Print and scan resistant watermarking scheme for colour images

Abstract

For digital images, many watermarking schemes regarding copyright issue have been proposed. However, there exist many attacks trying to break or remove the embedded watermark. Therefore, the embedded watermark should be robust against all kinds of attacks. Among various attacks, the print and scan (PS) attack is a challenging one because it not only alters the pixel values but also changes the positions of original pixels. Most of the existing watermarking systems would fail under such an attack. In this paper, a watermarking system operating in the discrete cosine transform domain is proposed for colour images. By efficiently integrating the three components, red, green and blue, the proposed system exhibits superior robustness against various attacks, including the PS attack. According to the simulation results, the system maintains an acceptable image quality while providing outstanding robustness against the PS attack.