FeatureDetector vs. FeatureFinder in OpenCV

Question

I'm trying to understand the difference between the FeatureDetector class and the FeatureFinder class. I've seen panorama examples written in OpenCV use both of these classes and it appears to be possible to use the SURF algorithm with either one. It was my understanding that the SURF FeatureDetector was moved to /nonfree because of possible issues with the SURF algorithm, but yet, FeatureFinder also can employ the SURF algorithm.

What's the difference between these two classes?

Answer 1

FeatureFinder can use the SURF algorithm because it is implemented using FeatureDetector. Whichever you use, you are actually getting the same SURF implementation, just different interface.

FeatureFinder has an interface compatible with the stitching pipeline whereas FeatureDetector has an interface to match the 2d features framework.