SIFT和SURF算法的版权问题

遇到该问题时，网友多是建议补个包，即
pip install opencv-contrib-python
我在补完之后又出现下面这样的错误：
OpenCV(3.4.3) C:\projects\opencv-python\opencv_contrib\modules\xfeatures2d\src\sift.cpp:1207: error: (-213:The function/feature is not implemented) This algorithm is patented and is excluded in this configuration; Set OPENCV_ENABLE_NONFREE CMake option and rebuild the library in function ‘cv::xfeatures2d::SIFT::create’
貌似是该算法被申请了专利还是咋的，将opencv版本退到3.4.2即可解决，卸载之前的包，然后
pip install -i https://pypi.tuna.tsinghua.edu.cn/simple opencv-python3.4.2.16
pip install -i https://pypi.tuna.tsinghua.edu.cn/simple opencv-contrib-python==3.4.2.16
亲测有效！

原文：https://blog.youkuaiyun.com/weixin_43167047/article/details/82841750