Human Visual System Based Watermarking for Color Images

In this paper, a human visual system (HVS) based water-marking scheme for color images is proposed in order to achieve robustness and transparency. A new just noticeable distortion (JND) estimator for color images is first designed in the wavelet domain. The key issue of the JND estimator is to integrate visual properties. The estimator is an extension to the perceptual model that is used in image coding for grayscale images. In a locally adaptive fashion based on the wavelet decomposition, the estimator applies to all subbands of luminance and chrominance components of color images and is used to measure the visibility of wavelet quantization errors. The subband JND profiles are effectively incorporated into a color image watermarking scheme. Performance in terms of robustness and transparency of the watermarking scheme is obtained by embedding the maximum strength watermark while maintaining the perceptually lossless quality of the watermarked color image. Simulation results show that the proposed scheme of inserting watermarks into luminance and chrominance components is robust and transparent.