Py3 OpenCV on Raspberry Pi 3

rpi3-install-py3-opencv.sh

# Remove useless programs to free up space
sudo apt-get remove --purge -y wolfram* libreoffice* sonic-pi minecraft-pi
sudo apt-get clean && sudo apt-get autoremove
# Update, upgrade, and install all OpenCV dependencies
sudo apt-get update -y && sudo apt-get upgrade -y
sudo apt install libgdk-pixbuf2.0-dev libpango1.0-dev libcairo2-dev libfontconfig1-dev libgdk-pixbuf2.0-dev libpango1.0-dev libcairo2-dev # GTK requires
sudo apt-get install build-essential cmake pkg-config libjpeg-dev libtiff5-dev libjasper-dev libpng12-dev libavcodec-dev libavformat-dev libswscale-dev libv4l-dev libxvidcore-dev libx264-dev libgtk2.0-dev libgtk-3-dev libatlas-base-dev gfortran python2.7-dev python3-dev # opencv requires
# virtualenv for Python, this is where OpenCV will be installed
sudo pip install virtualenv virtualenvwrapper
PROJECT_HOME=$HOME/Development
WORKON_HOME=$HOME/Development/.virtualenvs
mkdir -p $PROJECT_HOME
mkdir -p $WORKON_HOME
echo -e "\n# virtualenv and virtualenvwrapper" >> ~/.bashrc
echo "export VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3" >> ~/.bashrc
echo "export WORKON_HOME=$PROJECT_HOME" >> ~/.bashrc
echo "export PROJECT_HOME=$HWORKON_HOME" >> ~/.bashrc
echo "source /usr/local/bin/virtualenvwrapper.sh" >> ~/.bashrc
source ~/.bashrc
mkvirtualenv opencv
workon opencv # from this point on, we should be within the environment
# Necessary for OpenCV compilation
pip install numpy
# Download OpenCV
cd ~
wget -O opencv.zip https://github.com/Itseez/opencv/archive/3.3.0.zip
unzip opencv.zip
rm opencv.zip
wget -O opencv_contrib.zip https://github.com/Itseez/opencv_contrib/archive/3.3.0.zip
unzip opencv_contrib.zip
rm opencv_contrib.zip
mkdir ~/opencv/build
cd ~/opencv/build
# 1GB of swap space, avoid memory issues/hanging during compilation (http://disq.us/p/10ekwiz)
sudo sed -i -e 's/CONF_SWAPSIZE=.*$/CONF_SWAPSIZE=1024/g' /etc/dphys-swapfile
sudo /etc/init.d/dphys-swapfile stop
sudo /etc/init.d/dphys-swapfile start
# Begin compiling OpenCV
cmake -DOPENCV_EXTRA_MODULES_PATH=../../opencv_contrib/modules/ -DBUILD_TIFF=ON -DBUILD_opencv_java=OFF -DWITH_CUDA=OFF -DWITH_OPENGL=ON -DWITH_OPENCL=ON -DWITH_IPP=ON -DWITH_TBB=ON -DWITH_EIGEN=ON -DWITH_V4L=ON -DBUILD_TESTS=OFF -DBUILD_PERF_TESTS=OFF -DCMAKE_BUILD_TYPE=RELEASE -DCMAKE_INSTALL_PREFIX=$(python -c "import sys; print(sys.prefix)") -DPYTHON_EXECUTABLE=$(which python) -DPYTHON_INCLUDE_DIR=$(python -c "from distutils.sysconfig import get_python_inc; print(get_python_inc())") -DPYTHON_PACKAGES_PATH=$(python -c "from distutils.sysconfig import get_python_lib; print(get_python_lib())") ..
make -j4
sudo make install
sudo ldconfig
# Reset swap space size after compilation is done
sudo sed -i -e 's/CONF_SWAPSIZE=.*$/CONF_SWAPSIZE=100/g' /etc/dphys-swapfile
sudo /etc/init.d/dphys-swapfile stop
sudo /etc/init.d/dphys-swapfile start
# Symlink OpenCV shared library file for our virtualenv
# Feel free to replace *s with your Python's version numbers
cd /usr/local/lib/python*/site-packages/
sudo mv cv2.cpython-*-arm-linux-gnueabihf.so cv2.so
cd $WORKON_HOME/cv/lib/python*/site-packages/
ln -s /usr/local/lib/python*/site-packages/cv2.so cv2.so
# Done