为了提高隐写分析的检测率和效率,本文提出了一种加权融合的联合图像专家小组JPEG(joint photographic experts group)图像通用隐写分析方法.该方法分别计算离散余弦变换DCT(discrete cosine transform)系数块内和块间的水平、垂直和zigzag三向差分数组,采用联合概率密度矩阵来挖掘信息嵌入对DCT系数间相关性的影响,生成块内和块间三向特征.利用特征与分类类别间的互信息对特征权值进行量化,加权融合得到最终的特征向量,并使用支持向量机进行分类.对3种安全性较高的JPEG隐写算法F5、Outguess和MB2,在不同嵌入率下进行隐写分析.实验结果表明,在不同嵌入率的情况下其检测率均高于88.4%,同时特征融合算法使该方案具有更高的检测效率.
A new universal steganalysis scheme based on weighting fusion to attack JPEG(joint photographic experts group)steganography is presented to improve detection rates and efficiency.Firstly,difference arrays within and between DCT(discrete cosine transform)blocks along horizontal,vertical,zigzag directions are computed.Then,joint probability density matrix is applied to capture the impacts on the relevance of DCT coefficients caused by embedding process.And features from three directions are constructed.Finally,weights of each feature are quantified using the mutual information between features and classification classes.Final features vectors for steganalysis are derived by fusing the weighted features and are tested by SVM(support vector machine).The experimental results show that the proposed scheme provides reliable detection rates in attacking three steganographic schemes including F5,Outguess and MB2.The detection rates are higher than 88.4%,and the feature fusion method increases the detection efficiency.