Patent ID: 8687237

Claim:
An image processing apparatus comprising: a characteristic value calculator that calculates characteristic values of a preset area, which has been set around a pixel of interest, on the basis of conditions, each of the conditions being set by using a combination of pixel values of a plurality of color planes of each pixel contained in the preset area; a trapping determining unit that determines, for each of the plurality of color planes of an N-valued image which has been subjected to halftone processing, on the basis of the characteristic values of the preset area calculated by the characteristic value calculator, whether the pixel of interest is to be subjected to trapping processing; a pixel value calculator that sets, for each of the plurality of color planes, in a reference area used for analyzing a regularity structure of the N-valued image, a position of a reference pixel which is to be referred to when changing a pixel value of the pixel of interest, and that calculates a pixel value for changing the pixel value of the pixel of interest on the basis of a pixel value of each of the plurality of color planes at the position of the reference pixel and compares a number of reference pixels that are â€œonâ€ with a predetermined threshold; and a pixel-of-interest value changing unit that changes the pixel value of the pixel of interest positioned in the N-valued image into the calculated pixel value when the trapping determining unit determines that the pixel of interest is to be subjected to trapping processing.