Dissertation > Industrial Technology > Automation technology,computer technology > Computing technology,computer technology > General issues > Security and confidentiality > Encryption and decryption

Digital watermarking for image authentication algorithm

Author LiuNaiCheng
Tutor ZhouFeng
School Kunming University of Science and Technology
Course Applied Computer Technology
Keywords Digital watermarking Fragile watermarking Semi- fragile watermarking Image Authentication
CLC TP309.7
Type Master's thesis
Year 2009
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Digital watermarking technology is a new information security technology , copyright protection and content authentication is an effective method , involving a variety of subject knowledge comprehensive, high academic value and economic value . Authentication watermark technology as digital watermarking technology is an important part of the international academic community has become a hot research topic . This paper summarizes the digital watermarking and authentication watermark basics on the basis of in-depth analysis of the various existing typical algorithms home and abroad , pointing out that the main advantages and disadvantages , and through the authentication watermark technology depth research, improvement of proposed two certified for authenticity and integrity of the image digital watermarking algorithms: one is based on block DCT- fragile watermarking , the first use of DCT coefficients and Logistic mapping generation watermark information , and then the watermark information is embedded into selected among the DCT coefficients . Simulation results show that the algorithm has a good sensitivity and tampering localization capability, and image detection is simple, do not need to provide the original image and the watermark. Another is based on the JPEG compression invariant semi-fragile watermarking algorithms, this algorithm is then compressed using the JPEG standard quantization table to quantify the DCT coefficient matrix , then the encrypted matrix encrypted binary watermark information is embedded into the DC coefficient binary sequences lowest level , the algorithm robustness and fragility be fully balanced. Simulation results show that the conventional image processing algorithm is robust , while the replacement , shear and other malicious tampering with strong sensitivity and positioning capabilities . A meaningful binary watermark image as watermark information , more practical value .

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