An image processing unit of the present invention receives a first image, performs weighted addition on color information in the first image to generate a color component different from that of the color information in the first image, and outputs the generated color component as a second image. The first image is expressed in a plurality of color components and comprises a plurality of pixels each having color information corresponding to one of the color components. At least nine coefficient patterns consisting of values of not less than zero are prepared, and any one of the coefficient patterns is used for weighted addition. This allows an improvement in image quality with high precision.