Patent ID: 6449390
Filing Date: 2002-09-10
Classification: G06T

Abstract:
An image processing apparatus capable of varying the gradation characteristics of an image, comprising:(a) histogram distribution characteristics detection means for inputting an image signal and detecting the histogram distribution characteristics of pixel values constituting an image represented by the inputted image signal; and (b) histogram distribution characteristics conversion means for converting the histogram characteristics detected by said histogram distribution characteristics detection means into arbitrary histogram distribution characteristics, wherein said histogram distribution characteristics conversion means includes first gradation conversion means having gradation conversion characteristics for flattening the histogram distribution characteristics detected by said histogram distribution characteristics detection means; and second gradation conversion means having inverse gradation conversion characteristics to the gradation conversion characteristics for flattening the histogram distribution characteristics of the pixel values constituting an image represented by a reference image signal; and said first and second gradation conversion means are so arranged that the gradation of an image represented by an inputted arbitrary image signal is converted by said first gradation conversion means and then further converted by said second gradation conversion means.