#fingerprintcomparison

[forensicfield]

Question- How is fingerprint matching done? Answer- fingerprints can be compared to each other by examining the minutiae to determine whether: • the same minutiae are present (eg a bifurcation); • the minutiae flow in the same direction (eg the bifurcation is on a ridge running horizontally and the two divided ridges are to the right of the bifurcation); and • the minutiae occupy the same relative positions to each other (eg the bifurcation is separated from an enclosure below it by six intervening ridges). Where minutiae on two different fingerprint impressions meet these criteria, they are referred to as points of similarity. Where minutiae do not meet these criteria, they are referred to as points of dissimilarity. When sufficient minutiae are located in the same true relative sequence or unit relationship, then an identification is assumed, and the points of similarity are referred to as points of identification.

Fingerprints have usually 20 to 30 minutiae and two fingerprints are considered to be matched if they have more than 10 matched minutiae.

Question- How many points are needed for a fingerprint match? Answer- Fingerprint experts can disagree about how many points in common are needed to declare a match between two sets of fingerprints. For example, some experts will declare a match based on only 12 points in common, whereas other experts may require up to 20 points in common before declaring a match.