An image processing system comprising an image data acquisition unit for acquiring captured image data, with a first image processing unit for performing first image processing relating to color correction and gradation correction on the image data, a second image processing unit for performing second image processing relating to color correction based on a Color Appearance Model on the image data, a parameter calculation unit for calculating an image processing parameter used in the first image processing from the image data before the second image processing and the image data after the second image processing, and a control unit for setting the image processing parameter to the first image processing unit.