Fingerprint scanning is carried out using an electronic device (in this case a fingerprint attendance machine). The scanning results are then saved in digital format during registration or enrollment or fingerprint registration. The following are the current fingerprint reading techniques.
1. Optical
Fingerprint patterns are recorded or scanned using light, the reflection of light from the fingertips is captured by a receiver which then stores the fingerprint image into memory.
2. Ultra Sonic
In this technique, very high frequency sounds are used to penetrate the epidermal layer of the skin. The high frequency sound is created using a piezoelectric transducer. After that, the reflected energy is captured using a similar tool. This reflection pattern is used to construct the fingerprint image that is read.
3. Capacitance
In this method, the scan area functions as a capacitor plate, and the skin of the fingertip functions as another capacitor plate. Because there are ridges and valleys in the fingerprint, the capacity of each person's capacitor will be different.
4. Thermal
This technique uses the temperature difference between the fingerprint ridge and valley to determine the fingerprint pattern. The method used is to rub your fingertip (swap) over the scan area.
