Jitter face matrix geometrical installation

Hey

Im thinking of building a patch in jitter that recognises the posistion of a users face in different areas of the screen so for instance if someone was on the ground their face could be picked up at the bottom of the screen and a video plays from a projector onto the wall, same with if the user was crouching their face would be picked up in the middle of the screen then a video plays etc

I may not have explained this well but if anyone has any ideas it would be much appreciated.

Thanks
G