Research On Technology Of Digital Audio Watermarking

The fast growth of the Internet and the maturity of audiovisual media compression techniques make the widely on-line publication of digital products, such as audio, image, video, etc. Audio productions are one of the important digital multimedia, which transmit become more and more convenient. To prevent multimedia content from being stolen or illegally used, audio content protection techniques become increasingly important so that the full potential of these applications can be reached. As the important method of copyright protection, the digital watermarking technology has acquired widely research and application. Digital watermarking is the digital information or pattern, which can be embed into other data forever, and it doesn' t affect original data usability. For human auditory system (HAS) is more sensitive than human visual system (HVS), embedding mark to the audio signal is very difficult. Recently, research on digital watermarking is mainly based on static images, however only a few institutions have researched on audio watermarking.This dissertation selects audio as embedding object. The main research work and contributions of the dissertation are as follows: (1) research on adaptive audio watermarking algorithm based on signal-to-noise ratio in wavelet domain. The technology of embedding image into the audio signal was researched in this paper and an algorithm of additive audio watermarking based on SNR to determine a scaling parameter a is proposed. The visually recognizable binary watermark image could be embedded in the original signal wavelet domain in the algorithm. The intensity of embedded watermarks on the different audio segments would be modified by adaptively adjust the scaling parameter a .(2) research on blind watermarking algorithm based on chaos sequence encryption. In the dissertation, chaos sequence can be created by the encrypted watermark into the audio signal by quantization method. Watermark value is extracted without access to the original audio. The blind watermark detection has practical value. The original watermark image is hard to recovery if the key isn' t known.(3) Research on robust and fragile watermarking based on perceptive model. An audio perceptive model is proposed in this dissertation, we can calculate the acoustical masking threshold by the model of audio signal and the robust and fragile watermark can be embedded which play complementary roles, which is copyright protection and content authentication. Experimental results indicate that our multipurpose audio watermarking scheme is remarkably effective.The experimental result demonstrate that the watermark is imperceptible and the algorithm is robust to many operations to digital audio signal, such as resampling ,cropping, low pass filter, MP3 compression and so on, and if the fragile watermark is tampered, we can detect it easily.