Patent ID: 7418126

Claim:
An image distortion correcting apparatus comprising: an image input section to input an input image of a flat rectangular paper surface, generated by an imaging section; an imaging position estimating section to estimate an imaging position of the imaging section with respect to the flat rectangular paper surface from four image vertexes of the flat rectangular paper surface within the input image using relationships between the four image vertexes of the flat rectangular paper surface, and assuming that one of the four image vertexes is in a same plane as a projection of the imaging position on the flat rectangular paper surface; a rectangular paper surface estimating section to estimate four vertexes of the flat rectangular paper surface within a three-dimensional space based on the imaging position and the four image vertexes; and an image correcting section to correct a perspective transformation distortion of the input image based on the imaging position and the four vertexes within the three-dimensional space, and to output a corrected output image.