【作者】 张怡；

【导师】 王慧琴；

【作者基本信息】 西安建筑科技大学 ， 计算机应用技术， 2011， 硕士

【摘要】 随着信息技术的发展,高精度彩色喷墨激光打印机和高精度扫描仪得到广泛的应用,票据、证件、货币以及产品外包装等印刷品的篡改和伪造变得非常容易。因此需要一种新的印刷品防伪技术来解决印刷品的伪造篡改问题。抵抗打印和扫描过程对图像的攻击是印刷品数字水印技术的关键,本文首先介绍了打印机和扫描仪的工作原理及其机械特性,分析了打印和扫描过程对图片质量的影响,在此基础上研究了应用于印刷品防伪的数字水印算法。通过对数字水印、小波分析、混沌置乱和模糊积分融合理论的深入探讨,本文研究了一种基于模糊积分融合的小波域印刷品数字水印算法,该算法具有很好的鲁棒性,能够抵抗打印扫描过程的攻击。置乱算法具有良好的安全性和置乱效果,因此首先通过混沌置乱对水印图像进行加密,该方法将混沌序列的初始值作为置乱的密钥;然后对载体图像进行小波变换,选择在小波域的低频系数和高频系数中嵌入加密的水印图像;水印提取时对待检测图像进行小波变换,比较原始水印图像和待检测图像的小波低频系数和高频系数得到不同分量所含有的水印信息,通过模糊积分融合策略得到最终的加密水印,最后利用混沌置乱解密算法还原水印信息。本文的最后对数字水印技术未来的研究方向进行了展望,期待着越来越多的水印算法出现。更多还原

【Abstract】 With the development of information technology, the high accuracy color ink-jet laser printer and high precision scanners are widely used, the manipulation and falsification of presswork such as bill, certificates, currency and product outer package is easier than before. Therefore, we need a new presswork anti-counterfeiting technology to solve the problem of manipulation and falsification.Resisting attack on image during the process of print and scan is the key to print digital watermarking technology. This paper firstly introduces the working principle and mechanical characteristics of printer and scanner, analyses the influence of print and scan to the picture quality, and on this basis, to research the presswork anti-counterfeiting watermarking algorithm.Through further study on the digital watermarking, wavelet analysis theory, chaotic scrambling theory and fuzzy integral integration theory, this paper puts forward a kind of wavelet domain presswork digital watermarking algorithm based on fuzzy integral fusion, which has good robustness, and can resist the attack during the process of print and scan. Hashing algorithm has good safety and scrambling effect, therefore, we firstly encrypt the watermark image through the chaos of scrambling, which will take the initial value of chaotic sequence as the scrambling key; Then we carry out wavelet transform to the carrier image, choose to embed watermark image encryption in low-frequency coefficients and high frequency coefficients of wavelet transform domain; carry out wavelet transform to the images to be detected when extracting watermark; compare the wavelet low-frequency coefficients and high frequency coefficients of original watermark image and images to be detected and get watermark information of different components, get the ultimate encryption watermark through fuzzy integral fusion strategy, and finally, using the chaotic scrambling watermark declassified algorithm to restore the watermark information.At the end of this paper, we prospect the future research direction of the digital watermarking technique, and look forward to more and more watermarking algorithms.更多还原