一种基于DCT系数直方图差异的JPEG图像篡改检测

Detection Method for JPEG Image Based on the Difference of DCT Coefficient Histograms

JPEG图像是人们日常接触最广泛的图像格式,因此对此类图像的篡改检测有着更加重要的意义。以JPEG图像篡改压缩后篡改区域相当于一次压缩为理论基础,研究了一次压缩和双JPEG压缩的基本原理,分析了质量因子Q1、Q2之间的大小关系对双压后图像DCT系数直方图统计特性所引起的变化,并分2种情况对图像进行分块求其DCT系数直方图,根据不同的方法判定图像块经过了一次还是二次压缩,从而在此基础上提出了一种基于DCT系数直方图的JPEG图像篡改检测算法。实验表明,该算法不仅运算复杂度低,而且对篡改区域有很好的检测和定位效果。

JEPG format of images is the most widely used image format in people＇ s daily life, so the tamper detection on this kind of image has a more important significance. Under the theoretical basis that the tampered area in the compressed JPEG image is equivalent to one compression, the basic principles of one and double compressed JEPG image were researched. The influence of the size of rela- tlonship between quality factors Qt and Q2 on the histogram of DCT coefficients of the double compressed image was analyzed, and two cases were carried out to find its histogram by the image block DCT coefficients. Then different methods were used to determine whether the image block was compressed once or twice. Finally, image tamper detection algorithm for JPEG image based on DCT coefficients histogram was proposed. Experiments showed that the algorithm is not only low computational complexity, but also has a good detection and location results.