Patent ID: 8049908

Claim:
An image processing apparatus, comprising: a color processing unit configured to perform color image forming processing for a multi-color color original document made of more than one color; a first monochrome processing unit configured to perform monochrome image forming processing for a monochromatic color original document made of a single color and comprising, a base removing processing portion configured to output base-removed-RGB signals by removing a base of RGB signals of image data of the monochromatic color original document, a hue determination processing portion configured to determine whether the hue of each pixel is chromatic or black or white based on the RGB signals, a background color specifying portion configured to determine whether the color of each pixel is a background color or not by using the hue determination result of each pixel, and a monochrome signal generation processing portion configured to generate and output a monochrome signal by using the RGB signals, the base-removed-RGB signals, hue determination results, and background color determination results, the monochrome signal generation processing portion is further configured to generate the monochrome signal about a pixel of interest by using the base-removed-RGB signals when a color of the pixel of interest is chromatic and the background color and to generate the monochrome signal about the pixel of interest by using the RGB signals when the color of the pixel of interest is chromatic and not the background color; a second monochrome processing unit configured to perform monochrome image forming processing different from the monochrome image forming processing by the first monochrome processing unit for a monochrome original document; and a selection unit configured to enable appropriate selective use of the color processing unit, the first monochrome processing unit, and the second monochrome processing unit for each original document.