A Digital Image Watermarking Algorithm Based on Chaos and Fresnel Transform

In this paper, a digital image watermarking algorithm based on chaos and Fresnel transform is proposed. The original image is transformed into Fresnel diffraction plane by distance parameter, and watermark information is embedded in its amplitude spectrum after scrambled by chaotic sequence. The watermark information can be extracted without original image, and there is little influence on the original image after embedding. Chaotic scrambling can encrypt watermark information, and Fresnel transform can provide different diffraction planes with different parameters, so attackers couldn´t get right watermark information without knowing the parameters in these two processes. During the experiments, the algorithm is also robust against various common attacks, such as filtering, adding noise, JPEG compression and crop and so on. Experimental results show that this watermarking algorithm can provide enough invisibility, security and robustness.