I am trying to use SIFT in opencv4.1.1 but to know it is patented and need to compile from source to install Opencv-contrib-python.
I followed the instructions from below link
downloaded the install script
and changed cmake line 47 to add the flag to turn patented source
cmake -D OPENCV_ENABLE_NONFREE=ON
but still get following error
cv2.error: OpenCV(4.1.1) /home/xavier/Desktop/opencv_contrib-4.1.1/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 ‘create’