A Robust Image Watermarking Algorithm Based on Non-uniform Rectangular Partition and DCT-SVD

When embedding the watermark information into DC coefficient of each 8×8 DCT block of the host image, it is more likely to obtain a stronger anti-attack function against JPEG-compression attack. However, embedding the watermark with the same intensity into them may distort the watermarked image to a large extent. To solve this problem, a novel robust image-watermark algorithm is proposed with the characteristics of selective embedding intensity based on the non-uniform partition. In the meanwhile, Arnold Scrambling Algorithm is applied before the watermark is embedded to increase the security of the algorithm. The SVD values of the scrambled watermark will be embedded into the DC coefficient of each 8×8 DCT block of the host image in order and repeatedly and this may enhance the various anti-attack ability of the whole algorithm. The experimental results have showed that this algorithm is robust against cropping attack, filtering attack and noising attack, especially the JPEG-compression attack and no obvious distortion appeared in the watermarked image.