Fingerprint Authentication

A fingerprint is the feature pattern of one finger. It is believed with strong 

evidences that each fingerprint is unique. Each person has his own fingerprints with the 

permanent uniqueness. So fingerprints have being used for identification and forensic 

investigation for a long time.

A fingerprint is composed of many ridges and furrows. These ridges and furrows 

present good similarities in each small local window, like parallelism and average 

width. However, shown by intensive research on fingerprint recognition, fingerprints 

are not distinguished by their ridges and furrows, but by Minutia, which are some 

abnormal points on the ridges (Figure 1.1.2). Among the variety of minutia types reported in literatures, two are mostly significant and in heavy usage one is called 

termination, which is the immediate ending of a ridge the other is called bifurcation, 

which is the point on the ridge from which two Branches derive.

The fingerprint authentication problem can be grouped into two sub-domains. One is

fingerprint verification and the other is fingerprint identification (Figure 1.3). In

addition, different from the manual approach for fingerprint authentication by experts,

the fingerprint authentication here is referred as FAA (Fingerprint Authentication in

ATM), which is program based.