Patent ID: 7386185
Filing Date: 2008-06-10
Classification: G06T,H04N

Abstract:
1. An image processing apparatus comprising: a contrast improvement unit operable to perform a contrast improvement process on an input image by comparing an object pixel of the input image with pixels that belong to surrounding areas of the object pixel, the contrast improvement unit comprising a correction data calculation unit operable to find a contrast improvement amount for a pixel in the input image, an extraction unit operable to extract an effective range from distribution of the contrast improvement amount, and a pixel value conversion unit operable to convert a contrast improvement amount of the object pixel to a value of a corresponding pixel in the enhanced image according to the extracted range; an image combination unit operable to combine an enhanced image obtained by the contrast improvement unit and the input image; and an image output unit operable to output the image after combination, wherein the pixel value conversion unit comprises a standard intensity calculation unit operable to calculate a standard intensity value that indicates contrast intensity of the input image, a conversion curve estimation unit operable to estimate a conversion curve for converting the contrast improvement amount to a value in the enhanced image based on the standard intensity value, and a pixel value estimation unit operable to use the conversion curve to convert the contrast improvement amount to a value in the enhanced image, and wherein the conversion curve estimation unit comprises an initial candidate setting unit operable to set an initial population of search vectors that indicate conversion curves, a pixel value conversion candidate calculation unit operable to find a conversion value in a candidate for an enhanced image from the contrast improvement amount using a conversion curve candidate corresponding to each search vector, an evaluation value calculation unit operable to use the standard intensity value and the conversion value to calculate an evaluation value for evaluating the candidates of each conversion curve, a fitness calculation unit operable to calculate fitness of a candidate of each conversion curve based on the evaluation value, a recombination operation unit operable to perform recombination operation on a search vector selected based on the fitness of the candidates of each conversion curve and generate a next generation population, and an estimation end judgment unit operable to determine whether or not estimation of the conversion curve ends at a current generation.