US Patent 7126631 Sensing with defective cell detection

An image sensor may have on-board circuits for detecting defective pixels. In one embodiment of the present invention, high and low values may be determined for pixel intensities. Those pixels that produce intensity values that fall above or below these high and low values respectively, may be determined to be defective during the pixel readout process. In addition, spatial defects may be determined for rows and/or columns. By determining point and/or spatial defects during the pixel readout process, for example using circuitry containing on the image sensor itself, significant economies may achieved in the pixel manufacturing process.