解决cv2.error: OpenCV(xxx) C:\projects\opencv-python\opencv_contrib\modules\xfeatures2d\src\sift.cpp问题
Python版本：
Python 3.6 win64
问题一：
AttributeError: module 'cv2.cv2' has no attribute 'xfeatures2d'
问题二：
cv2.error: OpenCV(3.4.4) 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'
问题出现：适用opencv进行sift匹配出现的问题。
通用解决办法：
pip install opencv_python-3.3.0+contrib-cp36-cp36m-win_amd64.whl
如果下载不到，点击下面链接：
https://download.csdn.net/download/qq_33356563/10833684
开启我的opencv之路：
