基于扩频纠错码的水印向量形成策略研究  

The studying on the Watermarking Vector Forming Tactics of the Hybrid Spreading Coding and Error Correcting Coding

作　　者：曹华[1] 

机构地区：[1]华中科技大学软件学院,武汉430074

出　　处：《微计算机应用》2009年第8期1-6,共6页Microcomputer Applications

摘　　要：为了改善不可见水印的鲁棒性,可以在扩频水印中进一步引入纠错编码(Error Correction Coding,简称ECC),以进一步降低水印检测的误码率。但是受水印不可察觉性条件的限制,ECC纠错编码虽然增加了水印的鲁棒性,但其增加的冗余比特,又使得水印信号的嵌入强度被迫减少,这就使采用ECC纠错编码和保持水印强度在鲁棒性方面产生矛盾。本文对采用了ECC纠错码的扩频水印向量形成策略进行了研究,并提出了一种新的水印向量形成方式,通过在图像的不同部分交错的选择扩频水印比特,从而使算法对剪切攻击有更好的鲁棒性。Error correcting coding （ECC） can be applied in the CDMA based watermarking to decrease the detection bit error rate, which intend to improve the robustness of the oblivious watermarking. Although the ECC increases the robustness of watermarking, owing to the constraints of imperceptibility, the redundancy introduced by ECC will result in a decrease of the embedding strength for watermarking. Therefore, introducing ECC and decreased the strength of the watermark signal contradict each other concerning robustness. In this paper, it is studied for the scheme to apply ECC in the CDMA based watermarking. Furthermore, a new method for forming watermarking vector is introduced in which spread watermarking bits are in parts interleaved in different regions of the image to make the algorithm robust against cropping.

关 键 词：水印 扩频编码 错误校正码 鲁棒性 

分 类 号：TP309.7[自动化与计算机技术—计算机系统结构]