A perceptually optimized watermarking scheme for color visual information

With the growth of unauthorized access in Internet, the study of watermarking scheme for color visual information becomes more important. In this paper, a blind watermarking scheme for color images is proposed in the frequency domain. Through effective exploitation of perceptual redundancy that is estimated by a color visual model, certain of wavelet coefficients in each color channel are separately located for watermark insertion and the maximum strength of watermarks are determined for repeatedly embedding without resulting in perceivable distortion. With different codes being assigned to represent each bit of the binary watermark, the watermark is expected to be more robust. Experimental results show that the watermarked color image using the proposed scheme can achieve high visual quality and robustness in face of various attacks such as cropping, low-pass filtering, scaling, noise addition, JPEG and JPEG2000 compression with high compression ratio