http://www.gamespot.com/news/6145348.html
--Raz.A little over a week ago, a US patent was granted to Microsoft for a new method of spatial measurement. Basically, the setup proposed in the patent application can track an object's path through 3D space using multiple-range cameras in a more accurate and consumer-friendly manner than has previously been available. The patent was originally applied for in August of 2004.
The patent makes no mention of the technology being used for anything game-related, but it does say it would ideally be implemented with something that has the basic components of a personal computer, and also emphasizes that a number of modifications and variations to the technology are possible. The only use for the technology explicitly described in the patent is that of tracking a user's path walking around a room.