Nonfree module is missing in OpenCV 3.0

Question

I have built the openCV 3.0 alpha version from source with support for CUDA and TBB. Now, I want to do feature detection and feature matching using SURF algorithm. SurfFeatureDetector is present in the include file

opencv2/nonfree/features2d.hpp & opencv2/nonfree/features2d.hpp

But the module nonfree is missing in this version of openCV. I tried checking the opencv forums at answers.opencv.org but the site is under construction.

How to use the non free modules?

Answer 1

with opencv3.0, SURF/SIFT and some other things have been moved to a seperate opencv_contrib repo .

you will have to download that, add it to your main opencv cmake settings (please look at the readme there), and rerun cmake/make.

then:

#include "opencv2/xfeatures2d.hpp"

...
Ptr<SIFT> sift = cv::xfeatures2d::SIFT::create(...);
sift->detect(...);