Thursday, December 26, 2013

SURF and BRISK in OpenCV

Today I spent half a day to compare the two feature detector and descriptor SURF and BRISK.

The conclusion is

  • SURF is more accurate but takes much longer
  • BRISK is 10 times faster with comparable accuracy. 
One thing to notice:
when using Brute-force matcher, mind the normType. See HERE
C++: BFMatcher::BFMatcher(int normType=NORM_L2, bool crossCheck=false )
* normType – One of NORM_L1, NORM_L2, NORM_HAMMING,NORM_HAMMING2. L1 and L2 norms are preferable choices for SIFT and SURF descriptors, 
* NORM_HAMMING should be used with ORB, BRISK and BRIEF, NORM_HAMMING2 should be used with ORB when WTA_K==3 or 4.

The other thing to notice is the threshold used to select good matches. Maybe RANSAC should be used.
SURF feature
BRISK feature