Patent ID: 7268803

Claim:
An image processing method for correcting an image distortion caused by an oblique image pickup, comprising: moving a single image pickup device to at least two different positions so as to obtain a plurality of images of an object on an object plane, the plurality of images including at least two partially overlapping images, the at least two partially overlapping images sharing a common location on the object plane; determining a feature point of a first image of the at least two partially overlapping images corresponding to the common location and a matched point of a second image of the at least two partially overlapping images corresponding to the feature point of the first image; calculating a set of parameters based on the feature point and the matched point, the set of parameters including a unit vector indicating a direction of the object plane, an attitude value indicative of the attitude of the image pickup device at a viewpoint when taking the first image relative to that at a viewpoint when taking the second image, and a unit translation vector of the image pickup device from the viewpoint when taking the first image to the viewpoint when taking the second image; and generating a distortion-corrected image on a projection surface based on the set of parameters calculated in the calculating step, the distortion-corrected image appearing as if the distortion-corrected image was taken from a viewpoint perpendicular to the object plane, by projecting at least one of the at least two partially overlapping images onto the projection surface based on the direction of the object plane through a perspective projection.