运行cv2.xfeatures2d.SIFT_create()时报错：
错误代码：
cv2.error: 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'
解决方法：
卸载
卸载之前的opencv-python和opencv-contrib-python 版本。
pip uninstall opencv-python
pip uninstall opencv-contrib-python
重新安装
pip install opencv-python==3.4.2.16
pip install opencv-contrib-python==3.4.2.16
引自：原文：https://blog.csdn.net/weixin_43167047/article/details/82841750
