Fingerprint scanners, fingerprint readers or fingerprint readers use the biometric characteristics of the fingerprint to protect communication and IT systems. The scanner scans the biometric data - in this case the papillary lines of the fingerprint - and compares them with stored data for identification purposes. Compared to a personal identification number, fingerprint recognition has much higher security features.
Optical, capacitive, thermal and ultrasonicsensors are used to scan the fingerprint, and the corresponding scanners are built using microsystem technology. One of the oldest recognition methods is Automated Fingerprint Identification System( AFIS).
Inoptical methods, the fingerprint is photographed with a digital camera and stored. The photographed fingerprint captures the depressions and ridges of the paper lines and can therefore be clearly assigned. In addition, there is Frustrated Total Internal Reflection( FTIR), which is based on light scattering and has been used in fingerprint scanners for several years.
Capacitive fingerprint scanners have an array of miniature sensors that detect minute capacitive differences, which use microprocessors and appropriate electronics for signal processing to create a digital image of the fingerprint. Fingertip from Siemens and Touch ID from Apple work with capacitive charge images from the fingerprint.
The thermal method creates thermal images of the finger. In this process, many sensors record the surface structure of the finger via the different temperature gradients.
With ultrasonic sensors, the finger is scanned with ultrasound by several differently mounted ultrasonic sensors. The reflected ultrasonic waves differ in amplitude and travel time and are used to create a three-dimensional image of the finger surface.
In addition to the aforementioned static methods for fingerprint scanners, in which the finger rests on the sensor, there are also dynamic methods in which the finger is dragged over the sensor.