SIFT based geometric distortion correction method

It is very important to cope with geometric distortions especially for robust watermarking systems since these attacks break the synchronization between the watermark and detector. In general, robustness to geometric attacks is considered as a different concept as rotation, scale and translation (RST) invariant watermarking. However, it is inseparable part of a copyright protection system. There are different approaches to overcome this problem. Most of them are good in individual rotation, scaling and translation attacks but it is not the case for combination of them. In this paper, we propose and discuss the performance of a scale invariant feature transform (SIFT) based geometric distortion correction method against rotation, scaling, translation, cropping, flipping and so on. As it restores the approximate original, it can be used in watermarking as a synchronization step.