1. An image processing apparatus comprising: an acquisition unit configured to acquire information for identifying a position of a plane in a captured image, the captured image including a structure composed of a plurality of planes as an object; a determination unit configured to determine a correspondence relationship between a region corresponding to the plane in the captured image and a region in an overhead image to be created, according to the information acquired by the acquisition unit; and a generation unit configured to correct an image of the region corresponding to the plane in the captured image so that the corrected image corresponds to the region in the overhead image to be created, according to the correspondence relationship determined by the determination unit, and generate an overhead image composed of a plurality of corrected images that are combined with each other.