基于投影数据主成分分析的图像篡改检测算法

传统算法处理图像复制-粘贴型篡改问题时速度较慢。为此，提出一种基于投影数据主成分分析(PCA)的图像篡改检测算法。利用分块图像的行、列投影构建图像块投影特征矩阵，通过PCA对其降维，并使用字典排序法进行排序，结合图像块偏移置信距离判断图像复制-粘贴区域，完成被动取证。实验结果表明，该算法能准确找出篡改区域，与Posucue算法相比速度较快。

Detection Algorithm of Image Forgery Based on Principal Components Analysis of Projection Data

Aimming at the defects of Posucue algorithm which is time-consuming in finding copy-paste forgery in image tampering,a new algorithm based on Principal Components Analysis(PCA) of projection features is put forward.A tampered image is divided into many overlapped small image blocks.The horizontal projection and vertical projection of each image block are gained to build up a matrix.Dimensionality reduction of this matrix is completed by PCA.Then Lexicographic Sorting is applied.With a threshold distance of each neighborhood block in the dimensionality reduced matrix,the copy-paste area can be found.Experimental result shows that this new algorithm can find the exact copy-paste areas and be more rapid than Posucue algorithm.