Audio Watermarking Schemes and Embedding Algorithms

Abstract

Increasing amount of digital data sharing tools has created copyright infringement issues. This has become the threat to content providers. Digital watermarking remained the most powerful tool for intellectual property protection in literature. There are several applications of digital watermarking including copyright protection, fingerprinting, broadcast monitoring and content authentication.

Depending upon the requirements of an application, watermark can be robust, fragile or semi-fragile. Work is carried out on audio fragile watermarking schemes. Fragile audio watermarks possess the characteristic to get destroyed even after slightest modification and hence is used for temper detection. Fragility does not require watermark to possess robustness- one of three conflicting properties of watermark, i.e. robustness, imperceptibility and pay load. Thus robustness is not an important issue in this approach, so other remaining two parameters can be thought to improve to higher extent than usual. In proposed algorithm, imperceptibility is targeted and SNR = 68.89 dB and MSE of watermarked audio of order 10-9 is achieved. Achieved SNR and MSE proves to be better in MSE by 10,000 times and SNR by 30 dB, than algorithms reported recently.

Herein, a new signal adaptive fragile audio watermarking technique is proposed, in which audio signal is segmented and decomposed by Empirical Mode Decomposition. Mean of last Intrinsic Mode Function obtained for each segment is calculated and matrix is formed. Watermark bits are inserted into singular values of matrix via Quantization Index Modulation to assure some extent of robustness. Empirical Mode Decomposition and Singular Value Decomposition provide good degree of imperceptibility factor. Using all these techniques in one package provided us with better results than the recent researches.