Finger print classification

What is a fingerprint?

• Finger skin is made of friction ridges, with pores (sweat glands). Friction ridges are created during fetal live and only the general shape is genetically defined

Primates also have fingerprints

So do koalas!

General Characteristics – macro-singularities

• Loops

• Whorls

• Arches

Arch

Tented Arch

Loops

Left loop Right loop

Double loops

Whorl

Type lines

Ridge lines often flow in parallel producing features called whorl , loop and delta

The ridge-line flow can be described by a directional map

(or directional image) which is a discrete matrix whose elements denote the orientation of the tangent to the ridge

lines.

Minutiae

• Minutiae play a primary role for fingerprint matching, since most of the algorithms rely on the coincidence of minutiae to state whether two impressions are of the same finger or not.

• Minutiae matching, which is essentially a point pattern matching problem, constitutes the basis of most of the automatic algorithms for fingerprint comparison.

Types of minutiae

Micro-singularities, called minutiae or Galton characteristics, are determined by termination or

bifurcation of the ridge lines.

Fingerprint minutiae

Bifurcation, ridge ending, core, delta

Deltas

Fingerprint matching – finding points of correspondence

Accidental – unusual combinations

Scars produce unusual patterns

Some skin conditions can produce altered fingerprints

Twins have different fingerprints: overall pattern is similar, differ in fine details