Tracking Over Many Frames
Feature tracking with m frames
1.Select features in first frame
2.Given feature in frame i, compute position in i+1
3.Select more features if needed
4.i = i + 1
5.If i < m, go to step 2
Issues
•Discrete search vs. Lucas Kanade?
–depends on expected magnitude of motion
–discrete search is more flexible
•Compare feature in frame i to i+1 or frame 1 to i+1?
–affects tendency to drift..
•How big should search window be?
–too small:  lost features.  Too large:  slow