Research Of Digital Audio Watermarking Algorithms

With the development of information theory and network techniques, storaging and transmitting of the digital multi-media information become so convenient than before. In this case, more and more problems appeared, and the most significant problem is copyright protection. The technique of digital watermarking plays a key role in protecting the copyrights of the multi-media information.Digital watermarking technique is a process that watermark which has significant meanings can be encoded and also decoded easily in the host signal. The quality of the host signal should not be degraded during the processing. The research direction of this paper is the application of digital watermarking technique in the audio signal, including researching the system frame of digital audio watermarking, summarizing the familiar algorithms and attack methods of digital audio watermarking. Three algorithms of digital audio watermarking were proposed based on research works.1. Different from conventional echo hiding operated in time and Cepstrum domain, a new method of echo hiding that encoding and decoding are both operated in the time domain is proposed. PN- sequence is used to control the echo kernel and this kind of method can reduce the cacophony. This method preserves high detection ratio even if the amplitude of the echo is indistinct and divides the audio signal by the energy based on HAS for the adaptively encoding.2. According to the theory of Psychoacoustic model, the position used to embedding can be found exactly. A method of digital audio watermarking combining Psychoacoustic model and Cepstrum transform is proposed.3. A method of digital audio watermarking using wavelet transform is proposed. The robust of the watermarking is improved by pretreatment of watermarking. Watermarking has been embedded by coefficients quantization in the right position which was found by variance prediction.