Robust watermarking for text images based on Arnold Scrambling and DWT-DFT

With the rapid development of computer technology and Internet technology, it is easier to transmit, copy and distribute the digital text, and at the same time it faces the problem of transmitting illegally. Digital watermarking based on text document can protect copyright of digital products and prohibit piracy. According to 0/1 watermarking sequence and the synonymy substitution evaluation model, the watermark is selectively embedded in the original text. The majority voting rule improves the watermarking robustness and reduces the probability of false positives. Based on the studies of the document digital watermarking methods and techniques, this dissertation presents that the problems of existed documents watermarking algorithms can be solved by Arnold Scrambling and DWT-DFT technique. Theoretical analysis and experimental results show that the proposed scheme can improve the robustness and invisibility of watermarking.