I would like to extract out all the slides from a video lecture, using OpenCV. Here is an example of a lecture: http://www.youtube.com/watch?v=-hxOpz9c0bY.

What approaches would you recommend? So far, I've tried:

• Comparing the change in grayscale intensity from frame to frame. This can have problems when an object in the foreground moves around. For example, in this lecture, there's a hand that moves around: http://www.youtube.com/watch?v=mNzu42FrlHo#t=07m00s.

• Using SURF features and doing comparisons frame by frame. This approach seems kind of slow.

Does anyone have other ideas?