The Research Of Color Image Digital Watermarking Algorithm Based On Fuzzy Control

With the development of digitize technology and Internet, the spread of digital multi-media information has become more and more convenient, but it also has brought about the crisis of the copyright protection. Digital watermarking which is regarded as an effective method to protect the copyright of digital medium data has caused people great notice and already become international academic circles. For pictures spreading on the network are mostly color pictures, and the color image digital watermarking technology does not get very good popularizing at present, this paper researches and discusses color image digital watermarking technology, and a new color image watermarking method is proposed which makes full use of fuzzy control theory. MATLAB is used to carry out the simulated experiment and test performance of the algorithms. The main important work of this paper includes:(1) The characteristic of the image is analyzed first, then using the fuzziness of the human being definition to image border, vein, and fuzzy control having good control characteristic to complex system which has no way to gain accurate mathematic model, an algorithm based on fuzzy control is proposed, which has been able to control intellectively the strength of embedded watermarking according to the image characteristic. It achieves the watermarking adapting to the image itself entirely and balances the contradiction between invisibility and robustness.(2) A fuzzy adaptive color image watermarking algorithm based on DCT (Discrete Cosine Transform) is proposed. Because the key of the watermarking system is the strength and the position of embedded watermarking, this method adopts YUV color space. By using masking characteristics of human visual system, the watermarking is embedded into DCT middle-low frequency coefficients of color image Y, U, V component intellectively. It achieves the watermarking adapting to the color image itself entirely.(3) A fuzzy adaptive color image watermarking algorithm based on DWT (Discrete Wavelet Transform) is proposed. In view of the characteristics of wavelet, the original color image is decomposed, then the number of significant coefficients is selected according to the size of watermarking signal, at last the watermarking is embedded into DWT significant coefficients of color image Y, U, V component intellectively with the features of human visual system (HVS) taken into account during embedding. It allows embedding more robust watermarking with the prediction of high quality of image.The experiment results show that the watermarking generated with the proposed algorithms is not only invisible and robust , but also has strong robust against various signal processing such as cropping, filtering and noise adding. In a word, the feasibility of color image watermarking approach proposed is illustrated.