Autocorrelation Function Based Watermarking with Side Information

In this paper, we propose an improved autocorrelation function (ACF) based watermarking. The autocorrelation function based watermarking,has been known to be one of the effective watermarking schemes that are resilient to geometric transform attacks. In this watermarking scheme, both the peaks in the autocorrelation function of a marked image and the embedded watermark should survive after various attacks. Generally, the autocorrelation peaks are less robust than the actual watermark signal. The main focus of this paper is the improvement of the robustness of the peaks in an autocorrelation function. Since an original image and the detector structure are available at the embedding time, instead of simple addition of a watermark to an image, the watermark embedder analyzes the original image and uses this information actively during the embedding process so that the marked image has higher periodic autocorrelation peaks. The proposed watermarking scheme has higher robustness than a conventional ACF based watermarking against geometric attacks that are combined with removal attacks.