运行cv2.xfeatures2d.SIFT_create()时报错The function/feature is not implemented的解决方法，亲测可用

opencv-contrib-Python编译出现错误：
sift = cv.xfeatures2d.SIFT_create()
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：

卸载之前的opencv-python和opencv-contrib-python 版本。
pip uninstall opencv-python
pip uninstall opencv-contrib-python

 

pip install opencv-python==3.4.2.16

pip install opencv-contrib-python==3.4.2.16

你会发现，这个下载速度太慢，使用国内清华大学的镜像，速度飞起来

pip install opencv-python==3.4.2.16 -i https://pypi.tuna.tsinghua.edu.cn/simple/

pip install opencv-contrib-python==3.4.2.16  -i https://pypi.tuna.tsinghua.edu.cn/simple/

我的python版本是3.5