hi,
Its called a 'Star Profiler' I designed and manufactured the unit, you can buy one for £27,000 if thats in your budget..
Used to measure volumes of caverns or storage mounds.
I would have thought a video system would be complex piece of equipment to use to measure volume.
I suppose one way would be to use a fast laser, scanning a X,Y grid pattern, say in the infra red and using a computer to measure the reflected distorted grid of the X,Y as seen by the camera.
By doing a comparision of the two grids it should be possible to work out the volume and profile of the room.