In this paper, we present a forensic algorithm to discriminate between original and forged regions in JPEG images, under the hypothesis that the tampered image presents a nonaligned double JPEG compression (NA-JPEG). Unlike previous approaches, the proposed algorithm does not need to manually select a suspect region to test the presence or the absence of NAJPEG artifacts. Based on a new statistical model, the probability for each 8 × 8 DCT block to be forged is automatically derived. Experimental results, considering different forensic scenarios, demonstrate the validity of the proposed approach.
Analysis of Non-Aligned Double JPEG Artifacts for the Localization of Image Forgeries / T. Bianchi; A. Piva. - ELETTRONICO. - (2011), pp. 1-6. (Intervento presentato al convegno 2011 IEEE Workshop on Information Forensics and Security tenutosi a Foz do Iguaçu, Brazil nel November 29th - December 2nd 2011) [10.1109/WIFS.2011.6123159].
Analysis of Non-Aligned Double JPEG Artifacts for the Localization of Image Forgeries
PIVA, ALESSANDRO
2011
Abstract
In this paper, we present a forensic algorithm to discriminate between original and forged regions in JPEG images, under the hypothesis that the tampered image presents a nonaligned double JPEG compression (NA-JPEG). Unlike previous approaches, the proposed algorithm does not need to manually select a suspect region to test the presence or the absence of NAJPEG artifacts. Based on a new statistical model, the probability for each 8 × 8 DCT block to be forged is automatically derived. Experimental results, considering different forensic scenarios, demonstrate the validity of the proposed approach.
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