Patent ID: 6124587
Filing Date: 2000-09-26
Classification: G06F

Abstract:
A sensing device for a pointing device, comprising:a plurality of pixels, including a first and second pixel aligned along a first axis, responsive to said radiation reflected from a surface, said first and second pixels includinga photodetector element for receiving said radiation reflected from the surface and for converting said radiation into an electrical signal having a signal strength corresponding to an intensity value of said received radiation;a comparator unit, disposed to receive signals from said photodetector elements of said plurality of pixels at a first and second time, for comparing a first intensity value of said first pixel with a second intensity value of said second pixel at each of said first and second times, to identify if an edge condition exists between said first and second pixels at each of said first and second times, and to identify a movement of said edge condition between said first and second times wherein said comparator unit identifies that an edge condition exists when a ratio of said first intensity value and said second intensity value is not within a predefined range.