opencv 3.4.6报错cv::xfeatures2d::SIFT::create
由于opencv 3.4.6 cv::xfeatures2d::SIFT::create算法被申请了专利，调用时会报错
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’
将opencv版本退到3.4.2之前即可解决！
文章来源: https://blog.csdn.net/qq_41854650/article/details/97276690