GRADATION CONVERTING DEVICE, GRADATION CONVERTING METHOD, AND COMPUTER PROGRAM

摘要

A gradation converting apparatus, a method thereof and a computer program are provided to perform the gradation conversion without using a line memory, thereby miniaturizing the apparatus and reducing the cost. A dither unit(51) adds the random noise to a pixel value forming an image to perform the dither. An one dimensional gradation converting unit(52) performs the one dimensional gradation modulation in the image in which the dither is performed. The dither unit comprises an HPF(High Pass Filter) for filtering a signal to filter the random noise and adds the high frequency component of the random noise to the pixel value.