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Improving the Robustness of Image Watermarking for Publicly Copyright-Proving

Shakeri, Mahsa | 2011

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 42169 (19)
  4. University: Sharif University of Technology
  5. Department: Computer Engineering
  6. Advisor(s): Jamzad, Mansour
  7. Abstract:
  8. The advent of Internet and advancement of computer technologies have enabled convenient and fast exchange of multimedia so the illegal reproduction and modification of digital media has become increasingly serious. Hence, how to protect the intellectual property rights of digital multimedia is an imperative issue. Digital watermarking is one of the solutions to prevent unauthorized use of images. Traditional digital watermarking techniques embed a watermark such as logo, trademark, or copyright information into a host image so that it is not perceptible. These techniques, depending on the amount of embedded data, will distort the content of host image which results in quality degradation of watermarked image. Recently, a group of zero-watermarking methods have been proposed that extract some binary features as binary map from the host image. Then the binary map is XORed with a permuted watermark logo to generate a verification map. The verification map is sent to a trusted autority as a certificate for the host image. Although the copyright of the host image is protected, the quality of it remains intact. In this thesis, we first evaluate the related methods and find their advantages and disadvantages. Then we propose three new methods. The first one is based on discrete cosine transform and an image normalization technique. The normalization procedure makes our scheme robust against geometric attacks. The second proposed scheme which uses discrete wavelet transforms and image normalization has higher performance than the previous one. The third method is in spatial domain and it uses Canny edge detector to extract binary features. Experimental results show that our second proposed method has higher robustness than the first method. Simulation results show that our third method is efficiently robust against common geometric and nongeometric attacks and outperforms the other related schemes in most cases.

  9. Keywords:
  10. Resistance ; Discrete Cosine Transform ; Discrete Wavelet Transform (DWT) ; Image Watermarking ; Copyright Protection

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