[IPOL announce] new article: ZERO: a Local JPEG Grid Origin Detector Based on the Number of DCT Zeros and its Applications in Image Forensics

[announcements about the IPOL journal]

A new article is available in IPOL: http://www.ipol.im/pub/art/2021/390/

Tina Nikoukhah, Jérémy Anger, Miguel Colom, Jean-Michel Morel, and 
Rafael Grompone von Gioi,
ZERO: a Local JPEG Grid Origin Detector Based on the Number of DCT Zeros 
and its Applications in Image Forensics,
Image Processing On Line, 11 (2021), pp. 396–433.
https://doi.org/10.5201/ipol.2021.390

Abstract
This work describes a method for detecting JPEG compression as well as 
its grid origin. The JPEG algorithm performs a quantization of the DCT 
coefficients of non-overlapping 8 x 8 blocks of images, setting many of 
those coefficients to zero. The method described here exploits these 
facts and identifies the presence of a JPEG grid when a significant 
number of DCT zeros is observed for a given grid origin. This method can 
be applied globally to identify a JPEG compression, and also locally to 
identify image forgeries when misaligned or missing JPEG grids are 
found. The algorithm includes a statistical validation step according to 
Desolneux, Moisan and Morel's a contrario theory, which associates a 
number of false alarms (NFA) with each tampering detection. Detections 
are obtained by a threshold of the NFA, which renders the method fully 
automatic and endows it with a false alarm control mechanism.