Patent ID: 9619873
Date: 2017-04-11
CPC Classifications: G06T,H04N

Claim:
1. An image processing device comprising: a gray scale histogram calculator that calculates, with respect to an image signal having color components and gray scale components and forming an image, a gray scale histogram of the gray scale components for each color component, each gray scale histogram having classes each having a frequency; a maximum/minimum calculator that uses the gray scale histogram for each color component to calculate, for each color component, a maximum and a minimum of classes having a frequency greater than zero in the gray scale histogram; an image type determiner that generates, for each color component, an absolute difference value histogram having classes each having an absolute difference value between the frequencies of adjacent classes in the gray scale histogram, compares the absolute difference values in the absolute difference value histograms with a predetermined threshold value to determine, according to the presence or absence of an absolute difference value exceeding the threshold value, a size of an area of image regions where the gray scale components are uniform, and determines an image type of the image according to the determination; a gray scale correction curve generator that generates a gray scale correction curve for correcting a gray scale of the image signal for each color component, on a basis of a largest and a smallest of the maximum and the minimum of the classes for each color component calculated by the maximum/minimum calculator and the determination of the image type; and a gray scale corrector that uses the gray scale correction curve to perform gray scale correction on the gray scale components of the image signal for each color component, wherein for each color component, the maximum/minimum calculator: