Determining approximate age of digital images using sensor defects
Determining approximate age of digital images using sensor defects
复制标题
使用传感器缺陷确定数字图像的大致年龄
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
M. Goljan
中科院分区：
文献类型：
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作者：
J. Fridrich;M. Goljan
时间取证的目标是在两个或多个证据之间建立时间关系。在本文中，我们专注于数字图像，并描述了一种方法，使用该方法，分析师可以估计一个图像的采集时间给定的一组其他图像从同一相机的时间顺序是已知的。这是通过首先估计像素缺陷的参数，包括它们的起始点，然后检测它们在所研究的图像中的存在来实现的。这两个估计量都是使用最大似然原理构造的。这种方法的准确性和局限性的实验与三个摄像头。法医和执法分析师预计将受益于这种技术的情况下，存储在EXIF头的时间数据丢失，由于处理或编辑图像离线或当头不能信任。确定各个证据之间时间顺序的可靠方法有助于揭露对手或罪犯的欺骗企图。因果关系还可以提供有关摄影师下落的信息。
The goal of temporal forensics is to establish temporal relationship among two or more pieces of evidence. In this paper, we focus on digital images and describe a method using which an analyst can estimate the acquisition time of an image given a set of other images from the same camera whose time ordering is known. This is achieved by first estimating the parameters of pixel defects, including their onsets, and then detecting their presence in the image under investigation. Both estimators are constructed using the maximum-likelihood principle. The accuracy and limitations of this approach are illustrated on experiments with three cameras. Forensic and law-enforcement analysts are expected to benefit from this technique in situations when the temporal data stored in the EXIF header is lost due to processing or editing images off-line or when the header cannot be trusted. Reliable methods for establishing temporal order between individual pieces of evidence can help reveal deception attempts of an adversary or a criminal. The causal relationship may also provide information about the whereabouts of the photographer.