DC Coefficients Based Watermarking Technique for color Images Using Singular Value Decomposition
Arunkumar Thangavelu · 2011
As DC coefficients are perceptually most significant and more robust to many unintentional attacks (signal processing) and intentional attacks (unauthorized removal), in this paper we proposed a robust non-blind watermarking algorithm based on DC coefficients for color images. DC coefficients are obtained by applying discrete wavelet transformation technique (DWT) followed by block based Discrete Cosine Transformation (DCT) technique. The RGB color spaces of the cover image are decomposed into different frequency bands using wavelet decomposition and block based DCT is applied. DC matrix is SVD decomposed to obtain singular values in which watermark is to be hidden. The proposed algorithm increases the watermarking capacity of cover data watermark and provides robustness against many signal processing operations and intentional attacks. The quality of the extracted watermark from green and blue color spaces is very good. The measured psnr and NC values are tabulated.