Patent ID: 7423633

Claim:
An apparatus for controlling the position of a screen pointer, the apparatus comprising: a light source configured to illuminate an imaging surface to thereby generate reflected images; and a navigation sensor configured to generate digital images based on the reflected images to perform a movement computation based on the digital images, and to generate movement data based on the movement computation that is indicative of relative motion between the imaging surface and the apparatus, wherein the movement computation includes attenuating fixed pattern noise in the digital images; wherein the navigation sensor includes a processor including a noise attenuator, wherein the noise attenuator comprises an image buffer and at least one of a noise isolator and a noise filter, wherein the image buffer is configured to store digital images upon motion of the navigation sensor relative to the imaging surface and wherein the noise attenuator builds a composite image from a plurality of images stored in the image buffer in which intensity values of the images are averaged on a pixel-by-pixel basis to produce the composite image.