A circuit for the correction of pixel defects in image sensors

This paper describes an analog circuit which eliminates visible pixel faults from a video signal. The chip is coupled directly to an image sensor to enhance its cosmetic image quality. It operates with a pixel rate up to 10 MHz. The algorithm in the ASIC limits the value of every individual pixel between upper and lower bounds which are derived from the values of the pixels in its immediate neighborhood. The article describes this algorithm, and its analog domain implementation. This small circuit can also be used as a part of the readout electronics of a CMOS image sensor. A limited number of pixel defects can then be tolerated.