GRADATION CORRECTING APPARATUS, MOBILE TERMINAL DEVICE, IMAGE PICKUP APPARATUS, MOBILE TELEPHONE, GRADATION CORRECTING METHOD, AND PROGRAM

摘要

The present invention relates to a technique for correcting the gradations of digitized images and is used in mobile terminal devices and the like. The conventional image gradation correcting technique, when applied to a backlight correction, had a limit of improving a local contrast in a bright or dark area. According to the present invention, a block timing generating part (102) divides an image into a plurality of blocks; an average brightness calculating part (103) calculates the average brightness level in a block unit as designated by the part (102); a block unit correction amount calculating part (104) calculates the correction direction and correction amount from the average brightness level in the block unit; a pixel unit correction amount calculating part (105) interpolates the correction amount of the block unit into the correction amounts in the respective pixel units in that block; and a gradation converting part (107) uses, as addresses, the correction amounts in the respective pixel units and the brightness data of the corresponding pixels read from a memory (106) to read the ultimate correction amount from a gradation conversion table (108) and perform a gradation conversion.