一种基于心理声学模型的小波包域音频数字水印算法

首先根据心理声学模型 ,计算载体音频信号的掩蔽门限 ,并利用人耳听觉的临界频率与小波包子带间的相似特性 ,将DFT域掩蔽门限映射到小波包域 ;然后将水印信号嵌入到中低频小波包系数中 ,嵌入强度由掩蔽门限自适应控制。由于该方案是基于人类听觉系统的 ,在最大限度上挖掘了水印嵌入强度 ,使鲁棒性和不可感知性得到了很好的平衡。实验结果表明 ,利用这种水印算法 ,嵌入的水印信号是不可察觉的 ,并且对数据压缩、加噪、去噪、重采样 (D/A、A/D转换 )、低通滤波等常用音频信号处理技术具有很好的鲁棒性

An audio digital watermarking scheme based on wavelet packet and psycho-acoustic model

The masking threshold for each audio signal segment was calculated on the basis of psycho-acoustic model. According to the similarity between critical band of human auditory system and wavelet packet sub-band, a watermark was embedded into the low-band and mid-band coefficients of digital wavelet packet. The embedding strength was adaptively controlled by the masking threshold. This scheme gets a good balance between the inaudibility and robustness. The experiment results show that the embedded watermark signal is inaudible, and the watermarked audio signal has good robustness against many attacks such as compression, noise, re-sampling (D/A and A/D conversions), low-pass filtering.