[daveloyall]

I've never heard of a single infrared camera being used for depth-finding...

Are you thinking of some active scanning technology such as LIDAR? Or the infrared grid-of-dots projection that the kinect uses?

[JustUhThought]

Infra-red cameras are used in the LeapMotion controllers. I don't think it is anything special about the spectrum however, coupled with Infra-red lights it's an easy way to cut down on the noise in the comtrollers field of view.