Resolution and size of measured area influences on the short- and long-term aging of latent fingerprint traces using the binary pixel feature and a high-resolution non-invasive chromatic white light (CWL) sensor

Determining the age of a latent fingerprint trace found at a crime scene is an unresolved research issue since decades. Adopting a high-resolution, optical, non-invasive measurement device (FRT-MicroProf 200 CWL 600) from the area of surface quality measurement and combining it with pattern-recognition techniques might allow us to finally solve this important research challenge. Based on previous work, we evaluate the promising binary pixel aging feature, investigating its dependency on the resolution (1, 2, 3, 5, 10μm) and the size of the measured area (3×3, 5×5, 10×10mm) for the aging of 16 different latent fingerprint traces, in respect to the short-term aging (<;4days) and the long-term aging (>;4days), leading to a total of 739 scans. Our first experiments show a promising tendency that the binary pixel feature has a very characteristic, logarithmic aging curve for all tested resolutions and sizes of measured area for the short- and long-term aging.