Theory of distortion correction for scanner image of twisted plane object

The image of plane object that is obtained by scanner in situations that it is twisted to curved surface will be companioned with complicated distortions, which can be classified as gray distortion, projection distortion and imaging distortion. By theoretical analysis, the digital correction methods of projection distortion and imaging distortion are presented for twodimensional curved surface distortion model. The practical method of digital correction of gray distortion is also presented. 