Patent US 7,362,896

When performing predetermined color correction/modification processing on RGB image data including red, green and blue color components so as to perform hue correction thereon, a frequency distribution of respective tone values is obtained for at least one of these red, green and blue color components of the RGB image data; it is determined from the frequency distribution whether or not the RGB image data has already undergone tone transformation; and the predetermined color correction/modification processing is performed on the RGB image data so as to perform the hue correction thereon only when it is determined that the RGB image data has not undergone tone transformation yet.