文档介绍：西安建筑科技大学硕士学位论文变换域数字水印算法的研究专业: 信号与信息处理研究生: 雷洁指导教师: 王慧琴教授摘要随着计算机网络的飞速发展,数字媒体产品给工作和生活带来方便快捷的同时,也带来了版权安全等一系列的问题。数字水印技术作为一种有效的数字信息版权保护方法,得到了广泛的关注。本文在分析现有数字水印技术的基础上研究了两种变换域数字水印算法: ( 1 ) 基于 SVD(Singular Value position) 分解的 DCT (Discrete Cosine Transform) 域数字水印算法。将原始图像分块并计算熵值和标准差,根据人类视觉系统特点,选取熵值较大和方差较小的块嵌入水印。对选取的原始图像块进行离散余弦变换,将二值水印图像进行混沌加密后进行奇异值分解,然后嵌入到选取块奇异值分解的 S分量中。由于将水印进行了三次嵌入,加大了嵌入的水印信息量。水印提取采用了 3 选 2的方法。仿真实验证明了算法具有良好的不可感知性, 并且对有损压缩、图像添加噪声、中值滤波、剪切等图像处理操作具有较强的鲁棒性。( 2 )基于图像归一化的零水印算法研究。结合图像归一化技术,研究了一种新的零水印算法。首先利用图像归一化技术在原始图像中提取构造区域,然后在重要区域中进行离散小波变换,选择低频子带进行分块离散余弦变换,提取每块直流分量组成一个矩阵并求平均值,通过判断每块系数与平均值关系得到特征信息,最后结合版权水印信息构造零水印。仿真实验表明,算法对常规处理和几何攻击均具有较好的鲁棒性。关键词: 数字水印技术;离散余弦变换;奇异值分解;零水印西安建筑科技大学硕士学位论文 Resear c hof Digital Watermarking Te c hnique in Transform Domain Special ty: Signal and Information Processing Name : Lei Jie Supervisor : Prof. Wang Huiqin ABSTRACT With the rapid development puters works, digital media products to work and life, while convenient, it also brings security, and other copyright issues. Digital watermarking is an effective method for copyright protection of digital information, received extensive attention : Based on the analysis of the existing digital watermarking technique based on the propos ed two digital image watermarking algorithm: (1)Digital watermarking Algorithm Based on SVD in DCT domain. Firstly, Original image was divided into blocks and their entropy and standard deviation were calculated. According to HVS characteristics, selected some blocks with larger entropy and smaller standard deviation to embed watermark. Selected blocks are transformed into DCT domain and then operating SVD. The binary watermark image was embedded into the ponent of those SVD position after encryp ted by chaotic encryption. Due to the watermark was embedded three times, the amount of embedded information is increased. Watermark obtained by selecting best one from three watermarks extracted from watermarked image. The experiment results show the