无损信息隐藏技术

【作者】 陶奉芝；

【导师】 杨厚俊；

【作者基本信息】 青岛大学 ， 计算机应用技术， 2008， 硕士

【摘要】 随着信息和多媒体技术的飞速发展,多媒体信息给人们的生活创造了极大地便利,但同时也暴露出越来越多的安全隐患问题。信息隐藏技术作为信息安全技术研究领域中的一个新兴方向得到广泛关注,在版权保护、信息认证、篡改提示、国家安全、秘密通信等方面,也得到了广泛的研究和应用。但是由于在信息隐藏的过程中通常会引起原始数据发生不可恢复的改变,而这种改变所带来的失真对原始数据要求较高的应用领域中是不能忽略的,因此迫切需要一种既能有效地避免破坏原始数据信息,又能通过隐藏数据发挥作用的新方法—无损信息隐藏技术。无损信息隐藏方法作为信息隐藏技术的分支,不仅可以从载体数据中提取出完整的隐藏数据,还可以得到原始的不含隐藏数据的准确拷贝。本文首先回顾了信息隐藏特别是无损信息隐藏的技术发展,在现有理论基础上提出的已有的算法,并根据嵌入原理的不同,从空域和频域上分别进行了介绍;然后研究了整数小波变换的原理和其在无损信息隐藏技术的应用;最后着重介绍了频域中的无损信息隐藏方法实现。这其中贯穿了无损信息隐藏方法中涉及到的如直方图调整、置乱、压缩处理等技术的介绍说明。频域中的无损信息隐藏算法首先根据整数小波变换后频域上小波系数对空域中的像素值的变换,对原始图像进行直方图的调整,然后进行小波变换并选择在小波系数的高频中嵌入隐藏数据信息,再经过小波逆变换得到嵌入数据后的隐蔽图像,从而实现无损信息隐藏。为了突出本算法的优点,本文还进行了另外两种的实现方案:第一个方案是对图像进行一次整数小波变换,在三个高频区利用各自的峰值(零点处)嵌入数据,实现无损信息隐藏;第二个方案是对图像进行一次整数小波变换,然后在三个高频和一个低频嵌入数据,三个高频区的嵌入使用相同的算法,低频区的嵌入算法同空域中类似,最后进行整数小波逆变换实现无损信息隐藏。通过最后的实验结果表明在相同的峰值信噪比下,本文中提出的算法比已有的算法具有更高的数据嵌入量,而且在较高的峰值信噪比条件下,依然比其它方法有较大的数据信息嵌入量。更多还原

【Abstract】 In the recent years,the rapid development of computer information and the increased use of multimedia data via the Internet have resulted in the faster and more convenient exchange of digital information.On account of the ease of editing and perfect reproduction,it is important to prevent unauthorized manipulation of digital content. Information hiding,a technique to embed special labels in digital contents,has led to much research recelently.However,most information hiding methods introduce distortions to the original content,the embedding distortion is irreversible,it cannot be removed to recover the original host signal.But some other authentication applications such as medical imagery and military image prohibit the permanent loss of image fidelity during hiding.It is often desirable to embed the information in a reversible way—reversible information hiding.The reversible information hiding as a branch of information hiding technique can not only remove the hided information,but also get the copy of the original data without any loss.Firstly this paper looks back the development of the information hiding especially the reversible information hiding technique,the new methods on the basis of existing theories,and introduces those methods by the different hiding theories.secondly,this paper recommends the integer wavelet transform and it’s application in the reversible data hiding.Lastly this paper emphasizes the reversible information hiding in the frequency domain.it also shows the releted knowledge such as histogram modification,disarrange technique,compression throughout the last part.In the frequency domain,we make the modification of histogram by the transform of integer wavelet corresponding in the spatial domain,then embed the data in the high coefficient,at last make the countertransform to finish the method.The method chooses six frequences,three high and three low to embed data after two transforms of integer wavelet.In order to show the excellence of this method we also give other two projects. The first one chooses the peak of three high frequences to hide the data after one integer wavelet transform;while the second one chooses three high frequences and one low frequence.The same algorithm is used in the same high frequence;however the method in the spatial domain is used in the low frequence.In the end the experimental results show the method in this paper can embed more information and have good visual quality according to the same peak siginal-to-noise, especially the method has good result in terms of both capacity and visiual quality.更多还原