Abstract: In digital image forensics, it is generally accepted that intentional manipulations of the image content are most critical and hence numerous forensic methods focus on the detection of such `malicious' post-processing. However, it is also beneficial to know as much as possible about the general processing history of an image, including content-preserving operations, since they can affect the reliability forensic methods in various ways. In this paper, we present a simple yet effective technique to detect median filtering in digital images—a widely used denoising and smoothing operator. As a great variety of forensic methods relies on some kind of a linearity assumption, a detection of non-linear median filtering is of particular interest. The effectiveness of our method is backed with experimental evidence on a large image database.

  url          = {http://www.ws.binghamton.edu/fridrich/Research/SPIE_median.pd},
  booktitle    = {SPIE Conference on Media Forensics and Security},
  author       = {Matthias Kirchner and Jessica Fridrich},
  location     = {San Jose, CA},
  year         = {2010},
  title        = {On detection of median filtering in digital images},