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The Research On Digital Audio Watermark Algorithm

Posted on:2008-06-10Degree:MasterType:Thesis
Country:ChinaCandidate:Q X WangFull Text:PDF
GTID:2178360245479901Subject:Computer application technology
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With the development of the Internet and the maturity of audiovisual media compression techniques, a lot of digital products can be found in the Internet, such as audio, image, video, etc, and the transmission of audio productions becomes more and more convenient. To prevent the content of multimedia from being stolen or illegally used, techniques for audio content protection has been developed and become more and more important. As an effective method of copyright protection, the digital watermarking technology has been widely researched and applied. Digital watermarking is the digital information or pattern, which is added into the digital productions for ever, and it doesn't debase the usability of the original digital production. For human auditory system (HAS) is more sensitive than human visual system (HVS), embedding watermarking into the audio signal is very difficult.This dissertation selects the two-dimension binary image as the watermark information, and proposes three algorithms. The main research work and contributions of the dissertation are as follows:(1) A DWT Domain Digital Audio Watermarking Algorithm Based On Logistic-map Encryption. We use the logistic-map sequences to encrypt the watermark first, at the same time we take the CA parts of the original audio signal in the DWT domain, and then we separate the CA parts into some groups, which is determined by the ratio of the length of the CA parts and the length of the encrypted watermark. Every bit of the watermark is added into the relevant groups of the CA parts in the DWT domain until all the bits of the watermark are embedded. It is a nonblind watermark schedule.(2) A DWT Domain Digital Audio Watermarking Algorithm Based On Quantization. It is an algorithm base on energy quantization and DWT. First we use the logistic-map sequences to encrypt the watermark, and then we separate the original audio signal in the DWT domain into some groups by the rate you wanted. In every group we calculate its energy and quantize the energy both by the delta which you set and the value of the corresponding bit of watermark, and then we can get the relative value of them. We change every sample value of the group in the DWT domain by multiplying it with the ratio. Repeat the above steps until all the bits of the watermark are embedded and we can re-embed the watermark if the total number of the separated groups is bigger than that of watermark. It is a blind watermark schedule.(3) A DCT Domain Digital Audio Watermarking Algorithm Based on Quantization. According to characteristics of DCT coefficients, a DCT domain audio watermark algorithm was proposed. First, Original audio data was divided into pieces with fixed length. Then, Watermark information was embedded by modulating DC coefficients of DC matrixes. It is a blind watermark schedule.Experiments show that the three algorithms do well in transparency and robustness after StirMark software attacks.
Keywords/Search Tags:Digital audio watermark, Digital watermark, Copyright protection, Robust watermark, Discrete Wavelet Transform(DWT), Discrete Cosine Transform(DCT), Quantification, logistic maps, Arnold transformation
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