Fingerprint scanners are used for a variety of security and data-collection purposes, from identifying prisoners to allowing access to information or high-security areas. The types of fingerprint security systems include optical, silicon chip, ultrasound, and thermal. Once identified by a fingerprint security system, a person can be allowed access to something. For example, a fingerprint image can be used in place of a typed password for a computer system, or it can replace swipe cards that are used to gain access to a building.
The first step for any system is to capture a distinct fingerprint image. A scanner reads the fingerprint and records its features — especially the unique markings at the center of the fingerprint. An image of the fingerprint is then stored as a template for future recognition.
One type of fingerprint security uses an optical scanner, like a camera, to take a fingerprint image. The camera lights the fingerprint's ridges, takes a picture, and then makes an inverse black and white image. The camera automatically makes several scans of the fingerprint to ensure a clear image is saved. An image that is too dark or too light will be difficult to read. If that happens, the optical scanner's camera will continue taking pictures until it gets a clear one.
Optical fingerprint scanners have been around for many years. They are often used for business purposes. The advantages of optical sensors include their relatively low cost and a history of being quite accurate. One disadvantage can be difficulties in getting a clear fingerprint image.
A technology introduced in the 1990s uses silicon chips to identify fingerprints. It works by emitting a weak electrical current that senses and identifies pattern differences on a fingerprint. This type of security technology is most commonly found in laptop computers and other small electronic devices.
A third kind of fingerprint security scanner uses ultrasound — a high frequency sound — to identify a fingerprint. An advantage of ultrasound sensors is that they are not affected by dirt on a finger or a sensing pad. Good contact must be made between the finger and the sensing plate to get a good image, however.
Thermal fingerprint scanners work by measuring temperature differences contained within the patterns of a fingerprint. They offer a high level of security. Unlike some other types, these scanners are difficult to trick using artificial fingers.
In addition to identifying prisoners or people who have access to computer networks, fingerprint security scanners can be used in a variety of applications. These include national identification systems, identification of lost or missing children, passports, voter records, bank transactions for credit cards or debit cards, and criminal records.