Robust Watermarking in Singular Values ofContourlet Coefficients

To protect copyright of digital images, manywatermarking algorithms have been proposed in recent years.These methods are divided into two groups of spatial and frequencydomains. Robustness of a watermark against signal processingmodifications is important and most of the existing methods try toaddress this issue. In this paper a Contourlet based imagewatermarking algorithm is proposed which embeds a watermark inthe singular values of the Contourlet transform of an image.Watermarking is done in three scales of Contourlet transform.Redundant embedding of the watermark in different scales causeshigher robustness of the proposed method. In the extraction phase,the final watermark is derived by voting amongst the three extractedwatermarks. The experimental results and comparison with theother Contourlet based method shows that the proposed method hasbetter robustness against some of the usual image processingattacks, such as JPEG compression, Salt and Pepper, and Gaussiannoise.