cmake opencv_4.1.2+contrib

cmake opencv4.1.2 with opencv_contrib-4.1.2 :

cmake -D CMAKE_INSTALL_PREFIX=/usr/local -D CMAKE_BUILD_TYPE=Release -D OPENCV_EXTRA_MODULES_PATH=../opencv_contrib-4.1.2/modules -D BUILD_EXAMPLES=ON -D WITH_CUDA=ON ..


查看 gcc/g++ 版本 ：  gcc/g++ --version
Use 'sudo apt autoremove 'to remove them
切换版本 sudo update-alternatives --config g++/gcc