Patent ID: 8237688

Claim:
A contrast control apparatus, comprising: a statistic distribution unit, for receiving an image data to have a brightness distribution, wherein the brightness distribution has a plurality of statistic counting values at statistic nodes, respectively corresponding to a plurality of intervals of gray levels, wherein each of the intervals represents a range of the gray levels and the statistic counting value represents the number of pixels falling within the range of the gray levels; and a characteristic judging unit, for at least receiving the brightness distribution, and determining a brightness adjusting signal for the image data, so as to proportionally adjust a brightness strength of a display light source according to the brightness adjusting signal, and for outputting a contrast curve, wherein the contrast curve represents a plurality of adjusted nodes with adjusted contrast values respectively corresponding to the statistic nodes, so as to change gray levels of the pixels respectively within the statistic nodes according to the brightness strength of the display light source being adjusted, wherein the contrast curve IG(n) is calculated out according to Equations (1)-(4): IG ( n )= IG default +IG rest *( H n /H total ); (1) 0 <IG default <IG base ; (2) IG rest =N−M*IG default ; and (3) IG base =N/M, (4) in which the IG default is a setting value; the N is a maximum gray level, the M is the number of intervals and smaller than the N; the H n is the statistic counting value of the histogram at the n th interval, and H total is a total sum of all the statistic counting values of all the intervals, wherein the contrast curve is formed by connecting the IG(n) at each n th interval.