Researches On Digital Audio Watermarking For Copyright Protection And Tamper Detection

With the development of the Internet and digital multimedia technology, the production, transmission and storage of multimedia products become more and more convenient. Although the development of the technology makes people’s life more convenient, they also lead to a lot of security problems including illegal transmission, illegal copy, tampering and so on. Watermarking, as an effective technology for these problems, has attracted much attentions in recent years. However, audio watermarking is much less developed than that of image/video. In this thesis, researches on copyright protection and tamper detection for music are considered and the contributions are as follows:(1) The background of watermarking is introduced. A lot of researches on watermarking for copyright protection and tamper detection are analyzed, and the related works are discussed.(2) A robust watermarking scheme based on heuristic search is proposed for copyright protection. In this scheme, the relationships among the embedding strength λ, imperceptibility and robustness are firstly analyzed, and an audio watermark embedding strength optimization model is constructed based on the relationships. Then, a solution based on heuristic search is proposed for the optimization model. Experiments show that the proposed method is of good imperceptibility, and can resist to various signal processing and Stirmark attacks.(3) A blind semi-fragile MP3 watermarking based on window switching strategy is proposed for tamper detection. In this algorithm, the embedding is carried out by establishing a mapping relationship between the number of nonzero window type and the watermark bit sequence. And a temper detection method is designed to recognize tampering type and locate tampering range by analyzing of watermark bit sequence. Experiment results show that out method can detect the tamper, recognize the tamper category and give an accurate tamper range. Moreover, the method performs well in time efficiency, imperceptibility and advisable robustness.