Abstract: Illumination spot alignment is performed by capturing an image by an image array. The image is evaluated to determine an illumination spot size and location. Coordinates identifying the illumination spot size and location are stored.

Abstract: A technique for reducing navigation errors that are caused by uneven illumination involves using only the portion of the image data that is properly illuminated in the correlation process. The portion of the image data that is used for optical navigation is established by summing the image data on a per-slice basis, comparing the per-slice sums to a pre-established intensity threshold, and defining boundaries of the navigation window in response to the comparison. Boundaries are set at the points where the per-slice sums equal the pre-established intensity threshold.

Abstract: A technique for optical navigation involves summing intensity values from a photodetector array on a per-column and a per-row basis for both reference image data and sample image data and then performing separate one-dimensional cross-correlations on the per-column sums and on the per-row sums to separately determine displacement in the x and y directions, respectively.