An apparatus for detecting a pointer relative to a touch surface includes at least two spaced imaging assemblies having overlapping fields of view encompassing the touch surface. The imaging assemblies see the touch surface in three-dimensions as a perspective view. The imaging assemblies acquire overlapping...http://www.google.com.au/patents/US7492357?utm_source=gb-gplus-sharePatent US7492357 - Apparatus and method for detecting a pointer relative to a touch surface
