Forensic similarity is a digital forensics concept and technique that assesses whether two separate image regions share the same intrinsic forensic traces. These traces consist of visually imperceptible statistical patterns and device fingerprints introduced during capture and processing, including sensor noise, color filter array interpolation, and compression artifacts. Instead of classifying whether an image patch matches a specific, predefined editing method or camera model, forensic similarity measures the consistency of the underlying traces between pairs of patches. By identifying localized discrepancies across different areas of an image, this approach enables the detection and localization of tampering, such as image splicing or compositing, even when dealing with previously unseen processing operations or camera sources.
