Non-embedded audio watermark based on wavelet transform

This paper proposes a new non-embedded audio watermark scheme based on wavelet transform. The input audio signal is first transformed into a series of wavelet coefficients at different resolution via Fast Wavelet Transform. The energy ratio sequence (ERS) of the high frequency component in forth scale is then calculated. The copyright information is transformed into a key of digital watermark coding. The key is then XOR the ERS of the decomposition of the input audio signals as a third-party kept cryptographic key. Experiment result shows that the proposed watermark scheme can hide intellectual property copyright information into digital audio while without losing of sound quality of the signal.