Biometrics: science for measurable human characteristics


Biometrics is the science that studies the measurable physiological or behavioral characteristics  used to identify a person or to verify their identities.

The recognition and identification of people through technology based on biometrics are generally aimed at the realization of security systems in which the “immediate and certain” identification  of an individual is considered to be a priority.

Biometric technology, based on usually well defined  and easily measurable  physiological or behavioral characteristics guarantees uniquely recognition of an individual. For these reasons, this technology allows to produce a very efficient level of safety in all cases in which it is essential to obtain reliable identification, even in unfavorable environmental conditions, for example in implementing systems in which the recognition of an individual must be carried out without actively involve the individual himself.

Among the main applications of biometrics there are the following:

  • analysis of typical characteristics of populations living;
  • study of genetic associations between species;
  • epidemiology;
  • medicine;
  • pharmacology (dose);
  • identification of individuals.

It consists of an approximate value indicating how the biometric fingerprint used corresponds to the reference model. Extreme values​​, zero or 100%, are rather unlikely.
The definition of the threshold of recognition establishes the boundary between the acceptance or rejection of the request. In this way you can set the security level of the system.
Biometric technologies are based on the use of certain individual features to allow, in a safe, the recognition or identification of a person.

They are divided into two areas:
● Physiological characteristics (unique and invariant) – which include hand geometry and palmprint, fingerprint, retina or iris image, features (geometry) of the face.
● Behavioral characteristics (unique but variable) – including the signature, the way you walk, the voice, the way you write on a keyboard.
There are indeed other “footprints” biometrics, such as DNA, the shape of the ear, the heart beat.

Biometric technologies currently used are:
Fingerprint: consists in comparing a date stamp , acquired at the time of the request for access with a reference. The comparison is made with technologies similar to those used for the image processing. It requires low implementation costs and it is easily integrated in different security systems.

Geometry and palm print: it consists in comparing some measures of the hand ( fingers , shape of the palm ) , obtained in 3D, with similar reference measurements acquired in a controlled manner. The elements of the measurement object are those that maintain the geometric relationships constant throughout life .

Features voice: it consists in comparing some of the identifying elements that are characteristic of the individual voice regardless of the spoken words.

Retinal scan: is the optical reading of the size and the shape formed by the blood vessels that cover the retina. The reading is done by a light source at low intensity.

Iris scan: it consists in reading and subsequent interpretation of the characteristics of the iris captured by a camera or a conventional camera .

Signature verification: is the ” reading “ of some dynamic parameters ( speed, pressure, acceleration , etc.). Detected using special devices during signing.

Geometry of the face: is to compare some features of facial features with the corresponding identification model safely acquired. The comparison is made using scanned images, stationary and moving , with optical devices (usually cameras).

The process of identification or verification through fingerprint biometrics is generally common to all biometric technologies. It consists of several basic processes, such as:
● Acquisition footprint biometric reference template and its transformation into a binary reference

● Acquisition of a new imprint at the time of identification, processing the template and comparison with the reference

● If there is sufficient correspondence between the two template, identification is valid

This sequence of operations may differ according to the type of fingerprint biometric used, based on the characteristics of the devices used, and based on the environmental characteristics in which verification is performed.

The scheme is the following:




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