致命錯誤： opencv2/nonfree/nonfree.hpp：沒有那個文件或目錄
fatal error: opencv2/nonfree/nonfree.hpp: No such file or directory
sudo apt-get update sudo add-apt-repository --yes ppa:xqms/opencv-nonfree
sudo apt-get update
sudo apt-get install libopencv-nonfree-dev