projects on the Pi (such as face detection + tracking). Those chapters make for excellent starting points for projects.
I hope that helps!
Ah… I forgot about that book. Will take a look at it later. Thanks!
Hi Adrian
for me i don’t know why the comment bar is not showing up, so i decided to write in the reply section.
ok for me i find there is an error after make -j4 step.every thing up till then worked fine,but don’t know what went wrong. I just followed your post, i am not familiar with terminal window commands .please help.
thank you
Can i install OpenCV- 2.4.9 in Raspbian stratch…..?
It’s a bit of a pain, to be honest. You’ll need to combine the steps from this tutorial along with original one on installing OpenCV 2.4 on Raspbian Wheezy. Be prepared to run into problems and do a bit of debugging.
Thq…..very much Adrian . I successfully OpenCV-3.3.0 with Python-3.5 in pi 3.Only problem, it takes 6h duration . Anyway i install Opencv .
Congrats on getting OpenCV installed!
manda como lo isiste amigo
Hi Admin,
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
…
error: (-215) scn == 3 || scn == 4 in function cvtColor
this’s my error. can I know how to fix this error.
thankz in advance
Double-check your path to the input image. It sounds like the path is incorrect and cv2.imread is returning None.
I was the same issue, it was solved with the following command:
sudo modprobe bcm2835-v4l2
BTW: Thanks a lot Adrian, you’re a Rock!!!!
Thanks Oscar, and congrats on getting it working 🙂
Great post as always.
I wanted to share a neat little trick: You can actually enable SSH on the RPi just by placing an empty “ssh” file (case sensitive!) in the root of the sd card (once Raspbian is flashed).
This makes running a 100% “headless” RPi possible: From there you can keep working with SSH or enable VNC and see the desktop from there.
Wow, that’s a neat trick! Thanks for sharing Jorge.
Your page has been explained in an easy-to-understand and polite manner, so it’s always helpful very much.
I immediately installed the CV with reference to this page.
However, Python IDLE in the program menu causes an error in importing. How can I use CV from IDLE?
Hi Hidenori — as far as I understand, the GUI version of Python IDLE does not support virtual environments, thus you cannot use it. I would suggest you use IDLE via the command line (so you can access the Python virtual environment) or use Jupyter Notebooks. I hope that helps!
how to install open cv 3 without installing virtual environments?
Don’t install virtualenv/virtualenvwrapper and don’t use the “mkvirtualenv” command to create a Python virtual environment. You’ll need “sudo” permission to install any pip-based packages.
I already installed virtual environments. Now I’m not able to import cv2 in Idle. Any solution? I Don’t want to access Idle from command line.
Python IDLE does not respect Python virtual environments. You would need to the command line. Another approach would be to install Jupyter Notebooks which will give you an incredibly powerful IDLE-like environment.
If you aren’t going to run the tests, you can save a fair amount of compile time by not including them. To do that, add “-D BUILD_TESTS=OFF” and “-D BUILD_PERF_TESTS=OFF” to the CMake command line.
Great tutorial.
All your ” Quickstart Bundle and Hardcopy Bundle book, Practical Python and OpenCV” I bought are a jewel i am happy to have invested in.
in your blog on “Drowsiness detection with OpenCV of May 8, 2017 in dlib, Facial Landmarks, Tutorials” you suggested :
“If you intend on using a Raspberry Pi for this, I would:
1. Use Haar cascades rather than the HOG face detector. While Haar cascades are less accurate, they are also faster.
2. Use skip frames and only detect faces in every N frames. This will also speedup the pipeline.”
I have Pi 3, Kindly do a tutorial with an example to implement the above options.
Hi Abkul — thank you for picking up a copy of Practical Python and OpenCV, I appreciate your support! And yes, I will be covering an updated drowsiness detector for the Raspberry Pi in the future. I can’t say exactly when this will be as I’m very busy finishing up the new deep learning book, but it will happen before the end of the year.
Where new blog about pixel by pixel for loops
I already covered the blog post you are referring to here. I’ll also be doing an updated one on OpenMP in the future.
Followed step-by-step and it worked like a charm. Compile took about 4 hours, as expected. Thanks!
Congrats on getting OpenCV installed, Rick! Nice job.
Hi andrian
thanks for sharing
I have success installed opencv to raspberry pi 3
thanks to your guidance
but I wonder
for compiling OpenCV 3 for Python 2.7 and python3.5
the libraries, numpy and site packages only for phyton 3
I tried for 3x
the result are still same
any idea about that ?
You would need to create two separate Python virtual environments. One for Python 2.7 and one for Python 3. Form there you can run CMake + make from inside each virtual environment to build OpenCV.
Worked like a charm..mind you I installed opencv3.3 rather than 3.1 … still worked great 😀
Congrats on getting OpenCV installed, Charles! Nice job.
Upon following this latest tutorial The compile did hang up around 91% using 4 cores on RPi2. Following the tutorial RPi2 on Jessie however compiled on Stretch using all 4 cores without issue.
Thank you for sharing your experience, Larry!
I am following this install on a Pi 2b. If I backup the sd card – will it work on a Pi 3 ?
Hi Adrian,
I installed OpenCv on my raspberry pi3 (2017-08-16-raspbian-stretch) by following step by step your latest tutorial.
The compilation went well and the result is similar to yours.
When I launch a simple program, see what it returns me:
(cv) pi@raspberrypi:~ $ sudo modprobe bcm2835-v4l2
(cv) pi@raspberrypi:~ $ python script.py
Unable to init server: Could not connect: Connection refused
(video test:1029): Gtk-WARNING **: cannot open display:
(cv) pi@raspberrypi:~ $
This program works fine on my computer with Linux Mint.
Thanks for your reply and sorry for my approximate English.
Bonjour de France 🙂
Stéphane.
How are you accessing your Raspberry Pi? Over SSH? Enable X11 forwarding when you SSH into your Pi:
$ ssh -X pi@your_ip_addressVia ssh well on 🙂
Ok I’ll try the x11 server activation
cordially
The issue with the multi threaded build is the lack of size of the swap file. You need to increase it to something like 1GB for doing intensive builds.
I tried serveral times and did follow your great tutorial in detail. Anyhow, I am not able to get the virtualenvwrapper working (and, due to this, I have issues later on).
After the installation of virtualenv and virtualenvwrapper (both were successful, including the dependancies) and updating the ~/.profile file, I always get the error:
pi@raspberrypi:~ $ source ~/.profile
/usr/bin/python: No module named virtualenvwrapper
virtualenvwrapper.sh: There was a problem running the initialization hooks.
If Python could not import the module virtualenvwrapper.hook_loader,
check that virtualenvwrapper has been installed for
VIRTUALENVWRAPPER_PYTHON=/usr/bin/python and that PATH is
set properly.
I did not find any clue to overcome this problem.
Any help is appreciated.
Which Python version were you trying to install OpenCV + Python for? Python 2.7? Or Python 3?
I’m trying to do 2.7 and get the same error
I would suggest explicitly setting your Python version for virtualenvwrapper inside your
.profilefile, like this:Thanks …. It works.
Awesome, I’m glad to hear it 🙂
Thanks. I had the same error. This solved it.
Awesome, I’m glad it worked for you, Manu! 🙂
add below code in ~/.profile along with other part, it worked for me
export VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3
thank you guys
it is work when adding
export VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3
In setting up the ~/.profile, I had to add the line: “export VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3” before “source /usr/local/bin/virtualenvwrapper.sh”. Otherwise, I got the “No module named virtualenvwrapper.hook_loader” error.
I also had to add export VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3” otherwise I“No module named virtualenvwrapper.hook_loader” error.
But what is the implication for the next step: mkvirtualenv cv -p python2
Thanks
It should have have an impact.
I am using Python 3 and was able to fix the problem by running this command:
sudo pip3 install virtualenv virtualenvwrapper
using pip3 instead of pip to make the virtual env.
Well, it is very strange for my case. I installed on python 2.7, was seeing”no module named virtualenvwrapper”.
I added ”
virtualenv and virtualenvwrapper
export WORKON_HOME=$HOME/.virtualenvs
export VIRTUALENVWRAPPER_PYTHON=/usr/bin/python2
source /usr/local/bin/virtualenvwrapper.sh” Still didn’t fix the problem.
Then I modified to “export VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3”, the error is magically gone.
Just a word of warning: Stretch takes more space than Jessie (~4GB vs ~3GB) so to prevent OpenCV from building on a 8GB card.
Thanks for sharing, Tom!
Did not work on the 8GB, not enoght space. Fail in make -j4 at 30%.
Going for the no desktop version for more space
In setting up the ~/.profile, I had to add the line: “export VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3” before “source /usr/local/bin/virtualenvwrapper.sh”. Otherwise, I got the “No module named virtualenvwrapper.hook_loader” error.
Another note: It is possible to run the make with 4 cores. Stretch suffers a bit from software bloat, so the 2GB of memory isn’t sufficient to compile with 4 cores. Edit /etc/dphys-swapfile
and change CONF_SWAPSIZE to 2048 and reboot. You can then do make -j4. you also need to do the same thing to install dlib as that will also hang under stretch when it runs out of memory.
Great point Stephen, thank you for sharing.
How exactly is this done? I can’t save any changes to the swapfile after I make them.
Use sudo when you open the file
i.e. sudo vim /etc/dphys-swapfile
substitute vim for your preferred editor (nano, etc)
premision denied.. (with nano)
Make sure you use “sudo” to give yourself the proper permissions to edit the file.
why can’t I import cv2 directly from python shell? but when I go to terminal and write work on and import cv2 then it works.
But I like to import cv2 from the script. so what can I do for that? I am using python 2.7 and pi3.
please help me.
To clarify, are you trying to execute a Python script from your terminal? If so you still need to use “workon” before executing the script (workon only needs to be executed once):
Same problem here, except i’m using Python 3.5.3. Did you find a solution ? Does anyone have a solution ?
I got it to import from my python script using the following code (this is on the pre-configured version of raspbian that comes with the Practical Python and OpenCV + Case Studies starter bundle.
#!/usr/bin/python
activate_this = “home/pi/.virtualenvs/py2cv3/bin/activate_this.py”
execfile(activate_this, dict(__file__=activate_this))
import cv2
for more details here’s the site I found: https://www.a2hosting.com/kb/developer-corner/python/activating-a-python-virtual-environment-from-a-script-file
Hey Adrian Rosebrock ! Thanks for such a wonderful and simple tutorial, currently i am installing opencv (currently at installing numpy) i would like to know whether some of the open cv modules are dependent or matplotlib ? If so is it similar to installing like numpy ? with cv virtual environment “pip install matplotlib”
No, there are no OpenCV modules that are dependent on matplotlib. You can install it via:
$ pip install matplotlibThanks ! I was successfully able to install open cv on my pi3 . At end you forgot to mention about deleting those zips (open cv and contrib ) file which might add few more mb of free space.
How do we access the environment variable in VNC or desktop terminal as” source ~/.profile “and” workon cv ” give invalid option . SSH i am able to get the cv environment.
Running:
Will work over SSH, VNC, and terminal on the desktop.
I’m not sure what error message you are getting, but again, the above commands will work just fine on all setups (provided there is not a misconfiguration, of course).
Yes ! Now i am able run these line without any errors fron VNC ,dont kown what was the reason for such error . Anyways thanks !
It does not worked for me. I took Memory Error, although I have memory.
I tried “pip –no-cache-dir install matplotlib” command. Although I took again another error, at the end of I have installed matplotlib.
Correct, using:
$ pip install matplotlib --no-cache-dirWill help if you are running into a MemoryError.
Hi Adrian,
I have followed your tutorial to install opencv3 using python3 in raspberri Pi3 stretch.
I ran following commands:
source ~/.profile
workon cv
python file_name.py
error:
Traceback (most recent call last):
File “face_detection.py”, line 2, in
importError : No module named ‘picamera’
I tried to install ‘picamera’ using following commands:
sudo apt-get update
sudo apt-get install python3-picamera
Result:
python3-picamera is already installed the newest version (1.13)
0 upgraded, 0 newly installed, 0 to remove and 20 not upgraded
Again I tried to run:
python file_name.py
same importError :
Traceback (most recent call last):
File “face_detection.py”, line 2, in
importError : No module named ‘picamera’
I am not getting why this is happening. It’ll be very helpful if you can help me out of this.
You installed picamera via apt-get which will install it into your system install of Python, not the virtual environment. You should use:
And you’ll be all set.
Thanks man! It’s working perfectly fine 🙂 🙂 _/\_
Really great instructions Adrian, thank you, saved me loads of time. However, i installed everything and found it used up 9.5GB of the sd card, so it might be worth mentioning that 16GB is recommend. I noticed on your setup it only took ~4.2GB. Is that after removing LibreOffice and Wolfram engine?
Correct, that is after removing LibreOffice and Wolfram Engine.
So worth mentioning if you use a 8GB sd card, you will need to remove LibreOffice and Wolfram Engine, otherwise when you try and build openCV you will most likely run out of space and get an error, then have to build it again, and this step can take hours so not something you want to happen.
when I try to download https://gethub.com/Itseez/opencv/archive/3.3.0.zip the connection just times out over and over
Hi Bryan — please double-check your internet connection and try again. There might have also been a problem with GitHub when you tried to download the code.
Hi Bryan,
I’ve run in to that problem a couple of times using apt-get as well – bet you were running it in the afternoon. Try running it later at night or early in the morning. I suspect the servers get overloaded at peak times.
Cheers
missing link
you can try this https://github.com/Itseez/opencv/archive/3.3.0.zip
can openCV3.3 be installed in jessie
Yes, absolutely. I provide a number of OpenCV install tutorials for various Raspbian distributions here.
after expand the file system and reboot …
i cant access to the raspberry pi through Remote Desktop.
but able to use ssh access to the pi
Anyone can help ?
Hmm, I don’t think this is an issue related to expanding the file system and rebooting. Can you ensure the remote desktop service is properly running?
Love the content, I wish I had snapped up the newest course at the early bird discount.
If anyone waited 4 hours for compile, and without thinking pasted the “make clean” command. I feel your pain…from now on, read twice, paste once.
Silver lining: I’ll never forget what make clean does.
Ugh, I’m sorry to hear that Banjo. I’ll be posting an updated Raspberry Pi install tutorial this coming Monday, October 9th which will enable you to compile OpenCV on the Raspberry Pi in about 45 minutes.
Hi Adrian,
When I reached the creation of virtual environment part, I accidently created another virtual part for Python 2.7 as well. But I want to work with Python 3.
In Cmake output, both interpreter and numpy of Python 2.7 and Python 3 are located in the virtual environment cv.
Will it cause any problem in the future?
Thanks in advance
Just to be safe I would suggest deleting both your Python virtual environment via the
rmvirtualenvcommand and correctly creating your Python 3 one. From there, delete your “build” directory, re-create it, and re-run CMake.thank you
Hello, thank you Adrian for this tutorial.
I am having trouble at step 5:
when I try the cmake -D……
I get a bash: cmake: command not found.
Any ideas why?
Please make sure you “Step #2” where the “cmake” command is installed.
Hi Adrian,
I followed the instructions and were able to install OpenCV 3.3.0 on my Raspberry Pi 3. Everything seemed to work pretty well until I ran into a Face Recognition Script that contained the following line:
model = cv2.face.createEigenFaceRecognizer()
The following Error Message was shown when I ran Python on it:
“AttributeError: module ‘cv2’ has no attribute ‘face’ ”
Everywhere I looked, the answer seemed to point to the “OpenCV’s extra modules” which I thought was already installed with opencv_contrib from the github.
Any idea on how I can fix this?
TIA,
Huy –
Indeed, it sounds like your install of OpenCV did not include the “opencv_contrib” modules. You will need to re-compile and re-install OpenCV.
Hi.
the virtualenvironment is killing me.
Unless I’m in it, I can’t see cv2 library.
If I am in it, python can’t see picamera.array and other modules.
This makes the home surveillance blog that was suggested to try opencv out impossible.
time spent thus far: 10h compiling (even without make -j, it crashed at 83%, although power cycle -ie too hung to ssh into and stop cleanly) and 3h on this. Definitely not for the faint hearted!
Is there an easy way to get needed modules into virtual environment? I have to abandon this soon – it is consuming too much time. A pity really, because I was hoping to bring it to my classroom.
Cheers,
Leon
Hi Leon — that is the intended behavior of Python virtual environments. Python environments keep your system Python packages separate from your development ones. As far as your Pi crashing during the compile, take a look a this blog post which provides a solution. The gist is that you need to increase your swap space.
Will this tutorial work on a raspberry pi 2? Currently its os is raspian wheezy and from the offial website you can only download raspian stretch
Hi Aaron — can you please clarify your comment? Are you running Raspbian Wheezy on your Pi and want to install OpenCV?
I have changed to Raspian Stretch but i have a Raspberry Pi 2 just wondering will this tutorial work for it as you are using a Raspberry Pi 3
I have not tested on the Raspberry Pi 2, but yes, this tutorial should work.
Hi Adrian, i am using sift for features extratction. but it is showing that
“module” has no attribute “xfeatures2d”. I have downloaded opencv_contrib and unzip it properly but still getting error when i run my code on raspberry pi 3.
Hi Haseeb — it sounds like your path to the
opencv_contribmodule during the CMake step was incorrect. Double-check the path, re-run CMake, and re-compile + re-install OpenCV.Made it to the open CV compile
stopped at 86%
Spec ( Ras pi 0 wireless , stretch , python 2.7)
should I attempt to change to python 3.0, reformat the sd card and start over, or attempt optimizing open CV and make -j4? useing your oct 9th article.
Thanks
I would actually update your swap size, as I discuss in this post. From there, delete your “build” directory, re-create it, and re-compile.
sir i have done the solution you mention above that modify the the swap size , but still my installation get stuck at 98 % along with this whole RPI get hang and can’t do anything . So i have to forcefully switch it off directly. Please tell me the solution !!
Hey Kaustubh, if you are still having trouble compiling and installing OpenCV I would recommend taking a look at the Quickstart Bundle and Hardcopy Bundle of my book, Practical Python and OpenCV. Inside I have included a pre-configured Raspbian .img file with OpenCV pre-installed. Check it out as it will solve your current issue installing OpenCV.
is there a way you can you run the Idle shell for python in the virtual environment
No, IDLE does not respect Python virtual environments. Please use the command line. If you like IDLE, try using Jupyter Notebooks that do work with Python virtual environments.
Hi,
I am not able to import PIL from virtualenv. Can you please suggest how to fix the issue?
Thanks in advance
Raju
How did you install PIL? Did you install it into the Python virtual environment?
Why can’t your tutorial be run from a shell script? It would eliminate a lot of errors and retries?
It can be executed via a shell script in some situations; however, it’s also important to understand how the compile works, especially if you intend on optimizing your install. I also offer a pre-configured Raspbian .img file inside Practical Python and OpenCV.
Can this tutorial work on a 8GB card?
If you purge Wolfram Alpha and LibreOffice you should be okay, but I would really suggest using a 16GB card.
Oh man. I found this link for stretch. It seems to work because everything went smoothly untill I try to compile opencv. At this step cd ~/opencv-3.3.0/ it tells me that the directory does’t exist.
So I mkdir one then mkdir build, cd into build. when try to compile, it tells me it doesn’t contain CMakeLists.txt , where is this CMakeLists.txt ?
Hi Rich — it’s hard to say what the exact issue is without seeing the directory structure of your project. Can you ensure that OpenCV was properly downloaded and unzipped in your home directory?
I’m very new to this and I just followed your video and now I have it downloaded so thank you. However, I don’t know what to do know, like how to write and run scripts in this virtual environment because every time I type python into it, the shell pops up. Could someone tell me how to open blank scripts so I can start writing code. Thank you
Hey Daniel — you would need to supply the path to the Python script you would like to execute:
$ python your_script.pyOpen up the a file in your favorite plaintext editor, save it as a .py file, and insert your code. From there execute it via the command line.
Could add “nohup” to long-running commands? It’s not unusual to lose the ssh connection and it gets frustrating as the installation is pretty long already.
You could absolutely use “nohop”; however, I prefer using “screen”.
In step 5, after cmake completes I type ‘make’ but there are no Makefiles that it can run against.
Please check your output of “CMake” as it likely returned an error (and thus no Makefiles were generated).
I had gotten this error too, and the cmake log files told me that I was missing a header file. I went back through the instructions and found that I had missed installing the opencv_contrib package.
Hello adrian,
thank you. this is the best tutorial i ever seen.
but i got one problem
when i’m run this script
$ ls -l /usr/local/lib/python2.7/site-packages/
i just get 300+ (3 digit) even though you get 1852
and then i’m
$ ls -l /usr/local/lib/python3.5/site-packages/
i got 3500+ (4 digit) and you got 1852
please help me adrian to fix this, thank you
Hi Olivia — thanks for the comment. That number will depend upon the packages you have installed in your environment.
i just follow your step adrian, why i get that value? is that ok for my next step when i want to using python?
I think it is safe to carry on with the instructions. Don’t worry about these values.
ok.. thank you adrian
Hello Adrian,
I have installed the opencv inside the virtual environment ,
but i’m unable to access outside (i.e)., Inside the IDLE.
How to access it.
Hi Akash — thanks for the comment. Unfortunately, IDLE cannot access Python virtual environments. I would suggest using Jupyter Notebooks which do work with Python virtual environments.
Hello Adrian. I just wanted to say thanks. It took a long time but it was a problem-free installation. Nice guide.
Congrats on getting OpenCV installed, nice job!
Hi Adrian, great walkthrough, tutorial or wathever you want to call it, made it without any trouble in the times that are say… although this only work as long as someone work on the virtual environment, is there any way to make this work outside the virtual env. to use opencv on python directly??
Thanks for everything mate, cheers.
Hi Enzo — it’s a best practice to use Python virtual environments. Each Python virtual environment copies the binaries and libraries of your system Python but doesn’t keep any existing installed libraries. Therefore, you can use OpenCV + Python directly. If you do not want to use Python virtual environments you can either (1) follow the steps and ignore virtualen/virtualenvwrapper steps or (2) sym-link any packages into your system install of Python.
hi
i do everything in this tutorial but in step #5 when compiling opencv it freeze up at 86%….
i use $ make clean $ make
but freeze up again at 86%
.what can i do??? please help me….please help me…please (:
It sounds like you might be running out of swap space. Please see this tutorial on how to increase your swap.
is there a respbian stretch image that opencv and python have been installed on it??? and i just write this on my sd card and use…. is this possible????
Hi Mory — I would suggest you take a look at the Quickstart Bundle and Hardcopy Bundle of Practical Python and OpenCV. Both these bundles include a pre-configured Raspbian .img file with OpenCV pre-installed.
thank you very much Adrian..
Hi,
I’m getting following error after CMake it says “Configuration incomplete, errors occurred!”
Please check the output of CMake — it will report what the specific error is and why the command failed.
How i can do this ? I got same erro
As I mentioned in my previous reply: scroll through the output of “cmake” in your terminal.
Great tutorial… Is there a way to install SimpleCV on top of this? I’ve tried, but keep getting memory errors. Thanks Adrian..
Hi Shane — typically we recommend the power of OpenCV over SimpleCV, but SimpleCV still has merits. Try these installation instructions for SimpleCV.
I had completed installing the opencv to 100%. But when I check it using the code below
source ~/.profile
$ workon cv
$ python
>>> import cv2
it is showing errors that the file is not created or something like that
Make sure you’ve properly linked cv2.so to your virtual environment. See Step #6.
Hello Adrian,
do you have a similar guide to install scikit-learn on a pi as well?
Thanks
The easiest way is via PIP in your virtual environment:
pip install -U scikit-learnHi Adrian,
I have tried to follow these steps multiple times now, but at step I keep getting a wrong output from the cmake. The library, numpy and packages paths are missing. Do you know what I could be doing wrong?
Kind regards,
Suzanna
Hi Suzannna — perhaps you aren’t inside your virtual environment when you issued the CMake command.
Adrian, I followed, I believe all the instructions up to the actual compile where the last thing is type in ‘make’ and it should start compiling. What I get is an error message >> make: *** No targets specified and no makefile found. stop.
What did I miss doing?
Hey Don — try double-checking your output of CMake. It sounds like the “cmake” command exited with an error. Check the terminal output and you should be able to spot what threw the error.
Adrian, I got the same error for make -j4…. i also checked cmake command execution and it returned a few errors….what should i do next??
Be sure to check your output of the “cmake” command. CMake will report an error and what caused the error.
when i enter make this comes up:
(cv) pi@raspberrypi:~/opencv-3.3.0/build $ make
make: *** No targets specified and no makefile found. Stop.
Hi Raghuram, did you first use CMake which will generate the Makefile?
I started the process again and now it shows an error at 86% ,that says boostdec_bgm.i missing.
thanks for the reply please help me ou
I was able to install it but could and import cv2 worked on terminal , but it could not work in python please help!!
Hey Raghuram — I’m not sure what you mean by you could import the cv2 library in your terminal but not in Python. Could you please elaborate? Are you trying to use Python IDLE? Keep in mind that Python IDLE does not respect Python virtual environments.
Hi Adrian, how to generate Makefile using CMake file? Please explain
Adrian, i wanna restart my raspberry from zero. i have install following your step and now i want deleting all and start from zero.. how to do that?
If you want to start completely from scratch I would recommend re-flashing Raspbian onto your SD card. If you want to restart your OpenCV compile just delete your “build” directory and recreate it.
help!. in the step of executing cmake I have a problem only appear the directories for python 3 and not for python 2.7 I tried many times updating my profile and even repeat from the beginning the procedure and do not appear please could help me
You can only compile OpenCV bindings for ONE Python version at a time. If you have the correct directories for Python 3 then you can proceed with the compile to obtain your Python 3 + OpenCV bindings.
ln: failed to create symbolic link what do i do for this kind of error
Dear Adrian,
In step #5 , I am sure I am in the cv virtual env. — “(cv) pi@raspberrypi:~/opencv-3.3.1/build $ “.
But when I type “cmake -D CMAKE_BUILD_TYPE=RELEASE \…..”. I got a error message –“CMake Error: The source directory “/home/pi/opencv-3.3.1/build/CMAKE_BUILD_TYPE=RELEASE” does not exist.”.
Yours faithfully
Ivan Chuang
HI Adrian,
I got the answer, just like this “cmake -DCMAKE_BUILD_TYPE=RELEASE \”.
But I have another question. When I want to make sure my Python3 section, I don’t know I need to check which file.
Yours faithfully
Ivan Chuang
Congrats on resolving the CMake issue. As for checking your “Python 3” section just scroll up in your terminal and examine the output of the “cmake” command.
There is no sudo make install
I get it, “not exitis file install”
HELP !!!!
I would suggest checking the output of CMake. It sounds like the “cmake” command exited with an error and did not create the Makefile.
Hi Adrian,
I’ve been following a lot of your blog posts and tutorials, and I find them amazing! Thank you so much for this amazing and super easy to follow guide to setting up OpenCV 3 on the new Raspbian Stretch!
Big Fan,
Shiv
Thank you for the comment, Shiv! And congrats on getting OpenCV installed on your Raspberry Pi!
that was really helpful .
thank you very much for your help .
i did the make command when i was in the env .
and it worked just fine and finished successfully
when i did sudo make install
it is taking me the same time that “make” did. (that sentence makes no sense 😛 )
is it normal ?
Hi Jad — as long as the command executes without error you should be okay.
Hi Adrian
I have compiled OpenCV3 on a fresh version of Rasbian Stretch following your recipe, (although I did not use a virtual environment).
I am using a Python script that was developed in Jessie and OpenCV 2.4.9 and have updated the syntax where necessary. Everything seems to be successful apart from one thing, cv2.resize() and cv2.resizeWindow()are not working. They do not throw an error but have no effect on the size of the image or the window (I am using cv2.WINDOW_NORMAL). Is there anything obvious that I may have missed?
Thanks
Colin
I’m not sure about
cv2.resizeWindowas I’ve never used that function before but to checkcv2.resizeprint the resulting.shapeto your terminal. If that’s not your expected dimensions then there is likely a logic error somewhere else in the code.Hello Adrian
I enjoyed this tutorial. The most advanced project I’ve ever attempted but its not complete. I reached the total “1852”
I got to step 7 and entered “workon cv” and got command not found
To my horror I suspect I forgot, yes the sym-link step. Can’t get in the cv environment.
Help!! Thanks
Ronald
Hey Ronald, I would suggest going back to Step 4 and ensure you have updated your
.profilefile. I would also suggest ensuring virtualenv/virtualenvwrapper have been properly installed.Hello Adrian I’m also having an issue with the “make” command,
I’ve followed the previous step with the “cmake” command successful and when i “ls” in the “build” directory the make files are there but when i use the “make” command it says:
make: *** No targets specified and no makefile found. Stop.
Its defiantly in the (cv) environment also.
any suggestions would be much appreciated,
Kind regards,
Jonathan
Please see my reply to “Don” and “Raghuram”.
I saw your reply to “Don” and “Raghuram” and still don’t know what to do and I am wondering whether you have any input that could help, please?
I followed your instructions to the tee – brand new board, brand new stretch OS flashed.
As you suspected, CMake indeed spits out errors. What I’m curious about is why have those errors shown up for a few of us on here, but not for some others?
./opencv-3.3.0/build/CMakeFiles/CMakeError.log is 343 lines long —
i.e. CMake reports LOTS of errors under this recipe – I followed it perfectly.
There are 4 files on which CMake failed, as shown by this post cmake step command:
(cv) pi@pishow:~/workspace/opencv-3.3.0/build $ grep -A1 failed CMakeFiles/CMakeError.log|grep ‘source\ file’| sort -u
source file: ‘/home/pi/workspace/opencv-3.3.0/build/CMakeFiles/CMakeTmp/src.c’
source file: ‘/home/pi/workspace/opencv-3.3.0/build/CMakeFiles/CMakeTmp/src.cxx’
source file: ‘/home/pi/workspace/opencv-3.3.0/cmake/checks/cpu_fp16.cpp’
source file: ‘/home/pi/workspace/opencv-3.3.0/cmake/checks/cpu_neon.cpp’
Woops. I know what I did wrong and why CMake failed. It was MY mistake. The recipe works perfectly. The mistake was to cut and paste the CMake command as is. But I had downloaded the original packages and had unzipped them at a location OTHER than the user’s home directory, so the paths in the CMake command had to be changed. This solved the issues and a Makefile got created. Sorry about the false alarm and I hope this helps others.
Congrats on resolving the issue!
i am facing same problem how you solved it please tell me it will be great help
On my Pi no problem to compile with make -j4. But, I have added blas and lapack with :
sudo apt-get install libblas-dev liblapack-dev
Please you used the full or lite version for Raspbian ?
I used the full version of Raspbian but you can use the lite version as well.
Hello Adrian I’m also having an issue with the “make” command,
the compilation stops at 30% i even tried to increase the swap size to 1024
and compiling using make -j4 but still it does not compile more than 30%
Hi Sarthak — try using only a single core via
make. The compile will take longer but provided you increased your swap it should work.I did the make but did not increase the swap size just used make not make -j4 but the complilation stopped at 89%
Will increase the swap size help in this?
Yes. Increasing the swap size should resolve this issue completely.
I have installed opencv 3 as explained above and followed all the steps for python 3
When i am running a program of face recognition data set in python IDE 3 it is giving error in the line import cv2
Importerror: No module named “cv2”
Plz help me to solve this
Please see my reply to “Hidenori Kaga”, “bob”, “Akash”, and others. I have addressed this question multiple times.
Hello Adrian.
sudo apt-get update
sudo apt-get upgrade
sudo apt-get install libopencv-dev
sudo apt-get install python-opencv
Is this ok? install opencv
I DO NOT recommend this method. The apt-get package definitions are often out of date and you won’t have the additional extra modules with OpenCV. I highly encourage you to compile OpenCV from source, using apt-get is not recommended.
Hello Adrian,
I followed this tutorial and everything went well to step 5.
After the command cmake I get an instant error: “segmention fault” and i can’t go on.
Could you help me?
The “cmake” command caused a segmentation fault? That’s not good. It sounds like something might be wrong with your Raspberry Pi/Raspbian. Could you re-install Raspbian then try again? Unfortunately I’m not sure what the exact problem is here.
I got the same error and was pulling my hair out for days. The fix is easy. you just have to update the firmware of your pi. right after ” $ sudo apt-get upgrade”, give “$ sudo rpi-update”. This worked for me.
Thanks for sharing, Nisal!
Thank you so much sir you are such a great teacher for me. i going to order your book as soon as possible. thank you again God bless you.
Thank you Ali, I really appreciate the comment 🙂
I thing the virtual environment step is fragile.
Initially I created the cv env with python3 as shown, then I created another cvpy2.7 and used workon cv to switch back and then finished the instructions but the build failed. I then tried workon cvpy2.7 and got the failure message I posted above.
Before calling it a night I deleted both my virtual environments using rmvirtualenv and did rm -rf of my build directory. I then recreated the python2 virtual environment and finished the steps, but I did the make without the -j4 and went to bed.
Complie appears to have completed OK, doing the make install and ldconfig steps now,
So you can disregard my comment from last night, but perhaps you could explain the steps to make a second virtual environment using python3. Or is it not possible to have both on the same system?
You can create as many Python virtual environments as you want on a single machine. That is why we use Python virtual environments.
HOWEVER
You DO need to re-compile OpenCV for each Python version you want to use it for. You cannot use the same OpenCV bindings for multiple Python versions. I personally like to create a
builddirectory for each unique Python + OpenCV version and then sym-link the resulting .so file into my respective Python virtual environment.While using the cmake command , I get the following results:
Python2:
interpreter: /home/pi/.virtualenvs/cv/bin/python2.7(2.7.13)
and that’s it.
I don’t get the rest …the libraries,the numpy…..
how to solve this?
Hi Ravi — thanks for the comment. It sounds like you are indeed in the “cv” environment based on your “interpreter” output. Can you run “pip freeze” to ensure that NumPy is also installed?
While running the cmake step, it failed again and again and didn’t make the makefile until I added swap space. This was on a freshly installed stretch distribution running on a Pi Zero W. I’m now waiting for the compile to finish. Should finish sometime over night. It’s only 20% done after 4 hours.
As for wearing out the flash card, you can try running fstrim on the card every week to make sure the maximum amount of blocks are available for wear leveling.
Did you finally get it to work? Is this process mentioned above completely right for Pi Zero also?
I have virtual environments running on my Pi3 for both python2.7 and python3.
I think my problem was in step 4, where you forgot to mention that for a python3 virtual environment numpy needs to be installed with: pip3 install numpy instead of the pip install numpy listed. I failed to catch it.
Perhaps some guidance on choosing python3 vs. python2.7?
My take is python3 is the future and unless a module you need is not available for it, python3 is what should be used. Your samples seem to be written to be compatible with both.
I’ve successfully run the deep-learning-opencv example code in both my python2.7 and python3 virtual envirmonments.
Thanks for this great tutorial.
One other tidbit, current Raspbian throws an ugly gtk warning after each run, it can be stopped by adding: export NO_AT_BRIDGE=1 to .profile
This is my first experience with virtual environments, I’m not sold on their utility, but time will tell.
Hi Walter — my opinion is similar to yours. If you need legacy support and are perhaps running OpenCV 2.4 as well, go with Python 2.7. If you are developing a new project and are concerned with the future, absolutely use Python 3.
Also, thank you for the tip on the GTK warning message, that’s a great one!
Hello Adrian,
im really thankful for this tutorial, i got a problem i will appreciate it if you could help me,
after the workon and python commands, import cv2 couldnt work and it says “Traceback (most recent call last): File “”, line 1, in importError : no module named ‘cv2’
Hi Habib — there are a number of reasons why the “cv2” import would fail. Without physical access to your machine it’s impossible to diagnose just from the import error. I have compiled the most common reasons why the import would fail in the “Troubleshooting and FAQ” section. Please take a look at it.
Adrian!!!!!!!!!!!!!
Can’t say thank you enough. I completely forgot you put this together and tried to take your previous building OpenCV on Jessie instructions and update it for Stretch. It kept crashing 90% of the way through make leaving the cpu cranking full out doing nothing with a frozen screen. After a number of attempts at fixing it I stumbled upon the one source I should have started with.
You suggestion to expand the swap memory was spot on. Works perfectly!
Awesome, congrats on getting OpenCV installed Dayle 🙂
Hi – I’m doing a fresh install, and when setting up the build with CMake, Python 2 output looks like this:
— numpy: /usr/lib/python2.7/dist-packages/numpy/core/include (ver 1.12.1)
Will this create an issue? Am new to this, so not sure what to do, or if it matters.
Hi Suns — it sounds like you are not in the “cv” Python virtual environment as this blog post suggests. Make sure you run “workon cv” before you actually run CMake. I would also suggest deleting your “build” directory and restarting the compile.
I religiously followed all the steps until Step#5. However, I’m experiencing a fatal error while compiling opencv (using- make -j4). It says out of memory space..
I’m using 8GB SD card and installed Raspbian Stretch (Desktop version) using NOOBS. And I’ve deleted all the unnecessary software (SonicPi, Wolfram-engine, libreoffice etc.). Before executing make -j4, I had 1.7GB of free space.
I’ve tried to install both opencv3.3.0 and opencv3.0.0..
Please help me!!!
Hi Subrahmanya — it sounds like you may need to upgrade to a 16GB card to resolve this issue or continue to purge packages from your Pi that you do not need.
Thank you Adrian for your timely reply.. I upgraded to 16GB and it worked like a charm!
However, when I try to run my script using Python 3 (IDLE), it returns be traceback error for import cv2. I executed my script in the terminal after ¨source ~/.profile¨ and ¨workon¨, it executed.
Do you have any solution for that? I tried to include above two lines in my script before import cv2, but no help.
All I need is to run my script using python shell using import cv2!
Please help!
IDLE does not respect Python virtual environments. You would need to use either the command line, Python scripts (from within the virtual environment), or Jupyter Notebooks.
Hi Adrian,
Pretty sure I’ve installed openCV successfully as it imports and tells me its version. However I’m getting a strange error:
** (Displayed Image:1734): WARNING **: Error retrieving accessibility bus address: org.freedesktop.DBus.Error.ServiceUnknown: The name org.a11y.Bus was not provided by any .service files
It seems to be when I do cv2.imshow(“Displayed Image”,img)
Could you shed some light on how I can resolve this?
Cheers,
Jack
Hey Jack — take a look at the comment from “Walter B Kulecz”. Walter discusses how to remove the warning (it’s due to GTK). Again, it’s a warning not an error can be safely ignored.
i successfully installed opencv 3 in python 2.7
but while i’m working on face detection project it is showing
NO MODULE NAMED CV2
can any one help…
Hi Kumar — there are a number of reasons why you may not be able to import the “cv2” library. I have compiled the most common reasons in the “Troubleshooting and FAQ” section of this post. Please take a look and use them to diagnose the issue. If you are still having trouble with the install you can reply back but without knowing which methods in the troubleshooting guide you tried it’s hard to provide any suggestions.
Thanks for your step by step installation instructions
You can skip 4 hours of compilation by using UBUNTU-mate ,if your only purpose is to use
opencv you can just run:
sudo apt-get install python-opencv on UBUNTU-mate
I do not suggest doing this. Installing OpenCV via apt-get will install an old version of OpenCV rather than the latest release. You’ll also be missing out on the contrib module along with a bunch of optimizations.
Hi Adrian,
I’m following your tutorial but at step 5 I hit my personal nightmare.
I get a CMake error “the source directory “/home/pi” does not appear to contain CMakeLists.txt
and then I’m lost.
I folloed the video again to see if I did something wrong, but same result…
does anyone have a hint for me?
any help would be appreciated.
thanks
Matt
Hey Matt, I think I think you may have copied and pasted the “cmake” command incorrectly. Make sure you use the “<=>” button at the top of the code block to expand the entire code block and grab the command. It seems like there might be a space after “/home/pi” in your command.
Hi,
Thanks, I successfully installed the opencv for python 3 in my pi2 by your steps, I can access it from my terminal but i can’t access it with my python 3 idle. its show the following error.
Traceback (most recent call last):
File “”, line 1, in import cv2
ImportError: No module named ‘cv2’
Why is it?
please help me..
Hi Jack — IDLE does not respect Python virtual environments and thus you cannot use IDLE with Python virtual environments. I would suggest using either the command line, a Python script, or Jupyter Notebooks.
thanks, now i got the following error while i run imshow
OpenCV Error: Unspecified error (The function is not implemented. Rebuild the library with Windows, GTK+ 2.x or Carbon support. If you are on Ubuntu or Debian, install libgtk2.0-dev and pkg-config, then re-run cmake or configure script) in cvShowImage, file /home/pi/opencv-3.3.0/modules/highgui/src/window.cpp, line 605
Traceback (most recent call last):
but i installed libgtk2.0-dev and pkg-config then why is it coming?
It sounds like you have have installed GTK after running CMake. Try deleting your “build” directory, re-creating it, and re-running CMake + make. You should also verify that GTK has been successfully installed.
Hi Adrian,
Thanks for the excellent blog.
After successfully installed opencv, I tried to get frame with webcam (Logitech 310), it throw error like “Corrupt JPEG data: 2 extraneous bytes before marker 0xd1 Corrupt JPEG data: 1 extraneous bytes before marker 0xd6”.
I have tried to build opencv again with WITH_JPEG=OFF, it does remove the error but I am not able to write an image to disk anymore.
Do you know how to solve this problem?
Thank you.
Hey Jason, unfortunately I have not ran into this error before so I’m not sure what the exact problem or solution is. Sorry I couldn’t be of more help!
Thanks Adrian. The error disappear when I use raspberry pi camera camera module
No worries, it sounds like you were trying to use the
cv2.VideoCapturefunction to access the Raspberry Pi camera module (you can’t do that without installing more drivers). I put together a class to help switch between USB cameras and the Raspberry Pi camera module — you can find it here.Thanks Adrian for another clear and detailed guide! I’ve successfully used your guides for several opencv installations; I’ve now one interrogation. I have compiled Opencv in its “cv” virtual environment, but I now also want opencv in another separate virtual environment, with a slightly different python 3 version (3.4 for the new virtualenv vs 3.6 for “cv”). Do I need to recompile opencv in the new virtual environment? If not how should I proceed (maybe simply simlimk cv2.so into the appropriate ~/.virtualenvs/ sub directory?)?
Please see my reply to “Geoff Riley” as I discus show to do this.
Hi Adrian,
It appears that the current make process builds and installs for both versions of python at the same time, so if you attempt to compile once for python2.7 and then for python3.5 the latter install overwrites the previous sandboxed version.
I’m sure there must be a way around this, but the brief glance at the makefile didn’t reveal an obvious client.
Kind regards,
Geoff
Hey Geoff — the current process should only compile one Python version at a time. Run
sudo make installonce. Delete yourbuilddirectory. Re-create it. Runcmakeandmakeagain. Copy the resultingcv2.sofile to yoursite-packagesdirectory of your Python install.Hello Adrian,
I’m new to using OpenCV and I’m planning to use it for face detection on a raspberry pi. I’ve followed your tutorial exactly, but I can’t run the command: “make -j4″. This is the error that I get:
” $ $ make -j4
make: *** No targets specified and no makefile found. Stop. ”
I don’t know what I have to do now. And I did increase the swap size to 1024. I’m hoping to hear from you soon.
Kind regards,
Youssra
Please see my reply to “Don”, “Raghuram”, and “Jonathan”.
Hi all,
how can i add unofficial python modules/libraries (picar) to the virtual cv environment (cv)?
Regards,
Xare
All you have to do is use the “workon” command and “pip”:
And this will install the library into the virtual environment.
You could also use setup.py as well. Assuming you have already used the workon command:
$ cd your_library$ python setup.py --install
If you’re new to Python virtual environments I would suggest taking a look at this excellent guide.
Hi, thanks for sharing. I follow the steps and after successfully install the virtualenv and virtualenvwrapper, and update the ~/.profile file, I got the error : bash: source/usr/local/bin/virtualenvwrapper.sh: No such file or directory.
I have no idea about this error…
It sounds like virtualenv/virtualenvwrapper were not properly installed. Try running
pip freezeand ensuring both are installed.Will this work with the Stretch OS when downloaded with NOOBS?
When i went to resize my partition it says it was not possible, that i was running noobs and it was most likely already done.
If your partition is already expanded you can certainly use this method to install OpenCV on Raspbian Stretch.
Hey Adrian!
First of all thank you for this guide. I was following your guide and made it all the way to step 6. At step 6 where you say to verify that OpenCV + Python bindings are installed by using ‘ls’ command. I get an error saying “No such file or directory”. Does this mean that it installed with an error so I have to redo the “make -j4” command? How can I check what pythons are installed and if I have too many what should I?
Hey Alberto — did both “make” and “cmake” execute correctly?
Thanx Bro I just refollowed your guide and good to go. I realized where I made the mistake
same error for me. how did u fix it?
Hi adrian! i m too much furstrated because when i start building opencv3.3 on raspabian stretch it gives the error stack smashing detected and dont even start building i have reinstalled the whole os and again tried but the output is same .. kindly reply me because i am doing my final year project and time is limited.. thanks in advance..
Hey Muhammad, I’m sorry to hear about the issues installing OpenCV. However, without knowing what the exact error message is I can’t point you in the right direction.
Hi Adrian, if I install OpenCV in a virtual environment per the instructions, can I use OpenCV outside of the virtual environment? Thanks in advance!
This would not work. What is your reason for needing OpenCV outside of a virtual environment? There are a few reasons, so I’m interested to hear yours.
Hey!
I was trying to follow the guide with slight differences:
the environment I’m deploying to will not be used for development, so I felt no need of a virtualenv. Also the links to the project zips are not working anymore, I found /archives/master to get the latest version from the opencv and opencv-contrib repos.
Now the problem is the following:
I used ` wget -O opencv.zip https://github.com/Itseez/opencv/archive/master.zip` then I `unzip opencv-master.zip -d ~/repos/` which will unpack the zip into ~/repos/opencv-master/. I do the same with opencv_contrib, which will go into ~/repos/opencv_contrib-master.
The cmake command I use:
`cmake -D CMAKE_BUILD_TYPE=RELEASE -D CMAKE_INSTALL_PREFIX=/usr/local -D INSTALL_PYTHON_EXAMPLES=ON -D OPENCV_EXTRA_MODULES_PATH=~/opencv_contrib-master/modules -D BUILD_EXAMPLES=OFF -D BUILD_TESTS=OFF -D BUILD_PERF_TESTS=OFF ..`
Note: I tried to play around with the switches, turning then on and off, the results were the same.
and the error I get is:
`CMake Error at cmake/OpenCVModule.cmake:300 (message):
No extra modules found in folder: /home/pi/opencv_contrib-master/modules
Please provide path to ‘opencv_contrib/modules’ folder.
`
I checked ~/repos/opencv_contrib-master/modules/ and there are a bunch of modules defined there, I’m not missing them.
The cmake error log keeps crying about `Regex: ‘command line option .* is valid for .* but not for C\+\+’` so it’s really confusing me what am I missing.
Any hint would help 🙂
Cheers,
Pali
as soon as I submitted this comment the site loaded it in a way so the cmake command was in the middle of the screen so I noticed I specified `-D OPENCV_EXTRA_MODULES_PATH=~/opencv_contrib-master/modules` instead of `-D OPENCV_EXTRA_MODULES_PATH=~/repos/opencv_contrib-master/modules.
It indeed fixed the problem, sorry for taking your time for moderating! :DD
Cheers,
Pali
Congrats on resolving the issue Pali, nice job!
hello sir,
I am a beginner to the pi. i had done all your steps written on this page and the open cv has been installed and i checked it using “import cv2 ” commad in the terminal and it was also a sucess.
but unfortunately i can’t access open cv from python 3.5 using import cv2. it is telling me that no module named cv2. how will i rectify this.
please help me
thank u
I assume you mean that when “import cv2” is working that it works for Python 2.7? If you want to also use OpenCV for Python 3.5 you’ll need to compile OpenCV again, this time using a Python 3.5 virtual environment. The “make” command does not build OpenCV bindings for every Python version on your system (just the one specified in the “cmake” command).
Sir,
It is not working on python 2.7 too.I actually compilled for python3 but outside the terminal i can’t access it.
can u please explain the steps to do so.
Thank u
Can you clarify what you mean by “outside the terminal”?
Hey Adrian, I followed your guide because it was mentioned in this guide, https://makezine.com/projects/raspberry-pi-potter-wand/ I was able to successfully install OpenCV but I have never done any code stuff before and your guide is super easy to follow. While the link i mention is confusing, specially to someone with no code experience. I read through some of your other OpenCV guides and found some references that you suggested to other people. I am looking into learning python and linux commands. I was wondering if you could help me out with that project and understanding what some of the stuff means. Thank you Happy Holidays!
Congrats on getting OpenCV installed, nice job! As for the project you are referring to, I personally have not gone through it and unfortunately I do not have enough time to cover each individual command and Python function. All that said, if you’re new to the world of computer vision and Python please take a look at my book, Practical Python and OpenCV. Many readers have successfully used this book to learn both Python and OpenCV together.
ok yea thank you very much i will definitely be looking at your book. Thanks again!
Hi Adrian,
I am a beginner with no knowledge of Linux. My Raspberry Pi 3B hangs at 94% during make and I have tried all combinations of make like ‘make -j4’ with CONF_SWAPSIZE 1024 MB, and with 100 MB, with only ‘make’ with 1024MB and with 100MB, nothing seems to work.
I am using a 64 GB MicroSD card(earlier my 8 GB card got full during make), should I try by increasing the size from 1024 to a higher number ? Thought of checking with you first so that I don’t corrupt anything. Thanks.
I would suggest changing your swap to 2048MB and then use a single core via just “make”. The compile will take longer but it will be less likely to hang.
It worked !! Thanks and wish you a happy new year 🙂
hello Adrian, thanks for your time, i have a trouble: my rpi has a 8gb sd card, i tried install twice opencv but i got the same error: can’t write pch file: no space left on device.
i removed wolfram and office but the space that i can see on windows show me near to 1 mb free after the compilaton didn´t finish (37 % complete and the message about space on device).
i hope you’ll can identify the problem, thank you again.
Hey Javier, unfortunately it’s hard to say without access to your Pi. Can you reformat your Pi with a fresh Raspbian .img file and try again? I would suggest removing the Wolfram engine as soon as you boot the Pi.
I think I looked at all the questions, but did not see clearly whether this could be complied on a Pi Zero. So two questions. Can this be compiled on a Pi 3 and SD card used in a Pi Zero? Or is it possible to compile this on a Pi Zero? It will probably take forever but will it do it? Or is the build not platform specific?
Thank you for this tutorial.
Can you compile OpenCV on the Pi Zero? Yes, you can. It will take somewhere between 36-48 hours. Should you? No, I don’t recommend it. The Pi Zero is too underpowered for computer vision and image processing. I recommend a Pi 2 or Pi 3.
Comments are always rejected!?
I’m not sure what you mean by “Comments are always rejected”. All comments go into a moderation queue but comments are not rejected.
hi. I’v tried to install opencv3.3.0. Every thing goes fine except when trying to compile hdf5 module : don’t find hdf5.h.
Any idea?
Based on your error you can try installing HDF5:
$ sudo apt-get install libhdf5-serial-devOtherwise, you may want to turn off HDF5 by updating your “cmake” command to include the following switch:
-D WITH_HDF5=OFFThanks for your great tutorials.
Based upon them I created a simple command line tool that eases the whole build process by incorporating all steps. It automatically downloads the current OpenCV sources (v3.4.0), configures them, compiles them on the maximum available CPU cores and installs them inside the currently active virtual environment.
You can install it via pip from PyPI (https://pypi.python.org/pypi/cvbuilder) and just have to run „cvbuilder build“ to start the whole process. It takes around 10 min on a Core i5-3320M.
On a Raspberry Pi3 you need to run it on one core by overriding the CPU count „cvbuilder build –cpus 1“ due to memory constraints and heavy swapping. It will take approx. 2h, but you can install it into other virtual environments without compiling as long as the folder ~/temp/opencv remains.
Failed after 32h, won’t compile at all.
Hey Frank — I’m sorry to hear about the issue getting OpenCV installed. It can be quite a pain sometimes, especially if there is your first time installing OpenCV on the Raspberry Pi. Did you receive an error during the compile?
Hi, Adrian i have followed the steps and i have done it successfully.
The problem is i don’t have “module named skimage.measure” so i have to repeat step #4 and create a new environment named “cv2”,
and followed the rest of the steps.
$ mkvirtualenv cv2 -p python2
$ source ~/.profile
$ workon cv2
$ pip install numpy
$ cd ~/opencv-3.3.0/
$ mkdir build
When i try to create the “build” directory is says “cannot create directory build: File exists”
What shall i do? and i only have 3GB available will it be enough for the new environment?
If your error is that you do not have the scikit-image library installed is there a particular reason you can’t install it into your existing Python virtual environment?
$ workon your_original_env$ pip install scikit-image --no-cache-dir
This library and SciPy will take a long time to install so you should leave your Pi running overnight.
To answer your second question provided you have already ran “sudo make install” you can delete your “build” directory and re-create it.
Adrian, thank you for this step by step comprehensive guide.
I was able to install and compile the opencv on my Pi 3, using the 1024 big swap value and 4 cores in 50 minutes only :)…. a record, probably due to a very fast Sandisk SD.
I had the aluminum coooler installed on the CPU, but even with this, with the CPU usage that was constantly around 100%, I got an overtemp icon on the screen after 30 minutes…
I had to quicky add a fan over it to cool down the cooler, and so the overtemp icon disappear, and I was successfully able to finish the compile.
I was so impressed and interested that I decided to immediately purchase the Bundle 🙂
I wish you an Happy New Year.
Congrats on getting OpenCV installed on your Raspberry Pi — and in under 1 hour, great job! 🙂
And thank you for picking up a copy of my book, I hope you enjoy. Please reach out if you have any questions.
regarding virtualenv you mentioned: Any Python packages in the global site-packages directory will not be available to the cv virtual environment
I need the smbus package for I2C though. How can I use smbus in the virtualenv ?
Thnx.
ok….using the virtualwrapper command: toggleglobalsitepackages 🙂
This virtual blabla is confusing and probably unnessesairy when working on one project isn’t it. ?
You can also install any Python package you need inside your Python virtual environment:
Hi Adrian, love your tutorials. I was wondering if you know the proper name of the application that displays the openCV windows? I ask this because I’m trying to control the parameters of the opencv window in OpenBox (for example, no decor on opencv windows). OpenBox allows one to control how the window is displayed, but the correct name of each application needs to be called. I’ve tried python3, opencv, gtk, highgui, and many others. I’m stabbing in the dark at this point. Hopefully you have some insight in this.
If you installed OpenCV on the Raspberry Pi using this tutorial then GTK and the X window manager should be used. The name of the GUI library in OpenCV is called “highgui”. How that interfaces with OpenBox I’m not sure. I hope that helps!
Hi
great job !
I have following your tuto on my Pi on Rasbian Stretch and Rasbian strech lite.
For the first installation all work, but on the lite, my virtualenv only work when i’m superuser!
how to modify my actual virtual environment so that it is accessible as a simple user and that cv2 is recognized under python3?
regards
That is quite strange that it only works when you are the superuser. Did you install the Python virtual environment for the normal “pi” user or for the superuser account?
Thanks Adrian, it was actually the name I assigned to my imshow function…cv2.imshow(“MyWindow’sName”, frame). I found this out by running “xprop WM_CLASS” then clicked on my window.
Thanks for a really helpful tutorial Adrian.
The snag that I have is that previously installed packages (such as wx) are not available from within the virtual environment. Could you suggest a set of steps to either move cv2 out of the virtual env, or put other packages into it – whichever is most appropriate.
I’m not familiar with virtualenvs to sort this by myself
Many thanks Phil
Hey Phil, are your packages pip-installable? If so you can install of your packages via:
$ pip install your_package_nameHi Adrian
Thanks for the step by step tutorial
Everything is OK with the four first steps, but when it comes to compiling opencv (step #5) I get wrong path to the interpreter (/usr/bin/python3 instead of /home/pi/.virtualsenvs/cv/bin/python3)
I though I had forgotten the workon thing somewhere, so I did it again with a new virtual environment…same failure on step 5
How can I find what’s wrong ?
(I tried to “make” despite th error and it stops somewhere between 4% and 26% with ” error: stdlib.h: No such file or directory
#include_next “)
This isn’t a failure, it’s just picking up the Python 3 binary in your Python virtual environment. You’re okay there.
As for your error, try turning off pre-compiled headers by updating your CMake command to include the following switch:
-D ENABLE_PRECOMPILED_HEADERS=OFFMake sure you delete your “build” directory first and then re-create it before re-running CMake.
Hi Adrian
thank you for your help
it’s not a failure, but it is not picking the binary in the virtual environment…(wrong path)
I got a new SD card, installed Raspbian Stretch and everything is OK now
Congrats on resolving the issue, Ariane! Nice job 🙂
Hello Adrian,
Thanks for the tutorial. After installing everything going down the pyhton2.7 path, I test the installation with the import cv2 command and get nothing as a response, just the symbols >>> on a blank line.
My cv2 file ended up in the dist-packages folder instaed of the site-pacjkages folder, does that matter? I can’t figure out how to move it. I get “permission denied” when using the gui and “no such file or diresctory exists” with the mv command, can you help?
Thanks
As long as you can import it without an error you should be okay. I’m not sure why it would have installed in the “dist-packages” directory though. You can use the “sudo mv” command to move the file if you so wish.
hi Adrian, i am following your tutorial on my Pi on Rasbian Stretch on raspberry pi3. while editing swapsize i was not able to save /etc/dphys-swapfileit says permission denied . i am not able to figure out what to do .
i hope you will help me out ,
regards
Make sure you use the “sudo” command to give yourself root permissions to edit the file.
Dear Adrian,
The instruction is amazing!
I am using the Raspberry Pi zero W. I followed the instruction and it works well. However, I meet a problem.
I don’t know why the pi always stucked at “87% Building CXX object modules/python3/CMakeFiles/opencv_python3.dir/__/src2/cv2.cpp.o”. And I use the VNC to connect the pi. Once the process reach the 87%, the VNC will be stucked. And if I disconnect it and re-connect it. It will be failed. So the only thing I can do is disconnect the power line and reboot it. And when I process “make”. It will be stucked at 87% again. Could you please show me some hints to fix this problem?
It has already take more than 6 hours. And from 0% to 87%, it took me more than 15 hours.
Waiting for your reply. It is quite urgent. Thank you so much.
Best regards,
Damon
So a few things here:
1. I don’t recommend using a Pi Zero for computer vision. With only a single core it’s far too underpowered. I would recommend a Pi 2 or Pi 3.
2. It sounds like your might need to increase your swap size, as I do in this tutorial.
I hope that helps!
Hi Adrian can you please guide me through this? Can you tell me which commands to use in the terminal to do so? For a start how do I delete the build directory?
This isn’t a failure, it’s just picking up the Python 3 binary in your Python virtual environment. You’re okay there.
As for your error, try turning off pre-compiled headers by updating your CMake command to include the following switch:
-D ENABLE_PRECOMPILED_HEADERS=OFF
Make sure you delete your “build” directory first and then re-create it before re-running CMake.
Okay I managed to remove the directory build and create it again. And I tried to squeeze in the switch in cmake, but still got an fatal error: stdlib.h: No such file or directory.
cd –
rm -rf build
mkdir build
cd build
cmake -D CMAKE_BUILD_TYPE=RELEASE \ -D ENABLE_PRECOMPILED_HEADERS=OFF
-D CMAKE_INSTALL_PREFIX=/usr/local \
-D INSTALL_PYTHON_EXAMPLES=ON \
-D OPENCV_EXTRA_MODULES_PATH=~/opencv_contrib-3.3.0/modules \
-D BUILD_EXAMPLES=ON ..
It wasn’t really clear how and where to add the switch -D ENABLE_PRECOMPILED_HEADERS=OFF
I am using opencv 3.1.0 and not 3.3.0 as the video tutorial is based upon.
Best, Allan
Looking at your command above, your cmake command looks correct Nice job adding in the switch. Unfortunately, without physical access to your machine I’m not sure what the exact issue is. My only other suggestion would be to make sure you installed the development tools:
$ sudo apt-get install build-essential cmake pkg-configDuring step 5, after running cmake, my output in the python 2 section does not include the libraries, numpy, and packages paths. It only lists Interpreter. It does look correct for the python 3 section but I would much rather use python 2. How do I fix this?
Thanks, Scott
Hey Scott — did you use a Python virtual environment? Double-check that you didn’t accidentally create a Python 3 virtual environment instead of a Python 2 one.
$ make -j4
It is compiling till 90% and freezes out later. Tried 4 times reinstalling raspian stretch.
Any suggestions?
I would suggest increasing your swap size as I do in this blog post.
Thanks for the quick answer Adrian.
I have been trying everything all over again with version 3.3.0 instead of 3.1.0. That seemed to have fixed the issue. Atleast python doesn’t throw any import errors for cv2.
Awesome, I’m glad to hear it’s working! Congrats on resolving the issue, Allan 🙂
A more questions, Adrian.
I have a USB cam connected to my Raspberry Pi 3 and would like to test if everything is working and so forth.
Which IDE do I use to run the python code in? I was thinking of doing this example for a start: http://opencv-python-tutroals.readthedocs.io/en/latest/py_tutorials/py_gui/py_video_display/py_video_display.html
This example also requires that ffmpeg and gstreamer is installed. So before potientially disrupting the system, by installing more dependencies. I would like to hear you out, what your take is on this.
1. If you have a working system now make sure you backup your .img file to your laptop/desktop, just in case you ever want to flash your .img back to your SD card.
2. An IDE/code editor is a personal preference. I would suggest either PyCharm or Sublime Text. While you can code in your editor I would highly recommend that you execute the code via the terminal. If you’re interested in working with video a great beginner tutorial can be found inside Practical Python and OpenCV
make -j4 doesn’t work
Founds: make: *** No targets specified and no makefile found. Stop.
Please see my reply to “Don” on October 28, 2017 and and “Raghuram” on October 29, 2017. If you ctrl + f your error message on this page you’ll likely find a similar content.
Sir, in the pi terminal i can import the cv2 but when i try it in the python shell i got an error
Hey Paul, I’m sorry to hear about the import issue. So you can import the “cv2” library when executing a script from the command line? But not from the Python shell? Are you launching the Python shell from the terminal? Or using IDLE? Keep in mind that Python IDLe does not respect Python virtual environments.
Hi Adrian,
any tips on how to expand a NOOBS created image on a larger card? After a NOOBs install, “file expand” does not work (apparently because the max space is already available to the OS, although I don’t believe this).
This applies even if you copy the image and transfer it to a larger card. In my case, I started with an 8G card. df – h shows 5.0G is available to /dev/root. I copied the image to a 32G card, and /dev/root still only has 5.0G. If I try to expand it through raspi-config, Advanced Options , I still get the NOOBs error “Your partition layout is not supported by this tool. .. You are probably using NOOBs, in which case your file system is already expanded anyway”
It is extremely frustrating (and boring) trying to get something so simple done. Complexities expanding to a larger card should also be mentioned as a downside to installing with NOOBs.
Do I need to resort to editing the partitions directly with gparted? (as described here https://learn.adafruit.com/resizing-raspberry-pi-boot-partition/edit-partitions).
Thanks,
Rob
PS I’d rather not start over with a fresh install of Raspbian on the 32G card. I’ve downloaded quite a lot of packages.
Hey Rob, I’m sorry to hear about the issues expanding the SD card. As far as I understand, using raspi-config to expand should handle it. If the partition is still not being resized you’ll have to either use (1) gparted to resize the partition or (2) start over fresh if you cannot resize the partition. Other PyImageSearch readers might have better suggestions as well.
Hi Adrian,
thanks for your reply. raspi-config definitely won’t expand for an image created under NOOBs. I think this is reasonably well known.
I appear to have expanded the root partition of my 32G card with gparted. The tricky bit is to recognise the extended partition which contains other (sub?) partitions. You need to resize that first before you can increase the size of anything inside it. Not knowing much about partitions, I may have mucked this up but for the moment it appears to be working. Raspbian boots and the /dev/root has all the space I need.
I hope this helps others with a similar issue.
Rob
Thanks for sharing Rob! I’m glad you’re up and running with OpenCV on your Raspberry Pi 🙂
Hi Adrian,
Great tutorial thanks. I would like the Pi to automatically run a python file that uses OpenCV on boot. Am I right in thinking I will need to make it execute the
source ~/.profile
workon cv
lines before running the python file?
I have been trying to make up a shell script to do that but I get a ‘not found’ error when it encounters the source and workon lines.
This is the shell script:
#! /bin/sh
echo “switching to cv virtual environment”
source ~/.profile
workon cv
Hey Roy, I cover how to run a Python script on reboot in this blog post. You’re on the right track but be sure to read the comments section as well where I discuss a few alternatives as well.
Great, ideal! Thanks Adrian.
So I followed your guide, step by step on how to install open cv 3 with python 3 on raspbian stretch…. on my terminal it says that cv2 was imported, and shows me the correct version. Basically I get the exact same message that I see on your screenshot of step 7 which I assume is telling me that I have successfully installed openCV. However when I run a script that imports cv2, I get the message “No module cv2″ using the ” ls ” command to user/local/lib/python3.5/site-packages, I see cv2 on my terminal…but when I actually visit this path from my desktop, there is no cv2 on site-packages, or in dist-packages…Please help 🙁
Hey Ferishta — so if I understand your question, you can import the “cv2” library into your Python shell but you cannot import the “cv2” library from a Python script? When executing your Python script are you sure you are in the “cv” virtual environment? Make sure you are, otherwise the script will not be able to find your libraries.
Omg thank you for your quick reply!! When I try to run the python script it gives me that “no module named cv2 error” so you’re saying prior to running my script I should use the workon command to get on the virtual environment? Also when I follow the path to site packages, it says “no sub folders” and from my understanding that’s where cv2 should be installed. Correct ?
Correct, use the “workon” command to enter the Python virtual environment. You only need to run this command once per terminal session.
to answer your question, yes I am in the “cv” virtual environment when executing the python script
Hello,
When am running this command 1
$ sudo apt-get install libjpeg-dev libtiff5-dev libjasper-dev libpng12-dev in raspbian stretch (debain 9) normal pc version, there are some errors like no such file to install or download.
So how can I fix it ?
I also had this problem.
^^^ I got this error also
I ran sudo apt-get update and then everything worked
almost a year later, I just encountered this same error. apt-get purge jasper did not correct the problem. I did solve it. The issue was that the cached jasper-dev install image was corrupt. I had to manually remove the cached files sudo rm -f /var/cache/apt/archives/libjasper*
For the third time, I completely wiped out my sd Card, downloaded raspbian stretch, and installed “openCV”. I followed your guide step by step, and I got the same message that I see in your screenshot of step 7 which “verifies” that the installation was successful. However, upon running a python script that imports cv2, I get the same error message, “no module named cv2” and yes I’m in the virtual cv environment when running the script. I see that this is an issue that a lot of people have. I really think you should try to do some research in finding some possible solutions for this possible. Otherwise your blog can be very misleading, and shouldn’t be up for public…
Hi Ferishta — I’m sorry you are having trouble getting up and running with OpenCV. It can be a trying process, especially if this is your first time installing OpenCV. The first time I installed OpenCV back in undergrad it took me 3 days. Since then the install process has gotten easier. All install posts here on PyImageSearch are thoroughly documented and tested by me. There are undoubtedly some “gotchas” that creep up — that is part of configuring your development environment.
If you would like to share the command you are trying to run, or better yet, take a screenshot of your terminal as you run the command, it would be helpful in diagnosing the issue. Keep in mind that myself or other PyImageSearch readers cannot replicate your environment exactly and most of the time these issues creep up due to an error in a previous step that was missed or an issue when actually executing the command (for example, trying to execute the script as “sudo”). Help us help you by sharing more details. I get that you’re frustrated but without knowing more we cannot diagnose the issue.
Adrian, I want to apologize to you from the bottom
Of my heart. This is my first time working with openCV, so I was struggling a lot. The thing is, I was saving my script on my desktop. Instead of “home/pi” this helped resolve all of my issues. I can now access my raspberry pi camera with openCV. I was also able to run your Pokémon color detector game! Im very happy that I’ve found you, and I’m looking forward to learning a lot from you…
I did have one concern though. While all of the python scripts now run, and I see the excpected out, I do get a warning message on my screen.
WARNING**: error retrieving accessibility bus address: org.freedesktop.Dbus. Error. ServiceUnknown: the name org. ally. Bus was not provided by any. Service files
Could you please tell me what this warning is and how can I make it go away?
Thank you so much once again
Congrats on getting up and running with OpenCV, Ferishta. Nice job. This warning is related to GTK/X11. It can be ignored, it has no impact on your code running. As for making it go away, try this:
$ sudo apt-get install libcanberra-gtk*Thank you so much, Adrian!!!
I installed open cv 3.3 successfully yesterday but today when I am trying to import cv2 its giving error no module named cv2.Why is it like this?
Make sure you are in the “cv” virtual environment before trying to import the OpenCV library:
$ workon cvAnd from there open your Python shell or execute the script.
Dear Sir,
Huge thanks for the step-by-step tutorial. You are a savoir, however i still need to get over one obstacle to proceed.
i am certainly in the (cv).
And i have checked that the cv2.so exists in these paths (‘find’ command):
./home/pi/Downloads/cv2/cv2.so
./home/pi/.virtualenvs/cv/lib/python2.7/site-packages/cv2.so
./home/pi/opencv-3.3.0/build/lib/cv2.so
./usr/local/lib/python2.7/site-packages/cv2.so
BUT i am getting the import error no module named cv after executing a script (one you provided here: https://www.pyimagesearch.com/2015/03/30/accessing-the-raspberry-pi-camera-with-opencv-and-python/)
Please help me i have a competition two days from now.
From what I can see it looks like you have OpenCV correctly installed on your system but I would double-check that your sym-link points to a valid file. The “find” command would still report a “cv2.so” file on disk (since a sym-link is still a file) but the sym-link may be pointing to a file that does not exist. Make sure you double-check those paths.
If you’re in a rush and need to get up and running for your competition I offer a Raspbian .img file with OpenCV pre-configured and pre-installed inside the Quickstart Bundle and Hardcopy Bundle of my book, Practical Python and OpenCV. This would enable you to download my Raspbian .img file, flash it to your SD card, and boot.
Actually my problem is that while executing the compiling process of opemcv 3.3.0…it strucks at 48%…….give me some solution for it
When you say “stuck” do you mean the compile ends with an error? Or your compile + Raspberry Pi freezes? The more detail you can give the better myself and other PyImageSearch readers can help you.
The compile and raspberry pi freezes
Try increasing your swap size as I do in this optimized OpenCV install tutorial.
In the 6th step im getting an error…
When i type
>>cd/usr/local/lib/python3.5/site-packages/
Im not getting the respective line as shown in the tutorial video….
Thank you so much Adrian i have installed it all with your help, hope my anti drowsiness detection system will be done soon. Thank you!
I’m happy to help JP — best of luck with the project!
actually after completing the “make” code,the installing creates in problem
when attempting to type
<<import cv2
there occurs error
1st, thanks for all you do, I can’t get over how many tutorials you provide.
Step 5. When I do cmake CMAKE_BUILD_TYPE=RELEASE \ should the process hang at ”>” (if I include the ”-D” I get a ”bash: -D: command not found”)?
Nothing happens until I press [Enter] a second time. And then I get ”CMake Error: The source directory “/home/pi/opencv-3.3.0/build/CMAKE_BUILD_TYPE=RELEASE” does not exist.
Specify –help for usage, or press the help button on the CMake GUI.@ Except we aren’t using a GUI . . . and I thought the build was supposed to create the directory?
TIA
Ron
Hey Ron — I’m pretty sure there was a problem copying and pasting the cmake command. If you’re having trouble try copying and pasting it line-by-line (without hitting enter). Once the entire command is copied into your shell, execute it.
sudo mv cv2.cpython-35m-arm-linux-gnueabihf.so cv2.so
when I type the above code……….im getting error……..and to be frank,i have installed this in discontinuous manner…………….after some shutdowns……..do reply fast
Hello sir, Its been 1 and a half hour of compiling and its 90% already but as I’ve observed itt taking too long to make a progress. Is it a sign that I should repeat the installation or should I wait for it because as you have said it takes 4 hrs to finish. Hoping for your fast response. Thanks
It’s stuck in 90% i followed your swap size and it still doesn’t work. Please help me.
Hey Carl — can you try compiling with a single core via “make”?
Hello sir, thanks a lot! I tried compiling it with a single core via “make” and it was a success. I already installed it and it worked. However, i’m just curious, what’s the difference of the 4 cores and single core when compiling?
In short: speed. Using multiple cores can reduce the time the compile takes, making the compile run faster. It has no impact on how fast the OpenCV library will run after it’s installed.
hello adrian!
I could not install.Could you tell me solving?
Install error message is below:
[100%] Built target example_tapi_squares
[100%] Built target example_tapi_ufacedetect
Install the project…
— Install configuration: “RELEASE”
CMake Error at cmake_install.cmake:36 (file):
file cannot create directory: /usr/local/include/opencv2. Maybe need
administrative privileges.
regards,
My os was installed by NOOBS ver.2.4.5
I solved by myself
Hi, Adrian!
Thanks to you I have installed and I was able to run the sample program.
Can I run OpenCV on Thonny Python IDE (Python 3) without using Virtualenv on LXTerminal?
“Import cv2” always causes an error.
My environment is Raspberry pi 3, NOOBS 2.4.5.
regards
Yes you can, but you would need to skip all Python virtual environment instructions in this guide. I’m not familiar with the Thonny Python IDE but you might want to see if it has a project interpreter similar to PyCharm. You can set the project interpreter to point to the Python virtual environment that has OpenCV installed.
I had an issue where the builder stalled around 45%, but I reran make without the -j4 command and it worked – but had to be run overnight as it probably took at least 4 hours.
Many thanks for the excellent walk through – there is no way I could have installed openCV without your notes!
Congrats on getting OpenCV installed on your Raspberry Pi! 🙂
After using source ~/.profile command
I get error no directory found
Me too??? Did you find a fix?
Hi Kurt and Amber — did you follow Step #4 to create the
~/.profilefile with the importantvirtualenvwrapperinformation?Hello, while attempting to create my build files for my Pi 3 using a python 3 virtual environment using the cmake commands, I keep getting this error, “The source directory Blah/Blah/blah does not exist”. How do I fix this?
Hey Philip — make sure you are in the “build” directory before executing the “cmake” command. Don’t forget the “..” at the end of the cmake command as well.
Hello Adrian, I’m facing a problem when I try to compile opencv by typing make it freezes at 98% please help me
Also I have tried make -j1 and make j-4 neither are working please help me
Try updating your swap size as we do in this tutorial. Updating your swap size will resolve the issue in the vast majority of situations.
Thanks Adrian for your wonderful work and your time and help.
I have finally suceded on installing opencv-3.4.0 on the PI3.
After ten trials, what works for me was not to increase your swap space
size and build opencv with just a simple `make`
Just for the record, I created this logBook to register the trials and errors:
https://github.com/librerobotics/petite-machine/blob/master/opencv/ISSUES.md
Miguel
Thanks for sharing, Miguel!
Dear Adrian,
after rebooting the PI because of the activation of the picamera,
the pi3 has got the following error:
$ python
>>> import cv2
Traceback (most recent call last):
File “”, line 1, in
ImportError: /home/pi/.virtualenvs/cv/local/lib/python2.7/site-packages/cv2.so: invalid ELF header
any suggestion?
Miguel
Hm, I’m not sure on this one. My guess is that you compiled OpenCV for one version of Python but then imported it into a different version of Python. Check your cmake output and ensure you built the correct bindings for your Python version.
Thanks for the help Adrian! With your help I got past that problem. However, now I’m having a problem increasing the SWAPSIZE of my SD card. None of the changes I make to the swapfile save. I have tried using sudo nano to write to the file but after my changes are made the nano command just saves the swapfile under a different name; making my changes useless. Any insight?
Wow, that’s some strange behavior from the nano command. I’m not sure why that would happen. Have you tried using a different editor? And have you tried restarting the swap service after making the change?
Yes, I have restarted the swap service and I’ve tried using a different editor. As soon as I go to exit the editor and it asks me to save my changes I get an error that I can not due to permission settings.
Oh, I see the error now!
You are forgetting to add “sudo” to the command:
sudo nano your_fileYou need root permissions to edit the file.
l have tried different editors but the result is the same. I’ve been able to compile the build files to 97% so far but has taken days and I’ve had to powercycle the PI every time the compilation gets hung. Also, I have tried restarting the SWAP service too after making my changes but doesn’t work either.
Wow, that is very, very strange. I’m sorry, I’m honestly not sure what to suggest Philip. Could you try re-flashing your SD card with a fresh install of Raspbian and seeing if that fixes the issue? Again, I’m not sure why you would be unable to edit the file.
Hey guys, I tried to install OpenCV and Python on a raspberry Pi 2 Model B with this manual. I follow it step by step but after I tap “make -j4” it works fine untill it reached ~40% then every crash:
[ 40%] Built target opencv_ts
Makefile:160: recipe for target ‘all’ failed
make: *** [all] Error 2
Do you have any idea what I’m doing wrong?
Hey Derannson — could you share the full output of ‘make’ in a GitHub Gist? Without seeing the full output it’s unfortunately impossible to know what caused the error.
Hi;
I have just entered the command ‘make -j4’ and I get the following error:
(cv) pi@raspberrypi:~/opencv-3.4.0/build $ make -j4
make: *** No targets specified and no makefile found. Stop.
Am I in the wrong directory?
Hey Bill — you are not in the wrong directory. Instead, it sounds like “cmake”, the command before “make”, exited with an error. Double-check the output of “cmake” and correct any errors. Additionally, I’ve addressed this question a few times in the comments section so I would suggest doing a ctrl + f and searching for “no makefile” to find the relevant comments and solutions.
Hey Adrian, I have the exact same issue when compiling OpenCV to my Rpi 3 B+. Here is my GitHub Gist. I have tried compiling it two times and included the outputs.
https://gist.github.com/bandofpv/5b4f6f1571c26446fd03f0930efd9fe6
Take a look at your ‘make’ output. It’s complaining that GTK is not installed. You probably forgot this step:
$ sudo apt-get install libgtk2.0-dev libgtk-3-devInstall GTK and then recompile and reinstall.
hey did u solve the issue?
Thank you for an excellent post!
I was successful installing 3.4.0 following these instructions, on a Raspberry Pi 3 with a 32GB SD card. The opencv compilation step took 1 hour 47 minutes.
A few minor nits:
Instead of:
sudo mv cv2.cpython-35m-arm-linux-gnueabihf.so cv2.so
why not do
sudo ln cv2.cpython-35m-arm-linux-gnueabihf.so cv2.so
For that matter, given that you’re symlinking the file into the virtualenv, it doesn’t really matter what it’s called in /usr/local/lib/python3.5/site-packages/:
ln -s /usr/local/lib/python3.5/site-packages/cv2.cpython-35m-arm-linux-gnueabihf.so cv2.so
You can absolutely use sym-links if you so wish, that’s not a problem at all.
ok, perhaps I spoke too soon.
When trying test_image.py from https://www.pyimagesearch.com/2015/03/30/accessing-the-raspberry-pi-camera-with-opencv-and-python/, I get this error message:
OpenCV Error: Unspecified error (The function is not implemented. Rebuild the library with Windows, GTK+ 2.x or Carbon support. If you are on Ubuntu or Debian, install libgtk2.0-dev and pkg-config, then re-run cmake or configure script) in cvShowImage, file /home/pi/opencv-
Any help on this message?
an update on my error with test_image.py:
found that libgtk-dev had disappeared (perhaps an autoremove got rid of it?), fixed that
re-downloaded opencv.zip + opencv_contrip.zip, recompiled, and now test_image.py runs
I think I’ll keep opencv+opencv_contrib around for a while before removing them
Thanks again for the great blog. On to writing programs based on your book!
Congrats on resolving the issue, Tony!
Tony, which version of opencv did you redownloaded? Im facing the same problem using 3.4.1
Could you elaborate more on your solution?
SOLVED!
You have to set PKG_CONFIG_PATH in the ~/.profile
update the ~/.profile file to include the following at the bottom(remember to do it out of the cv virtual environment):
export PKG_CONFIG_PATH=/usr/lib/arm-linux-gnueabihf/pkgconfig/
once you run cmake, make sure the output has GUI GTK+ set to YES and GThread set to YES
you’ll need to execute make -j4 again
Awesome, thanks so much for sharing! 🙂
Hello,
I tried to compile openCV 3.4.0 and CMake produces the following error:
Determining if the include file linux/videodev.h exists failed with the following output:
Change Dir: /home/pi/opencv-3.4.0/build/CMakeFiles/CMakeTmp
…
fatal error: linux/videodev.h: No such file or directory #include
What can I do to fix the problem?
Best regards, Martin
It’s been solved.
Regards, Martin
Congrats on resolving the issue, Martin! Was the problem due to not having the video I/O packages and libraries installed?
hi how did u solve this issue?
I had the same issue when compiling OpenCV 3.3.0. I applied the solution described here: https://stackoverflow.com/a/14026861
Hi,
We have worked thru this step by step quite a few times double checking everything, but on cmake we get errors. On review, our Python 3 links only show:
Interpreter
— but no Libraries, numpy, or packages path lines.
Numpy is definitely installed, and all the libraries?
Do you have any ideas or how we can check these dependencies?
Thanks!
We’ve fried a Pi + sd card at a festival and are trying to get a new environment up and running :/ …starting to run out of time !
I’m sorry to hear about frying your Pi + SD Card. It sounds like you may not be in the “cv” virtual environment when executing “cmake”. Could you double-check that?
If you’re in a rush, I offer a pre-configured Raspbian .img file (with OpenCV pre-installed) inside my book, Practical Python and OpenCV. If you need to get up and running quickly with OpenCV, this would be the fastest way to do it.
Hi, I’ve followed instructions (thank you!) and after all the work, got through to the final check but receive this:
$ python
>>> import cv2
…
ImportError: numpy.core.multiarray failed to import
Any ideas as to what’s wrong?
It sounds like NumPy may not have been installed properly in your Python virtual environment. Try installing NumPy via:
Hi,
i followed the tutorial and finished Step#4. Everything was done with the standard user pi.
Then I did a reboot. Now I am asked for a passwort. I tried to leave the passwort empty and I tried “raspberry” – not working.
WWhat have I done wrong? How can I get back in?
Regards
Stephan
Hey Stephan — I’m honestly not sure what happened there. The default password is “raspberry” for the “pi” user. Installing OpenCV would not change the username or password on your Raspberry Pi. I’m sorry I couldn’t be of more help here, but I do not know what could have changed your password.
Hey, thanks for this great tutorial! Isn’t there some way to install OpenCV without building from source? (ie: via apt-get or something?)
I would not recommend using apt-get. It will install an older, outdated version and one that is less optimized.
I followed this tutorial, and setup completed with no problems, but when I try to actually use cv2 in python, VideoCapture.isOpened() always returns False.
>>> import cv2
>>> cap=cv2.VideoCapture(0)
>>> cap.isOpened()
False
>>>
What am I doing wrong? Where can I even begin looking to find out what’s going wrong? Are there log files somewhere?
Hey Phil — are you using a USB webcam? Or Raspberry Pi camera module? The Raspberry Pi camera module will not work with the cv2.VideoCapture function without additional drivers. I prefer to instead my VideoStream class which is compatible with both USB and the Raspberry Pi camera module.
I hope that helps!
Life saver! Yes, I’m using the Raspberry Pi camera module. I’ll check out that link. Thanks again!
I loved the guide found it very helpful however i am having a problem around step 5, its telling me “include could not find load file:cmake/OpenCVMinDepVersions.cmake” i checked the cmake file and it was there not sure whats going on. Also i was unable to use a virtual environment because the PI already has dependencies on that that we are using in conjunction with OpenCV. I am new to this so i’m by no means an expert but any help would be appreciated.
Hey Owen — could you share your complete CMake output as a GitHub Gist?
Hi, Adrian. Good article always.
I’d would like to ask a serious question.
I did follow every step of your tutorials and my pi3(official raspsbian stretch 2017-11-29) won’t show any image or video with cv2.imshow (opencv 3.4.1) function. ( I ran this code on Windows10 / Mac OSX 10.13, it totally worked )
Also everytime I start a QT/ pyQT/ GTK on pi3 , it will show some warnings like:
libEGL warning : DRI2: failed to authenticate
After days of searching, I found it’s GL driver related, so I turn it on at raspi-config->Advanced Option->GL Driver->GL Full/Fake, and the warning did change, but into this:
libGL error: MESA-LOADER: failed to retrieve device information
MESA-LOADER: failed to retrieve device information
Anyway, I still can’t see any thing with cv2.imshow, not even a pop window.
I tried re-install the whole system and re-compile opencv, nothing changes.
So, please, I can really use your help right now. And I wonder how come everyone else did it so smoothly.
I solved it myself. It seems to be a bug of raspbian / it’s GL driver.
The driver should be default off but I still got warnings with default settings.
And when I turned GL Driver on, warning messages changed, but imshow was still not working.
And it’s the strangest part, I turned off the driver, and magically everything works just fine!
Solution :
1. Turn on the GL Driver (sudo raspi-config->Advanced Option->GL Driver->GL Full/Fake)
2. Turn it off. (sudo raspi-config->Advanced Option->GL Driver->Legacy)
Also, further thinking, I run “sudo apt-get install at-spi2-core” and I got only one warning left (libEGL warning : DRI2). I think there may be a potential solution that rpi3 can run opencv with opengl that supports hardware-accelerate
Hey Carl — I think this issue is related to QT. I normally use OpenCV with GTK. After running “cmake” run “ccmake ..” (yes two “c” characters) and look for an option to disable QT and enable GTK.
Hi Adrian,
I’d like to share a weird thing that on pi3 stretch, it seems “/usr/local/lib/python3.5/site-packages/” is the site-package path for python 2.7.
Because it’s normal for me to import cv2 on virtual python3, but when I import cv2 outside virtual env on python3, it said “No module named cv2” and the most strange thing is that I can import cv2 on python2.7 even if I had only one real cv2.so on “/usr/local/lib/python3.5/site-packages/”!!!
I believe it’s bug that you mentioned on the comments which is related to the “Python (for build)”
I forgot to say that the real “site-package” path is “/usr/local/lib/python3.5/dist-packages/”
SUPER STRANGE
That is strange, thank you for sharing Carl!
To solve the “no module named cv2” problem, copy cv2.so to the dist-packages directory (Raspbian Stretch). Then it will import into the cv environment after you follow all the steps in this guide exactly as they are. I just copied the actual cv2.so file from site packages to dist packages directory in python3.5 directory and it worked. Probably could have symlinked instead of copy.
Hello~. I have same problem.
how did you do that??
I tried to copy cv2.so, but I failed.
because of the permission denied…
can you explain about it?? plz~~
I have some problems to install opencv in my ras-pi….
I daon’t know why, but whenever I install the problems occur..
this time, after I finished all courses and open the python shell… and I saw this sentese. ” no module named cv2″
It really painful….
Sorry to disturb you Adrian Rosebrock , I am happy to tell you that I am successful after changing the mirror resource ip . Thank you so much for your patient tutorials !
Congrats on resolving the issue, Zimeng!
Very helpful. Thank you so much!
Thank you Ceren, I’m glad you found the tutorial helpful! 🙂
When I run the ‘make -j4’ command, the Pi will start working, but after it hits 5% or so, it crashes. I can reboot and run the command again, and occasionally it will add on another percent or two, so that now when I run it, it immediately jumps to 14%, but it seems to be stuck there.
Any ideas?
Thanks in advance!
Have you tried increasing the swap size as I do in this tutorial? Additionally you may want to try compiling using a single core (i.e., just “make” with no other flags).
How to run opencv code without this “source ~/.profile and workon cv” command line? Tks Adrian1
You can specify the full path to the Python interpreter in the virtual environment:
$ /home/pi/.virtualenvs/cv/bin/python your_script.pyhi
how to detect human activity monitoring in sensor
example for reberry base and live tracking process pls guide me
sir Adrian, how to install proper numpy . it causes No maching distribution found for numpy
That’s very strange. NumPy can be installed via:
$ pip install numpyI’m not sure why your Raspberry Pi + pip would not be able to find the NumPy library. Perhaps try with a fresh install of Raspbian?
Hello Adrian! Now some new programmings ideas and I started with Stretch using this tutorial. When installing using cmake to build OpenCV 3.4.1, in the output from cmake, only python 2.7 is listed, even as “which python” in my (cv) shows me a link to python3.
I had an error regarding not finding libf77blas.so.3, but I solved it with some google search advice to install “sudo apt-get install libatlas-base-dev”. Still only python2.7 in cmake output though…
Any ideas?
Hey Joakim — could you share a screenshot of what your Python 2/Python 3 section of the cmake command looks like?
Hi Adrian,
did you install libtbb-dev as a pre-requisite? This gives OpenCV automatic tread level parallelism.
I have not tried with libtbb-dev.
Hey everyone !
First, thanks Adrian for this amazing tutorial, very helpful 🙂
After installing openCV, everything was running good until I shutdown my raspberry. When I would like to turn it on, no signal detected on the sreen, like the raspberry never boot.
But I have the solution, a very easy way to fixe this problem (don’t delete and install openCV anymore like i had done ahah.
– take your sd card and connect it to your computer (under Linux)
– go on the boot partition, and open the config.txt (you can also open it with the “nano” command from a terminal)
– Search this two lines :
* #hdmi_force_hotplug=1
* #hdmi_drive=2
Just remove the “#” at the beginning. Save, put your SDcard on your raspberry, it’s done ! 🙂
These two lines are used to :
– Force HDMI display even if no HDMI screen is detected
– Force HDMI display even if no HDMI screen is detected
If you don’t have Linux, maybe you will find how to fixe this on internet, I hope for you 🙂
Ho, and sorry for my English guys ^^ I’m going to fixe this problem as soon as possible 😀
14.3.2018
Hi,
1) Instead on virtualenv would Venv work? https://docs.python.org/3/library/venv.html
2) I suggest using .bashrc instead of .profile – .bashrc always starts and also include the alias sudo alias workoff=’deactivate’
3) the https://github.com/Itseez/opencv_contrib/archive/3.3.0.zip is no loger valid and the link is passed to the opencv.org (one sees this after the wget https://github.com/Itseez/opencv_contrib/archive/3.3.0.zip) – sorry,I did not write down the actual link.
3) After compile the so output is called kiwisolver.cpython-35m-arm-linux-gnueabihf.so
and I think the ln command takes a sudo.
4) when I tried to BUILD without Virtualenv on my Pi, I keep getting the python 2 entries and only on line for the python3 build – dispete me setting the standard python2 to python3. Python clearl whoed python 3.5.x. Any tips on this ? I only use Python 3
As ever your OPENCV information is suberb and I recommend you to all people interested in Vision processing…well done on the very high standard!
1. Venv should work but I haven’t tried it.
2. I normally use .bashrc for Ubuntu but you could use it here as well. They are both Debian based.
3. I haven’t heard of “kiwisolver” being in the name before. I’m not sure where that is coming from.
4. Ignore the “Python for build” section, it’s a bit buggy. Or am I misunderstanding your question?
Hi I followed instructions and managed to successfully install OpenCV 3.4.0….however, there seems to be an issue with OpenCV_contrib:
Traceback (most recent call last):
File “/home/pi/Desktop/trainingMOD.py”, line 13, in
recognizer = cv2.face.LBPHFaceRecognizer_create()
AttributeError: ‘module’ object has no attribute ‘face’
I was able to detect faces no problem, so OpenCV is fine, just something wrong with opencv contrib
Do I have to install the entire thing again?
Hey Michael — did you install OpenCV 3.4 with opencv_contrib support? Make sure you supply the correct path to the opencv_contrib directory when running “cmake”, otherwise the additional modules will not be built.
Hi Adrian, this is the error i get when installing opencv3 on raspbian stretch…i already removed wolfram and libroffice*. can you suggest me something to get done with the installation?? i am stuck at 18%. (i use a 8gb memory card for my pi
)
ERROR:
fatal error: can’t write PCH file: No space left on device
} // cv
^
compilation terminated.
compilation terminated.
Your Pi is out of space. You need to either (1) use a larger SD card or (2) delete files from your Pi. I would suggest deleting Wolfram and LibreOffice to free up ~1GB.
Hi Adrian,
Thank you so much for this post,
In the beginning, I only installed python3 for virtual environment and is it ok to install python2 on the same virtual environment (mkvirtualenv cv -p python2) after I complete the whole installation of opencv3 ?
You can absolutely create a new Python virtual environment; however, if you use Python 2.7 instead of Python 3, you will need to recompile OpenCV for Python 2.7. The OpenCV bindings are not cross-version compatible and will require a recompile for each unique version of Python.
Hello Adrian!!
I have a problem in this line: ln -s /usr/local/lib/python3.5/site-packages/cv2.so cv2.so
Error: Failed to create a symbolic link ‘cv2.so’ file exists. How to solve this problem?
Another question is about 3D face reconstruction. Did your book covers this 3D face reconstruction?
Thank you very much if anyone reply my message and sorry for my English..
1. I’m not sure why the sym-link would already exist unless you previously created it. You can delete it and recreate it if you wish.
2. Sorry, I do not cover 3D face reconstruction in any of my tutorials, blog posts, or books. I will certainly consider this for the future though and I appreciate the suggestion.
I found the fix to the issue “Error: Failed to create a symbolic link ‘cv2.so’ file exists”
Instead of doing “ln -s /usr/local/lib/python3.5/site-packages/cv2.so cv2.so” type the command “ln -s /usr/local/lib/python3.5/site-packages/cv2.so..cv2.so” apparently this is a common issue with symbolic linking. Just wanted to let you know.
Welp that was easier than Jessie. First try! Thanks to you Adrian, of course. This must’ve been the third install tutorial I’ve had to follow and I think I’ve gotten the hang of the command line by now, hah.
Congrats on getting OpenCV installed on your Raspberry Pi, Spencer!
Hi,
thank you very much for this tutorial! By following it I successfully installed OpenCV 3.4.1 and I have a few short questions:
#1
When I wanted to check which is the newest OpenCV version available for download I went to https://github.com/Itseez/opencv/archive hoping to list all the files but that is not possible (error 404). Then I went to https://opencv.org/ and saw the newest version i 3.4.1 but I was not sure if that .zip file was already present in the archive so I had to first test if 3.4.1 .zip file is there – is there a way to check the contents of the archive?
#2
I installed OpenCV because I’d like to port a program I wrote on PC. Although I was using OpenCV I have a feeling that might be overkill because I only need cv2.imread(), cv2.cvtColor(img, cv2.COLOR_BGR2GRAY) and img.shape – that is, I only need to read a .png image and convert it to an array containint grayscale values and read the dimensions. Is there a simpler way of doing the same without installing full OpenCV? Mayme by using PIL or something similar?
#3
I compiled OpenCV for both Python 2.7 and Python 3 and it left me with just 3.8 space on 16 GB SD card. The output of ls command differs from your output:
(cv) pi@raspberrypi:~/opencv-3.4.1/build $ ls -l /usr/local/lib/python2.7/site-packages/
total 4496
-rw-r–r– 1 root staff 4603896 Mar 15 07:32 cv2.so
(cv) pi@raspberrypi:~/opencv-3.4.1/build $ ls -l /usr/local/lib/python3.5/site-packages/
total 4500
-rw-r–r– 1 root staff 4604912 Mar 15 07:32 cv2.cpython-35m-arm-linux-gnueabihf.so
Your output was:
total 1852
-rw-r–r– 1 root staff 1895772 Mar 20 20:00 cv2.so
Why is that huge difference in the number of files and used space?
I know I can remove build directories but the difference in the installed package is huge.
Best regards
1. Try using the official OpenCV GitHub:
https://github.com/opencv/opencv
Itseez, which used to own OpenCV, hosted a fork of OpenCV before OpenCV was on GitHub.
2. Use PIL or Pillow. Additionally, a grayscale conversion is a weighted average of the individual RGB channels. NumPy could do this as well.
3. I’m not sure on this one. I don’t know why that would be.
@ issue 3: I have exactly the same:
(cv) pi@raspberrypi:~/opencv-3.4.1/build $ ls -l /usr/local/lib/python3.5/site-packages/
totaal 4500
-rw-r–r– 1 root staff 4604912 mrt 23 02:25 cv2.cpython-35m-arm-linux-gnueabihf.so
Hey Adrian! I followed the steps until the point where I have to run “mkvirtualenv cv -p python3”. I face the following issue:
AttributeError: ‘NoneType’ object has no attribute ‘startswith’
Any idea what could be going wrong?
Hi Adrian,
I, too, am facing the same issue.
thanks
even though I ran into AttributeError: ‘NoneType’ object has no attribute ‘startswith’ after running mkvirtualenv cv -p python3, I can still get into the cv virtual environment by using workon cv. Does it mean I am ok?
thank you
You should not be running into that error. What version of Python are you using?
Hi Adrian,
I am using python3.5.3. I am reinstalling again, and I ran mkvirtualenv cv -p python3 just now, but i didn’t run into this issue this time.
Thanks Adrian for this amazing tutorial.I successfully installed opencv on my raspberry pi.Through ssh only it is working.when i run through python shell it is showing error no module cv2.what should i do to run on python shell?.
I am using vnc server for remote desktop(i am accesing python shell from remote desktop). thank you sir
I think you may be forgetting to access your Python virtual environment before trying to import the “cv2” library:
Hi, While moderating my last post, maybe take a note on this one as well.
If you get get an error on the ‘source ~/.profile’ claiming that virtualenvs and virtualenvswrapper are not installed, make sure python3 is the default linked to the python command, as described here:
https://linuxconfig.org/how-to-change-from-default-to-alternative-python-version-on-debian-linux
It took some time to find out where the error came from, as everything was perfectly well installed, but as python2.7 was linked to python, the wrong version was launced.
You could do what Rene suggested in the link, but I think it might be easier to just update your .profile file to include:
export VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3Which would set the default interpreter to the Python virtual environment as “python3”.
Hi Adrian,
In response to JaneLI’s post and that of Rene:
I had the same error. I added
export VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3.5
to my ~/.profile and then ran source ~/.profile. The reason being that there was no /usr/bin/python3 after following the instructions on this page. No errors arose yet, so I’m assuming that the rest of the install will be fine.
This worked! Thank you very much.
Hi,
thank you very much for the reply (sorry I didn’t reply immediatelly, I was in the middle of some work).
I would now like to install OpenCV onto my second RPi without compiling from scratch, can you please tell which files do I need to copy onto another RPi so I could install already compiled files? Could I just copy build folder to another RPi and then run:
$ sudo make install
$ sudo ldconfig
to bypass hours of compiling again?
Provided you’re using the same operating system version and same Python version you can reuse the “build” directory. This could be problematic if you’re new to Unix systems so instead I would recommend creating a “master” Raspbian .img file and then just flashing it to each Pi you want OpenCV installed on.
Yes, I know I could make an image of complete SD card but that is time consuming and besides not every SD card has the same ammount of space, there are differences even between ‘the same’ SD cards from the same manufacturer. Copying the whole build directory is still over 4 GB, I am looking for transfering only the files needed by make install. It seems checkinstall can do what I was looking for: https://help.ubuntu.com/community/CheckInstall
Indeed, checkinstall seems to be exactly what you need for this. I hope it works out for you!
i am instaling open cv for python 3.5.3 but why it only can be import by python 2.7
Double-check your output of “cmake”. It sounds like your Python 3.5 Libraries, Interpreter, and NumPy section was not properly filled out.
Thanks for this project.
I am using a pi3.
I am following the steps listed here.
32GB SD card.
2GB swap
1GB RAM
I have situation where the pi crashes when running ‘make -j4’ , and it crashed at different points 8% or 25%.
Is there something I can track to determine the cause?
Thanks
ChrisW
I believe it’s a race condition caused by the multiple processes in the compile. Try compiling with just a single thread:
It will take longer to compile but it should work.
Thanks for this great tutorial Adrian.
Easy to follow, and all the comments and answers were very helpful in finding answers to some small mysteries.
The make -j4 phase terminated a few times, even with 2048 mb swap, but luckily it seems to continue where it failed before.
I don’t know if it is the recommended way, but all seems fine so far.
Now finally onto learning CV. I’ve started once before, but chronic lack of time stopped me then. Looking forward to it!
Kind regards,
Peter Lans
Thank you for the kind words, Peter. If the “make -j4” command continues to give you trouble I would:
To start a fresh build with only a single core. It will take longer but will ensure the compile doesn’t fail due to race conditions or threading problems.
Thank you, it worked exactly as you mentioned, Adrian. I just wanted to share that I was originally using ‘pyenv’ for version management but it did not work until I disabled it, just so others may find it useful.
Congrats on getting OpenCV installed on your Raspberry Pi — and thank you for sharing the “pyenv” nuance.
in step 5 cimpile and install OpenCV, when i try to write cd ~/opencv-3.3.0/ i am getting no such file or directory. How do i fix this ? I followed ur step by step.
You should double-check where you downloaded the OpenCV source code to. It sounds like you may have not properly downloaded the code or you placed it elsewhere on your system.
please help
im getting a message “no mudule named virtualenvwrapper found”
Start by making sure both the install of virtualenv and virtualenvwrapper installed without an error.
Hi! Thanks for a nice step-by-step guide.
We had problems following the second command line “sudo apt-get install build-essential cmake pkg-config” of step 2 because cmake does not seem to be available via apt-get in the stretch version we used.
So we changed it to “sudo apt-get install build-essential pkg-config”…
…and then followed the instructions on https://osdevlab.blogspot.se/2015/12/how-to-install-latest-cmake-for.html to get cmake – but with the modification of changing version number to 3.11.0 in appropriate paths and filenames (https://cmake.org/files/v3.11/cmake-3.11.0.tar.gz etc.)
We used a fresh Raspbian Stretch image from https://www.raspberrypi.org/downloads/raspbian/
(Desktop because it’s used by a kid.)
RASPBIAN STRETCH WITH DESKTOP
Version:March 2018
Release date:2018-03-13
Kernel version:4.9
Hi Erik — thanks for sharing. However, the fact that the apt-get command was failing in the beginning is a bit troubling. When that happens you should run:
$ sudo apt-get updateTo try to refresh the package repos. If lots of apt-get commands are failing it might be indicative of a Raspbian install issue or a DNS issue with your network.
Hi! You were right we had not gotten the apt-get update+upgrade to have desired effect. (Compiling the latest cmake was a bad idea that introduced other compatibility errors later.)
It worked better when we started again with a newly flashed card and rebooted right after running the “sudo apt-get update && sudo apt-get upgrade” step in your guide, before continuing.
Perhaps that reboot trick cold be hinted about in the guide if somebody else has problems getting cmake or other apt-gets to work.
Congrats and resolving the issue, Erik!
I’ve been trying this with several sources of Stretch and nothing..
Is there an image with the whole thing precompiled or would a simple apt-get be enough of the program to track images.
I get distraught at pip python3, not compiling, and attempting to recreate pip python2, for it to start giving me the same garbage.
Hey Matthew — I’m sorry to hear about the issue with getting OpenCV installed on the Raspberry Pi. Is there a particular problem you were encountering?
For what it’s worth, both the Quickstart Bundle and Hardcopy Bundle of Practical Python and OpenCV include a Raspbian .img file with OpenCV pre-configured and pre-installed. You would just need to download the .img file, flash it to your Pi, and boot. OpenCV is totally configured and ready to go. I just wanted to mention that just in case you were interested.
hi adrian, i ‘m following your tutorial steps but got an error at compiling opencv 3.4.1 files,
cmake -D CMAKE_BUILD_TYPE=RELEASE \
> -D CMAKE_INSTALL_PREFIX=/usr/local \
> -D INSTALL_PYTHON_EXAMPLES=ON \
> -D OPENCV_EXTRA_MODULES_PATH=~/opencv_contrib-3.4.1/modules \
> -D BUILD_EXAMPLES=ON
CMake Error: The source directory “/home/pi/opencv-3.4.1/build/BUILD_EXAMPLES=ON” does not exist.
Specify –help for usage, or press the help button on the CMake GUI.
sorry my mistake, i forgot to type “..” on the last line
Congrats on resolving the issue, Putra!
hello Adrain,
while using _canvas = np.zeros((300,300,3), dtype = “unit8”) I get an error stating_ data type “unit8” not understood. I am working on CV vintual enviorment and have imported both libs i.e CV and numpy.
There is a typo in your code. Make sure you double-check any typos and read the documentation. The correct data type is “uint8” (standing for unsigned 8-bit integer), not “unit8”.
hello there i tried to follow your tutorial but on running the command make -j4
i am getting an error
make: *** No targets specified and no makefile found. Stop.
i dont know how i can solve this error… please help
It sounds like “cmake” exited with an error. Double-check your output of “cmake”. If cmake does not correctly execute your build files will not be created.
Hello
I have the same problem.
I have checked the output of cmake and the error came from opencv_contrib.
Adrian explains to do (be careful of the version number):
$ wget -O opencv_contrib.zip https://github.com/Itseez/opencv_contrib/archive/3.3.0.zip
$ unzip opencv_contrib.zip
I have just forgotten to unzip the file opencv_contrib.zip.
So check if you have all the folders defined in the cmake command line.
regards
Emmanuel
I seen same error and i double check the ” cmake ” step & step does not throw any error.
If “cmake” did not throw an error but you’re getting an error from “make” saying no build files were found then either:
1. You are not in the “build” directory when executing “make”
2. Or “cmake” actually did exit with an error and you should double-check the output
Hi Adrian
Thanx for the great tutorial. By the way instead of Open Cv 3.3.0 I am installing 3.1.0. I have an issue while compile it with “make”.
The process is stopped around %15 , and here is the error message:
/usr/include/c++/6/cstdlib:75:25: fatal error…. stdio.h…
Have you ever seen the error before? How can I resolve the issue. Could you please help? Thank you
Hey Murat — I’ve answered this question a few times in the comments thread. The gist is that you need to update your cmake command to turn off pre-compiled headers by adding the following switch:
-D ENABLE_PRECOMPILED_HEADERS=OFFDo a ctrl + f and search for
ENABLE_PRECOMPILED_HEADERStext to find the other comments.Hello guys
Finely i got openCV3 on my Pi3. bu there is one thing after install i lose 5GB of memory space, i don’t know why. If there is any way to free up the space. Pls give me a suggestion.
OpenCV is a sizable library and takes a lot of space to compile. Once you have it installed you can delete the “opencv” and “opencv_contrib” directories to free up some space.
Only to b sure, those folders that are in the /home? opencv is 4.5 GiB and opencv_contrib 91 MiB
Correct, those are the folders in your home directory. They can be safely deleted once OpenCV has been successfully installed.
100% -> Built target opencv_perf_stitching
The system freeze and don’t do anything.
In order to make lighter the installation I don’t have installed with cmake the python examples so the only modification that I’ve done of your tutorial il about the step #5:
cmake -D CMAKE_BUILD_TYPE=RELEASE \
-D CMAKE_INSTALL_PREFIX=/usr/local \
-D OPENCV_EXTRA_MODULES_PATH=~/opencv_contrib-3.3.0/modules ..
what can I do?
Thx a lot
So, the Raspberry Pi is freezing? If so, delete your “build” directory, re-create it, and re-run “cmake”, and then execute just “make” (no “-j4”). This will compile with a single core. The compile will take longer but should avoid the Pi running into a threading race condition.
I’ve used the command “make -j1” so only one process at time have been done; the process takes very long time but succesfully done.
Awesome, I’m glad that worked Angelo 🙂
Every time that I want to use cv2 I have to enter into the cv?
You only need to execute the “workon cv” command once per terminal session. Once you execute “workon cv” you are free to import the “cv2” library into any of your scripts.
If I need other libraries that have to interact with cv2 (likes TF), do I have to install them into the cv workspace?
You are correct, you would need to install them in the “cv” virtual environment.
Got an error regarding installing ibjasper-dev
‘no release candidate’ for libjasper
I red this lib is no longer part of the stretch package because it has not been updated in 10 years, I wonder if libjasper is needed.
hello Adrian,
Thanks, Everything worked well…
but while running this code in raspberry pi using webcam , its showing an error
Corrupt JPEG data: 1 extraneous bytes before marker 0xd3
and its working very slow thats the main problem..
please help me!!
This sounds like it may be an issue with your webcam or driver used to access the webcam. I’m not sure what the problem may be. Could you try using a different webcam or perhaps a Raspberry Pi camera module?
Hi. I am using a sd card with 8GB memory and I am unable to compile opencv since it is running out of space. Is there a way by which I can compile opencv on a USB stick attached to the raspi? If yes, what are the steps to be followed?
Yes, you can do that. Move your “opencv” and “opencv_contrib” directories on to your USB stick, then run the “cmake” and “make” commands.
Hi Adrian,
Facing some weird issue in make -j4
please help me out
Without knowing what the exact issue is I cannot provide any help. If you want to elaborate on the problem I can try to point you in the right direction. I cannot help you if you do not explain the problem.
hello adrain, i have a raspberry pi3, SD card pre installed with NOOBS. can you show me the way or link to install opencv on raspberry pi3. thank you.
This tutorial will show you how to install OpenCV on your Raspberry Pi. Follow it up and you’ll be all set. Additionally, if you want to skip the install process, I offer a pre-configured Rasbian .img file inside the Quickstart Bundle and Hardcopy Bundle of Practical Python and OpenCV which comes with OpenCV pre-installed. Just flash the .img file to your Pi and you’ll be all set.
And one more question, can you share your beginning ( i.e) your first open-CV Tutorial. I want learn it from beginning. Is in your sit? or where i get that. Pls..
PyImageSearch is a blog. Go to the homepage and then use the links at the bottom labeled “1”, “2”, … , “N” to navigate to previous pages. You can always start from the beginning if you would like. I would also recommend reading through Practical Python and OpenCV to help get you up to speed — that was the first book I ever wrote and would be an excellent starting point.
Adrian , i worked in your tutorial for 1 year and everything is ok , but yesterday i delete some folders , so when i write the command “source ~/.profile” i got error ” no such file or directory….etc”
what can i do for this status? can i get this directory from you directly?
You would need to re-create the .profile file:
$ touch ~/.profileOpen it up and add back in the contents using this tutorial.
Hello,
thank you for all these helps Adrian.
Unfortunatly i have a problem that completly blocked me.
i was following the process step by step with no problems but
in the section : Step #4: Python 2.7 or Python 3?
after editing the ~/.profile and uptdate it
I logged out to then long back in.
But i can’t log in anymore i keep on having the log in pop up.
Could you please help me lease ?
thanks a lot.
I’m not sure what you mean by you cannot login anymore and having the login pop up. How are you accessing your Pi? Via HDMI monitor and keyboard? Via SSH or VNC?
Hi Adrian,
really appreciate the massive effort you’ve made here.
My issue is that after editing then ~/.profile then reading it back to make sure my edits were still there. I close and open a new terminal, run the source command and get the following output.
pi@raspberrypi:~ $ source ~/.profile
bash: /usr/local/bin/virtualenvwrapper.sh#: No such file or directory
I’m new to Linux so it’s probably something simple. Any hints?
-thank you for your time
-Kurt
Can you double check that you installed
virtualenvandvirtualenvwrapper?I have the same issue, I installed both packages successfully but then got stuck with the same error.
Double check your output from installing both virtualenv and virtualenvwrapper. My guess is that these packages were not installed successfully.
Hi Adrian,
I was following your tutorial for configuring open cv3 in raspberry pi 3. but encountered an error while executing the code line “sudo apt-get install libavcodec-dev libavformat-dev libswscale-dev libv4l-dev”
I am getting the following error:
E: Unable to fetch some archives, may be run apt-get update or try with –fix-mixing?
Any idea how to rectify this error?
Hi Aanchal — Try to install each package individually to determine which one has a problem. Also try
sudo apt-get update --fix-missingas instructed. Let me know if this works.Hey Adrian got my Pi today — I had the same problem AND I did the –fix-missing … and then re=ran the lib4l-dev piece and still got the same error. Any ideas?
Hey Paul — I would recommend you follow the pip install opencv tutorial as it’s a lot easier and will get you up and running faster. If you really want to compile from source use this guide.
Hi Adrian,
Thank you for creating instructions to install OpenCV for the community.
I would like your assistance or anyone else who may chime in.
I am stuck at the virtualenv & virtualenvwrapper stage. I am running RPi Stretch (latest), python 3 and trying to install CV 3.4.1.
I have installed this process several times, adjusted the .bashrc and .profile files but still receive an error when i type in source ~/.profile.
I receive the following error:
pi@raspberrypi:~ $ source ~/.profile
mkdir: cannot create directory ‘/.virtualenvs’: Permission denied
pi@raspberrypi:~ $ workon cv
NOTE: Virtual environments directory /.virtualenvs does not exist. Creating…
mkdir: cannot create directory ‘/.virtualenvs’: Permission denied
Are you able to shed any light on what i need to do?
I really admire how you support the community.
Hi Benjamin — the
.virtualenvsdirectory should be placed in~/(not/). Check the changes you made to~/.profileagain, or copy and paste mine. If that doesn’t work, you might need tochownyour~/directory.Hi Adrian,
Please disregard my help request. Worked it out with the links you provided to RealPython. Don’t really know what went wrong but got there in the end.
Your instructions are great!
Regards
Ben
I’m glad you were able to resolve your issue!
Hi Adrian,
thank you for the great tutorial! I did all the steps correctly but the only problem is that when I run the command ‘make -j4’. During the process, I got the signal of overheating on the right-top of the screen and around 50% the screen went black. I decided to leave it like that for a while. Now, it’s been almost 9 hours but the screen is still black. The green and red leds are on. What should I do? How can I reboot the pi? Can I pull the plug?
After rebooting the pi, should I use ‘make -j1’ command? If so, what should the ‘CONF_SWAPSIZE’ be?
Thank you in advance,
Best regards
Hi Riza: I would suggest pulling the plug and adding a small heatsink to your processor. From there, delete your
builddirectory and rerunCMake+make. It could be possible that you have a defective processor because I’ve never encountered this behavior.Hi Adrian,
I am in the cv environment and when I tried to execute this command below:
cd ~/opencv-3.3.0/
it said no such file or directory but the opencv-3.3.0 is installed in the system.
I could not get through this one. Please shed the light for me.
Thanking you,
Erwin
Make sure you have successfully downloaded the OpenCV source code and unzipped it. From there use the “ls” command to very your directory contents before trying to “cd”.
Using your directions on an updated/upgraded Raspbian Stretch (and substituting libpng-dev for libpng12-dev), I was able to build OpenCV 3.4.1 on a Pi Zero W. (It took >30 hours)
Thanks!
Congrats on getting OpenCV installed on your Pi Jim, and thanks for sharing the compile times.
Thank you for all this help with openCV.
I want to try out the dual USB camera configuration on my R_Pi 3 w/ Stretch.
My cams are located in ‘stereo vision’ mode, being ~ 6 inches apart focussed on one object.
Rather than ‘motion detection’, I want to interlace the sequential images from the left & right cams. This should create the stereo vision effect on one monitor.
How would you recommend interlacing the L&R images?
Thanks for all your efforts.
best,
Don
There are a few ways to accomplish this but I would suggest starting with the official OpenCV docs that include some stereo image examples using two separate cameras.
Hi;
When I come to “make -j4” part in the process raspberry pi 3 terminal stacks at one point (like %2,%8) and it does not respond afterwards. How can I fix this issue? By using single core???
Thanks in advance.
Yes, I would recommend running a single core:
The compile will take longer to complete but it will avoid the threading/race condition you are encountering.
after the installation, i run spyder 3 to run my program.
but when the program is running, open cv is not detected.
please help me.
I’m not a Sypder user but my guess is that you need to set the Python Project Interpreter to be your Python virtual environment where you installed OpenCV. A similar setting exists in PyCharm.
Hi,
I followed your tutorial up to the point where I run
‘make -j4’.
After doing so, it says ‘make: *** No targets specified and no makefile found. Stop.’
I am in the cv virtual environment and did change the swap size.
What can I do to fix this?
I installed version 3.4.0 but switched out any 3.3.0 to 3.4.0. Would this make a difference?
Thanks
If you are getting that error then your “cmake” command is exiting with an error. Go back to the “cmake” step to see what the error was and then resolve it.
Hi Adrian, thank you for the awesome tutorial, worked flawlessly.
I have a question,
How do i go into virtual environment from python script specifically on this open cv. What i mean is that i dont need to type source profile and workon cv to be able to run the python script. Please, i really need this for my project. Thank you
nvm i solved the issue, just put
activate_this = ‘/home/pi/.virtualenvs/cv/bin/activate_this.py’
execfile(activate_this, dict(__file__=activate_this))
into your code before import . Note that your directory might be different from mine
For what it’s worth the “source” and “workon” commands only need to be executed once per shell session. Just wanted to mention that for other readers on this post.
I’m not sure why this error keeps showing when I try to run face detection
…
File “face_detection.py”, line 13, in
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
error: (-215) scn == 3 || scn == 4 in function cvtColor
Your path to your input image is incorrect and the image is “None” as a result. Double-check your path to the input image. You can learn more about NoneType errors in OpenCV here.
hello Adrian
I have followed your manual.
But when checking, I do not have enough files with python3
The rest is missing?
I have installed everything on new but with no result
Sincerely
jeroen
Python 3:
– Interpreter: /home/pi/.virtualenvs/cv/bin/python3 (ver 3.
Hey Jeroen — I’m not sure what you mean by “I do not have enough files with python3”. Could you elaborate on that?
Adrian,
I really appreciate your commitment to helping folks on this webpage and for writing this tutorial. I have a question I am hoping you might be able to answer. I am trying to download opencv on a pi3 using Python 3. When I execute the cmake commands and read the output, the first problem I notice:
Traceback (most recent call last):
File “/home/matt/.virtualenvs/cv/lib/python3.5/site-packages/numpy/core/__init__.py”, line 16, in
from . import multiarray
ImportError: libf77blas.so.3: cannot open shared object file: No such file or directory
and as a result of this error, many other exceptions occur. Slightly further down the output, I see:
ImportError:
Importing the multiarray numpy extension module failed. Most
likely you are trying to import a failed build of numpy.
If you’re working with a numpy git repo, try `git clean -xdf` (removes all
files not under version control). Otherwise reinstall numpy.
All of the exceptions mentioned above were related to the numpy folder. I went back to make sure numpy was indeed installed. I deleted the install file and reinstalled. It said the installation was successful. I tried the Cmake commands again, but the same problem occured…
Scrolling down to the tests, I notice that most pass, but occasionally some will fail. Below the tests, I see that MANY packages were not found. Finally, regarding the part that you noted about the interpreter and numpy being found in the virtualenv and not in another folder, I only see a section for Python2 and Python (in build), not Python3. And cmake found the interpretter and numpy in /bin/ and /lib/ NOT in the virtualenv. I know these problems will prevent me from successfully installing opencv. Any advice to troubleshoot?
(p.s. I am definitely in the virtual environment, so that is not the problem)
Many thanks!
It’s totally normal to see some tests fail and some tests pass. OpenCV includes the ability to compile support and optimizations for MANY different libraries and packages. OpenCV will test to see if each is installed and then report back on it. It doesn’t mean that the compile will fail, it’s just a test for a specific package. If there is an actual error CMake will say so and the build scripts will not be created.
As far as your error with “libf77blas.so.3” goes, I have not seen that particular error before. Are you running your install of OpenCV on a fresh Raspbian .img file? Or have you previously used this .img for different projects?
Ok. Even though it looks for the Python and Python2 Interpreter and numpy files in /bin/ and not in the virtualenv folder, and doesn’t even have a section for Python 3, you don’t think this will be problematic? I’m puzzled because I thought that since I executed the cmake commands in the “cv” virtual environment, that the Python2 or Python3 Interpreters and numpy should be found in a similar path to the ones in your pictures in Step 5. As for the libf77blas.so.3 error, it’s not a completely new .img install, but I have not changed much. I downloaded linux’s RPi-Cam-Web-Interface and had to delete some directories after a few failed attempts at the download. It’s possible that I deleted the libf77blas.so.3 file in the process, but I don’t think it’s too likely. I’m not sure what I can do to resolve that error though.
Provided you are trying to compile OpenCV for Python 2.7 it won’t be a problem. If you are trying to compile OpenCV for Python 3 it will be a problem though. Perhaps you created your Python virtual environment for Python 2.7 rather than Python 3?
Hello Matt. I got the same problem. Solved it by running this command from within my virtual environment:
sudo apt-get install libatlas-base-dev
OK. Solved my issue. To successfully install OpenCV 3.4.1 with python3 I had to:
1) Run this command:
sudo apt-get install libatlas-base-dev
I thought I had installed the libatlas-base-dev by following this blog instructions, but I had to use this command again. I did it from within the virtenv.
2) Add this to the cmake command:
-D BUILD_opencv_python3=yes \
-D PYTHON_LIBRARY=/usr/lib/arm-linux-gnueabihf/libpython3.5m.so \
(don’t know if the last line was necessary, but it did not hurt)
3) remove the build directory and create a new one. I ran the cmake command from within this new directory (i.e. build2).
Hello, thank you very much for doing these tutorials, they helped me a lot and i successfully installed python 2.7 and OpenCV 3.3 on my raspberry pi. But additionally i am trying to install pyodbc module to connect with MSSQL Server which in on another computer. I’m really having hard time time figuring out how to do it using virtualenv. I will be very happy if you help me on that.
I’m not familiar with the particular Python module you are referencing but provided it’s pip-installable you should be able to use the “workon” command to access the “cv” Python virtual environment and then install it:
my connection wifi went down at 35 % of the make command during installing open cv 3 on using Raspberry pi 2 model B , when i want to restart the work it gives me errors 35 % .
I would suggest running a “make clean” and then restarting the compile. If you think your connection could drop make sure you use the “screen” command.
thank you so much . i ‘m actually doing a project in my school , a device that can detect birds using the image and the sound of birds in areas using raspberry pi 3 and triggering an alarm if the bird is in area and want to eat our product .
like a ” ScareCrow” hhh .
is there any library or module i that can help me to record and manage the voice of birds and compare it with my database ? Can i manage the voice and the picture of the bird or not ?
Any advice please . i’m confused
Regards
This blog primarily focuses on computer vision, not audio, but yes, it’s absolutely possible to compare audio snippets and images of birds as well. Can you elaborate more on your project? Is your goal to simply detect that there is a bird in an image/video? Or do you need to recognize the species as well?
You need to add
VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3.5
if you use python 3.5 in .profile file
Great Tutorial, Have one question, I have been following along just fine, but during complying
I keep getting errors, and the complying stops I just keep restarting it with the $make -j4.
and it starts again were it left off. I changed the swap file and confirmed size change. stopped the process and restarted like directions stated. Is it ok to keep restarting the complying process?
It’s hard to know what the exact issue is without knowing the specific error you are receiving. What is your error?
I got the same issue. It seems to be related to overheating and the processor shutting down. The last time it stopped, the heatsink was too hot to touch. I’m recompiling but with two processors (-j2) and it’s already getting further along than before.
Hi Adrian, A question… Is it possible to do cross-compilation and install it in a virtual environment ?
As long as your Python versions for each Python virtual environment are the same I think that should work (I haven’t tried it though).
will opencv work on raspberry pi zero w? and on raspbian stretch because i am facing a problem after i am running the make command for compilation and the pi is freezing on 86% and not working after it.
Yes, but I don’t really recommend the Pi Zero or Zero W for computer vision or image processing. It’s just too slow. Start by reading this tutorial. You should read this one as well as you’ll likely need to increase your amount of swap size.
It is showing no targets and no makeup file is found……please help
Double-check your “cmake” output. The CMake command likely exited with an error. Resolve the error so CMake can run properly and generate your Makefiles.
Hi Adrian,
Thank you for your instructions, it really helps.
I need to delete the current version of opencv, compile and install another version. Please point me what I need to do. Thanks.
I would suggest starting with a fresh install of Raspbian to avoid running into any errors.
import error: no module name cv2 found ..what is this?? and why??
There are a few reasons why this could happen. Be sure to refer to the “Troubleshooting and FAQ” section of this post for more details on how to diagnose and resolve the error.
Hi,
I have followed your tutorial and have a couple of observations and questions. This is with a brand new Pi3 B+ running Raspbian.
1. You refer to /usr/local/bin/virtualenvwrapper.sh; however, this file is located in /usr/share/virtualenvwrapper/virtualenvwrapper.sh. Not sure why the change
2. When creating the virtual env, -p python3 did not work for me. I had to use –python=/usr/bin/python3 which worked
3. What is the difference between using the virtualenvwrapper stuff and the traditional mkvirtualenv venv and then using source venv/bin/activate? Is it just a convenience thing to use the wrapper or is there something more.
4. I am running into a perplexing issue. I have followed everything and am in the virtualenv when running cmake, but it seems to ignore it in the out and shows the external python3 binary and file paths. What could I be missing? (I followed your instructions exactly…)
Thank you.
That’s odd that you had to supply the full path to the Python binary. Do you have multiple Python 3’s installed on your system? That would be my best guess. The benefit of virtualenvwrapper is that it makes virtualenv easier to use — that’s all. I also noticed from your other comment that you were able to get OpenCV installed correctly 🙂
Hi,
I figured out the answer to my issue with CMake. The solution was that I had to wipe the “build” directory when I ran CMake again to get it recognize the virtualenv. Once I did that, it recognized it without an issue. The compilation went smoothly.
Thank you!
Congrats on resolving the issue and congrats on getting OPenCV installed on your Pi 🙂
hi, i followed your tutorial and when i was downloading -j4 raspberry shutdown so when i opened it again i don’t know how to get in build to start compile
If your Raspberry Pi shutdown during the compile it may have left the compile in an inconsistent state. I would suggest you start the compile over again via:
hi adrian……
I lost power for the pi while installing ( I was at step 5 on the command ” make -j4″ ) should I continue when power is on or start at step 1 again…
I would recommend doing a “make clean” and then restarting the compile.
Hi Adrian, I have followed your steps in the tutorial without error. When I tried to run make -j4, my rasp pi reboots. Is that normal?
That is not normal. It sounds like your Raspberry Pi is overheating. Try compiling with only a single core:
$ makeI managed to install opencv, thank you 🙂
For people having compilation problems, try with 1 core, worked for me. My Raspberry Pi kept freezing or getting compilation errors with 4! (found the answer to this problem on a french website)
Congrats on getting OpenCV installed on your Pi, Mandar!
Hello Adrian,Thank u so much for your instructions and tutorial videos.They really helps me a lot for my thesis.
Thank you for the kind words — and best of luck with your thesis! 🙂
This looks great, thanks. I have a couple of questions though.
1. I Only intend to use python 3. Is it necessary to download the python2-dev stuff?
2. It’s ok to purge the dev stuff once I get opencv built, isn’t it? I’ve only got 8 GB, and space is at a premium.
Thanks again.
1. If you only want Python 3 you can skip installing the python2-dev package.
2. Once it’s built you should be able to purge the headers.
Hello Adrian,
Thank you for the great instructions. After the part in step 5, at “Configure your swap space size before compiling” It seems that the steps are different in the video than in the website. (at 21:07 in the youtube video) I’ve been following the instructions on the website and checked the youtube video and saw you type “make” so I did it and it started the process. So essentially I skipped the configuring swap space stuff. Also, I used “make” instead of “make -j4”. Will there be any differences or problems? Thanks.
Hey David — as long as the compile succeeds there won’t be any problems. If your Pi runs out of memory or freezes you should go back and increase your swap size though.
I am not sure of what kinda errors you guys were getting. But I was getting issues due to C example not getting compiled. So you can use the below to get cmake to install right.
$ cd ~/opencv-3.3.0/
$ mkdir build
$ cd build
$ cmake -D CMAKE_BUILD_TYPE=RELEASE \
-D CMAKE_INSTALL_PREFIX=/usr/local \
-D INSTALL_PYTHON_EXAMPLES=ON \
-D OPENCV_EXTRA_MODULES_PATH=~/opencv_contrib-3.3.0/modules \
-D BUILD_EXAMPLES=ON
-D INSTALL_C_EXAMPLES=OFF ..
Hi Adrian
thank you very much for this excellent tutorial. I managed to install cv 3.4.1 on my PI and it seems to work.
I configured all steps for python 2.7.13 but now I realized that I have also version 3.5.3 on my PI. I skiped step 6 for python 3 and have still this file cv2.cpython-35m-arm-linux-gnueabihf.
Can the 2 python version cause any problems?
My idea would be to work with python 2.7 or should I go for version 3?
Thank you in advance.
If you ended up compiling Python 3 bindings you cannot use them directly with Python 2 — you would need to recompile. That said, I highly recommend you use Python 3 moving forward. Python 2.7 should only be used for legacy codebases that require it.
Thanks Adrian for your tutorial.
I have successfully installed Open Cv 3 in mi raspberry pi 3. But i have a question. Everything worked when i did the step #7, the comand import did not have errors, but when I open a new terminal and i enter to the virtual enviroment, the comand import does not work. Do i can only use Open CV if i am here (cd /usr/local/lib/python3.5/site-packages/)?, because it only works if i run the python program in that repository.
Sorry for my mistakes, English is not my native language.
Congrats on getting OpenCV installed on your Pi, Diego. Great work.
As for your error — my guess here is that your sym-link to your “cv2.so” bindings in not correct. Delete the original sym-link and then re-create it. Double-check that path and it should work.
Hi Adrian
thank you very much for this excellent tutorial. Great work!
Thanks Peter, I’m glad you liked it! 🙂
hi Adrian ..
how do I uninstall opencv if i need?
is there a problem if i uninstall Python 3.5 which is shipped with the rasbian?
If you are not well versed in Unix environments I would just re-flash your .img file. There are too many problems that could be caused and they would be impossible to diagnose without knowing you had a fresh system. I also would not uninstall any Python package that ships with any OS — there are scripts on your OS that may rely on that specific version. Instead, you should install whatever version of Python you would like to use.
in your video , after the make command and back to the terminal, when you type sudo make install you are not in cv virtualenv, I confused. When and Why you are not in cv env
You do not have to be in the “cv” virtual environment for either “make” or “sudo make install”. These commands are just for compiling.
I successfully installed on raspberry pi zero, however the 2nd time I tried to use the pi zero, it will not even turn on.
Congrats on getting OpenCV installed on your Pi Zero; however, the boot issue would not be related to the install of OpenCV. I think your SD card may have gotten corrupt at some point. Could you try with a new SD card?
I compile opencv3.4.1 on raspberry pi zero v1.3 and it take me almost one whole day. I have to use a fan to cool it.
But I find you just need 1.5 hours. Why?
Thanks for your explain.
I used a Pi 3B for this tutorial. You’re using a Pi Zero. They are not the same. A Pi Zero has only one core while a 3B has four. It’s totally normal for a Pi Zero to take many, many more hours to compile (likely 24+).
Oh, by the way. I use sandisk 16G TF card. It declare the read speed is 98M/s.
I use make -j4 to compile.
I even close my desktop. But my buffer just have 401M. I also fellow your instruction to add 1024M to swap-space.
Wait for your reply.
Thanks very much.
Hi Adrian
Thank you very much. I fellow your instructions and finally compile and install opencv3.4.1. But my problem is I spend about 24-hours to compile all. It is so unbelieveable. I have to set a fan for CPU in case of too hot.
And cv.so is about 4.4M. But yours is so small.
Thanks
when editing /etc/dphys-swapfile
use
$ sudo nano /etc/dphys-swapfile
find the place for swap. and follow the guide
When making make -j4 be sure to be in the CORRECT FOLDER that; opencv-3.3.0/build
make -j4
thats what I learned today.With trying too much.
And Adrian Rosebrock if you can add those too everyone will be grateful I am a beginner now and need to make a thesis project fast 😀
just add the editing things and going back to the build folder 🙂
thank you so much 🙂
Hi Adrian,
Thank you so much for this tutorial, its great.
I am using raspberry pi 3 with 8MP camera. Raspbian Stretch and open cv (as you mentioned in this tutorial) for the detection of pedestrian and cars.
The program is working, but the FPS is too slow.
I noticed that the CPU usage is around 26% to 29%.
This means that I may be depending on a single core for the processing.
Do you know how I can improve the FPS in my program?
I am using HOG for people detection and cascade for cars detection.
Please help…
Thanks again.
Be sure to take a look into OpenCL (not to be confused with OpenCV). With OpenCL support OpenCV can infer when to distribute computation across all cores. Keep in mind that not every algorithm can be naturally parallelized and sped up — some algorithms are naturally only meant to run on a single core.
plz help meeeeee
there is no site-pakage directory.and if it is,it is empty
all o steps run without error and I dond knw wht should I do :`(
Make sure to check your “build/lib” directory to ensure your OpenCV bindings were actually built. You may have also forgotten to run “sudo make install”.
it is wonderfull!
even I cnt update my raspberry any more ! when I run “sudo apt-get update” i have a connection faild error while there is no internet problem
Thanks for this awesome guide! Just have a few questions that I also want other readers to comment on in case they’ve tested these use cases:
(1) Will the same steps work on Raspbian Stretch Lite (with a 3B+?; and
(2) Will your photo and video recognition guides here on PyImageSearch (using OpenCV 3 DNN) work on Raspbian Stretch Lite (with 3B+)?
Please advise. Thanks!
1. Yes, it will work on Raspbian Stretch Lite.
2. Yes, they will work on Raspbian Stretch Lite as well.
Keep in Raspbian Lite does not have an X-server so if you want to use OpenCV’s GUI functions (like “cv2.imshow”) on your Pi you’ll want to install X-server before compiling and installing OpenCV.
Hi Adrian! Does this include the “optomized” version CV? Trying to understand the difference between https://www.pyimagesearch.com/2017/10/09/optimizing-opencv-on-the-raspberry-pi/.
No, it does not include the optimizations you linked to. The primary differences are the NEON and FVPV3 optimizations which will make OpenCV run faster on the Pi.
Hi Adrian,
your tutorial worked almost like clockwork. I liked the uniform format and detailed explanations of all commands. Keep it up, thank you.
I compiled OpenCV 3 for Python 3 and ran into the Error “ImportError: No module named cv2”. Maybe I haven’t looked right to the compilling output but the packages were installt in …/dist-packages. After copy the renamed cv2.so to /dist-packages and sym-link to that path everything works fine.
Again, thanks for that really good tutorial. Looking forward to try your other projects.
Congrats on installing OpenCV on your Pi, Patrick! 🙂
Bro I have to thank you, this step by step was so easy to follow and there was not a single error, thank you so much!……
Do you think that with this opencv/raspberry box with a decent usb camera could be acurate enough to deploy a simple access control to open a door at a small office and register employee attendance time based on the face?…. I already have a small python that allows an mqtt message to allow/deny the door activation and the circuit to activate the door based on the mqtt message…..I’ve been tested face recognition on my lap and I’ve been using LBP algorithm, and playing with parameters I get each time better accuracy…..but I would like to know your opinion on deploying an access control with a raspberry pi (btw, to increase security the face recognition system only is executed on working hours and deactivated after the office time is ended)….do you have other suggestions for increasing the accuracy, like the best algorithm, the angle of the face after training should be different, how many faces for each user, etc?….
Thank you so much, I hope in just more weeks being able to purchase your book, and I would gladly purchase your content if it was in udemy or in other videocourse plattforms, have you any plans to do some of that in the future bro?…..
Greetings!
Congrats on getting OpenCV installed on your Raspberry Pi, Joseph! Great job.
Yes, you can absolutely use a Raspberry Pi to build an access control system. LBPs are a good start but the highest accuracy will come from deep learning embeddings. The downside is that while they are more accurate they are also slower. You can read more about them here.
I do not have any plans to host my content on Udemy. It’s a long story, but they do not treat their content creators fairly. They are also known for allowing pirated content without giving original authors a way to check for pirated content without actually purchasing it in the first place. It’s not a good platform if you are a content creator.
Hi Adrian,
I installed without issues, thank you for tutorial.
As newcomer, do we need IDE for convenience or just we can create .py file and continue to write with any editor and run our codes with terminal?
(If we need IDE, which one do you suggest?)
Thank you.
You can use an IDE if you would like. I would recommend Sublime Text or PyCharm. You can also create a .py file and edit it using a simple text editor. Regardless of which route you choose, I do recommend actually executing the script itself via the command line argument though. That will give you the greatest control.
hello, when compiling the open cv program in python I get the following error :
Corrupt JPEG data: 1 extraneous bytes before marker 0xd4
Would You know why ?
Hi All, Adrian thanks for putting in the effort and time to structure everything in this tutorial.
Just wanted to share my “wget’s” for the latest version everything else is as Adrian states 🙂
wget -O opencv.zip https://github.com/opencv/opencv/archive/3.4.2.zip
wget -O opencv.zip https://github.com/opencv/opencv_contrib/archive/3.4.2.zip
Working successfully on RPi Zero, took almost 16-20 hours to make though.
Congrats on getting OpenCV installed on your Pi!
could u plz help me
I have ” waiting for headers ” problem when I want to update RPi or installing cmake . it means the process is stoped at this point and then I have connection fail error
It sounds like your internet connection is unstable. Try again on a stable internet connection.
Hi Adrian,
Out of interest have you seen this website
https://www.piwheels.hostedpi.com/packages.html
It has pre-compield python packages for the raspberry PI, one of which is opencv, created by
http://bennuttall.com/
I downloaded python-opencv in a couple of minutes but now have to sort out the dependancies, libjasper and others.
Steve Gale
PS I keep reading the blog, some interesting articles, one day I will find the time to try them!
Yep! I actually know Ben. We discussed some of the PiWheels he was putting together and I gave some recommendations for the OpenCV ones. I’ll be doing a dedicated post on pip installing OpenCV in the future.
Hi Adrian!
i’m trying to compile opencv 3.4.2 on RPi Zero W (latest Rasbian Stretch), but it crashes on 82% with virtual memory exhausted notice. Is it because of swap space size (failed to change to 1024, can’t write to file error)? I run make without attributes because it’s single core CPU and i don’t use virtual environment because there will be no other projects on this RPi (i think no other deviations from your tutorial).
It sounds like you ran out of swap size. Try increasing the swap size amount.
Dear Adrian,
Thanks for your reply via email. However, I didn’t save down those information because the pi cannot boot up successfully. Today, I tried to install it in other SD (64GB). Unluckily, the make -j4 process got stuck at 97% more than 2 hours. The pi have no response. What I can do is to take a picture
Hi Adrian
i have problem in my case i have /usr/local/lib/python3.5/dist-packages/ but i see you /usr/local/lib/python3.5/site-packages/
why it can be different when I have done the same thing?
I don’t believe anything is technically “wrong”. Simply copy your OpenCV bindings from the “dist-packages” directory to your “site-packages” directory.
Thanks very much sir Adrian Rosebrock.
At this point of writing this comment, numpy installation is still on, and I thrust it will go well.
I appreciate the time and effort spent writing this post. Not a single error up to this point.
Thanks.
I plan to do some image vision for my bachelor’s project thesis. It’s a home security system (on wheels) running mapping a house, and recognises persons. I’ll be using your resource ( Practical Python and OpenCV). Is there any other resource you propose which could help me as well?
You’re a great man! I look forward to your reply.
Hi Matt-Klaus — depending on the complexity of your project you may also want to consider the PyImageSearch Gurus course. Practical Python and OpenCV will certainly teach you the fundamentals of the OpenCV library but for a more in-depth treatment of the material, including facial recognition, I would highly suggest the Gurus course.
Dear Adrain,
Sorry for bothering you. I finally install it successfully (hopefully).
Once again, thank you very much
Congrats on getting OpenCV installed on your Pi! 🙂
Thanks a lot.
Between, I am now facing another problem that how to get (read) a frame from a class with a function which return a buffer of video data (bytes), says, AAA.get_video_stream. Normally, av is imported and use av.open(AAA.get_video_stream). However, I found it difficult to install PyAV , ffmpeg in respberry pi.
I am not sure OpenCV or imulti has such function even I have been goolging for three days.
Hey Adrian,
Thanks for this amazing tutorial. I have finished the installation of opencv version 3.3.0 as per the instructions in this video. Unfortunately, when I try to import cv2 in my virtual environment, I get an error : No module named ‘cv2’. When I run $ ls -l /usr/local/lib/python3.5/site-packages/ I get a similar output as the one you are getting with cv2.so being linked. Any ideas what went wrong?
It sounds like that you have correctly compiled and installed OpenCV but you need to go back to the “site-packages” directory of your Python virtual environment and ensure the sym-link points to the “cv2.so” file from your install. My guess is that you either forgot that step or the sym-link points to a file that doesn’t exist.
Thank you very much for your extraordinarily well written installation guide. It took me straight through to completion without a hitch, and I appreciate the care you put into your explanations. Thanks again.
Thanks Kent, I really appreciate that 🙂
Hi Adrian, please help me. I’m stuck at the pip install numpy command. I am in the virtual env and I’ve followed all prior steps properly. However, the install for numpy is giving me errors I don’t understand. It’s saying it failed to build numpy and I’m not sure why. I’ve done a redone this tutorial twice with the same result. Am I doing something wrong? I chose to use python 3 before this step.
Hey Simeon — what is the exact error you are receiving? Keep in mind that I cannot possibly know what your error is. You’ll need to share it if you would like help.
I have OpenCV 3.1.0 installed, now I want to install OpenCV 3.4.2, is it necessary to uninstall OpenCV 3.1.0 or I just need to repeat the proccess for the new version?.
Thank you for your tutorials
You can simply repeat the process for OpenCV 3.4.2. There is no need to delete the previous install of OpenCV 3.1.0.
I already uninstalled it, but I’m glad to know that next time it will not be necessary. Thank you!
Hi Ardrian, thank you so much for your guide.
I followed the instructions exactly, i think, but when i come to the make -j4 command, at about 50% i get an error:
c++: internal compiler error: Segmantation Fault (program cc1plus)
Have you got any guesses as to what i have done wrong?
Thank you for your time.
It sounds like your Raspberry Pi has ran out of memory. Try increasing your swap size like I do in this tutorial.
hello Adrian
while installing the open cv i got this error in step3
wget: unable to resolve host address ‘github.com’
will you please help me for this error solution
It sounds like there may be a problem with your Raspberry Pi connecting to the internet. Double-check your internet connection and try again.
hi can anyone help how to run this script on boot
Here’s how you can run a script on reboot.
hey adrian,
thank you for the solution but i have one more problem after executing command
$ unzip opencv.zip
i get the error
unzip:cannot file zipfile directory in one of opencv.zip
It sounds like you either forgot the “wget” step of downloading the .zip archive of the code or you’re not in the home directory where the opencv.zip file should have been downloaded to.
hey.!!!! go to the directory where the downloaded file is . right click on that file and go to properties. after clicking on the properties go to Permissions TAB in that you can find 3 dropdown box. select ayone for all the dropdown.:-) this worked with me
Hi Adrian,
I’m installing opencv following your tutorial, but when I try “make -j4” there’s a problem: make: *** No rule to make target ‘install’ . Pare(stop)
Double-check your output of “cmake”. The cmake command likely exited with an error, implying that your build files were not created.
Thank you so much for this site and this tutorial, it is such a great resource!
I was also having issues with libf77blas.so.3, but I’m lazy and just downgraded numpy to 1.12.1 which is fine for my purposes.
Hi, Adrian!
ok for me i found an error in the m -j4 command. everything until then works well, but doesn’t know what’s wrong. I have tried repeatedly the installation process stopped at 96%, I tried to leave the full 12 hours still no response.
I use Raspberry Pi 3 Model B 16 GB Class 10 SDcard.
Please help.
thank you
It sounds like your Pi is locking up due to some sort of race condition. Try increasing your swap size as I do in this post.
No errors, appreciate the work you put in on this step-by-step installation, Adrian. Will brave the harder tutorials next 🙂
Congrats on getting OpenCV installed on your Pi, Doan! Nice job 🙂
What if because of electricity Pi gets switch off and compiling aborted, what to do for such case? Should I start the whole procedure from starting?
I would suggest you delete the “build” directory, re-create it, and then re-run “cmake” and “make”.
Thanks Adrian… This worked for me…
Awesome, I’m glad that worked 🙂
Hi Adrian: Great blog post and tutorial!
Unfortunately, I found it after I had started virtualenv journey following some other blog post and created ssp27env and ssp35env (without knowing about virtualenvwrapper).
Now following your post to continue (not restart) and prepare for adding OpenCV3 in ssp35env which already contains other packages I installed.
Should I install virtualenvwrapper and continue? How?
Or do I need to restart from scratch?
Thank you for your guidance.
Raj
Please ignore my earlier post and the inadvertent duplicate post.
I followed your steps through but without step 4 for recreating the ssp27env and ssp35env using virtualenv/virtualenvwrapper.
I like the virtualenvwrapper approach but I’ll live with the ssp**env/bin/activate[deactivate].
Thanks,
Raj
Sorry, when I execute cname, command ends with: “Configuring incomplete. error occurred”. But I’ve done all previous steps without errors
Take a look at the output of the “cmake” command. You may need to scroll through the output. You will find the reason for the error in the cmake output.
Yep. The error is that it doesn’t find module folder. I cut and paste relative and absolute path of opencv_contrib/modules but nothing…..
Solved. I just thrown make -j4. Thanks
Congrats on resolving the issue, Benny!
Dear Adrian, I’m trying to install OpenCV 3 on my Raspberry pi3 Model B for several time. When going through step by step tutorial of your blog post you said
$ pip install numpy
this step will take approximately 11min. But It takes only couple of min on my pi and output is not same.
Again, when I started make command, the compiling started every time it stopped at 80% or 83% or 90% or 93% or 97%. Actually it stops when
building target python3 dir src2/cv2.cpp.o this line or similer one come.
If I resstart the pi and compile again the installation process increase a little portion of %. And this way I have done compilation but output is not same like your screen shot.
After that when I run your code on python IDLE or terminal it says It’s not finding some module I listed below.
1. imutills
2. cv2
3. cv2.cvtColor
Help me here. I tried a lot of time, more then 10 times but I failed every time.
And I’m confused, In your video, before compiling make command you were following Raspban Jessie tutorial post and you took a break. When you came back you were in Raspbian stretch tutorial post.
I’m really in trouble. Please find me a solution.
Just to clarify, have you installed OpenCV on your system? Or are you still stuck at the “make” stage? Secondly, Python IDLE does not respect Python virtual environments. You should be using the “cv” virtual environment from your terminal.
src2 also not found. If you want I can try one more time and give you step by step screen shots of my problems.
I installed a brand new latest version of raspbian from NOOBS on an Rpi 3 model B and followed all the steps carefully. I had to change the permissions on the dphys-swapfile to modify it (it would have been nice if there would have been instructions about that), but otherwise everything seemed to work as stated. But then on the compile step. “make -j4” it stopped with an error 25% of the way through. Honestly, I do not think that anyone but a true expert (not me) can figure this stuff out. I guess I’ll have to stick with doing things with numpy arrays and with the image processing that comes with scipy. These things seem to install with about one or two lines.
Hey Larry — this newer Raspberry Pi + OpenCV install tutorial does include the swapfile instructions. You may want to consider using that one instead. As far as your error, what error did you receive? Without knowing what error you had I cannot help or point you in the right direction.
Hey Adrian,
I completed all the steps until step 6 but when I am importing cv2 in step 7 it is giving me an Importerror: libQtGui.so.4: cannot open shared object file: no such file or directory.
Can you help?
I had the same problem but solved this with:
sudo apt install libqtgui4
In my case, it would be: sudo apt install libqt4-test
100% Built target opencv_test_face freezed
What could be reason? Can i reboot to proceed from here? As raspberry pi is being stucked for hours and continuously used from 1 day (with proper cooling)
What should i do? As i already have to do it again and again due to errors.
Any help will be really appreciated
It sounds like your Raspberry Pi has hit some sort of threading or race condition, causing the compile to free. I would suggest restarting the compile and compiling with only a single core:
The compile will take longer but it should avoid any race condition issues.
Thank you SO much for the comprehensive step-by-step for installing OpenCV … I found a couple other tutorials that attempted to do it in one or two lines, it was confusing and frustrating. Thank you for the time you put into making all of the explanations and set up of this tutorial! Whenever something didn’t run quite right I double checked and I had a typo on my side … so, everything worked awesome! Although, being very new to Linux and RPi, I had to search for how to open the /etc/dphys-swapfile … other than that everything was straight forward and easy to follow! Thanks heaps!
Thank you for the kind words Diana! 🙂 And congratulations on getting OpenCV installed on your Raspberry Pi!
Note: if the install fails, be sure to remove the contents of the Build directory before you restart. !!!!!!
These instructions worked great for me. The only side effect is that after I expanded my disk space on the SD card, when I make an backup.img to copy to another sd card, it wont’ work. The backup.img is just shy of 32gb. Etcher and Win32diskmanager complain that there isn’t enough space….
Also, how do I know when opencv3 updates are released and can I patch my system or do I have to download and repeat the build?
You can follow along with OpenCV and updates via their official website at OpenCV.org. You’ll need to manually compile and install a new version of OpenCV if you want to use. My install guides will help you out.
good day after updates (sudo apt-get update && sudo apt-get upgrade) stop working keyboard and mouse. what is the problem with the 2A 5 volt power supply
It unfortunately sounds like a problem with your Raspberry Pi. I would suggest you re-flash your Pi with Raspbian and try again.
One reason errors in the cmake causes make -j4 not to work is if you changed the version number of OpenCV (if you changed that from 3.3.0. to e.g. 3.4.1) but forgot to also change it in the cmake command.
.
Superb, after third try, finally succeeded!! Third time I installed Stretch Lite, i.e. without desktop and for this reason or other, now everything went like in your guide, thank you very much! Next I will add camera to Rpi and start playing
Congrats on getting OpenCV installed, Pauli! 🙂
Hey,
Whenever i type source ~/.profile, this error comes up:/usr/local/bin/python3: No such file or directory.
I had followed all the steps before that, itll be great if you could help.
P.S.: if i open /usr/bin and type python3, im able to execute python commands
i need tutorial for installing raspbian strech in my sd card
Refer to the official Raspberry Pi instructions.
awesome!
would you mind updating your cmake with the FLAGS from the optimized OpenCV library for Raspberry Pi? (or maybe just link to the optimizing post?)
-D ENABLE_NEON=ON \
-D ENABLE_VFPV3=ON \
I came across the optimized option in another post:
https://discourse.nodered.org/t/standalone-raspberry-pi-security-camera-with-ai-person-detection/1470/4
and had to rerun my cmake 😛
oh. just had to read through the comments… found this:
https://www.pyimagesearch.com/2017/09/04/raspbian-stretch-install-opencv-3-python-on-your-raspberry-pi/#comment-471312
so, nvm I guess 😀
Thank you so much for this! Worked on my raspberry pi 3 b+. Much appreciated…
Awesome, congratulations on getting OpenCV installed on your Pi!
i think it has been installed in python2.7 as ls -l is showing section of cv2.so in python2.7/site-packages and not in python3.5/site-packages
any help please
Hi guys. When I tried to compile OpenCV the screen froze and RPI became hot! Anyone could help?
It sounds like your Pi locked up. Reboot your Pi, delete your “build” directory, re-create it, re-run “cmake”, and then re-run make, but this time only compile using a single core:
$ make -j1The compile will take longer but it will ensure your Pi doesn’t lockup.
I just tried this but the RP got frozed any way
Please help me with this as soon as possible
Hello Adrian.
I installed this on RPi 3b+ Stretch exactly as the instruction and everything works fine. Thanks a lot.
the only problem I had was switching between Python 2 and 3.
My request: I am trying to install an icon on the desktop to run the program from VNC (on a mobile)with one click. Can not manage it. It is working for me with simple camera command but not opening the VC. Please help write the sh file to do it.
Hello Folks if you face a problem try to use make -j1 instead of make -j3!
Thanks a lot Adrian!
Hello, I cannot install opencv_contrib from CMake at all. I’ve just tried multiple versions and still without result. The only way that it is working is getting it through pip install opencv-contrib, but after this GStreamer support suddenly disappears. I’m developing streaming app with face recognition and I both need GStreamer and LBPHFaceRecognizer.The error I get when trying to use recognizer – ‘module’ object has no attribute ‘face’ regardless of Python 2/3. Version of both interpreter and contrib is of course matching. I even tried this on Ubuntu and still same error.
Will be grateful for any advice.
Double-check that your path to the “contrib” modules is correct in the “cmake” step. My bet is that the path is not correct and thus the contrib modules are not being built.
In the 6th step im getting an error…
When i type
>>cd/usr/local/lib/python3.5/site-packages/
Im not getting the respective line as shown in the tutorial video….
Hi
If not work :
make -j4
can use these commands instead of :
make clean
make
Darn – installing on an RPI2, get all the way to “verify CV2 in Python…
Using the (CV) environment, typing “Python” brings up the Python version (2.7.13), and the Pything prompt (>>>).
However, when I type “import cv2” – it jusr drops down to a new Pything Prompt, rather than actually showing anything, as shown in the tutorial?
$ python
>>> import cv2
>>>
K – scrub that – just me being thick and not used to the Python prompt (>>>) in the tutorial listings, i.e I have to type in ” cv2.__version__” to get the version number!
Oh well, something learned! 🙂
Not a single error in the whole tutorial. Just a breeze!! Thank you so much for making it available to all. The time estimates are also extremely nice to have. Fantastic! 🙂
Thanks Antonio 🙂 And congrats on getting OpenCV installed on your Pi!
hi Adrian,
I installed opencv on my raspberry pi 3b + following all ur steps..
i was facing lot of issues earlier but all got resolved now and i am very thrilled to start working on my project now.
but as i completed everything, i went to IDLE and typed import cv2
but it gave me this error—
ImportError: No module named ‘cv2’
please tell me what to do and where should i start coding….
please reply ASAP Adrain…And thank You for everything….
thanks ,
Sagar…
Python IDLE will not work with Python virtual environments. You will need to use the command line. If you like IDLE-like environments you should take a look Jupyter Notebooks.
Thank you so much.
Hi !
While i was in the CV virtual env,
I wanted to setup the build for CMake, and after typing down the setup I received an error stating that I do not have CMake List.txt
So how can I resolve this?
Hope to here from you soon 🙂
It’s working now !
The last part of the setup build instead of putting “..”, I put ” . .”
My goodness.
Congrats on resolving the issue!
hello, how can i direct install on the PI?
Thank you
I’m not sure what you mean by a “direct install” — could you clarify?
my device freezes while running make -j4 at 90%. i am using raspberrypi 3
Try increasing your swap size like I do in this tutorial.
I am getting error like this =Importerror: No module named imutils.video. What should I do to solve this error.
You need to install imutils via pip:
$ pip install imutilsIf you are using a Python virtual environment make sure you use the
workoncommand first:Hi Adrian and friends,
Following this very good tutorial I managed to install OpenCV 3.4.4 on the new Raspberry Pi A+.
I’m using a NodeJS binding called opencv4node and plan to do some colour recognition for the coming PiWars 2019 challenge!
Thanks again for the amazing articles.
Awesome, congratulations Jason! Best of luck with the PiWars challenge.
One more comment related to the installation of OpenCV 3.4.4 on the new Raspberry Pi A+:
I’m using Raspbian Stretch Lite (version November 2018)
The OpenCV library was available here: `/usr/local/python/cv2/python-3.5`
The file is called `cv2.cpython-35m-arm-linux-gnueabihf.so`
I had to increase the swap and use a simple `make` (no `j4` option)
It took me at least 5 or 6 hours (hard to say exactly as I was doing other things at the same time.)
May be this info can help someone else 🙂
Thanks for sharing, Jason!
I replaced the last item in step #6 (for python3) with
cd ~/.virtualenvs/cv/lib/python3.5/site-packages/
ln -s /usr/local/lib/python3.5/site-packages/cv2 cv2
This is for OpenCV 3.4.5 on Raspbian GNU/Linux 9 (stretch)
Maybe it will help someone
Hi Adrian, thanks for this wonderful post. I installed OpenCV on my Raspberry Pi-3.
I have some projects using Open CV that I want to run on the Pi. When I open the default Python env., it doesn’t open in the CV virtualenv. How can I fix that?
Congrats on getting OpenCV installed on your Pi!
Regarding your question, you must execute the “workon cv” command to enter the Python virtual environment. By definition, a virtual environment is separate from your default Python interpreter.
Hi, I did it without installing virtualenv. and I got upto ‘make -j4’. It’s been 100% for a while, is it normal? I mean I have been waiting for about 45 mins and it is stuck on 100%
It sounds like your Pi has locked up. Reset it and then compile using a single core (“make”). The compile will take longer but your Pi shouldn’t lock up.
sorry if I am posting this twice. I am experiencing an issue on my pi0w that was talked about elsewhere in this thread at about the 60% mark of the make -j4 step I get an error I have included the error and the output log in the following gist, (I probably didn’t do that right). if there is any more info required let me know. any idea what my problem is? any help would be great!
Hello Adrian and thanks for the big help!
If I delete the folder you said at step 7 and then unzip them again, will they work correctly?
Because I want to use the haar cascade classifier and i need those folders when i use detector=cv2.CascadeClassifier(‘haarcascade_frontalface_default.xml’)!
Thanks in advance!
You don’t have to delete them if you don’t want to. You can also delete them and re-unzip them if you wish.
Super good stuff!!! working on mi PI3 version 4.0.1
Took almost a day (3 retries incuded :))
Thank you so much!!!!
Congrats on getting OpenCV installed!
HI,
When I run python, it starts 2.7 instead of 3.5 – how can i get it to start 3.5 instead please?
I didnt install into virtual environment – or do I *have* to use a virtual environment to make sure the right version starts. I dont need python 2.7 so I could de-install it ( will older python files run on newer python version ?).
You can simply type:
$ python3That will launch a Python 3 shell.
What version of the gcc compiler do you recommend having on Raspberry Pi Raspbian Stretch that will work for your instructions?
Also, I noticed there are two new support versions of OpenCV in the OpenCV github (3.4.5 and 4.4.0). Do you recommend installing installing those using your instructions? Or should we stick with 3.3.0 from the github repository mentioned in your notes? I did notice that you said we can use newer versions, but there are multiple github repositories.
Thank-you for you assistance
Best regards
Hey Derek — this guide has been replaced with a more recent OpenCV + Raspberry Pi install guide. Make sure you refer to this page for my most recent install guides for each operating system.
Hello!
I want to use opencv with led matrixes, but matrix need to run script as sudo (for access to /dev/mem).
If I trying it – python can’t find cv2.
Sorry for my english.
(cv) pi@raspberrypi:~/rpi-rgb-led-matrix/utils $ sudo python test.py
Traceback (most recent call last):
File “test.py”, line 5, in
import cv2
ImportError: No module named cv2
You’re trying to run the script as root? If so, you need to supply the full path to the Python virtual environment binary:
$ sudo /home/pi/.virtualenvs/cv/bin/python test.pyHi, In the past I have used your installation on a raspberry pi3 and it worked great! Now, I am installing this same software on the pine-Rock64 4g with Armbian Debian and this were going well until getting this error on: Step #3: Download the OpenCV source code…Before I get too deep in looking for the problem, I thought I should ask for help 1st. Thank you.
Connecting to github.com (github.com)|192.30.253.112|:443… failed: No route to host.
This sounds like a network issue, perhaps even a DNS problem. Double-check your internet connection.
hello Adrian
I have followed your manual.
at step 5 after cmake…..while comparing with the given screenshot for python 3 the liabraries and numpy files are missing in terminal
Make sure you are in the “cv” Python virtual environment before running “cmake”.
After struggling for a couple of hours, I come across this tutorial and could manage to install OpenCV on RP without a headache and it works flawlessly J. Thanks a million Adrian. However, I have faced a minor problem which sounds strange. With the OpenCV installed on Ubuntu, I can read the coordinates and current RGB values when I move the mouse pointer on a window which is generated by “cv2.imshow” command. And interestingly in my RP I can not see that information anymore with the same command. How come? Any advice to solve the problem?
Congrats on getting OpenCV installed on your Pi! I also really appreciate the kind words, thanks so much.
As far as the “cv2.imshow” and RGB values go the Ubuntu machine must be using a different GUI backend. I’m not entirely sure which one though without having access to your machine.
Thank you for your reply. Finally, I managed to get the needed information using cv2.SetMouseCallback() function. Cheers.
Congrats! 🙂
Dear Sir,
Congratulations and thank you for this great guide-through tutorial. Simple and straight forward as it should be.
All the best,
Thanks so much, Parovel! And congrats on getting OpenCV installed on your Pi.
Hi,
I have problem, that after running cmake, it shows something, but there is only python2, no python 3.
I have newly installed raspbian full on raspberry pi 3.
Do you have any idea, what can be wrong?
Is it the “Python for build” section? If so, you can safely ignore it as that section is buggy. Make sure your Python interpreter, Numpy, and Libraries output matches mine though!
To anyone who has the No such Gstreamer factory: v4l2src message to access the Camera with processing, just apt-get install gstreamer0.10-plugins-good . This solved my issue.
Hello Adrian Rosebrock
Thanks you for your great tutorial,
I have a problem, when running cmake I get error, any advice to solve the problem?
Thanks and Regards
What is the error you received? Without know the specific error I cannot provide any guidance or suggestions.
Hi Adrian, thank you for this great tutorial. I was able to install openCV on my raspi via SSH (headless) a month ago. Now I just received my raspi camera module and want to play with it, unfortunately when I tried to run “workon” command direct from raspi desktop it says : “workon: command not found”, but if I run the command from SSH its works and I can see all my virtual environment. Can you give me some advice?
I think you might be forgetting to “source” your “.profile” file first:
$ source ~/.profileFrom there you can use the “workon” command.
Hi Adrian
I want to use openCV in node-red But I have problem.
My problem is I can’t open the virtual cv laboratory in node-red. I want to run source~/.profile & workon cv in boot by your teaching but it can’t work.
Please Do it for me.
thank you Sir
Hi Adrian,
Great tutorial. You may want to tip also with:
“$ find / -name cv2*.so”
because mine was in /usr/local/lib/python3.5/site-packages/cv2/python-3.5/cv2.cpython-35m-arm-linux-gnueabihf.so, and I thought I made a mistake in a previous step, before finding the correct location.
Kind regards.
Hey Adrian !
Once again great tutorial !
Quick question:
“make -j4” has to be executed in which directory ?
1. home dir ?
2. opencv-3.3.0 ?
3. opencv-3.3.0/build ?
[apologize if this is a dumb question]
Waiting for your reply.
Cheers !
It needs to be executed in “opencv-your_version/build”, assuming that:
1. “your_version” is whatever version of OpenCV you downloaded
2. You have successfully executed “cmake”
Hello Adrian,
This question is not related to Opencv, rather it is with the virtualenv.
I wanted to use Thonny as the IDE and for using virtualenv, interpreter needs to be set. What is the location where can I set my interpreter for cv virtualenv ?
The virtualenv is located inside “~/.virtualenvs/your_env_name/bin/python”
Hi Adrian,
Great tutorial.
Follow your guide, I finally install opencv3 on my Raspberry 3B+.
Since I have a project which use opencv to detect the size of a strawberry and return the result to Makeblock robot via bluetooth connection.
My problem is whenever I connect the robot with raspberry using the UI interfaced “Bluetooth Manager”, then I can’t find the bluetooth device inside the “cv” environment.
Any suggestion to solve my issue?
Thanks.
How did you install the bluetooth library?
thanks for all the efforts adrian,
i think you will greatly help humanity if you can do installation of openCV on raspberry pi without the use of virtual environments at all.
this is because, sometimes people have issues with working with virtual envs (depending on the project).
thanks
hey Adrian, thanks for the blogs. They are really helpful.
I am new in this and your blogs have helped me out a lot.
but i am stuck and i would appreciate if you could help me out.
while installing OpenCV on my raspberry pi 3 B+, whenever i execute the “make -j4” command, after a while my pi freezes. and i have to restart the pi. i am using a 16 GB sd card. also, /etc/dphys-swapfile file doesnt exist in my pi.
i have tried every alternative i could find on the internet. please help me find where i might be going wrong.
thanks!
The swap file should exist, that’s odd. Try following this updated guide.
Hello Adrian, just wondering if its common for your raspberry pi to crash or act extremely slow during this installation? I’m new to this and I’ve got almost no idea what I’m doing so i need a little help with this. Other than that, your website was awesome.
Your Pi will take a considerable amount of computational resources to compile OpenCV. Be patient with the compile.
THX BRUV
I finally did it!! Thank you so much this was amazing!!!
Congrats Nava!
Hi Adrian,
great service you provide and I look forward to trying some of the things you describe but I can’t seem to get to first base. I can run cmake on my raspberry pi successfully, and then make, make install, all without error. The problem is I want to use java, and I do it from the command line. I can find the jar file and put it in the classpath, and the library .so file and my code finds it in the load.library.path. Running my java code I get segmentation fault with no more information. I’ve spent 2 weeks trying different cmake parameters, and older versions of opencv. Any idea what I am doing wrong?
Hey Petr — you’re following an older tutorial. Follow this one instead.
Hi Adrian,
I followed this tutorial exactly, and I’m trying to use it to utilize another tutorial of yours on real time panorama image stitching. However, when I run the program it says I have no xfeatures2d, even though I cloned both opencv3.3.0 and opencv contrib3.3.0. I used the cmake command: -D OPENCV_EXTRA_MODULES_PATH=~/opencv_contrib-3.3.0/modules ..but for some reason in the opencv build>modules folder xfeatures2d doesn’t appear… BUT it IS in the opencv_contrib folder.
I’m very much a beginner, and this doesn’t make sense to me so any help would be appreciated. Thank you!
If you are running into problems try doing a pip install instead.
Just an FYI the path to cv2 above is /usr/local/lib/python3.5/site-packages/cv2/python-3.5 in version 4.1.0. Took me a while to figure out
Hi Andrian
this is a great tutorial and it works for me perfectly.
What about upgrading to Raspberry pi 4.
1.Have you or someone else try to install opencv & opencv-contrlib in Raspberry pi 4 ?
2.If yes, what are the changes to be done to make it work as expected ?
Best regards
Michael
Hey Mike — I’ll be doing a separate tutorial on installing OpenCV on the RPi 4 very soon. Keep an eye on the OpenCV Install Guides page. I’ll be updating that page with the link once the guide is published.
is this tutorial is also working on rasbian buster ?
I’ll be doing a separate tutorial for Raspbian Buster.
Hi Andrian Sir I am very happy to say that . its a very clear installation guide. I done it on raspberry pi 3. Thank you very much.
Congrats on getting OpenCV installed!
Hey Adrian,
I did this tutorial on Rasbian Buster and got and error while doing “make” on 39%.
Is this tutorial can’t work in Rasbian buster too?
Maybe I can do some changes and it will work if not when the tutoial on buster will come out?
Best Regards,
Mantvydas
I’ll be doing a dedicated tutorial on installing OpenCV 4 on the RPi 4 later this month.
Great turorial. Works like a charm on RPi2 😉
Hey Adrian,
awesome tutorial and very detailed one Thank you.
i have one issue. i am using OpenCV3 + smart mirror
i want to enable/disable OpenCV using commands. is it possible ?
When i turn on the raspberryPi OpenCV keep camera buys for the facial recognition. i want to enable/disable it using commands so i can use that camera somewhere else also.
Thank you very much
If you want your camera to be available to other scripts you would need to kill the OpenCV script that is accessing the camera.
Hello Adrian,
I have two main questions. But first I must admit to being a neophyte on Linux.
I followed your directions to the letter and my installation was successful. When I import cv2 to python I have success,
My first question is that I did everything from the cv environment per your instructions. For a test, I opened a new terminal, and from python I imported cv2. I expected it to fail because I was out of the CV environment. But it did not fail. Why would that be?
My second question involves running python from one of the IDEs. I’m testing within the CV environment writing “import cv2”. From Idle it works fine, but that runs python 2.7. From Idle3, or Thoony, both running python 3, it fails saying it can’t find cv2. I should mention that when I run python from the command line it does bring up python 3.5.3, and “import cv2” succeeds. I certainly would like to use idle3 or Thoony to write python code. Any suggestions?
Thanks
1. Because OpenCV is installed in your global “site-packages” directory after running “sudo make install”.
2. Refer to this post if you need help with configuring your IDE.
Hi Adrian,
I followed the instructions and want to install OpenCV 3.3.0 on my Raspberry Pi 3. But it doesn’t work,leaving the error ” Configuring incomplete,errors occurred!”.I have tried so many times but after compiling OpenCV for Python 3, only that the Interpreter points to python3.57 exists.Can you give me some advice?Thanks a lot!
Check your “cmake” output, it will tell you what the error is.
Additionally, you should look at Practical Python and OpenCV and Raspberry Pi for Computer Vision which include pre-configured Raspbian .img files with OpenCV pre-installed.
Hi Adrian. if i already have opencv3 and python 2.7 binding installed in my Pi3 B+ then how to change it to opencv3 + python 3.5 ? Thanks
You cannot. You need to create a separate Python virtual environment for Python 3.5. OpenCV binaries are not cross-Python version compatible.
Had a error free compile and install of 3.4.6 but encountered “no module named cv2”, upon investigation found cv2.cpython-35m-arm-linux-gnueabihf.so was under /usr/local/lib/python3.5/site-packages/cv/python-3.5 . Changed the directory and followed the steps. Success !!
Thanks for sharing, Renu!
Adrian – first thanks in providing this community support !!! you are a saint… Im using above (Stretch) instructions on Raspbian “Buster” to load OpenCV 3.3.0 and Python 3.7.3-1. My build does not complete… 17% – 38% with errors that appear similar… last one is “make: *** [Makefile:163: all] Error 2” I have Pi3 ModelB V1.2 32G micro ssd class 10 Sandisk.
I have attempted these instructions multiple times many combinations with swap 1024, 2048, single core 4 cores, deleting build files and directory each time and starting at cmake instructions. I have encountered and fixed multiple issues explained in your thread. I also have searched this thread for “% ” build not completing (51 instances) for direction. Other variables that I wonder about are I have micro camera plugged into board – does that matter? Are there Cmake variables that could save time?
Adrian – I read the troubleshooting instructions and understand I can go with img file. Still Im hoping to learn to do a successful compile. I also re-read detailed instructions and believe the only mistake I may have made is version mismatch. Q: If I want to restart, do I need to reformat SD card to start over or just delete certain directories? or repeat steps that I may have done wrong. Is there a command to check versions I did load?
PS – I am coming out of closet developer… decades ago… started on APL, PL1, Fortran, DOS 1.0, Visicalc and desire to modernize into cloud, DORA best in class using Pi. OpenCV intrigues me w endless possibilities… thanks again – your blog is huge contribution to community.
I found my answer on: https://www.pyimagesearch.com/2019/09/16/install-opencv-4-on-raspberry-pi-4-and-raspbian-buster/
Different instructions for Buster.
Will try later.
Hey Adrian,
I really liked how detailed your tutorial is, but for some reason, whenever i cmake the build file, in the Python3 section, i can never see the virtualenv cv variable path interpreter at all. My path for the interpreter is always /usr/bin/python3 (same for python2.7) Do i have to actually install both python dependencies when im in cv? Also i made sure to be in cv before running cmake. It kinda getting frustrating no offense.
You’re following an old tutorial to installing OpenCV on the RPi. You should be following this one instead.
hi Adrian,
thanks for the great tutorial, i have one question about this.
can i use this with my ip camera not the pi camera
I don’t recommend using IP cameras if you can avoid it. Try using ImageZMQ.