基于后验概率的最低比特位隐写分析  

LSB Steganalysis Based on the Posterior Probability

作　　者：彭圆圆[1] 刘本永[1,2] 

机构地区：[1]贵州大学计算机科学与信息学院,贵阳550025 [2]贵州大学智能信息处理研究所,贵阳550025

出　　处：《科学技术与工程》2014年第5期120-123,共4页Science Technology and Engineering

基　　金：国家自然科学基金(60862003);科技部国际合作项目(2009DFR10530);贵州省工业科技攻关项目(黔科合GY字(2010)3054);教育部高等院校博士点基金(20095201110002);贵州大学研究生创新基金(2013044)资助

摘　　要：LSB隐写是将欲嵌入的秘密信息取代载体图像的最低比特位,是图像隐写最流行的方式之一。已经有大量算法来检测LSB隐写,但是对于图像最低位变化率的估计误差较大。探讨了一种基于后验概率的隐写分析算法:首先利用图像像素是否处于局部平滑区域进行建模,然后采用EM算法估计出图像中每个像素属于上述模型的后验概率并将后验概率作为此像素的权重,最后结合WS模型来估计图像最低位变化率。实验结果表明,该算法能有效地并且准确的估计图像最低位变化率。LSB steganography is a popular method for secret information embedding wherein the lowest bit plane of cover image is replaced by that of the embedded information.There are many efficient algorithms for LSB steganography detection,but the low bit rate change of cover image cannot be accurately estimated.A novel method is proposed to tackle the problem by using the posterior probability.Firstly,the relationship between the image pixels and the pixels around representation is established,based on which the EM algorithm is adopted to estimate the posterior probability for each pixel,and then the posterior probabilities are taken as weights to the pixels,so that the WS model is applied to estimate the low bit rate change.Experimental results show that this method can effectively and accurately estimate the low bit rate change,and thus the performance of the LSB steganography detection algorithm is improved.

关 键 词：最低比特位(least significht bit LSB)隐写 隐写分析 后验概率估计 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]