Watermarking and Steganography 1

An invisible robust, non blind watermarking scheme for digital images is presented. The proposed algorithm combines the Discrete Wavelet Transform (DWT) and the Bi-dimensional Empirical Mode Decomposition (BEMD). Unlike previous works where the watermark bits are embedded directly on the wavelet coefficients, the proposed scheme suggests rather the embedding of the wavelet coefficients of the mean trend results by performing the BEMD on the host image, using Singular Value Decomposition (SVD). The watermarked image has a very good perceptual transparency. The extraction algorithm is a non-blind process, which uses the original image as a reference for retrieving the watermark. The proposed algorithm is robust against rotation, translation, compression and noise addition. It has also a superior Peak Signal to Noise Ratio (PSNR) for the watermarked image. The obtained results, tested on different images by various attacks, are satisfactory in terms of imperceptibility and robustness.