A sequential multiple watermarks embedding technique
In this paper, we propose a novel multiple watermarks embedding scheme. We assume M watermarks have already embedded in the image using M sets of secret key. With the availability of these M sets secret key, another N watermarks can be embedded using the proposed technique while the energies of the watermarks are minimized. And the watermarks embedded later will not interfere with the first M watermarks. Experimental results show watermarked images have good visual quality and the watermarks are robust to JPEG compression and noise attacks.