Patent ID: 7742082

Claim:
A method of increasing the sensitivity of an optical detector formed from a two-dimensional array of sensor elements, each of said sensor elements having a dynamic range, said method comprising: applying a gradient-detection algorithm to an image received from the optical detector in order to identify a shape and position of a first subset of pixels which correspond to a shape represented in the image, said shape represented in the image being in the foreground over at least one other object in the image or the at least one other object being in the foreground over said shape; determining whether one or more of the sensor elements corresponding in shape and position to the first subset of pixels have been exposed outside of said dynamic range; and if said one or more sensor elements have been overexposed, adjusting at least one of a gain or offset associated with said one or more of the sensor elements, such that said one or more sensor elements are exposed within said dynamic range; wherein said adjustment of the gain or offset of said one or more sensor elements is performed independently of any gain or offset adjustment applied to other sensor elements in the optical detector.