Study Of Watermarking Strength Based On PSNR

This thesis is concerned with one of the most important branches in information hiding, the digital watermarking technology, with its emphasis on how to estimate the embedding strength according to the PSNR (Peek Signal-to- Noise Ratio) of digital image in DCT transform field. Firstly, it introduces the basic concepts of information hiding and digital watermarking and some typical algorithms, presents the experimental results of these algorithms, and makes analyses and evaluation on it. Secondly, the thesis conducts research on the watermarking strength in a systematic way: since different users under different occasions have their own requirements for the PSNR of the watermarked image, it analyses how to estimate the embedding strength of digital watermarking according to the PSNR of the watermarked digital image so as to exert reasonable control of the watermarking embedding, and presents three formulas of the embedding strength and the experimental results. The experimental results show the three formulas of the embedding strength have minor errors and show their certain veracity. Finally, this thesis discusses the digital image scrambling technology, presents a new scrambling algorithm for the binary image, and presents two digital watermarking embedding strategies. The experimental results show that these two strategies have certain imperceptibility and robustness.