On Digital Audio Watermarking Algorithm

With the rapid development of the digital technique in recent years,digital image,audio and video have become more popular,and increase the efficiency of the information broadcasting. The development of computer network technique predigests the exchange and transmission of the information more. But,with the side effect,there are some despiteful individual organizations copying , tampering and broadcasting the copyright content,without admission of the work owner. Therefore, 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.This paper describes the concept , framework , the technique requirements and other traits to fragile watermarking techniques ,summarizes all kinds of existent audio watermarking algorithms,finally introduces the attacks and benchmarks of audio watermarking techniques.This paper presents a new algorithm based on wavelet transform and complex cepstrum transform. This algorithm uses the thought in traditional algorithm of echo hiding for reference. It adds echoes to the wavelet coefficients, selecting different delays according to watermarking bit to be embedded. In the detection, it uses complex cepstrum analysis to extract the watermarking bit. It is a blind detection. In this paper, we first introduce the basic theory of wavelet analysis and complex cepstrum analysis, and deduce how to deconvolve the signal to separate the original signal and its echo using complex cepstrum analysis. Then we present the main thought of this algorithm, and discuss how to select the proper wavelet and its decomposition level. After that, the detailed process of watermarking embedding and detecting are presented. In the end, we conclude the simulation results to show the transparency and robustness. This algorithm can resist against common attacks such as resampling, low-pass filtering and synchronization attacks such as jitter, random clipping, and so on.Another algorithm this paper presents is a quantization algorithm based on wavelet transform. This algorithm quantizes the wavelet coefficients to different region according to the watermarking bit to be embedded, and introduce the features of human auditory system (HAS) to gain the proper quantization step. In the detection, it uses threshold judgment to achieve blind detection. This paper first introduces two approaches of quantization algorithm and the recent study of fragile audio watermarking algorithm. Then it discusses some important issues in the algorithm design, and presents the detailed process of watermarking embedding and detecting. At last, it concludes the simulation results, which shows that the watermarking is transparent and sensitive to attacks such as resampling, compression and low-pass filtering, and so on.