Biometrics

• Biometrics is the science and technology of measuring and analyzing biological data

• In information technology, biometrics refers to technologies that measure and analyze human body characteristics, such as fingerprints, eye retinas and irises, voice patterns, facial patterns and hand measurements, for authentication purposes.

Definition of Biometric Recognition

Verification

1:1

Yes/NO

Identification

1:N

A

A

A

Major biometrics

facefingerprint

iris

ISO/IEC JTC 1/SC 37 Standards

ISO/IEC 19785-1: 2006

Common Biometric Exchange

Formats Framework (CBEFF)

Biometric information record format, including header, biometric data and security block

Has procedures for Registration Authority to come up with own data format

ISO/IEC 19794: 2006 Face, finger, palm, iris, vascular image data

Finger templates: minutiae, spectral, skeletal

Specifies data storage format conforming to 19785

ISO/IEC 19784:2006 Biometric Application Programming Interface (BioAPI)

Framework for use of multiple biometric technologies/ vendors. Covers enrollment, verification, identification and database interface. Provides interface for storage, search and management of biometric data.

Conforms to ISO/IEC 19794, 19785

Fingerprint

• A fingerprint is an impression of the friction ridges found on the inner surface of a finger or a thumb.

• The science of fingerprinting constitutes the only unchangeable and infallible means of positive identification known to man

Why Fingerprint

• Ridge patterns and the details in small areas of friction ridges are unique and never repeated.

• Friction ridges develop on the fetus in their definitive form before birth.

• Ridges are persistent throughout life except for permanent scarring.

• Friction ridge patterns vary within limits which allow for classification

Friction Ridges

• On the palmar surface of the hands and feet are raised surfaces called friction ridges.

• Friction ridges are formed during fetal development where their unique characteristics emerge due to genetic and epigenetic factors (maternal diet, pH, temperature, movement of the fetus, etc.).

• Even identical twins do not have the same fingerprints.

Minutiae

• Minutiae, in fingerprinting terms, are the points of interest in a fingerprint, such as bifurcations (a ridge splitting into two) and ridge endings.

Ridge Bifurcation

• the ridge bifurcation is the point where the ridge splits into two or more branches.

Ridge endings

• A ridge ending is defined as the point where the ridge ends abruptly.

Short ridges

• Short ridges (or dots) are ridges which are significantly shorter than the average ridge length on the fingerprint.

Thinned Image• This is a result to a false

minutiae (i.e. false bifurcation and false end point.

• These false minutiae must be detected and deleted from the initial minutiae set.

• A thinned image shows in the figure where P1, P2 are a pair of false end point and P3 is a false bifurcation.

Finger Print Classification

Ten-print classification

Roscher System Vuvetich System Henry System

Developed in Germany and implemented in Both

Germany and Japan

Developed in Argentina and

Implemented inSouth Africa

Developed in IndiaAnd implemented In most English-

Speaking Country

Henry System

• There are three basic fingerprint patters:

Arc(5 % population), Loop(60 - 65 %) and Whorl(30 - 35 % population).

In the Loop pattern there are two focal points: the Core and the Delta

• The Center of the loop is defined as Core.

• The delta is the area of pattern where there is a triangular or a dividing of the ridge.

Core and Delta in the Whorl Pattern

• A Whorl pattern will have two or more deltas. For a whorl pattern, all deltas and the areas between them must be recorded

Fingerprint sensors

Optical Sensor (by L1) 500 dpi, 25mm 25mm Good quality image Dirt, latent fingerprints

Capacitive Sensor (by Fujitsu) 500 dpi, 12.8mm x 15.0mm Electro-static discharge, Nosiy, Moisture dependent Light

Thermal Sensor (by ATMEL) 500 dpi, 0.4mm 14mm Artifacts in image Reduced function in warm weather

Ultrasound Sensor (by Ultra-scan) 500 dpi Capture of difficult fingers possible Bulky

RF modulation Sensor (by Authentec) 500 dpi , 9.75mm x 0.81mm Electro-static discharge Light, Low cost

FBI standard requires 500 dpi resolution for minutiae data

ISO 19794-4 provides flexible fingerprint image storage format

Scan resolution 125 dpi - 1000 dpi

Image resolution

<= Scan resolution

Gray levels 2 – 200 (up to 65536)

Number of fingers/palms

>=1

Image compression algorithm

Uncompressed, bit-packed, JPEG, JPEG 2000, WSQ, PNG

Finger/palm position

0-15, 20-36

Number of views

1-256

Finger/palm image quality

0-100

ANSI/NCITS 358-2002, “BioAPI H-Level Specification Version 1.1”.

Impression type

Live/inked, plain/ rolled, latent, swipe, live contactless

Horiz. line length

2 bytes (65536 values)

Vert. line length

2 bytes (65536 values)

Image data < 43x108

bytes

Scan resolution

• The number of pixels per unit distance used by a sensor or scanning device to initially capture a fingerprint or palm print image.

• It should be 125 ppi - 1000 ppi.• 125 ppi is sufficient for verification (1:1

match).• 500 ppi to 1000 dpi is used for higher

security or for identification (1:N match).

Image Resolution

• The number of pixels per unit distance in the interchanged image.

• The image resolution <=Scan resolution (i.e125 ppi to 1000 ppi)

Grey Scale level