A Digital Watermarking Algorithm Based On JPEG And HVS

During the last decade, access to multimedia data has become much easier due to the rapid growth of the Internet and wide applications of computer. This also makes unauthorized copying and distributing of multimedia data much easier, therefore a new challenge in the field of copyright protection is presented. As an effective way of copyright protection, digital watermarking has been proposed and developed quickly.With the rapid growth of computer network, transmission of digital productions is faster and faster. Furthermore, most of them are transmitted by compression. It is urgent that how to assure the digital watermarking not to be erased in transmission. We propose a new watermarking algorithm based on JPEG compression, together with the characteristic of the human visual system. Unlike existing watermarking algorithms of the space domain or the transform domain, we embed the watermark into JPEG compression domain. JPEG has been one of the most popular compression standards of digital image. It is ensured that the watermarking algorithm is very robust against image compression, especially JPEG compression. In order to improve the robustness, we propose a new method of double bits. By corresponding experiments, we determine the embedded intensity of the watermarking, and choose the threshold value of extraction, and obtain the highest information ratio in the case of holding quality of the image. The experimental results and analysis show that the new watermarking algorithm and the method of double bits are feasible and superior. The proposed watermarking scheme is very robust against cutting, filtering, noise and compression, especially JPEG compression.