Research On Adaptive Image Digital Watermarking Algorithm Based On Contourlet Domain

With the development of the Internet and multimedia technologies,a large number of digital works are being spread on line and off line,so the frequency of infringement events is becoming more and more high.The schemes about protection of digital works are widely needed,and the digital watermarking technology is a kind of scheme to protect the copyright.In order to find the optimization of the fidelity and robustness of watermarking algorithms,the framework of the digital watermarking technology is reviewed firstly in this paper.Secondly the theory of Contourlet transform is introduced detailedly in order to find the suitable embedding positions and embedding strengths in Contourlet domain.Then two digital watermarking algorithms based on Contourlet transform are proposed,through the experiment simulation,the results confirmed that the proposed watermarking algorithms in the aspects of the robustness,fidelity and security have a good performance.The innovations of this paper include these:(1)The basic theories of Contourlet transform have been analysed to research new characteristics of Contourlet transform,which provides the theoretical basis for embedding the watermarking information in Contourlet domain.(2)The adaptive robust digital watermarking algorithm based on the suppositional tree model and FOA-SVR in Contourlet domain is proposed.In order to choose a kind of better embedding positions and strengths of the watermark in Contourlet domain,the defect that the last layer of the low frequency subband of Contourlet transform has not been divided is overcome.Then the construction method of the Contourlet quotiety suppositional tree model is put forward.The watermarking algorithm is proposed by combining the suppositional tree model,Chaos Technology and Support Vector Regression(SVR).And the Fruit Fly Optimization Algorithm(FOA) is utilized to optimize the parameters of SVR.At last, the robustness and fidelity of the watermark are enhanced by selecting the suitable embedding positions and embedding strengths in Contourlet domain.(3)The novel spread spectrum watermarking algorithm based on the fountain code and Human Visual System(HVS) in Contourlet domain is proposed.In order to select the suitable embedding positions and embedding strengths in Contourlet domain better,the visual masking based on HVS and only for Contourlet transform is proposed.We use this visual masking to select the appropriate embedding strengths and embedding positions in Contourlet domain,so the invisibility of the watermarking algorithm is improved.The watermark image is pre-processed by using the fountain code to encode the watermarking image, which increases the security and the decoding rate.The spread spectrum watermarking technology is used to enhance the ability of the watermarking algorithm to resist against common watermarking attacks,which improves the robustness.The experimental results show that the proposed algorithm has higher invisibility and robustness compared with the common watermarking algorithms,and the security is also improved.