【作者】 田佳卉；

【导师】 陈玉华；

【作者基本信息】 大连海事大学 ， 计算机应用技术， 2005， 硕士

【摘要】 在公安刑侦及法庭判案领域中,数字图像作为重要的证据,其真实性和完整性 直接影响到执法结果。随着数字图像处理技术的快速发展,对数字图像进行处理 修改变得越来越容易,处理效果也越来越逼真。蓄意修改图像证据的内容以便遮 掩事实得到期望的断案结果通常被称为恶意篡改,其后果的严重性已经受到有关 部门的关注。因此,公安刑侦图像证物的篡改提示这一课题亟待解决。 鉴别图像是否被篡改,嵌入水印是行之有效的方法。本文就是以数字水印技 术为基础,展开这个课题的研究。通过调研发现:用于证据图像篡改提示的数字 水印,对图像细微的更改要具有高灵敏度,对常规的图像处理(如:滤波,亮度 增强)要具有一定的容忍度。针对这两个特点,本文在对现有的数字水印算法及 相关技术进行了大量分析、研究的基础上提出了两个改进算法,分别满足图像证 物水印的不同要求: (1)基于LU矩阵分解和Arnold置乱变换的空域水印算法; (2)基于JND的小波域水印算法。 同时,结合实际应用,开发出水印嵌入及提取模块,将其添加在公安刑侦图像 处理软件中并投入使用,达到了预期效果。更多还原

【Abstract】 With the rapid development of digital images processing, It turns to be easy to modify digital images and the result is more and more similar to the original images. As the most important evidence, the images always decided the result that made by policemen and judges. The illegal modification of images could get the expected result. The serious infection was focused on by policemen and the departments concerned and should be solved urgently.Fragile watermark is the efficient way to judge whether the images were changed or not. The dissertation research the issue based watermark. Firstly, I investigated the forensic images and get results that the watermark in forensic images should be fragile and they should found the tiny change in images, on the other hand the watermark should be robust to some common image process, for example, adjust brightness and filter. After that, I found out a lot of watermark arithmetic and do research on them. Finally, two method were bring out aim at the two attributes:(1) the watermark based LU decomposition and Arnold transfer.(2) the watermark based JND and wavelet decomposition. They were put into works and run well.更多还原