Deb package for introducing OpenCV to RaspberryPi3.
cmake -D CMAKE_BUILD_TYPE=Release \
-D CMAKE_INSTALL_PREFIX=/usr/local \
-D OPENCV_EXTRA_MODULES_PATH=/home/pi/opencv_contrib-3.4.2/modules \
-D ENABLE_VFPV3=ON \
-D ENABLE_NEON=ON \
-D BUILD_TESTS=OFF \
-D WITH_TBB=OFF \
-D INSTALL_PYTHON_EXAMPLES=ON \
-D BUILD_EXAMPLES=ON ..
$ cd ~
$ sudo apt autoremove libopencv3
$ wget https://github.com/PINTO0309/OpenCVonARMv7/raw/master/libopencv3_3.4.2-20180709.1_armhf.deb
$ sudo apt install -y ./libopencv3_3.4.2-20180709.1_armhf.deb
$ sudo ldconfig