I briefly talked about IR rear illumination in an earlier post. But there's also IR illumination from the front (ambient IR). Therefor it would be suitable to have a general name for both these methods. Whitenoise came up with the word Diffused Illumination, which sounds as a fairly good description of both methods. You beam IR light from either the front or the rear of the surface onto the surface. Because of the fact that the IR needs to be diffused to prevent it from creating hotspots, it's being called Diffused Illumination.
A couple of people within NUIgroup are exploring the possibilities of this method over the method of FTIR.
Like mentioned earlier, we are going to do some DI testing ourselves as well, next week.