Study on the failure of SVD-based watermarking schemes for copyright protection applications

In recent years, some methods have been proposed for watermarking of digital images based on singular value decomposition (SVD) scheme, however they ignored the failure of this scheme for extracting the embedded true watermark. Indeed, the extracted watermark is not the embedded watermark but the key matrices. The key matrices are the pair of orthogonal matrices obtained during the SVD of the watermark. Our observation shows that the singular values of most images used for watermarking, nevertheless using image blocks or whole image data, a a re highly correlated. Using these correlated values to embed the reference watermark into a host image results that during the watermark detection step, the extracted watermark will be the one which its key matrices;is employed in the detector. So, any watermark call be detected form any watermarked image. In this paper, we study this failure in details and demonstrate the e\Perimental results to support our conclusion.