计算机应用 ›› 2015, Vol. 35 ›› Issue (11): 3198-3202.DOI: 10.11772/j.issn.1001-9081.2015.11.3198

• 2015年全国开放式分布与并行计算学术年会(DPCS 2015)论文 • 上一篇    下一篇

基于JPEG双量化效应的图像盲取证

段新涛1,2, 彭涛1, 李飞飞1, 王婧娟1   

  1. 1. 河南师范大学 计算机与信息工程学院, 河南 新乡 453007;
    2. 河南省高校 "计算智能与数据挖掘"工程技术研究中心, 河南 新乡 453007
  • 收稿日期:2015-06-17 修回日期:2015-07-06 发布日期:2015-11-13
  • 通讯作者: 段新涛(1972-),男,河南新乡人,副教授,博士,CCF会员,主要研究方向:盲信号处理、图像处理.
  • 作者简介:彭涛(1989-),男,河南驻马店人,硕士研究生,主要研究方向:图像处理、盲分离; 李飞飞(1990-),女,河南新乡人,硕士研究生,主要研究方向:深度学习、盲分离;王婧娟(1992-),女,河南商丘人,硕士研究生,主要研究方向:数字图像处理、盲分离.
  • 基金资助:
    国家自然科学基金资助项目(U1204606);河南省科技攻关项目(142102210565);河南师范大学博士启动项目.

Blind image forensics based on JPEG double quantization effect

DUAN Xintao1,2, PENG Tao1, LI Feifei1, WANG Jingjuan1   

  1. 1. College of Computer and Information Engineering, Henan Normal University, Xinxiang Henan 453007, China;
    2. Henan Province Engineering Technology Research Center for Computing Intelligence & Data Mining, Xinxiang Henan 453007, China
  • Received:2015-06-17 Revised:2015-07-06 Published:2015-11-13

摘要: JPEG图像的双量化效应为JPEG图像的篡改检测提供了重要线索.根据JPEG图像被局部篡改后,又被保存为JPEG格式时,未被篡改的区域(背景区域)的离散余弦变换(DCT)系数会经历双重JPEG压缩,篡改区域的DCT系数则只经历了1次JPEG压缩.而JPEG图像在经过离散余弦变换后其DCT域的交流(AC)系数的分布符合一个用合适的参数来描述的拉普拉斯分布,在此基础上提出了一种JPEG图像重压缩概率模型来描述重压缩前后DCT系数统计特性的变化,并依据贝叶斯准则,利用后验概率表示出图像篡改中存在的双重压缩效应块和只经历单次压缩块的特征值.然后设定阈值,通过阈值进行分类判断就可以实现对篡改区域的自动检测和提取.实验结果表明,该方法能快速并准确地实现篡改区域的自动检测和提取,并且在第2次压缩因子小于第1次压缩因子时,检测结果相对于利用JPEG块效应不一致的图像篡改盲检测算法和利用JPEG图像量化表的图像篡改盲检测算法有了明显的提高.

关键词: 双量化效应, 盲取证, 图像篡改, 拉普拉斯分布

Abstract: The double quantization effect of JPEG (Joint Photographic Experts Group) provides important clues for detecting image tampering. When an original JPEG image undergoes localized tampering and is saved again in JPEG format, the Discrete Consine Transform (DCT) coefficients of untampered regions would undergo double JPEG compressing, while the DCT coefficients of tampered regions would only undergo a single compression. The Alternating Current (AC) coefficient distribution accords with a Laplace probability density distribution described with a suitable parameter. And on this basis, this paper proposed a new double compression probability model of JPEG image to describe the change of DCT coefficients after the double compression, and combined the Bayes criterion to express the eigenvalues of the image blocks which have undergone the single and double JPEG compression. A threshold was set for the eigenvalues. Then the tampered region was automatically detected and extracted by using the threshold to classify the eigenvalues. The experimental results show that the method can detect and locate the tamped area effectively and it outperforms in terms of the detection result compared with the blind detection algorithm of composite images by measuring inconsistencies of JPEG blocking artifact and image forgery detection algorithm based on quantization table especially when the second compression factor is smaller than the first one.

Key words: double quantization effect, image blind forensics, image tampering, Laplace distribution

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