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

Research of Digital Watermarking Based on DCT

Author ZhaoJunLing
Tutor FuShuJun
School Shandong University
Course Software Engineering
Keywords Digital Watermarking Discrete Cosine Transform Passage MATLAB
CLC TP309.7
Type Master's thesis
Year 2009
Downloads 356
Quotes 3
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With the rapid increase in computing power and storage capacity, the widespread popularity of the computer and the Internet has become more sophisticated, many of the traditional way of life is to develop in the direction of digitization, networking and promoting online sales of music, digital cinema, on-line information , sales of e-books, online banking, online shopping and so on. In addition, in the wireless arena, with the mobile network evolution from second generation to third generation, mobile users will be able to facilitate fast access to the Internet, digital media content, digital media content applications based on wired or wireless network is about the information age The new logo. However, information security is becoming precarious security problem has become the bottleneck of digital media content, once constrained the process of information. Although mature cryptography security pass and access control can be solved, but as decipher the rapid development of technology, data encryption, like the brink of a crisis. Cryptographic techniques only play a role in the transmission, Once decrypted, the digital media content can be freely copied, spread, which is the digital media content super-distribution (Super Distribution) problem. Become powerless when the need for data detection in the case of normal use of the property rights of the legitimacy of the data and data tracking, data encryption technology. It caused a great loss to the media content manufacturers, thereby constraining the conduct of the digital multimedia applications. Digital watermarking as a potential means of settlement, in recent years, has become the focus of attention of the business community and academia. The paper first introduces the basic problems of the basic characteristics of digital watermarking principle, purpose, meaning and the current domestic and international status, and then describes the basic framework of digital watermark and classification of digital watermarking for digital watermarking algorithm proposed, implementation and testing provides a theoretical basis. As an important part of the digital watermarking algorithms, the paper details the the meaningless watermark signal and the the meaningful watermark signal design and produce, and describes the basic features of the pseudo-random sequence of real numbers m sequences, chaotic sequence and error correction coding and its The application of digital watermarking. As a theoretical basis for part of the digital watermark algorithm, the paper introduces the basic theory of the discrete cosine transform. 1, of the watermark embedding of the effective image channel, and separately embedded in the red, blue and green channels of the embedded performance experiment proved, the watermark embedded in the green channel, having the better robustness. 2, a color image watermarking algorithm based on DCT watermark image is embedded into the host image in the green channel. The experiments show that the algorithm to improve the robustness of the watermark watermark imperceptibility conditions. 3, using the MATLAB design of the experimental program, selection of features of different images as the host image imperceptibility and robustness validation proved that the algorithm has good imperceptibility. 4, describes a digital watermark embedded DCT-based image fusion algorithm, the host image separation channel and DCT transform, respectively, and then after the DCT transformation of the watermarked image is embedded into the the converted color channel in, last channel to flatten. The experiments show that the algorithm can also meet the imperceptibility and common attacks robustness.

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