Halftone Image Watemarking

In this paper, we present a new and simple watermarking algorithm for halftone images. The method is based on the principle of error diffusion techniques for halftoning in order to embed a watermark to by creating a second image (a key type) from the halftone one. The security of this algorithm is guaranteed by the key which is image dependent and contains the secret information. In addition embedding is carried out so that the human eyes can not distinguish the difference between this key and the original image. Experimental results under different attacks have been carried out to demonstrate that the proposed algorithm performs efficiently in terms of robustness, capacity and imperceptibility. Results have shown that one can embed maximum bits as 100% with good quality watermarked images which are robust to geometry transform and cropping attacks.