1. An image processing apparatus, which processes an image of a tomogram obtained by capturing an image of an eye to be examined by a tomography apparatus, comprising: a layer candidate detection unit configured to detect layer candidates of a retina of the eye to be examined from the tomogram; an artifact region determination unit configured to determine an artifact region in the tomogram based on image features obtained using the layer candidates; and an image correction unit configured to correct intensities in the artifact region based on a determination result of said artifact region determination unit and image features in the region.