IMAGE PROCESSING METHOD, IMAGE PROCESSING APPARATUS, IMAGE PICKUP APPARATUS, AND NON-TRANSITORY COMPUTER-READABLE STORAGE MEDIUM

An image processing method of performing an image restoration processing of an image, includes the steps of generating a plurality of first optical transfer functions depending on a position of the image using coefficient data depending on an image pickup condition of the image, generating a plurality of second optical transfer functions by rotating the first optical transfer functions around a center of the image or around an optical axis of an image pickup optical system, generating an image restoration filter based on the first optical transfer functions and the second optical transfer functions, and performing the image restoration processing of the image using the image restoration filter.