Daily Archives: January 29, 2009

Fingerprint identification is the oldest biometric method. Everybody has a set of unique fingerprints, formed by the ridges and valleys on the skin. Fingerprints have been used in many fields, such as crime scene investigation and criminal database to identify people. In terms of technology, biometrics are used as an authentication method, alone or in combination of other techniques, such as password or another biometric forms.

A fingerprint scanner collects, prints, and creates images that can then be analyzed and compared to images already on record. Optical and capacitance are the two major scanners used on the market to collect and analyze fingerprints. An optical scanner works like a digital camera where it collects data on the light reflected off of one’s fingerprints. The lightness/darkness of the reflection is created by ridges and valleys on the skin. A capacitance scanner also creates an image of one’s print; however, it uses electrical current and conductivity to mark the light/darkness area of the print.

After an image collection, a fingerprint scanner system compares specific features of the print (or minutiae), such as angle of certain ridge/valley, location of circles, etc. To get a match, the system doesn’t need to find every pattern in both the sample and the record, it just needs enough matches, and threshold varies. Continue reading →