Watermarking in binary document images using fractal codes

• This paper presents a novel watermarking method based on fractal theory.
• Information is embedded into binary document host images.
• Watermarked image quality is not only acceptable to human eyes, but it is robust to the common attacks.

This paper presents a novel watermarking method based on fractal theory. In the proposed method, information is embedded into binary document images. First, host image is coded by the proposed fractal coding method which is designed particularly for binary images. To insert the watermark uniformly over the entire host image, specific Range segments with predefined conditions are selected. Then, the watermark is added to the number of ones in the fractal code of the selected Range segments. Finally, the watermarked image is obtained by the fractal decoding procedure. Experimental results show that the output image quality of the proposed methods is acceptable to human eyes. Furthermore, empirical results show that the proposed fractal based watermarking is robust to the common attacks.