Elevating watermark robustness by data diffusion in Contourlet coefficients

As concerns about copyright protection increased amongst multimedia owners in recent years, many watermarking algorithms proposed to protect copyright of digital images. These methods are either spatial or frequency domain techniques. It is essential for a watermarking method to have acceptable robustness. That is why many existing methods try to improve their robustness against signal processing modifications. In this paper a block based watermarking scheme is proposed that embeds a binary logo into Contourlet coefficients of image. To increase robustness, embedding is done in two scales and watermark is inserted into DCT coefficients of Contourlet blocks to diffuse the effects of the embedding throughout the coefficients. Experimental results, and comparison with a robust Contourlet domain method, show that the proposed scheme has better robustness against some image processing attacks, while improving fidelity. Furthermore the proposed algorithm has the advantage of having a blind extraction phase.