文档介绍：职工工资综合管理系统的设计与实现
摘要
随着网络对媒体技术的广泛应用和发展,国际互联网已成为知识经济时代重要传播途径之一。但随之而来的盗版和侵权行为也越来越猖獗。近年来在数字世界里出现了多种能够保护多媒体信息安全的技术。图像数字水印技术作为一种新兴的防盗版技术,其实质是一种运用图像处理实现的信息隐藏技术。核心就是将数字水印信息嵌入到图像中,同时保证人眼感觉不到图像质量的下降,即尽量保证所加的水印不可察觉。这是解决版权问题的有效方法。
本文叙述了数字水印的一些基本知识,包括数字水印的分类、基本特性、基本框架;以及现有的一些关键的数字水印的方法。在分析总结前人研究的基础上,我主要研究的是图像方面的数字水印。在这里我向大家介绍基于DCT域和LSB算法的图像数字水印技术。数字水印是符合标准正态分布的伪随机序列。为保证视觉透明性和稳健性,将水印嵌入在图像的中频部分,用水印序列对中频部分进行加权非线性调制。
最后我用MATLAB实现了图像文件数字水印技术,包括嵌入水印,检测水印。而且给出了所做程序的源代码及运行的结果。
关键词:信息隐藏、数字水印、离散余弦、LSB。
Abstract
With the evolution and booming work and multimedia technology, es one of the most important ways for information spreading. But illegal copies and es together with it. There have emerged many techniques for protecting the security of multimedia information in digital world in recent year. Image digital watermark technique is a new copyright protection technique , which, in fact, is information hiding technique used in image processing field. The fundamental of this approach is embedding digital watermark information into image, at the same time keeping the image quality degradation imperceptual . This is an effective way for copyright protection.
This thesis describes the fundamental knowledge of digital watermark, including categorizes and basis characteristic and basis frame of digital watermark; and some key watermark method existed at on analyzing and studying the current research, I major in the image digital watermark. I will introduce watermark based in DCT and watermark need to be embedded in image is a pseudo-random sequence of real numbers. In order to provide perceptual transparency and robustness, this thesis embeds the watermark into middle frequency of image, that means middle frequency coefficients are modulated in a non-linear way according to the watermark sequence .
Finally I carry out watermark with the encode the watermark and decode the watermark . Furthermore, I give the source codes and results of MATLAB p