I tried to compile a function for extracting the features. Ptr<Feature2d> kaze = KAZE::create(); But I get an errors with that. First is "Use of undeclared identifier 'KAZE'" The next line is kaze->detectAndCompute(img, noArray(), keypoints, descriptors);. There it is said: "No member named 'detectAndCompute' in 'cv::Feature2D'". I have included the header #include <opencv2/features2d/features2d.hpp> and I also linked the libs. I tried to use AKAZA instead, but I got the same error. I don't know what is wrong.