Patent ID: 6911972

Claim:
A user interface device for determining the position of one or more objects within a three dimensional zone, the device comprising: first imaging means for forming a first two dimensional image, from a first viewpoint, of the object(s) against a first background; and second imaging means for forming a second two dimensional image, from a second viewpoint different from the first viewpoint, of the object(s) against a second background overlapping the first background; wherein the first and second backgrounds are two dimensional views of the whole of the three dimensional zone; the device further comprising position determining means for determining the position of an object within the three dimensional zone from its position relative to the two backgrounds; means for associating one or more object positions determined by the position determining means within the three dimensional zone with corresponding information; and means for generating a signal in accordance with the information corresponding to the one or more determined object positions within the three dimensional zone.