Research Of Audio Digital Watermark Technology

With the development of digital technology and internet, digital watermark technology becomes one kind of effective protection technology for digital product copy right and maintenance technology for data security, and it is one of the branches of research aspect of information hiding technology. It confirms the property right of digital product or checks its originality and completeness through putting signs with special significance into the digital product. However, because people are very sensitive to the audio signals, so it is always the research key and important points for keeping inaudible of the audio digital watermarks.This thesis mainly focuses on the problem of embedding satisfactory robust and imperceptible watermarks into the audio digital products. Main ideas as follows:Research of audio digital watermark Algorithm based on Fast Fourier Transforms and psychoacoustic auditory model. This thesis presents a new audio digital watermark algorithm based on HAS model. The steps: First, it classifies the signals through FFT; second, calculating the tones, noise and the overall masking threshold of different phases through HAS, and changing the energy value of tones which are more than that of the overall masking threshold to embed the watermark information. The result of simulation implied that this calculation can keep not only the better audio quality, but also has the better robustness for the attacks such as: noise addition, lossy compression, low pass filtering and re-quantization.Technical research of audio digital watermarks based on wavelet transforms. This thesis presents a new self-adapted audio digital watermarks algorithm of wavelet domain based on MPEG. This algorithm utilizes Masking model provided in the MPEG compressing algorithm and embed the watermarks self-adapted through wavelet transforming . Although the complexity of the process of embedding the watermarks has been increased, it reduces the complexity of extracting watermarks and makes it more useful. Furthermore, this algorithm can get better hide capability because the wavelet transforming has better distinguishing rate of time and frequency. Theoretical analysis and experiment results show the feasibility of this algorithm.The last part of the thesis implement one effective audio digital watermarks systems. With using the Matlab platform, we achieved the conscious sound analysis of the audio signals ,the embeding, detection and extracting of watermarks and did some...