IMAGE PROCESSING APPARATUS AND METHOD, AND STORAGE MEDIUM CAPABLE OF BEING READ BY A COMPUTER

First image data and second image data different from the first image data are input in an image processing apparatus/method. At least one of the first image data and the second image data is encoded while being subjected to orthogonal transformation processing. The first image data and the second image data are transformed into first and second orthogonal transformation coefficient data, and the first and second orthogonal transformation coefficient data are synthesized. A recording medium capable of being read by a computer stores an image processing program for the image processing method.