I did this as part of a class project last year with opencv. It's actually not too difficult:<p><a href="http://www.youtube.com/watch?v=XcEsDJA0CWE" rel="nofollow">http://www.youtube.com/watch?v=XcEsDJA0CWE</a><p>Edit: forgot to mention it was done with just a webcam...no fancy glasses