Patent ID: 7199840

Claim:
An image processing apparatus which corrects a gray scale by extending part of a luminance level range of an input video luminance signal to a dynamic range of a processing system to output an output video luminance signal, comprising: minimum value detecting means for detecting a minimum value of the input video luminance signal; luminance distribution detecting means for detecting luminance distribution information of the input video luminance signal from a histogram; minimum value correcting means for obtaining a corrected minimum value by correcting the minimum value detected by said minimum value detecting means based on the luminance distribution information detected by said luminance distribution detecting means; and luminance signal correcting means for correcting the input video luminance signal by extending the signal so that, when a level of the input video luminance signal is at the corrected minimum value, a level of the output video luminance signal becomes a minimum value of the dynamic range of the processing system, and outputs the corrected signal as the output video luminance signal.