Color image watermarking based on a color visual model

Abstract

To locate the right places for embedding watermark signals, and to set the proper strength of the embedded watermark signal is a critical problem for obtaining a robust and transparent watermark in color images. In this paper, a color visual model and the associated watermarking scheme are proposed for solving this problem. The visual model can estimate the profile of error visibility thresholds for each wavelet subband in each color channel of the host image, by which groups of perceptually significant wavelet coefficients are located for watermark embedding and the quantizer step sizes for quantization index modulation can be appropriately determined. Simulation results show that robust watermarks can be attained while retaining high image quality.