[IPOL announce] new article: A Reliable JPEG Quantization Table Estimator

[announcements about the IPOL journal]

A new article is available in IPOL: http://www.ipol.im/pub/art/2022/399/

Tina Nikoukhah, Miguel Colom, Jean-Michel Morel, and Rafael Grompone von 
Gioi,
A Reliable JPEG Quantization Table Estimator,
Image Processing On Line, 12 (2022), pp. 173–197.
https://doi.org/10.5201/ipol.2022.399

Abstract
JPEG compression is a commonly used method of lossy compression for 
digital images. The degree of compression can be adjusted by the choice 
of a quality factor QF. Each software associates this value to a 
quantization table, which is an 8 x 8 matrix used to quantize the DCT 
coefficients of an image. We propose a method for recovering the JPEG 
quantization table relying only on the image information, without any 
metadata from the file header; thus the proposed method can be applied 
to an uncompressed image format to detect a previous JPEG compression. A 
statistical validation is used to decide whether significant 
quantization traces are found or not, and to provide a quantitative 
measure of the confidence on the detection.