AN OPTIMAL WATERMARKING SCHEME BASED ON SINGULAR VALUE DECOMPOSITION

Watermarking, the process of embedding data into a multimedia element, can be used primarily for copyright protection and other purposes. The schemes that have recently been proposed modify the pixel values or transform domain coefficients. The Singular Value Decomposition (SVD) is a practical numerical tool with applications in a number of signal processing fields including image compression. In an SVD-based watermarking scheme, the singular values of the cover image are modified to embed the watermark data. We propose an optimal SVD-based watermarking scheme that embeds the watermark twice. In the first layer, the cover image is divided into smaller blocks and a piece of the watermark is embedded in each block. In the second layer, the cover image is used as a single block to embed the whole watermark. Layer 1 allows flexibility in data capacity, and Layer 2 provides additional robustness to attacks.