Date of Graduation
Eberly College of Arts and Sciences
Forensic and Investigative Science
Fingerprints are one of the most widely used identification features in both the biometric and forensic fields. However, the comparison and identification of fingerprints is made difficult by fingerprint variability arising from distortion. This study quantifies the limits of fingerprint variability when subject to heavy distortion, and the variability observed in repeated inked planar impressions. Fingers were video recorded performing several distortion conditions under heavy deposition pressure: left, right, up, and down translation of the finger, clockwise and counter-clockwise torque of the finger, and planar impressions. Fingerprint templates, containing `true' minutiae locations, were then created from 10 inked planar impressions for 30 separate fingers. The 30 fingers studied consisted of 10 right slant loops, 10 plain arches, and 10 plain whorls. A minimal amount of variability, .18 mm globally, was observed for minutiae in inked planar impressions. When subject to heavy distortion minutiae can be displaced by upwards of 3 mm and their orientation altered by as much as 30 degrees. Minutiae displacements of 1 mm and 10 degree changes in orientation are readily observed. The results of this study will allow fingerprint examiners to identify and understand the degree of variability that can be reasonably expected throughout the various regions of fingerprints.
Fagert, Michael, "Quantifying the Limits of Fingerprint Variability" (2014). Graduate Theses, Dissertations, and Problem Reports. 327.