On the use of Schur Decomposition for Copyright Protection of Digital Images

This paper presents a robust image watermarking scheme for copyright protection of digital images. In this work, Schur decomposition of host image is explored for watermarking . Watermark image is embedded in the two decompositions of Schur decomposition. Schur decomposition is computationally faster and robust to image attacks than Singular Value Decomposition (SVD). Watermark image is embedded in the D component using scalar quantization. A copy of the watermark is embedded in the columns of U matrix using comparison of the coefficients with respect to the watermark image. Since same watermark is embedded in both U matrix and D matrix the robustness is improved. The proposed algorithm is more secure and robust to various attacks, viz., JPEG2000 compression, JPEG compression, rotation, scaling, cropping, row-column blanking, row-column copying, salt and pepper noise, filtering and gamma correction. Superior experimental results are observed with the proposed algorithm over a recent scheme proposed by Chung et al. in terms of Normalized Cross correlation (NCC) and Peak Signal to Noise Ratio (PSNR).