1. An image processing apparatus for extracting a color feature of an image from digital image data of the image, comprising: a color transformation controller for transforming an input image data of each pixel expressed by RGB values into HLS values through an HLS transformation; a hue correction controller for correcting a hue value of the image data transformed into the HLS values by the color transformation controller so that a region between a green color and a yellow color in a direction of hue and a region between the green color and a light blue color in the direction of hue are narrowed and a region between a red color and the yellow color in the direction of hue is widened in an HLS color space represented by the HLS values; and an extraction controller for extracting color feature information of the image on the basis of the hue value of the image data corrected by the hue correction controller.