FINGERPRINT:FINGER BIOMETRICS

by

Rajasekaran.T

INTRODUCTION

Fingerprinting was first created by Dr. Henry Fault, a British surgeon in 1882.

It based on “KEY”.

Fingerprint Patterns

Arch- The ridges enter from one side of the finger, rise in the centre forming an arc, and then exit the other side of the finger. Loop-The ridges enter from one side of a finger, form a curve, and then exit on that same side. Whorl-Ridges form circularly around a central point on the finger.

Arch Loop Whorl

Sales

LoopwhorlArch

The human population has fingerprints in the following percentages:

Loop – 65% Whorl -- 30% Arch -- 5%

population

LoopWhorlArch

Whorl1.Double Loop

Whorl.

2.Plan whorl.

3.Central.

pocket Loop whorl.

4.Accidental whorl.

Loop1.Uinar Loop.

2.Radial Loop.

Arch1.Plain Arch.

2.Tented Arch.

Different Identification on Fingerprint

Crossover: two ridges cross each otherCore: centreBifurcation: ridge separatesRidge ending: end pointIsland: small ridge b/w two spacesDelta: space between ridgesPore: human pore

Bifurcation Bridge Dot Double bifurcation

Opposed bifurcation

Island (short ridge)

Hook (spur) Lake (enclosure)

Ridge crossing Ridge ending TrifurcationOpposed bifurcation/ridge ending)

Fingerprint matching techniques

There are two categories of fingerprint matching techniques:

1. minutiae-based .2. correlation based.

Minutiae-based techniques first find minutiae points and then map their relative placement on the finger. 

The correlation-based method is able to overcome some of the difficulties of the minutiae-based approach. 

Two main technologies used to capture image of the fingerprint

Optical sensor – use light refracted through a prism. An optical sensor based reader uses light to read and acquire fingerprint images. Optical sensors can be affected by a number of real life factors such as stray light, surface contamination or even prior fingerprint impressions present on the sensor surface. Hence it is essential to clean the fingerprint reader glass on a regular basis for optimal performance.

Capacitive sensor – detect voltage changes in skin between ridges and valleys. Capacitive sensors use electric current to sense a fingerprint and capture the image. As sensors apply a small voltage to the finger, a real fingerprint is required rather than a visual impression of it. This technique makes the fingerprint reader more reliable as it becomes harder to fake enrolment.

Image Processing

Capture the fingerprint images and process them through a series of image processing algorithms to obtain a clear unambiguous skeletal image of the original gray tone impression, clarifying smudged areas, removing extraneous artifacts and healing most scars, cuts and breaks.

Bio-Link SDK

Advantage of Fingerprint:

a. Very high accuracy.b. Is the most economical biometric PC user authentication technique.c. Easy to use.d. Small storage space required for the biometric template, reducing the size of the database memory requirede. It is standardized.

Disadvantage of Fingerprint:

a. For some people it is very intrusive, because is still related to criminal identification.

b. It can make mistakes with the dryness or dirty of the finger’s skin, as well as with the age (is not appropriate with children, because the size of their fingerprint changes quickly).

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