Abstract: In this paper, we describe a new forensic tool for revealing digitally altered images by detecting the presence of photo-response non-uniformity noise (PRNU) in small regions. This method assumes that either the camera that took the image is available to the analyst or at least some other non-tampered images taken by the camera are available. Forgery detection using the PRNU involves two steps – estimation of the PRNU from non-tampered images and its detection in individual image regions. From a simplified model of the sensor output, we design optimal PRNU estimators and detectors. Binary hy-pothesis testing is used to determine which regions are forged. The method is tested on forged images coming from a variety of digital cameras and with dif-ferent JPEG quality factors. The approximate probability of falsely identifying a forged region in a non-forged image is estimated by running the algorithm on a large number of non-forged images.

  publisher    = {Springer},
  author       = {Mo Chen and Jessica Fridrich and Jan Luk\'{a}\v{s} and Miroslav Goljan},
  url          = {http://www.ws.binghamton.edu/fridrich/Research/Digital_xray_full.pdf},
  journal      = {Proc. of 9th Information Hiding Workshop, Saint Malo, France, June},
  year         = {2007},
  title        = {Imaging sensor noise as digital {X}-ray for revealing forgeries},