Complex-log mapping approach to rotation and enlargement or reduction of digital images and its performance evaluation

A novel technique to rotate and enlarge or reduce digital images is proposed. The complex-log mapping plays an important role in the proposed method. In the complex-log mapping, the original images are mapped from the orthogonal coordinate system to the polar coordinate system. The rotation and enlargement or reduction of original images is achieved by simple shifts of the mapped images. And the objective images are obtained by the inverse complex-log mapping. Because the mapping process depends only on the size of images, mapping tables can be calculated previously. By using these tables, the mapping is achieved by simple substitution of data. So, the proposed method offers the fast image processing technique. The processing samples are included.