A novel digital watermark algorithm based on chaos, image iteration and wavelet transform

In order to enhance robustness and security of the embedded watermark, a novel digital watermark algorithm based on chaos, image iteration and wavelet transform is proposed in this paper. Firstly, we obtain a watermark carrier of original image's low-frequency smooth part by a wavelet multilevel decomposition of original image. Then, we iterate this carrier with watermark to generate a sub-image. Finally, we reconstruct the sub-image and other part images, which are decomposed by wavelet transform. By this means, an image embedded a watermark is obtained. Sensitivity to the initial condition of chaotic system ensures watermark's security, meanwhile, watermark iterated at low-frequency part of original image also guarantee watermark's robustness. At last, the simulation results have certified rationality of this scheme.