A color image watermarking scheme based on secret sharing and wavelet transform

This paper proposed a novel copyright protection scheme for color images using image secret sharing, Just-Noticeable-Distortion (JND) model and wavelet transform. The scheme contains two phases: the watermark embedding phase and the watermark extracting phase. In the watermark embedding phase, the color space of the color host image is first converted from RGB to YCbCr. Then a special sampling plane is created from the YCbCr color space. Next, the discrete wavelet transform is used to extract the features from the sampling plane. Then, a principal share image is generated according to the features and the watermark. Finally, the JND value and the discrete wavelet transform are used to embed the principal share image in the color host image to generate the watermarked image. In the watermark extracting phase, the principal share image is first retrieved from the suspect image. Then, an expanded watermark is reconstructed using the features of the suspect image and the retrieved principal share image. Finally, the recovered watermark is obtained after the reduction of the expanded watermark. The recovered watermark is then verified against the original watermark to examine the copyright. The experimental results show that the proposed scheme can resist several attacks such as cropping, blurring, sharpening, scaling, JPEG compression, brightness adjustment, and contrast adjustment.