| In recent years, with the development of network technique and the rapid increase of digital media application, digital audio watermarking technique has become one of the research hotspots. With such techniques we may embed secret information into audio files, so as to get'cover communication'and'copy right protection'etc. Some basic theory for digital audio watermarking is introduced in this paper. The characteristic and disadvantage of the watermark arithmetic is analyzed. By the researching of the spread spectrum in communications and the theory in audio watermark, some digital audio watermarking algorithms are proposed and improved.An DCT audio watermarking algorithm has been put forward. First, the audio signal has been divided and made DCT. The watermark image will be embedded into the low-frequency of DCT based on mean-quantization theory. In the last section, this algorithm is implemented. The experiment results show that the algorithm has good robustness and sensitivity in the watermark confrontation additive Gaussian noise, MP3 compression and other aspects. An improved adaptive audio digital watermark algorithm is put forward in the DWT domain. This method is based on m sequence modulation. First, the visually recognizable binary watermark image should be converted into a one-dimension signal sequence in the algorithm. The sequence is permuted pseudo-randomly and is modulated by the m sequence. Then the digital audio signal is converted into segments and discrete wavelet transform is performed. Finally, according to the character of the HAS, the algorithm modifies the quantization step by adaptively adjusting the quantified SNR and determines the intensity of the embedded watermark according to features of the audio signal. The experimental results show that the watermark is imperceptible and the algorithm is robust to digital audio signal. Copyright protection and information safety can be solved by embedding the watermarking in the audio signal. |
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