New hybrid additive-multiplicative watermarking with better tradeoff between image quality and detection accuracy

An important issue of robust watermarking for image is to achieve a better tradeoff between quality of watermarked image and accuracy of watermark detection. In this paper, we present a hybrid method of two basic embedding schemes, additive and multiplicative schemes, which embeds a watermark by both rules so that the degradation of image quality caused by one embedding is decreased by the other. Thus, the proposed hybrid method allows us to have a larger watermark strength while keeping the image quality high. A larger watermark strength improves the accuracy of watermark detection. We experimentally confirmed that the optimum detection scheme for the proposed hybrid scheme shows a better performance than both additive and multiplicative ones in the DWT domain.