Information Hiding And Digital Watermarking Technology Research Based On Image Cover

The paper is devoted to researching information hiding technology and transform domain robust watermarking technology based on image cover. First, the theory of information hiding technology is illustrated, and a method of hiding secret text information based on image LSB is proposed.The method successfully hides the secret text dually and then extracts it without any distortion. Second, the theory of digital watermarking technology is presented, and then the way to reinforce the robustness of transform domain watermarking technology is discussed in detail. Third,the paper researches the watermarking technology based on image discrete cosine transform (DCT), and puts forward to an algorithm for adaptive blind watermarking techenology based on DCT and error correcting coding. Afterward , The influences of parameter a on invisibility and robustness are fully analysed in theory, and the theoretic inferior limit of peak signal-to-noise ratio between watermarked image and original cover image is estimated. Fourth, the paper researches the watermarking techenology based on image discrete wavelet transform (DWT), and puts forward to an algorithm for watermarking techenology based on quantifying low frequency subband coefficients. Afterward ,The influences of quantifying step A on invisibility and robustness are fully illustrated in theory. Finally, the watermarking techenology based on singular value decomposition(SVD) is studied, and an algorithm for spread-spectrum watermarking techenology based on SVD is introduced. The rusults turn out that all watermarking algorithm possess good invisibility, have excellent robustness towards common attacks, realize blind extraction so as to take advantage of practical application , and possess safety.