Image Digital Watermarking Based On Redundant Wavelet Transform And Ica

Digital watermarking technology is an effective method that protects the copyright of the digital products and ensures data security, and it is an important branch of information hide technology. Digital watermarking technology, which embeds special information into digital media, is a new method for copyright protection. With the help of digital watermarking, we can prove the originator's owner to digital media that he creates, and the watermark can be the proof of authentication and prosecuting illegal copyright infringing. Usually, a watermarking algorithm contains three parts:the design of watermark, the process of embedding and detection watermark. Wavelet-based blind image watermarking is discussed in detail in this paper. We proposed two self adaptability image watermarking algorithms based on wavelet transform and Independent component analysis. The essential contents can be listed as follows:1. The basic theory of redundant discrete wavelet transform (RDWT) and independent component analysis (ICA) is studied, and the basic flow of watermark based on RDWT and ICA is given. The flow effectively combines the features of RDWT and ICA in the process of watermarking. As a result the RDWT and ICA based watermarking has following features.1) The method's robust feature is improved by RDWT's redundancy.2) The method is of excellent invisibility.3) The shift-invariable trait of RDWT enhances the embedding capacity.4) The blind source separate characteristic of ICA ensures that the wartermark can be extracted effectively.2. The method of constructing the vector of observed signals which is used in the ICA based watermark extraction is given. This method first create a key matrix which is as large as the carrier image, then construct a encoded carrier image which is linear mixture of the key matrix and the carrier image. Finally, the ICA based blind watermark extraction is realized by the vector of observed signals which are composed of the key matrix, the encoded carrier image and the embedded watermark image.3. A new self adaptive image watermarking algorithm which based on redundant wavelet transform is presented. This algorithm combines the technology of RDWT and ICA, which makes full use of the RDWT characteristics whose redundancy and shift invariable to enhance the robusticity and capacity of watermarking method. Simultaneity, this method possesses the blind source separate trait of ICA, which can keep the balance of robustness, transparence and capacity. Experimental results show that the algorithm is not only invisible but also large in capacity. At the same time it is more robust to many attacks like adding noise, cutting down, filtering, rotation, JPEG and JPEG2000 compression, etc.4. A novel image watermarking algorithm based on wavelet packets transform is devised which extracts watermark without original image. The algorithm can analyze the carrier image more precisely by the RDWT packets transform, and increase the selection of watermark embedded areas. The algorithm's embedded capacity is greater because of RDWT, and the robusticity is enhanced because of wavelet packets transform, and the balance between robusticity and invisible is well resolved because of combination of human visual system traits and ICA method. The experimental results show that this novel watermarking algorithm can resist many attacks effectively, and be of nice application foreground in the field of copyright protection.