Patent ID: 7355160

Claim:
A pointing device comprising: an illumination system that generates light in a plurality of wavelength bands and illuminates a surface below said pointing device with light from one of said wavelength bands; an imaging system that records images of said illuminated surface; and a controller that selects said one of said wavelength bands used to illuminate said surface, that compares first and second images recorded by said imaging system at different times when said surface is illuminated with that wavelength band, and that determines a displacement indicative of a direction and distance said positioning device moves between said two different times; wherein said controller operates in a first mode in which said controller determines one of said wavelength bands to be used in recording images and a second mode in which said controller determines said displacement utilizing said determined one of said wavelength bands for a plurality of successive displacement determinations; wherein said controller sets a level of illumination in said first mode to a first value and wherein said controller alters said level of illumination if a level of detail of one of said recorded images is greater than a predetermined level of detail in said second mode.