Method of image watermarking by dividing watermark into two chrominance channels

In this paper, we consider the digital watermarking based on the modulation of image pixels in YCbCr color space, and propose a method to improve its performance. Basically, we divide the watermark into two parts, and embed each part into each chrominance channel. Based on this concept, in the watermark extraction process, we can reduce the number of the watermarked pixels used in the original pixel prediction process by half. Set of experiment were carried out to verify our concept. The results show that the accuracy of the extracted watermark in term of NC is significantly improved compared to the previous methods. The improved robustness of the embedded watermark against different types of attacks at various strengths is also illustrated and compared.