Patent ID: 7015956

Claim:
A method of automatically controlling the exposure time and gain of an image sensor, said image sensor including a matrix of pixels, said method comprising: determining if a first image provided by said image sensor has an overall brightness that falls within a stable range; if said brightness of said first image falls within said stable range, maintaining the exposure time and gain of said image sensor for capture of a subsequent second image; if said brightness of said first image falls outside of said stable range, then adjusting said exposure time downward by a first predetermined increment if said brightness is higher than said stable range, else adjusting said exposure time upward by a second predetermined increment if said brightness is lower than said stable range; and determining if said adjustment of exposure time downward or upward is greater than a predetermined threshold, and if so, increasing said gain of said image sensor if said exposure time is adjusted downward, else decreasing said gain of said image sensor if said exposure time is adjusted upward, wherein said predetermined threshold is substantially a magnitude of said stable range.