Going to the "build" folder directory of opencv from terminal, and execute the following：

1. $ sudo make uninstall
2. $ cd ..
3. $ sudo rm -r build
4. $ sudo rm -r /usr/local/include/opencv2 /usr/local/include/opencv /usr/include/opencv /usr/include/opencv2 /usr/local/share/opencv /usr/local/share/OpenCV /usr/share/opencv /usr/share/OpenCV /usr/local/bin/opencv* /usr/local/lib/libopencv*

这一步可能有error
下面执行如下操作：
5. sudo apt-get remove --purge opencv-doc opencv-data python-opencv libopencv*

ubuntu卸载opencv并重装