Watermarking Techciques For Digital Audio

Waermark technique is a copyright protection tool of multimedia data, suchas image, audio, video and so on. Wth the global informationizing and e-commerce boosting, the requirement of the copyright protection becomes more andmore urgent. Under this condition, the watermark technique is put fOrward. In thispaPef, we focus on the audio watermark technique and at the time discuss the audiowatermark embedding algorithm.First, we give a general concept of the audio watennark. We intrOduce thewatermark characteristic, the watermark classification, the general operation of themedia and the common attack methods aiming at embedded watermark.Second, we analysis the character of the human auditory system, especiallythe psychoacoustic model. Then we analyze the principle of the audio part ofMPEG-1 which aPply the psychoacoustic model to compressing the audio data. Thefrequency analysis of the psychoacoustic model can give the inaudible, redundanelements of audio. In this paPer we employ it to gUarantee the inaudibility of theembedded watermark.Third, we imPlemeni and analyze the following audio watermark algorithms:the least significant bit algorithm in time domain, the watermark algorithIn usingpercoptual masking, the watermark embedding algorithIn based on wavelettusform and based on quantizing wavelet transfOrm coefficients. Wth regard to thethreshold Which used in the algoritlun based on wavelat transfOrm and aredetermined by experience, we put forward a automatic and adaPtive algorithm thatcan calculate the suitable threshold. This suggested algorithm makes use of thefrequency analysis of the psychoacoustic model to make the embedded watermarkinaudible. This idea can be used in such sort of watermark embedded algorithInsbased on wavelet transfOrm.At last, we summarize our works. Conceming the proposed adaPtiveaigorithIn, we give a farther discussion which can uPgrade the rObustness of thewatermark algorithm.