State of the machine vision art?

Laser triangulation for 3D imaging is a pretty hot topic in machine vision right now, which is why I had to take a close look at the cover of September’s NASA Tech Briefs. This shows a robot carrying a camera laser line generator, and judging by the image on the monitor in the background, they’re building up a height map of the concave surface.

All well and good, but bear in mind that the vision system is really just measuring the distance from the camera to the concave surface. The height map may be telling us something about the surface form but mixed in with that is the natural variation in the position of the robot head.

I’m sure the problem here is that I’ve just not understood the task, because if it was really a case of just mapping the concave surface wouldn’t it be easier just to buy one of the IVC-3D products from SICK?