1. An image processing apparatus configured to correct at least part of a face image, comprising: an image acquisition unit that acquires an input image; a region extraction unit that extracts a pupil region, which is a region corresponding to an eye of a person, from the input image; a pixel extraction unit that extracts a pixel from the pupil region whose brightness value is higher than a threshold value; a determination unit that determines, based on the result of extraction performed by the pixel extraction unit, whether or not halation has occurred in the pupil region; and a correction unit that performs, based on the result of determination performed by the determination unit, processing for correcting halation on the pupil region, wherein the pixel extraction unit sets the threshold value based on a bias of a brightness distribution of the pixels included in the pupil region.