Biometrics [10 mn de lecture - paru le 5/1/2004 10:23:27 AM - Public : Débutant]

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M. B. Elève-Ingénieur Supinfo Paris Promotion SUPINFO 2007    Lui écrire    Tous les projets de cet auteur    Le mini-CV de cet auteur

2. Biometric methods

It exists different biometrics used in various domains and among which one finds:

2.1. The digital prints:

It is one of the first biometrics used in machines of authentication merchandised in the beginning of years 1960. The formation of prints depends on the initial conditions of embryogenique development, what makes them unique to every person and even to every finger. The picture of print is taken very well according to the traditional fashion that is a scanning of the finger covered with ink is while using a specific picture acquirement device. Pictures of prints foxgloves are relatively easy to treat, as most information is contained in the shape of lines. The treatment is generally done on the binary pictures.

2.2. The face:

The authentication of the face is the technique the more common and popular. Features judged meaningful for the recognition of the face are: eyes, the mouth and the tour of the face. The face is relatively little a biometric sure. Indeed, the signal acquired is a lot topic to variations more elevated than of other features. These can be caused, among others, by the makeup, the presence or the absence of glasses, the ageing and the expression of an emotion.It is as appreciable to the variation of the lighting and the change of the position of the face at the time of the acquirement of the picture. In addition, he/it is recommended to use the same type of camera in several applications (captures of pictures defer a camera to another) .The FaceIt, a product using this biometric, is used in certain airports.

2.3. The voice:

Identification by vocal print supposes that some physical vocal organ features, that influence the quality of the sound of the speech, are not precisely identical of a person to another. These features are the vocal cavity size, the throat, the nose and the mouth, and the shape of muscles of joint of the language, the jaw, lips and the veil of the palace. The process of vocal print was finalized from experimentations achieved by scientists wanting to convert the linguistic sounds in visual registrations destined to be analyzed and measured. The vocal sounds are converted in electric impulses and are recorded on a magnetic tape, as in a plain resonant registration, but impulses are treated then electronically by a successive sweep of the original magnetic registration and are converted in a registration under shape of pictures on a paper of spectrogram sensitized electrically.Pictures that result some can be classified systematically by length, frequency and intensity and can be compared with pictures from other sources. The vocal print is sometimes used by the police to identify people uttering some telephonic threats or to the anonymous call origin.

2.4. The retina:

It has been shown that every eye possesses in its retina an unique blood vessel arrangement. The technique based on the retina uses the texture of these vessels. This technique is relatively old, and has been used essentially in environments of high security, as the access to the military nuclear sites. This method requires a narrow collaboration on behalf of the topic, because it must place his eye extremely close to the camera.

2.5. The iris:

If the color, the shape and the general appearance of the iris is determined genetically, its detailed texture is different from an individual to an other, or even to every eye. Besides, this texture is steady and cannot be modified without loss important of the visual capacities. This technique (identification by the iris) is sure and less coercive for the user that the one of the retina, but it required until now that the user places his eye in good position in relation to the camera. However, the incorporation of techniques of localization of the eye permits to relax the constraint to which the user is submitted, and his/her/its use is considered in distributors of banknotes and for access secure to Internet here is a scanner of iris named IRIS ACCESS:

2.6. The hand:

The silhouette of the hand is a characteristic of every individual. The shape of the hand is acquired by a specialized scanner, generally to infrared (to see the photo of the scanner). Of parameters as the length of fingers their thickness and their relative position are extracted of the picture and are compared to the basis of data.This biometric is submitted however to modifications in the shape of the hand bound to the ageing.