Benchmarking contact-less surface measurement devices for fingerprint acquisition in forensic investigations: Results for a differential scan approach with a chromatic white light sensor

With the advent of new contact-less sensors for forensic investigations of latent fingerprint traces, the authors see the need for a benchmarking framework to evaluate existing devices and promising combinations of data acquisition and signal processing techniques. This paper extends the existing benchmarking framework from [1] by categorizing it into properties from a forensic point-of-view (end-user) and a technical point-of-view (scientific-user) and applies a known differential image technique for the subjective evaluation of which traces are visible. We show exemplary results for a chromatic white light (CWL) sensor for the surface quality assessment, using and comparing the experimental setup of 10 surfaces from [1] and additional 10 surfaces, including real-world objects, to determine its potential for detecting latent fingerprints. Using a differential image approach, the particular influence of sensor noise signals is analyzed, showing that this differential approach cannot always be considered as an ideal filter for fingerprint pattern detection.