IMAGE PROCESSING APPARATUS CONFIGURED TO SHARPEN IMAGE HAVING COMPLEX BLUR, IMAGE CAPTURING APPARATUS, IMAGE PROCESSING METHOD AND STORAGE MEDIUM STORING IMAGE PROCESSING PROGRAM

The image processing apparatus is configured to perform image processing on an input image produced by image capturing through an optical system. The apparatus includes a first distribution producer configured to produce a first distribution by using data for approximating a point spread function that corresponds to a condition relating to the image capturing, a second distribution producer configured to produce a second distribution by mirroring a part of the first distribution, a filter producer configured to produce, by using the second distribution, a first filter to be used for a sharpening process, and a processor configured to perform the sharpening process on the input image by using the first filter to produce a sharpened image.