Patent US 5,973,804

A color image processing apparatus which processes an original image data line-by-line. The color image processing apparatus includes a detector for detecting a portion in a line where an original image exists. In accordance with an output of the detector, a line-by-line determination is made as to whether the original image is a color image or a monochromatic image. The apparatus further includes a processor for processing the image of the original image in accordance with the result of the determination.