Fingerprint scanner

Fingerprint scanners are security systems of biometrics. They are used in police stations, security industries, smartphones, and other mobile devices.
Function.
Everyone has patterns of friction ridges on their fingers, and it is this pattern that is called the fingerprint. Fingerprints are uniquely detailed, durable over an individual's lifetime, and difficult to alter. Because there are countless combinations, fingerprints have become an ideal means of identification.
Types of fingerprint scanners.
There are four types of fingerprint scanner: the optical scanner, the capacitance scanner, the ultrasonic scanner, and the thermal scanner. The basic function of every type of scanner is to obtain an image of a person's fingerprint and find a match for it in its database. The measure of the fingerprint image quality is in dots per inch (DPI).
All fingerprint scanners are susceptible to be fooled by a technique that involves photographing fingerprints, processing the photographs using special software, and printing fingerprint replicas using a 3D printer.
Construction forms.
There are two construction forms: the stagnant and the moving fingerprint scanner.