基于图像的数字密写技术研究

【作者】 董雯；

【导师】 冯乔生；

【作者基本信息】 云南师范大学 ， 计算机软件与理论， 2007， 硕士

【摘要】 近年来,随着计算机、网络、多媒体以及数字信号处理等技术的飞速发展,信息隐藏技术成为了科学技术领域的研究热点。信息隐藏技术应用范围广泛,其中数字密写是它的一个重要应用领域,因为密写通信与传统通信方式相比,具有良好的隐蔽性和安全性,因此日益受到国家有关部门尤其是国家安全和军事部门的重视。数字密写是以图像、音频、视频等数字媒体作为掩护,把需要传递的秘密信息嵌入到载体的信号内部以不引起外界注意的方式,通过公共信道,特别是互联网进行传递,其目的是保护被嵌入的秘密信息。本文围绕密写技术所做的主要研究工作如下:一、提出了一种基于Logistic映射的新的混沌序列二值化方法。该方法可以使得所二值化的序列保持其原混沌序列所具有的良好随机性,而且该序列具有良好的初值敏感性,进一步提高了由此序列所加密的密写信息的安全性。二、对一种基于离散余弦变换的大容量信息隐藏盲提取算法进行了深入研究,实验了该算法的有效性,并在研究已有成果的基础上使用了一种更容易实现的分块方法,考虑到人眼的视觉特性,将秘密信息嵌入在分块DCT系数的中频系数上,使得用同一副灰度图像嵌入信息时,在选取相同阈值及嵌入信息量相同的情况下,提高了峰值信噪比(PSNR)。三、将改进过的方法应用到彩色图像中,由于人眼对红、绿、蓝三种颜色的敏感程度不同,人眼对绿色敏感度最高,红色次之,商蓝色最低,由此提出了一种嵌入信息时对不同的颜色分量采取不同修改幅度的方法,兼顾了人眼的视觉特性。四、对LSB(最低有效位)算法进行了研究,实验了该算法的有效性,并在研究已有成果的基础上提出了一种大容量低有效位嵌入算法,将混沌调制过的秘密信息嵌入到灰度图像的最低及次低位平面,嵌入过程用另一个二值混沌序列来控制选择嵌入一个或两个位平面,进一步增强了安全性。更多还原

【Abstract】 In recent years, with computers, networks, multimedia and digital signal processing of the rapid development of technology, Information technology has become a hidden area of science and technology research focus. Hiding information technology applications, which covers a wide range digital steganography is one of its important areas of application, because steganography communication with the traditional means of communication, it will have a good concealment and security, So increasingly relevant departments of the state, particularly national security and military departments attention. Digital steganography is based on images, audio, video and other digital media as a cover, requiring the transfer of secret information embedded within the vector signal not attracted the attention of the way through public access, in particular the Internet transmission, its purpose is the protection of secret information embedded. This paper around steganography technology has done research work are as follows :1. Raise a logistic-based mapping of the new chaotic sequence binary method. This method can be made by the two values of the original series maintain its chaotic sequence with a good randomness, but the sequence has good initial sensitivity to further enhance the resulting sequence of steganography encryption information security.2. Based on the discrete cosine transform, large capacity information Hiding Algorithm for in-depth study Experimental the validity of the algorithm, and the study results have been used on the basis of a more easily achieve the block, Taking into account the human visual characteristics of secret information embedded in a block of DCT coefficients IF coefficient, Deputy makes the same gray images embedded information, the selection of the same threshold value and amount of information embedded in the same circumstances, improves PSNR (PSNR).3. It will improve over the method is applied to color images, as people focus on red, green, blue three colors of the different sensitivities, human eye is more sensitive to green, followed by red and blue minimum, This presents a embedding information on different colors, different components of the revised range, taken into account the human visual characteristics.4. Study the LSB (Least Significant Bits) and experiment of the effectiveness of the algorithm, and the results of the study have been submitted on the basis of a large-capacity effective low-embedding algorithm, Modulation of chaos over the secret information embedded in the gray-scale image and the second lowest low level, embedding process another two values to control the chaotic sequence embedded in a choice of two or plane, further enhance security.更多还原