Study On The Digital Audio Watermarking Scheme

As the development and application of computers and Internet, multimedia data has gradually become an important way to get information. How to carry out copyright protection and ensure the security of the information has become one of the urgent problems to be solved in digital communication. As an effective way to solve this problem, digital watermark technique has attracted many attentions. At a word, digital watermarking is a scheme to insert some information that can represent the author's identity into the original data, to verify the property or the integrity of them.In this paper, a robust audio watermark technique is discussed. Firstly, the author introduces the meaning of the task, the research background, and the related concepts and characteristics. Some typical methods are reviewed as well. Secondly, due to the initial value sensitivity of the chaotic sequence, the author brings forward a method to use the chaotic sequence spread spectrum m sequence to generate the original watermark signal. After that, two kinds of BSS based digital audio watermark methods were proposed. The first method is to use the Independent Component Analysis (ICA) algorithm to separate the estimating value of the watermark signal and the host signal, and then to separate the watermark signal desired further more by the fourth order statistical value. By observing the correlation detection waveform between the embedding watermark signal and the estimating value of it, the existence of the watermark information can be determined. To improve the robustness of this method, an improved edition of it is discussed later in this paper. In the improved method, the frequency-domain and the time-domain masking are performed, so the power distribution and waveform of the generated watermark signal are in accordance with those of the host signal's, the robustness of the algorithm is improved consequently. The second one is a method based on Independent Component Analysis with reference signal (ICAr). Unlike the former, this method can separate the estimating value of the watermark signal separately by using the information provided by the reference signal, so the computing complexity of the first method can be greatly decreased, at the same time, the shortcomings of the ICA based method, such as disorderliness and randomicity can be overcome.Experimental results show that, both of the two methods can satisfy the requirements of transparency, robustness and the security; the watermark signal can be extracted without the covert signal; it is more intuitionistic to determine the existence of the watermark in the host signal by observing the correlation detection waveform between the watermark signal and itsseparated estimating signal, and it is practicable. According to practical applications, the watermarking scheme proposed in this paper can be applied in copyright protection and business track.