Well, I’ll try to explain the idea with a bad draw :

Since I can’t use the screen I’ve planned to use on an FTIR or DI device because I can’t disassemble it, I have to find an other solution. The easy way around is to use “side-DI” but it can only track 2 fingers since there are positions (there is an example of such a position on the attached picture) which make the system go “wrong”. The following is still side-DI but there are some changes.

On the attached draw, there are a 16 mirrors (which can be modify regarding the device) which form a circle and they are inclinated. The camera is placed centered under the desk, allowing it to see the configuration from different points of view (there is a gap between the desk and the mirrors). This way 3 fingers tracking is possible (I think 4 too if there is no square configuration). The problem is the mirror circle has to be bigger than the screen since the mirrors are small.

The purpose is to integrate the system in a coffee table (this way the circle form isn’t a problem, but of course the screen doesn’t cover all the table).

Do you see a problem that I didn’t see ? Do you think this is doable ? And more important is the draw explicit enough ^^ ?