a. pip uninstall python-opencv
b. conda uninstall opencv
c. ./release$: sudo make uninstall
d. 依次删除以下内容，不同版本的ubuntu可能存储路径有不同，不同opencv版本可能文件内容不同，注意一定确定把opencv相关的所有文件全部删除一遍
sudo rm -r /usr/local/bin/opencv_*
(opencv_annotation opencv_interactive-calibration opencv_version
opencv_createsamples opencv_traincascade opencv_visualisation)
sudo rm -r /usr/local/lib/libopencv_*
(libopencv_calib3d.so libopencv_imgcodecs.so libopencv_stitching.so
libopencv_calib3d.so.3.3 libopencv_imgcodecs.so.3.3 libopencv_stitching.so.3.3
libopencv_calib3d.so.3.3.0 libopencv_imgcodecs.so.3.3.0 libopencv_stitching.so.3.3.0
libopencv_core.so libopencv_imgproc.so libopencv_superres.so
libopencv_core.so.3.3 libopencv_imgproc.so.3.3 libopencv_superres.so.3.3
libopencv_core.so.3.3.0 libopencv_imgproc.so.3.3.0 libopencv_superres.so.3.3.0
libopencv_dnn.so libopencv_ml.so libopencv_videoio.so
libopencv_dnn.so.3.3 libopencv_ml.so.3.3 libopencv_videoio.so.3.3
libopencv_dnn.so.3.3.0 libopencv_ml.so.3.3.0 libopencv_videoio.so.3.3.0
libopencv_features2d.so libopencv_objdetect.so libopencv_video.so
libopencv_features2d.so.3.3 libopencv_objdetect.so.3.3 libopencv_video.so.3.3
libopencv_features2d.so.3.3.0 libopencv_objdetect.so.3.3.0 libopencv_video.so.3.3.0
libopencv_flann.so libopencv_photo.so libopencv_videostab.so
libopencv_flann.so.3.3 libopencv_photo.so.3.3 libopencv_videostab.so.3.3
libopencv_flann.so.3.3.0 libopencv_photo.so.3.3.0 libopencv_videostab.so.3.3.0)
sudo rm -r /usr/local/share/OpenCV
sudo rm -r /usr/local/include/opencv
sudo rm -r /usr/local/include/opencv2
除了检查上述5个路径外，建议检查一下/usr/lib/,/usr/bin/,/usr/share/,/usr/include/opencv/,/usr/include/opencv2 5个文件夹看看是否包含与opencv有关的文件，如果有可按照上述办法一一删除
Reference：
http://www.cnblogs.com/mar-q/p/7490271.html