A structural method for quality evaluation of desynchronization attacks in image watermarking

Geometric transformations are known to be one of the most serious threats against any digital watermarking scheme. The goal of this work is to design an objective measurement scheme for geometric distortions in order to investigate the perceptual quality impact of geometric attacks on the watermarked images. The proposed approach is a full-reference image quality metric focusing on the problem of local geometric attacks and it is based on the use of Gabor filters. The novelty of the proposed metric is that it considers both the displacement field describing the distortion and the structure of the image.The experimental results show the good performances of the metric.