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

Research of Digital Image Watermarking Algorithm Based on Wavelet Transform

Author TaoFeng
Tutor JinCong
School Central China Normal University
Course Applied Computer Technology
Keywords Discrete wavelet transform (DWT) Human visual system (HVS) Singular value decomposition (SVD) Blind Watermarking Image Scrambling Robustness
CLC TP309.7
Type Master's thesis
Year 2007
Downloads 188
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With the rapid development and wide application of multimedia technology and network technology , the transmission and sharing of multimedia data become increasingly common. These data can be easily copied and modified , therefore the copyright protection of the digital product has become a very important issue. As an effective means for copyright protection of digital products , digital watermarking technology came into being . Digital watermarking technology is generally specific watermark information is embedded into the digital products , digital products copyrighted to confirm the case or to ensure true and reliable data . For digital watermarking technology, the general requirements of the embedded watermark information is not visible , and able to resist a variety of attacks, having a certain robustness . Firstly, from the concept of digital watermarking , classification , made ??an overview of the basic model , the watermarking algorithm to study the background of its main application areas of digital watermarking technology . Second, a brief introduction to the definition of the wavelet transform , wavelet transform the nature of the two - dimensional orthogonal wavelet decomposition , Mallat algorithm and wavelet theory in digital watermarking . Subsequently, two digital image watermarking algorithm based on wavelet transform . The first algorithm is based on the characteristics of the human visual system (HVS) image watermarking algorithm . The algorithm will be meaningful binary image watermark instead of a random sequence , then all first watermark Arnold scrambling encryption embedded into the low frequency sub-band coefficient . The algorithm makes use of the human visual system (HVS) characteristics to enhance the robustness of the watermark and guarantee the invisibility of the watermark embedding strength adaptively adjust . The second algorithm is a digital image watermarking algorithm based on discrete wavelet transform (DWT) and singular value decomposition (SVD) combined . The algorithm of the original image for Wavelet decomposition and wavelet decomposition of the low-frequency sub- band block , each a singular value decomposition , select each piece of the largest singular value through quantitative methods embedded after the watermark Arnold scrambling information . The watermark extraction does not require the original image, but is limited by the key , and does not know the key can not be correctly restored digital watermark . The experimental results show that the algorithm has good invisibility , robustness and security .

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