Summary: | 碩士 === 東海大學 === 資訊工程與科學系 === 94 === Following the fast development of the Internet, most of multimedia materials are digitally stored and transmitted. Varieties of digital multimedia materials (such as digital sound, image, movies, etc.) spread in a great speed in the Internet; they are easy to be accessed and vulnerable to illegal duplication, therefore, in the opening Internet world, protection of multimedia materials and rights of legal owner from pirates becomes a pending issue. In this thesis, we propose a digital watermarking scheme based on the Singular Value Decomposition (SVD) method and the Distributed Discrete Wavelet Transformation (DDWT) method. Our scheme transforms original image data from the spatial domain into the frequency domain by using DDWT technique, and then obtains singular values of sub-bands from applying SVD technique. Afterward, watermark information is embedded in the four sub-bands in the frequency domain. In this way, we propose the Full-Band Image Watermarking (FBIW) method. We exploit both of the advantages of the DDWT method, which is robust against the cropping attack, and the SVD method, which is robust against geometric attacks such as rotation, rescaling and transposition and non-geometric attacks such as Gaussian noise, sharpening and blurring. Experimental results show that the quality of the stego-image is superior and the embedded watermark has high resistance against a variety of common geometric and non-geometric attacks.
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