1. An image processing apparatus to perform an enlarging process for an original color image data, comprising: a target color selecting unit that selects two target colors C 1 and C 2 for each local region of a plurality of local regions of the original color image data, the local region being a 2×2 pixel block having four pixel locations, the target color C 1 being a pixel color of a first single pixel in the local region, each first single pixel of each local region being in a same first pixel location, and the target color C 2 being a pixel color of a second single pixel in the local region, each second single pixel of each local region being in a same second pixel location, the first and second pixel locations being different, so that the two target colors C 1 and C 2 are selected from the first and second single pixel locations, respectively, and the target color selecting unit does not select, for each local region, colors from any other pixel location than the first and second pixel locations; a sorting unit that categorizes the local region based on a layout of the target colors selected by the target color selecting unit; a processing unit that determines pixel values after enlargement from the target colors C 1 and C 2 in accordance with a result of the categorizing performed by the sorting unit; an enhancing unit that performs at least one of an antialiasing process and an antialiasing-enlarging process as an image quality improving process for the original color image data; and a controller for controlling the processing of the target color selecting unit, the sorting unit, the processing unit and the enhancing unit, wherein the target color selecting unit selects the two target colors C 1 and C 2 for each local region independently of selecting two target colors C 1 and C 2 for any of the remaining local region or regions, and the original color image data is formed of image pixels, the image pixels containing more than two different colors.