Patent ID: 6233011
Filing Date: 2001-05-15
Classification: H04N

Abstract:
An apparatus for compensating the gray-scale value of an image sensor comprising:a power supply for providing a plurality of different levels of voltage sources;an analog multiplexer for receiving said plurality of different levels of voltage sources, being controlled by a digital signal to output one of said plurality of different levels of voltage sources;an image sensor to scan an image pixel and output an image voltage of said image pixel;an analog/digital converter for receiving the voltage output from said analog multiplexer as a top voltage V.sub.TOP, and the image voltage output from said image sensor as an analog input, wherein said analog/distal converter outputs an original gray-scale value g(x,y) of the pixel;a microprocessor to find a maximum white-level value G.sub.MAX among a plurality of original gray-scale values g(x,y) for one row of white pixels along an x coordinate axis, wherein a maximum white-level voltage V.sub.PMAX is defined as a voltage output by said image sensor while scanning pixels corresponding to G.sub.MAX, said digital signal being set to control said analog multiplexer to output a voltage source closest to V.sub.PMAX to serve as the voltage output, and calculate an average white-level value G'(x) of the plurality of original gray-scale values g(x,y) for a plurality of white pixels along the y-axis direction, computing a compensated gray-scale value g'(x,y) of the pixel with said plurality of original gray-scale value g(x,y) of the pixel according to G'(x).