Generating color difference image data on the basis of the input image information, in the determination target image comprised of color-difference image data, determines whether the isolated region of the evaluation results has characteristic color of the predetermined respect object.
Generating color difference image data on the basis of the input image information, in the determination target image comprised of color-difference image information, and sets a determination target region for determining an object, the periphery of the determination target region and the determination target region based on each of the color difference image data of a plurality of peripheral regions set, calculates the color difference average values of the respective regions, color information indicating a color difference average value in the determination target region has characteristic color of the predetermined respect object evaluates whether the information, based on the difference between the color difference average value of the color difference average value and the peripheral region in the determination target region, and the determination target region and the peripheral region to assess whether the isolated region, characteristic color based on the information in which whether the evaluation results of and whether it is isolated region of the evaluation results, the determination target area determined whether including the object.