Patent ID: 8611584

Claim:
A system for performing optical navigation comprising: an image sensor having an array of photosensitive elements configured to capture frames of image data of a navigation surface; a feature detector operably connected to the image sensor to receive a particular frame of image data of the navigation surface, the feature detector being configured to determine whether the particular frame of image data includes a portion with prominent trackable features, the portion of the particular frame of image data including fewer pixels than the particular frame of image data; and a cross-correlator operably connected to the feature detector and the image sensor, the cross-correlator being configured to cross-correlate the particular frame of image data with another frame of image data using every pixel of the particular frame of image data and the another frame of image data if the feature detector determines that the particular frame of image data does not include the portion with the prominent trackable features, the cross-correlator being further configured to cross-correlate the portion of the particular frame of image data with a corresponding portion of the another frame of image data if the feature detector determines that the particular frame of image data does include the portion with the prominent trackable features, the corresponding portion of the another frame of image data including fewer pixels than the another frame of image data, the results of cross-correlation performed by the cross-correlator being used to estimate displacement with respect to the navigation surface, wherein the feature detector is configured to determine whether the particular frame of image data includes a second portion with the prominent trackable features, and wherein the cross-correlator is configured to cross-correlator the second portion of the particular frame of image data with a corresponding second portion of the another frame of image data if the feature detector determines that the particular frame of image data includes the second portion with the prominent trackable features.