From announce at list.ipol.im Tue May 24 15:32:00 2022 From: announce at list.ipol.im (announcements about the IPOL journal) Date: Tue, 24 May 2022 15:32:00 +0200 Subject: [IPOL announce] new article: A Reliable JPEG Quantization Table Estimator Message-ID: 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.