earticle

영어

Geometric transformations such as rotation or mirroring of JPEG images may result in image quality distortion. Our experiments found further quality degradation of rotated JPEG images as the number of rotations increases. In this paper, we propose a fast and lossless JPEG image transformation in spatial domain based on changes of discrete cosine transform (DCT) coefficient in frequency domain. The key idea of our proposed approach is that permutation and/or sign changes of DCT coefficients in JPEG image results in geometric change without any information loss. Our experiments shows that the proposed transformation algorithm results in no information loss and is faster than conventional methods by 1.67 times on average.