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The 3DV site has a number of papers showing how the underlying technology works. They've spent the last several years refining it to make it smaller/cheaper, but the physical principles are the same: In addition to a regular video camera to capture RGB, a pulsed infrared source illuminates the entire scene. A fast shutter on the camera then allows it to infer distance to each pixel, based on the time-of-flight of the reflected infrared pulse. The literature for an earlier version claims 1-2 cm depth resolution at full video rates, but I haven't seen specs for the latest small/compact/cheap version.

Using this as a game controller strikes me as potentially very interesting, but with caveats. First I think this would be hard to program: You get all of this per-pixel RGB/depth information out of the camera, from which you need to extract limb orientations, etc. Seems pretty hard to do well, although I suppose a library would abstract that away from the game developer. A more fundamental limitation is the low spatial resolution: Basically it just detects gross movements of the limbs, and by itself could only support a few types of games. I think this would be most useful in combination with a controller for faster/finer motions (e.g., a button-based interface). Maybe that's where the future is headed: Overall body tracking at low resolution, selected "high-sensitivity" parts (hands, eyes) tracked at high resolution.

Another potentially interesting next-generation game controller is the Sixense 6dof controller. It is basically a magnetic tracker (full absolute position/orientation sensing) combined with a button-based interface. I could see a lot of interesting games working well on that. At any rate, what's cool about the success of the Wii is that people are innovating here, and the console makers now seem willing to spend a nontrivial part of their overall COGS on controllers.

After reading the article I'm unclear whether this camera produces metric depth information. I did come across another camera that's about the size of a webcam and uses laser and time of flight to measure distance. Saw it mentioned at a conference I was attending. A demo of the Z-CAM is at http://www.3dvsystems.com/gallery/gallery.html. Pretty cool. It's targeted at consumer applications, still in prototype stage last time I enquired.

Having read the article it's unclear to me how they actually get depth information, depth from focus?

Another camera that can capture 3D that I came across during a conference trip is the Z-CAM. Demonstration videos at http://www.3dvsystems.com/gallery/gallery.html. It uses a laser for each pixel to measure depth. It's still in prototype but I know at least one Korean university has manage to get hold of one to play around with.

Here's one way to do it, based upon time-of-flight for a light pulse:

http://www.3dvsystems.com/technology/technology.ht ml