IMAGE PROCESSING APPARATUS

A system for performing gain correction of the image of an object obtained by image capture. A first white image is obtained by image capture at a first time with no object present, and a second white image is obtained by image capture at a second time later than the first image, with no object present. The first and second white images are then compared to determine if they meet predetermined criteria. If the predetermined criteria is met, a third white image is provided based on the comparison of the first and second white images, and the image of the object obtained by image capture is gain corrected based on the third white image.