An image processing system performs image processing on images including overlapping image regions as overlapping regions. The system includes a calculator configured to calculate an evaluation value for evaluating each image using pixel values of pixels in each overlapping region; a determination controller configured to determine, based on the calculated evaluation values, whether there is an image to be corrected in the images; an image determiner configured to, when there is the image to be corrected, determine a correction reference image as a reference, out of the images, based on the evaluation values; and an image corrector configured to correct the image to be corrected based on the correction reference image.