What is a fingerprint ?
Finger skin is made of friction ridges, with pores (sweat glands). Friction ridges are created during foetal live and only the general shape is genetically defined. Friction ridges remains the same all life long, only growing up to adult size. They reconstruct the same if not too severe injury.
La peau des doigts est constituée des empreintes digitales, qui servent essentiellement à aggriper les objets par friction. Les crêtes ont des pores, les ouvertures des glandes sudoripares. Les empreintes digitales sont créées durant la vie foetale, et seule l'allure générale est génétiquement définie. Les empreintes restent les mêmes toutes la vie durant, avec un simple accroissement jusqu'à la taille adulte. Elles se régénèrent si la blessure n'est pas trop importante.
Minutiae are the discontinuities of the ridges:
- Endings, the points at which a ridge stops
- Bifurcations, the point at which one ridge divides into two
- Dots, very small ridges
- Islands, ridges slightly longer than dots, occupying a middle space between two temporarily divergent ridges
- Ponds or lakes, empty spaces between two temporarily divergent ridges
- Spurs, a notch protruding from a ridge
- Bridges, small ridges joining two longer adjacent ridges
- Crossovers, two ridges which cross each other
- The core is the inner point, normally in the middle of the print, around which swirls, loops, or arches center. It is frequently characterized by a ridge ending and several acutely curved ridges.
- Deltas are the points, normally at the lower left and right hand of the fingerprint, around which a triangular series of ridges center.
Fingerprint recognition
Many algorithms for fingerprint recognition have been developed to detect the minutiae. See the fingerprint algorithms page to get more information, as well as algorithm makers.
De nombreux algorithmes ont été développés pour reconnaitre les minutiae. Voir la page sur les algorithmes de reconnaissance d'empreintes digitales pour plus d'information, ainsi que des liens vers des concepteurs d'algorithmes.