Patent ID: 7315013
Filing Date: 2008-01-01
Classification: G06F,G06T

Abstract:
1. An optical navigation method comprising: obtaining first image data from an image sensor comprising an m×n array of photodetectors with m being greater than one and n being greater than one; obtaining second image data from the image sensor; summing, at a pre-processing hardware circuit, intensity values of the first image data on a per-column basis and on a per-row basis; summing, at the pre-processing hardware circuit, intensity values of the second image data on a per-column basis and on a per-row basis; cross-correlating, at a one-dimensional cross-correlation hardware circuit, the per-column sums of the first image data and the second image data; cross-correlating, at the one-dimensional cross-correlation hardware circuit, the per-row sums of the first image data and the second image data; determining relative displacement between the first and second image data in a first direction in response to the cross-correlation of the per column sums; determining relative displacement between the first and second image data in a second direction in response to the cross-correlation of the per-row sums; and using the relative displacement in the first and second directions to track the movement of an optical navigation system relative to a navigation surface.