【作者】 丁可；

【导师】 马小虎；

【作者基本信息】 苏州大学 ， 计算机应用技术（专业学位）， 2013， 硕士

【摘要】 互联网的发展给人们获取数字作品越来越方便，但是数字产品的版权问题也日益突出，迫切需要一种新技术对数字产品信息的版权、完整性和真实性进行保护。数字水印技术通过将一些有特殊意义的信息嵌入到数字产品中，通过对嵌入信息的提取与检测分析，用以证明原创作者的版权所有权，有效解决了数字产品的知识产权保护问题。本文在分析和研究国内外数字水印技术现状并借鉴了前人研究成果的基础上，重点研究了基于变换域的数字图像水印技术算法，设计了基于变换域的两种数字图像水印算法，并分别进行仿真实验测试以验证算法的有效性和可行性。1、提出了一种简单的基于离散余弦变换的数字图像水印算法。该算法首先将整幅图像分成块，对每一块分别进行DCT计算，在每一块中选取合适频段的系数，将水印信息分散嵌入到每一块所选取的DCT系数中，本算法简单且易于实现。实验结果表明该算法的水印不可见性较好。针对一般的攻击，水印具有较好的鲁棒性，但是针对大幅度的剪切攻击，提取水印效果较差。2、提出了一种基于奇异值分解和离散余弦变换的数字图像水印算法。该算法对分块DCT变换的系数矩阵进行SVD变换，奇异值分解的稳定性、隐藏性和降秩的特性有利于增强嵌入水印的不可见性和鲁棒性，MATLAB仿真结果表明，算法具有较好的不可见性和抗JPEG压缩、高斯通滤波和旋转等能力，同时对大幅度剪切攻击也具有较好的鲁棒性。更多还原

【Abstract】 The development and application of the Internet give people more and moreconvenient access to digital works, but digital copyright issues are also increasinglyprominent, there is an urgent need for a new technology of digital to product the copyrightof digital products and maintain the authenticity and integrity of digital works. Byembedding some particular information into digital works then extracting and detectingthese information， digital watermarking technology can prove the original author’scopyright and protect intellectual property rights of digital products. By studying digitalwatermarking technology status at home and abroad, this article focus on the transformdomain algorithm for digital image watermarking technology and designed two transformdomain-based digital image watermarking algorithm, and simulation experiments werecarried out tests to verify the validity and feasibility.1. This article proposed a simple DCT-based digital image watermarking algorithm.This algorithm divided a whole image into blocks，and DTC calculated for each blockseparately, then selected the appropriate frequency coefficients from each block andembedded the watermark information into each piece of dispersing the selected DCTcoefficients. This algorithm is simple and easy to implement. Experimental results showedthat the algorithm can extract a clear watermark. And for the general attack, the watermarkhas good robustness，but when subjected to shearing, salt and pepper filter, resize, rotate,attack，the robustness is not very good，the watermark information is difficult to identify.2. This article proposed an algorithm which based on SVD and DCT transform digitalimage watermarking. The algorithm block DCT transform coefficients matrix SVDtransform，the stability of singular value decomposition, hidden features and reduced rankis conducive to enhancing the embedded watermark invisibility and robustness. MATLAB simulation results showed that the algorithm has a relatively good invisibility andresistance to JPEG compression, and low pass filtering and shear capacity, while alsohaving a good noise suppression.更多还原