基于复倒谱变换的数字音频水印研究

Research on Digital Audio Watermark Based on Complex Cepstrum Transform

提出了一种基于倒谱变换的数字音频水印算法,把音频信号划分为包含相同采样点的若干帧,计算指定帧的均值,对均值大于0的帧实施复倒谱变换,将复倒谱系数的均值与阈值进行比较,结合水印序列为“0”或“1”,采取缩小、增加或不改变复倒谱系数均值的方法,在复倒谱系数中嵌入水印。实验证明,该算法具有健壮性、透明性,可以进行添加噪声、重采样、低通滤波、重新量化、音频格式转换等常见信号的处理与承受各方的攻击。

This paper proposes a new algorithm of digital audio watermark based on the complex cepstrum transform. The audio signal is divided into several frames which include the same samples, the mean value of frames is calculated, the frames of mean value is greater than or equal 0 is transformed by complex cepstrum, and mean value of complex cepstrum coefficient of the frames and threshold value is compared, according to the result of comparison and combining watermark bit, adopting the way of not changing, increasing or reducing coefficient of the complex cepstrum. Watermark is embedded into the complex cepstrum coefficients. The result demonstrates that the algorithm is robust, transparent and blind against common signal processing manipulations and attacks, such as re-sample, remodulation, noise, low-pass filter and conversion etc.