module 'cv2.cv2' has no attribute 'xfeatures2d' 問題已解決

使用opencv進行圖片特徵提取和描述的過程中需要使用：

cv2.xfeatures2d_SIFT.create()

來提取圖片的特徵點，但是顯示：module 'cv2.cv2' has no attribute 'xfeatures2d'

首先卸載opencv-python包

然後安裝：opencv-contrib-python

sudo pip install opencv-contrib-python == 3.4.2.16

另外如果不卸載opencv-python將會出現：

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’
已入坑請避雷走。