Contrasting results of surface metrology techniques for three-dimensional human fingerprints

Abstract: Fingerprints, otherwise known as dermatoglyphs, are most commonly thought of in the context of identification, but have myriad other roles in human biology. They are formed by the restricted ability of ridges and furrows of the epidermis to flatten. The patterns these ridges and furrows make can be represented as 2D fingerprints, but also as 3D structures with cross-sectional shapes that may add new levels of detail to identification, forensic, and behavioral uses/studies. Surface metrology techniques better allow for the quantification of these features, though it is unclear what tool and what scale is most appropriate. A Sensofar S Neox white light reflectance confocal microscope and a Gelsight Mobile 2 were used to independently measure the surface roughness of the fingerprints of four individuals from preserved cadaveric remains. Scale-sensitive fractal analyses (SSFA) were performed on the data from the S Neox (a small area), Gelsight (a larger area), and the same Gelsight datasets cropped down to the size of the S Neox scan size. Though fewer SSFA parameters identified differences between individuals from the smaller, extracted Gelsight area, all three forms of measurement found significant differences between some individuals from the study. No significant differences were found that differ between fingers themselves. Though only an initial step, these data suggest that a variety of surface metrology techniques may be useful in differentiating individuals.