基于DCT的置乱水印算法研究

昆明学院2015 届毕业论文（设计）论文（设计）题目基于图像的信息隐藏技术研究

子课题题目基于DCT的置乱水印算法

姓名王宏斌

学号 201111010322

所属院系信息技术学院

专业年级2011级计算机科学与技术

指导教师李凯佳

2015年 5 月

数字化产品的广泛使用和传播中不可避免的引发非法复制以及篡改等问题，使数字产品的版权保护和数据安全成为科技发展中的一个重要问题，信息安全中的数字水印技术成为解决这个问题的关键，它利用数字产品中的冗余数据，将具有特定意义能被区分但不易察觉的水印信息加入其中，从而保护数字产品的完整性和版权。

本文深入了解国内外对信息隐藏中数字水印技术的研究，根据(DCT)离散余弦变换和(Anrold)置乱算法的原理，提出了一种基于DCT的置乱水印算法，其算法的思想是：首先对有意义的水印图像进行置乱处理，形成无意义的置乱水印。其次对载体图像和置乱后的水印进行分块，再进行DCT变换。最后运用嵌入算法和提取算法实现水印的嵌入和提取。由于运用了置乱算法，所以可以保证第三方无法对含水印图像进行水印提取，最大程度的保证水印的保密性。

论文最后对算法进行检验，首先对含水印图像进行剪切、旋转、加噪、滤波和压缩攻击，其次运用直方图算法比较水印攻击前后的相似度和运用峰值信噪比计算图像遭攻击前后的破坏程度。本算法能保证数字水印的透明性和安全性，对一般图像攻击具有一定的鲁棒性，为数字产品的完整性和版权保护提供了理论基础和实用价值。

关键词：信息隐藏; 数字水印; 置乱; DCT;鲁棒性;直方图;峰值信噪比

Abstract

The digital products widely use and spread inevitably lead to some problems such as illegal copying and tamper. These problems make the copyright protection and date security of digital product become an important problem in the development of science and technology. However the digital watermarking of information security is the key to solve this problem. Using the digital products redundant data, put the watermarking in formation join which has a specific meaning can be divided but imperceptible, so that e nsure the copyright and integrity of digital products.

This article in-depth knowledge the research at domestic and oversea for digital w atermarking technology in the information hiding, according to the theory of DCT for Discrete Cosine Transform and Scrambling algorithm, base on DCT came up with Scra mbling watermarking algorithm, The idea of algorithm is : Firstly, scrambling to deal with the meaning watermarking picture, make it become the meaningless Scrambling watermarking , Second, make the image carrier and the watermark which after scram bling to block, and then to DCT transfer. Finally using the embedding algorithm and ex traction algorithm realizes the watermark embedding and extraction. Due to the use of scrambling algorithm, so that ensure the third party can’t watermark extraction to wat ermarking image, Maximum guarantee the confidentiality of watermarking.

Finally of Test paper, the test algorithm, first of all to shear of the watermark imag e, rotate, adding noise, filtering and compression attack, then using the histogram algor ithm is compared the similarity of before watermark attacks and after,and using the pe ak signal-to-noise ratio to calculating the degree damage of images which have been att acked before and after. The algorithm can ensure the transparence and security of wate rmarking, have robustness for common image attack, stand up provides the theoretical basis and practical value for the integrity and copyright protection of digital products.

Keywords: Information Hiding; Digital Watermarking;Scrambling; DCT; Robustness; Histogram; Peak Signal to NoiseRatio

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