Patent ID: 6111980
Filing Date: 2000-08-29
Classification: H04N

Abstract:
A luminance gradation correcting method in an image pickup apparatus having a dynamic range, comprising the steps of:detecting pieces of histogram data respectively indicating the number of pixels of a luminance level from an input picture signal produced in the image pickup apparatus, the input picture signal indicating a particular image;detecting a maximum luminance level from the luminance levels of the pieces of histogram data;detecting a luminance gradation characteristic of the particular image indicated by the input picture signal from the pieces of histogram data corresponding to the luminance levels;producing a corrected luminance gradation characteristic of the particular image from the luminance gradation characteristic of the particular image according to the maximum luminance level and the dynamic range of the image pickup apparatus;correcting the luminance levels of the pieces of histogram data to a plurality of gradation corrected luminance levels according to the corrected luminance gradation characteristic of the particular image to set the gradation corrected luminance levels corresponding to the pieces of histogram data within the dynamic range of the image pickup apparatus; andproducing a luminance gradation corrected picture signal composed of the pieces of histogram data corresponding to the gradation corrected luminance levels to reproduce the particular image, in which each of the pixels has one corresponding gradation corrected luminance level, from the luminance gradation corrected picture signal.