Fingerprint recognition or fingerprint authentication is a automated method of how to verify matches between two human fingerprints. There are two major types of algorithms called minutia and pattern. The pattern algorithm is based on that there are three basic patterns of fingerprints, the arch pattern, the loop pattern and the whorl pattern. In the arch pattern, the ridges enter from one side of the finger and creates an arc and then ends on the other side of the finger. The loop pattern starts with the same, the ridges enter from one side of the finger but then creates a curve and tends to end in the same way that it was starting from. The whorl pattern basically creates ridges in a form of circles around the central point of the finger. Lately scientists have discover that family members often share the same finger-pattern which leads them to believe that these pattern are inherited.
The other way of identifying the fingerprint with an algorithm is the minutia. Minutia is based on the ridge ending, bifurcation and short ridges. The ridge ending is basically where the ridge terminates. Bifurcation are points where a normal ridge splits into two ridges, making a kind of “Y” look. In the way of determine uniqueness, the minutia algorithm has seen to be flawless since two fingers have never shown to be identical.
Instead of using an algorithm, you can choose another method called Fingerprint sensors. The sensor is used to capture a digital image of the fingerprint pattern. The pattern is then digitally processed to create a biometric template which is then used for matching. The most common sensors are:
- Optical
- Ultrasonic
- Capacitance (Passive and active)
The optical sensor is pretty much a digital camera with a touch surface. The biggest disadvantage of this method is that the result is depending on the quality of the skin used on the surface.
An ultrasonic sensor uses the medical ultrasonography to create a visual image of the pattern. Unlike the optical sensor this sends out high frequency waves that penetrates the epidermal layer of the skin and this results in that the quality is not depending on the quality of the skin.
The capacitance sensor uses capacitance to form a fingerprint image. When you use an active capacitance, you use a charging cycle to apply voltage to the skin before the measurement begings.
