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Photographic documents both in digital and in printed format plays a fundamental role in crime scene analysis. Photos are crucial to reconstruct what happened and also to freeze the fact scenario with all the different present objects and evidences. Consequently, it is immediate to comprehend the paramount importance of the assessment of the authenticity of such images, to avoid that a possible malicious counterfeiting leads to a wrong evaluation of the circumstance. In this paper, a case study in which some printed photos, brought as documental evidences of a familiar murder, had been fraudulently modified to bias the final judgement is presented. In particular, the usage of CADET image forensic tool, to verify printed photos integrity, is introduced and discussed. Language: en

Counterfeiting digital images through a copy-move forgery is one of the most common ways of manipulating the semantic content of a picture, whereby a portion of the image is copy-pasted elsewhere into the same image. It could happen, however, instead of a digital image only its analog version may be available. Scanned or recaptured (by a digital camera) printed documents are widely used in a number of different scenarios, for example a photo published on a newspaper or a magazine. In this paper, the problem of detecting and localizing copy-move forgeries from a printed picture is focused. The copy-move manipulation is detected by verifying the presence of duplicated patches in the scanned image by using a SIFT-based method, tailored for printed image case. Printing and scanning/recapturing scenario is quite challenging because it involves different kinds of distortions. The goal is to experimentally investigate the requirement set under which reliable copy-move forgery detection is possible. We carry out a series of experiments, to pursue all the different issues involved in this application scenario by considering diverse kinds of print and re-acquisition circumstances. Experimental results point out that forgery detection is still successful though with reduced performances, as expected.