Performance Analysis of Color Image Watermarking Schemes Using Perceptually Redundant Signal Spaces

In this paper, the performance analysis of color image watermarking schemes employing perceptually redundant signal spaces is undertaken. A watermarking scheme that searches for perceptually redundant signal space for embedding transparent watermarks in color images is presented. The search is performed in the wavelet domain of the host color image. A color visual model based on the uniform color metric of the CIEDE2000 color difference equation is used to measure the perceptual redundancy inherent in each wavelet coefficient of various color spaces. Binary watermark signals are repeatedly embedded in qualified wavelet coefficients by the way of quantization index modulation. The watermarking schemes using the uniform and non-uniform color spaces for hiding watermarks are conducted to compare the robustness of the embedded watermark. Experimental results of the analysis show that the non-uniform color space can provide a certain part of color signals a large amount of perceptual redundancy for hiding high-strength watermark signals. The watermark embedded in the non-uniform space is always robust than that embedded in the uniform space.