Fingerprint recognition is already used for numerous applications, mostly thanks to the fact that required technology and complexity are far less when compared to other biometrics. However, a secure and reliable fingerprint reader requires more than just the technology to read a fingerprint. We leave traces of our fingerprints practically everywhere, and material as well as instructions to produce ‘fake’ fingerprints of a victim are easily attainable. liveness detection is therefore a must-have on a good fingerprint reader.
Existing applications of fingerprint readers are for access control on computerized systems or on portable media, for time and attendance management, for physical access control such as fingerprint locks on doors and safes. Also some governments are using fingerprint readers for border control, this is already the case in the United States and in Japan.
There exist four types of fingerprint readers:
- Optical readers take a visual image of the fingerprint using a digital camera. These fingerprint readers come at cheap prices, but also have some disadvantages. Optical readers are more easy to fool than other fingerprint readers and more quickly yield false negatives in less than ideal conditions.
- Capacitive or CMOS readers use capacitors and thus electrical current to form an image of the fingerprint, this image is based on the actual shape of the fingerprint. Therefore CMOS readers are more difficult to fool than optical readers, while they still come with price tags starting well below 100 euro’s.
- Ultrasound fingerprint readers use high frequency sound waves to penetrate the epidermal (outer) layer of the skin. They do not read the fingerprint on the outer layer of the skin and therefore eliminate false rejects due to scars or uncleaned hands. These fingerprint readers are supposed to be very difficult to fool, which makes them very popular even if the price is significantly higher than for a CMOS reader.
- Thermal readers sense the temperature differences on the contact surface, in between fingerprint ridges and valleys. The fact that thermal fingerprint readers have a number of disadvantages makes them far less popular than the previous types. These fingerprint readers have high power consumption, which makes them difficult to use in mobile applications, and their performance is very dependent on the environment temperature.
Next to these four types, fingerprint readers are divided in between touch and swipe readers. A swipe reader has a small contact surface over which you swipe your fingerprint. On a touch reader you just have to press and release your finger. In general touch readers are more easy to use, swipe readers require a bit of practice the first times the device is used.
An overview of fingerprint reader manufacturers, with links to devices which have been reviewed by biometric-solutions.com:
- Upek fingerprint readers are integrated in Lenovo Thinkpad and Sony Vaio notebooks as well as in certain notebooks of Acer, Asus and Dell. The same fingerprint readers you will also find in mobile harddisks of LaCie, in safes from Honeywell, and for physical access control (door security). Upek also developped different standalone (USB) readers such as the Upek Eikon and the EikonTouch series. Unfortunately Upek has been acquired by AuthenTec in 2010, this company in its turn has been acquired by Apple in 2012 which makes it unlikely that they will market any more standalone fingerprint readers.
- Futronic is a Hong Kong based company specialized in fingerprint recognition.
- Digital Persona is the company behind the popular U.are.U fingerprint readers.
- Secugen is mostly known from the Hamster series of fingerprint readers, they also offer combined fingerprint / smart card reader devices.
- Qualcomm offers ultrasound fingerprint readers.