Patent ID: 7391449

Claim:
A method for processing pixel signals output from a pixel matrix of an image sensor, the pixel signal including a black level component, the pixel matrix including both imaging pixels and mask pixels, comprising: amplifying the pixel signals; extracting information for the amplified pixel signals corresponding to the mask pixels; and calculating from the extracted mask pixel information a black level compensation signal, comprising calculating a difference between the extracted mask pixel information for a current image in a sequence of images and the extracted mask pixel information for a preceding image in the sequence of images, wherein the black level compensation signal is a current image black level compensation signal calculated from the extracted mask pixel information of the current image in the sequence if the calculated difference exceeds a threshold, and wherein the black level compensation signal is a preceding image black level compensation signal calculated from the extracted mask pixel information of the preceding image in the sequence if the calculated difference does not exceed the threshold; wherein amplifying includes taking the black level compensation signal into account throughout the processing of the current image in the sequence when amplifying the pixel signals.