September 5 2018 update: simpler, better process for OpenCV 3.4.3.
I am using the B version, purchased on Amazon, with the following specs:
- 1.2GHz 64-bit quad-core ARMv8 CPU, 1 GB RAM
- 802.11n Wireless LAN, 10/100Mbps LAN Speed
- Bluetooth 4.1, Bluetooth Low Energy
- 4 USB ports, 40 GPIO pins, Full HDMI port, Combined 3.5mm audio jack and composite video
- Camera interface (CSI),Display interface (DSI), Micro SD card slot (now push-pull rather than push-push), VideoCore IV 3D graphics core
There is a newer version ("B+") there now and it should work the same way, but some steps (such as compiling OpenCV, which took almost 2 hours on my device) should be faster.
Also, as expected, compiling OpenCV made the fanless CPU overheat 30 min into the process - so I had to place a powerful fan next to it, until I receive a case with proper cooling.
Step 1: make sure you have the latest version of OS
To upgrade, open (as sudo) the files /etc/apt/sources.list and /etc/apt/sources.list.d/raspi.list in your favorite editor, and change all occurences of your current distro name (e.g. "jessie") to "stretch". Then, open a terminal and run the update:
sudo apt-get update sudo apt-get -y dist-upgrade
Step 2: configure SSH and utilities
Make sure SSH is enabled. Change the default password, too!
Some of my favorite utilities on Linux are screen (to keep processes running if your terminal session is dropped) and htop (performance monitoring) - these may already be pre-installed:
sudo apt-get install screen sudo apt-get install htop
Step 3: free up 1GB+ by ditching Wolfram and Libreoffice
It's unlikely that you will need these two packages on your computer vision box, so:
sudo apt-get purge wolfram-engine sudo apt-get purge libreoffice* sudo apt-get clean sudo apt-get autoremove
Step 4: install dependencies
sudo apt-get install build-essential cmake pkg-config sudo apt-get install libjpeg-dev libtiff5-dev libjasper-dev libpng12-dev sudo apt-get install libavcodec-dev libavformat-dev libswscale-dev libv4l-dev sudo apt-get install libxvidcore-dev libx264-dev sudo apt-get install libgtk2.0-dev libgtk-3-dev sudo apt-get install libatlas-base-dev gfortran
Step 5: install Python 2.7 & 3
We need this in order to enable Python bindings in Open CV:
In OpenCV, all algorithms are implemented in C++. But these algorithms can be used from different languages like Python, Java etc. This is made possible by the bindings generators. These generators create a bridge between C++ and Python which enables users to call C++ functions from Python. To get a complete picture of what is happening in background, a good knowledge of Python/C API is required. A simple example on extending C++ functions to Python can be found in official Python documentation. So extending all functions in OpenCV to Python by writing their wrapper functions manually is a time-consuming task. So OpenCV does it in a more intelligent way. OpenCV generates these wrapper functions automatically from the C++ headers using some Python scripts which are located in modules/python/src2
sudo apt-get install python2.7-dev sudo apt-get install python3-dev
Step 6: get the latest OpenCV source code
I am using version 3.4.1 of OpenCV. You can check the Releases section of the official site (or Github) to see what the current build is. If your desired version is different, update the commands and paths below accordingly.
Download and unzip OpenCV 3.4.1 and its experimental modules (those are stored in the opencv_contrib repository):
wget -O opencv.zip https://github.com/opencv/opencv/archive/3.4.1.zip wget -O opencv_contrib.zip https://github.com/opencv/opencv_contrib/archive/3.4.1.zip unzip opencv.zip unzip opencv_contrib.zip
Step 7: install pip and virtualenv
These are the lowest-level tools for managing Python packages.
Get pip first:
wget -O get-pip.py https://bootstrap.pypa.io/get-pip.py sudo python get-pip.py sudo python3 get-pip.py
Then, install virtual environments:
sudo pip install virtualenv virtualenvwrapper
Modify your ~/.profile file to include the following lines:
This is what my file looks like:
# ~/.profile: executed by the command interpreter for login shells. # This file is not read by bash(1), if ~/.bash_profile or ~/.bash_login # exists. # see /usr/share/doc/bash/examples/startup-files for examples. # the files are located in the bash-doc package. # the default umask is set in /etc/profile; for setting the umask # for ssh logins, install and configure the libpam-umask package. #umask 022 # if running bash if [ -n "$BASH_VERSION" ]; then # include .bashrc if it exists if [ -f "$HOME/.bashrc" ]; then . "$HOME/.bashrc" fi fi # set PATH so it includes user's private bin if it exists if [ -d "$HOME/bin" ] ; then PATH="$HOME/bin:$PATH" fi # virtualenv and virtualenvwrapper settings export WORKON_HOME=$HOME/.virtualenvs export VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3 source /usr/local/bin/virtualenvwrapper.sh
... activate the changes:
Step 8: create a virtual environment
mkvirtualenv cv -p python3
... or, if you want to use Python 2.7 instead of Python 3:
mkvirtualenv cv -p python2
These are the basic commands for working with virtualenvwarapper:
mkvirtualenv virtualenv_name # create virtualenv workon virtualenv_name # activate/switch to a virtualenv deactivate virtualenv_name # deactivate virtualenv
In our case, we can activate a virtualenv called "cv":
pi@raspberrypi:~ $ workon cv (cv) pi@raspberrypi:~ $
Step 9: install Numpy, Scipy
sudo pip install numpy scipy
Step 10: finally, install OpenCV
Note: this will take a long, long, long time. Took almost 2 hours on my device. Also, your Raspberry Pi will overheat without proper cooling.
Again, I am using version 3.4.1 of OpenCV. If you aren't - update your paths accordingly:
cd ~/opencv-3.4.1/ 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-3.4.1/modules \ -D BUILD_EXAMPLES=ON ..
Make sure cmake finishes without errors.
Now, get yourself a glass of beer, and prepare for the final step - compiling. To speed things up, temporarily increase the swap file size in your /etc/dphys-swapfile by changing CONF_SWAPSIZE from 100 to 1024:
# 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
To avoid rebooting in order for these changes to take effect, simply restart the swap service:
sudo /etc/init.d/dphys-swapfile restart
There's a detailed guide on how to compile OpenCV with packages here:
What I did (using all 4 CPU cores):
Once OpenCV compiles successfully, continue the installation:
sudo make install sudo ldconfig sudo apt-get update
... then reboot the system - and you should be good to go!
One more thing:
Test the installation:
$ python3 Python 3.5.3 (default, Jan 19 2017, 14:11:04) [GCC 6.3.0 20170124] on linux Type "help", "copyright", "credits" or "license" for more information. >>> import cv2 >>> cv2.__version__ '3.4.1' >>>
If you are getting an error (ImportError: No module named 'cv2'), the library may be named incorrectly:
(cv) pi@raspberrypi:$ ls -l /usr/local/lib/python3.5/site-packages/ total 4500 -rw-r--r-- 1 root staff 4604912 Apr 27 14:41 cv2.cpython-35m-arm-linux-gnueabihf.so
Fix it by renaming the library file to "cv2.so":
cd /usr/local/lib/python3.5/site-packages/ sudo mv cv2.cpython-35m-arm-linux-gnueabihf.so cv2.so
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