Jiafu Wen

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A novel digital watermark against RST distortion based on SURF is proposed. The algorithm is the second watermark, SURF is fast than SIFT, so that the algorithm is faster, and the ability against RST is nearly the same with feature based SIFT. The watermark algorithm use odd-even detector properly to avoid the distortion procedure when watermark is embedded.
0/1 knapsack problem belongs to combination optimization problem. Its optimal solution exists in the problem space including substantially large useless solutions besides optimal solutions. Differing with other SA (simulated annealing) algorithms that getting the approximate optimization solution from the whole problem space often need much computation(More)
In this paper, an efficient and secure encryption scheme for JPEG2000 codestream is proposed. The scheme encrypts each codeblock contribution to a packet (CCP) and does not introduce superfluous JPEG2000 markers in the protected codestream. It achieves full information protection for data confidentiality, and maintains all the advanced features of the(More)
Features extraction is the steganographic images (stego-images) classification detection key. How to extract high susceptibility statistic features to noise jamming is a very important thing. A new effective features extraction method was proposed, aiming at the steganographic model with additive noise being the main focus. With the theoretic and experiment(More)
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