Home : Biometrics : Fingerprint

Fingerprint

Fingerprints of a person are completely formed approximately 5 weeks before birth and do not change over the lifetime of the person. This property makes the use of the fingerprint as a biometric identifier invaluable.

A fingerprint is the reproduction of a fingertip pattern, produced when a finger is firmly pressed against a smooth surface. The characteristic of a fingerprint is a pattern of interleaved "ridges" and "valleys". Ridges show up as dark lines in a fingerprint and valleys are the bright regions between the dark ridge lines.

Minutiae based matching is the most popular and widely used technique used for fingerprint comparison. Minutiae are extracted from the fingerprint and stored as a set of points in a two dimensional plane. Minutiae points are local ridge characteristics that occur at either a ridge bifurcation or a ridge ending.

When a fingerprint is captured the minutiae are extracted and compared to the minutiae of the stored template. Essentially the matching of the fingerprint consists of the alignment of the two sets of minutia, the captured and the stored.

Fingerprint Minutia Capture

The unique nature of a fingerprint makes it ideal for use in automated recognition systems. A fingerprint is made of a series of ridges and grooves. Once a fingerprint is captured the system locates the minutia points. These minutia points occur where the lines of the ridges begin, end, branch off and merge with other ridge lines. These points are then mapped and a line is drawn between each point. This creates a map of how each point relates to the other points. The map is then stored as a data stream called a minutia template in a database for future comparison with other presented fingerprints. It is important to note that during the entire process no fingerprint images are stored on the system and a fingerprint image cannot be recreated from the minutia template