PICTURE QUALITY CORRECTING CIRCUIT

PROBLEM TO BE SOLVED: To provide a picture quality correcting circuit generating a correction curve corresponding to a kind of an image by roughly deciding the image. SOLUTION: The picture quality correcting circuit is equipped with: a pixel sampling processing portion which extracts one pixel for every N (N: a natural number) pixels as to a luminance signal Y; a distribution detection portion which comprises a plurality of counters and counts up according to luminance levels of the pixels extracted by the pixel sampling processing portion to detect a histogram distribution by counting; a correction curve generation section generating a correction curve of the luminance signal Y based on this histogram distribution; and a gradation characteristic correction portion which corrects gradation characteristics by using the generated correction curve. The circuit is also is provided with: a spatial frequency detection portion which detects a spatial frequency; and a counter selection portion which selects counters. The correction curve generation portion is equipped with a limitation processing portion which adjusts a counted value from a counter selected by the counter selection portion and where pixels having low spatial frequency values are concentrated. COPYRIGHT: (C)2006,JPO&NCIPI