A Semi-fragile Watermarking algorithm against rotation based on fractal compression and differentials record theory

Semi-Fragile Watermarking could provide an effective solution for both the authentication of image content and the detection of any changes in image. This article puts forward an algorithm of restorable and robust against rotation of semi-fragile Watermarking based on fractal compression and differentials record theory. Three components (R, G, B) of a colorful image are processed respectively by fractal compression. In view of cone cells of vision have some differences in sensitivity to color, the compressed data have been stored in B component to restore the colorful image and the R component and G component have been processed with differentials record theory for the detection of any changes in image. Binary image have been concealed in B component in order to resist rotation. The presentation of modification precisely approaches pixel-level with the help of the algorithm, and the results of tests have proved a good restorability of this algorithm.