【作者】 高尚伟；

【导师】 李金；

【作者基本信息】 哈尔滨工程大学 ， 控制理论与控制工程， 2002， 硕士

【摘要】 随着计算机技术的发展和相关信息技术的进步，特别是Internet用户的急剧增加和多媒体技术的飞速发展，数字化产品越来越普及。由于数字化产品的传播、复制、篡改和窃取比较容易，所以如何有效的保护数字产品的版权和防止数字产品的盗版就变得越来越紧迫。作为一种新型的有效的版权保护手段，数字水印技术倍受人们的关注。本文通过对数字水印技术的研究和讨论，设计并实现了基于小波变换基础上的静止图像数字水印系统。 论文首先系统地研究了数字水印的基本概念和定义、数字水印技术的基本属性、数字水印技术的基本原理、数字水印技术的分类、数字水印技术的评价标准，并讨论了传统的保密技术的缺陷及与数字水印技术的区别。 针对小波分析理论，论文介绍了小波和小波理论的基本定义、正交小波与多分辨率分析、尺度方程和构造方程和Mallat算法及在图像处理中的应用。在此基础之上，详细讨论了小波理论在数字水印中的应用，重点讨论了二维离散小波对静止图像的分解和重构原理。 对于静止图像的水印技术，论文首先介绍了静止图像的格式，然后重点讨论了水印的选取、水印变换方法的选择以及水印的嵌入位置和嵌入、抽取算法及其相关技术。在保证水印不可见和鲁棒性的前提下，论文基于小波变换提出一种图像自适应的数字水印方案。这种方案以图像为水印，基于扩频原理，充分利用小波变换的优良特点和人眼视觉特性，结合图像自身特性，使嵌入的水印既有良好的鲁棒性又有良好的容量。 基于图像自适应的数字水印方案之上，论文利用小波变换在YUV颜色模式空间以视觉上直观可见的图像作为水印，设计了灰度图像自适应数字 哈尔滨工程大学硕士学位论文 一 水印系统和彩色图像数字水印系统，并进行一系列鲁棒性试验。实验结果 硼。本文所设汁的两个数字水印手钩中的水口具有电好的不可m付＃ 能抵抗有损压缩、剪切、平滑和放缩等常见的图像操作，具有良好的鲁棒 性。更多还原

【Abstract】 Wth the advancement of computer technology and the progresses ofiriformation technology, especially the sharp increase of the Intemet users andfast development of the multimedia technology digitalized products havebecome more and more popular It is much easer for transmitting, copying,tampering and pilfering of digital data. Thus, it is increasingly urgent that how toprotect the copyright of digital data effectively and prevent the pirate of digita1data. As a new tyPe and effective means fOr the protection of digital dat4 muchattention fOcuses on digital watermarks. On the basis of the discussion andinvestigation of digital watermarks, the design and realization of the still imagedigital watermarking systems on the wavelet transform are presented in thisdissertaion.The fundamentals, such as basic concepts, definition, main feature. basicprinciple, classification and the evaluation standard of digital watermarking, aresystematically stUdied in this dissertation. The difference is discussed betweenconventional cryptographic systems and digital watermarking systems also.Besides, the basic definition, orthogonal wavelet and multi-resolution anaIysis,scaling equation and construction equation and the aPplication of MallatarithInetic in the image processing are introduced in the dissertation as well. Anddetail discussion of the aPplication of the theory of wavelet in the digitalwatermarking, especially, the discussion centered on the theory of the two-dimension wavelet decomposition and reconstruction for the still images, aregiven in this dissertation.Fol1owing the introduction of the format of still images, the selection ofwatermark and the choice of the transform, embedding position of the watermark,embedding and extYacting arithInetic of the watermark are discussed. At last anew image-adaPtive Waermarking scheme is brought forward, which takes fulladvatage of the good characters of wavelet bof Orm and human visual systembased on spread spectri theory And the algorithrn has good robusiness andcaPacityBoth the gray - l ev e l - im ag e - adapti ve watermarking system and c o lor- imagewatermarking system based on the image-adaptive watermarking scheme in theYUV color-mode space are implemented. The results of compuler simulationshow that the proposed watermarking methods satisfy the requirements ofrobustness and transparency. This scheme can resist the conunon imageprocessing operations, such as lossy compression, cropping, filtering and scaling.更多还原