基于NSCT变换的轮廓匹配水印算法  

CONTOUR MATCHING WATERMARKING ALGORITHM BASED ON NSCT

作　　者：张长伟[1] 张文祥[1] 

机构地区：[1]浙江万里学院智能控制研究所,浙江宁波315101

出　　处：《计算机应用与软件》2012年第11期119-122,214,共5页Computer Applications and Software

基　　金：国家重大专项(2009ZX1039-002-001-04)

摘　　要：针对常见抗几何攻击水印算法存在的不足,设计一种基于非采样NSCT Contourlet(Nonsubsampled Contourlet Transform)变换的鲁棒水印算法。算法利用NSCT提取图像轮廓并用于几何校正。水印嵌入过程分为三步:首先利用NSCT域高频系数提取图像轮廓;其次依据图像轮廓提取特征点用于几何校正;最后水印信息自适应量化嵌入NSCT域低频系数。实验结果表明,该算法不仅具有很好的透明性,同时对常见图像处理攻击和几何攻击均具有很强的鲁棒性。An approach for a robust watermarking algorithm based on Nonsubsampled Contourlet Transform（NSCT） is designed in this paper in light of the deficiency of common watermarking algorithms of geometric attacks resistance.The image contour is extracted with NSCT for geometric correction.The process of watermark embedment has three steps： firstly,the high frequency coefficients in NSCT domain is employed to extract the image contour;secondly,the feature point extracted according to image contour is used for geometric correction;finally,the adaptive quantisation of watermark information is embedded to the low-frequency coefficients of NSCT domain.Experimental results show that the proposed algorithm has excellent transparency and is very robust to common image processing and geometric attacks.

关 键 词：数字水印 非采样CONTOURLET变换 轮廓匹配 特征点 

分 类 号：TP309[自动化与计算机技术—计算机系统结构]