Patent ID: 6859199

Claim:
A method of determining a movement vector of an optical mouse comprising: capturing a first image comprised of a plurality of pixels; extracting a first feature set from said first image, wherein the process of extracting said first feature set comprises: (a) calculating a first pixel gradient map of said first image, said first pixel gradient map comprised of a plurality of first pixel gradients; and (b) determining which of said plurality of first pixel gradients exceed a predetermined threshold and identifying those first pixel gradients as features of said first feature set, wherein said first predetermined threshold is changed until a predetermined number of features is obtained; capturing a second image subsequent in time from said first image, said second image comprised of a plurality of pixels; extracting a second feature set from said second image, wherein the process of extracting said first feature set comprises; (a) calculating a second pixel gradient map of said second image, said second pixel gradient map comprised of a plurality of second pixel gradients; and (b) determining which of said plurality of second pixel gradients exceed said predetermined threshold and identifying those second pixel gradients as features of said second feature set; comparing said first feature set to said second feature set to determine a shift in position of said second image relative to said first image; and outputting said movement vector based upon said shift in position.