Patent ID: 8165418
Filing Date: 2012-04-24
Classification: G06T

Abstract:
1. An image processor comprising: a reduced image forming unit that forms a reduced image by reducing an original image; a reduced image peripheral average value generating unit that generates a peripheral average value for each pixel of the reduced image by performing a filtering operation on a peripheral pixel region for the each pixel, the peripheral pixel region including peripheral pixels for the each pixel, the peripheral pixels for the each pixel including the each pixel and pixels adjacent to and surrounding the each pixel; a reduced image reflectance component calculating unit that calculates a reflectance component indicating a ratio of brightness between each pixel and the peripheral pixels thereof for the each pixel in the reduced image based on the results of logarithmic operations performed on the peripheral average value and the value of the each pixel in the reduced image; a frequency distribution generating unit that generates a frequency distribution of the frequency of each value of reflectance component calculated by the reduced image reflectance component calculating unit; a representative reflectance component determining unit that determines a representative reflectance component based on the frequency distribution; a normal correcting unit that performs a normal correcting operation for correcting a value of a target pixel in the original image, the normal correcting unit including: a simplified correcting unit that performs a simplified correcting operation for correcting the value of the target pixel in the original image by converting the value of the target pixel to an output value based on the representative reflectance component and the value of the target pixel in the original image.