Chaos-based gray image watermarking algorithm

In this paper, a kind of gray image digital watermarking algorithm is put forward. And this algorithm is to use the technology of combining discrete wavelet transform and discrete cosine transform with singular value decomposition based on chaos, and scrambling for the purpose of raising security, invisibility and robustness of watermark. It hided the digital watermarking in the discrete cosine transform domain. The image that contained the watermark was restored and the watermark was extracted by the singular value decomposition. The conclusions demonstrate that the watermark not only has good invisibility by use of this algorithm but also has good robustness against geometric distortion, noise attack and so on.