该文提出了一种新颖的量化水印.该方案通过调制由宿主信号变换产生的特征信号嵌入水印信息.特征信号由源宿主信号与一个随机信号的归一化相关系数构成.对该信号的调制方法是从水印信息对应的码本中选择一个码字,码本设计使用了均匀量化器并考虑了多进制的情况.加水印的宿主信号在最小化嵌入失真的意义下产生,并使其与随机信号具有调制后的归一化相关系数.同时,该文给出了嵌入失真与可移除水印信息的最小通道失真的表达式,根据它们可以在码本中搜索最优的码字以提高水印性能.该文方案对幅值缩放攻击具有不变性,而且抗噪能力优于著名的扩展变换抖动调制水印.图像仿真结果表明,该方案具有良好的不可感知性以及能抵抗广泛的攻击,和几种典型的水印方案相比具有显著的性能优势.%This paper presents a novel quantization-based watermarking method. The method embeds the watermark information by modulating a feature signal generated from the host signal. The feature signal is suggested to choose the normalized correlation between the host signal and & random signal. Information modulation is carried out on the generated feature signal by selecting a code word from the codebook associated with the embedded information. The structured code-books are designed using uniform quantizers for M-ary modulation. The watermarked signal is produced to provide the modulated feature in the sense of minimizing the embedding distortion. Meanwhile, we derive the expressions of the embedding distortion and the minimal channel distortion to remove the hidden message. According to them, the optimal code word can be found in the codebook for the watermarking performance improvement. The proposed scheme is theoretically invariant to valumetric scaling and can resist stronger noise than the well-known spread transform dither modulation. Numerical simulations on real images show that it achieves the good imperceptibility and strong robustness against a wide range of attacks and significantly outperforms other state-of-the-art watermarking methods.
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