A core part of biometric home security systems is the adoption of fingerprint scanners as part of door locks, safe locks and alarm activation systems.
Whilst fingerprints have their origins in Ancient Babylonia, it would take several thousand years before automatic fingerprint scanning and identification would become a major part of biometric security, with the first mobile phone to have a fingerprint scanner appearing in 2004.
Typically, fingerprints are determined by a combination of their primary pattern and tiny features known as minutiae. There are three main patterns to fingerprints;
- Arch – where ridges enter from one side of the finger, form a bump or arc and then leave via the other side,
- Loop – where the ridges form a curve,
- Whorl – where ridges form as circles and ovals from a central point on the finger.
These, in combination with minutiae, create a unique fingerprint profile that can be stored and then matched later.
The scanners themselves vary in form and use a wide range of technologies to actually detect, capture and process fingerprints:
- Optical Scanners – these are the most simple example, and use a digital camera to take a picture of the fingerprint and determine identifying traits from there,
- CMOS Scanners – also known as capacitive scanners, these scanners use capacitors (similar to modern mobile phone touch screens) to complete electrical currents and form a fingerprint image.
- Ultrasound scanners – these use high-frequency sounds such as those used for diagnosis to penetrate the outer layer of the skin and return a complex fingerprint pattern.
- Thermal scanners – these are precise thermal detectors that sense the temperature difference between where ridges make contact with the surface and places where they do not.