Robust Digital Color Image Watermarking in Hybrid Domain

Digital watermarking techniques have been proposed for copyright protection and authentication of multimedia data. In this paper we are providing one such watermarking scheme for color images.The suggested method presents a watermarking scheme based on a Redundant Discrete Wavelet Transform (RDWT), Discrete Cosine Transform (DCT) and Singular Value Decomposition (SVD) in which two level RDWT is applied on the host image which results in four frequency bands LL2, LH2, HL2 and HH2. As it is found that lower frequency band is less prone to attack, so the singular values of the DCT Transformed coefficients of the LL2 band of the image are being modified using the singular values of the DCT transformed coefficients of the watermark by using scaling factor. Modification of the appropriate sub-band leads to a watermarking scheme which favorably preserves the quality. The experimental performance of the proposed system is analyzed against different types of attacks, the results show that the proposed RDWT-DCT-SVD method provide the improved imperceptibility, robustness under attacks, provide high data capacity and preserve copyrights. The results demonstrated that the proposed method is more robust to various attacks compared to DWT-DCT-SVD based method.