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| Most of the previous (semi-) fragile audio watermarking schemes adopted binary image as watermark, which might reduce the security of watermarking systems. Moreover, the applicability of content or feature-based second generation digital watermarking is limited, and partial feature points may be damaged under watermarking operations and various common signal processing. Aiming at these problems, a novel centroid-based semi-fragile audio watermarking scheme in hybrid domain is proposed in this paper. The theoretical lower limit of signal to noise ratio (SNR) used to objectively evaluate the imperceptibility of watermarked audio signal is deduced and given. In addition, the watermark embedding capacity and the ability of tamper detection are also theoretically analyzed. Initially, the centroid of each audio frame is computed, and Hash function is performed on the obtained centroid in order to get the watermark. Finally, the audio sub-band which carries centroid of audio frame is performed with discrete wavelet transform (DWT) and discrete Cosine transform (DCT), and the encrypted watermark bits are embedded into the hybrid domain. Theoretical analysis and experimental results show that the proposed scheme is inaudible and suitable to different kinds of audio. Furthermore, the ability of tamper detection and tolerance against common signal processing operations are all excellent. Comparison with the existing schemes, the proposed scheme can not only resolve the issue of the veracity and integrity of audio content authentication effectively, but also popularize the applicability of content -based audio watermarking scheme. |
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| Keywords:semi-fragile audio watermarking; centroid; inaudibility; tamper detection |
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