A robust watermarking scheme based on informed coding and informed embedding
A watermarking algorithm that relies on informed coding and informed embedding is presented. This method embeds one bit of the watermark in every image block, but offers higher watermarked image quality as well as higher robustness to image processing operation attacks than other known methods using informed coding and informed embedding. The method is shown to withstand high values of added Gaussian noise, valumetric scaling, low-pass filtering as well as lossy JPEG compression. Each bit (0 or 1) to be embedded is represented by a subset of codewords. For every image block, a vector is extracted. This vector is modified so that its correlation with the codewords related to the bit to be embedded in it has higher probability than those of the codewords representing the other bit even if the image is later modified by image processing operations. The vector modification is also carried so that the change in the image fidelity is minimal.