In image processing method and apparatus of the present invention, image distortions caused by oblique imaging are corrected. A feature point of one of a plurality of partially overlapping images corresponding to a common location of an original image, shared by the plurality of partially overlapping images, is determined. A matched point of one of the other partially overlapping images corresponding to the feature point is determined so that a direction of the object plane is calculated based on the feature point and the matched point. One of the plurality of partially overlapping images is selected as a standard image whose image distortions are to be corrected. A distortion-corrected image is generated on a projection plane by projecting the standard image onto the projection plane based on the direction of the object plane such that image distortions in the standard image are eliminated.