Blind Forensics of Median Filtering in Digital Images

• Published in: IEEE transactions on information forensics and security Vol. 6; no. 4; pp. 1335 - 1345
• Main Author: Yuan, Hai-Dong
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-12-2011; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Blinds; Computer information security; Digital; Digital forensics; Digital images; digital tampering; Filtering; Filtration; Forensic engineering; Image coding; Image compression; Image databases; median filter; Noise reduction; steganalysis; Transform coding
• ISSN: 1556-6013; 1556-6021
• DOI: 10.1109/TIFS.2011.2161761

Exposing the processing history of a digital image is an important problem for forensic analyzers and steganalyzers. As the median filter is a popular nonlinear denoising operator, the blind forensics of median filtering is particularly interesting. This paper proposes a novel approach for detecting median filtering in digital images, which can 1) accurately detect median filtering in arbitrary images, even reliably detect median filtering in low-resolution and JPEG compressed images; and 2) reliably detect tampering when part of a median-filtered image is inserted into a nonmedian-filtered image, or vice versa. The effectiveness of the proposed approach is exhaustively evaluated in five different image databases.