look at what the PSEye does in Eye of Judgment. It renders a 3D creature out of a card, then if you make the motions around where the creature is, on screen it will make it seem like your petting or hitting your creature. Id say it picks up some depth of motion.
From what I saw it sensed motion and the location of the motion on the screen but from what I have seen (and I looked at quite a few trailers and demos before making this post) it doesnt detect any more. The only depth I saw it detect was that it detected the size of the cards (and hence the distance from the camera) and changed the size of the models as compared to that.








