A fingerprint classification algorithm is presented in this paper. Fin
gerprints are classified into five categories: arch, tented arch,left
loop, right loop acid whorl. The algorithm extracts singular points (c
ores and deltas) in a fingerprint image and performs classification ba
sed on the number and locations of the detected singular points. The c
lassifier is invariant to rotation, translation and small amounts of s
cale changes. The classifier is rule-based, where the rules are genera
ted independent of a given data set. The classifier was tested on 4000
images in the NIST-4 database and on 5400 images in the NIST-9 databa
se. For he NIST-4 database, classification accuracies of 85.4% for the
five-class problem and 91.1% for the Four-class problem (with arch an
d tented arch placed in the same category) were achieved. Using a reje
ct option, the four-class classification error can be reduced to less
than 6% with 10% fingerprint images rejected. Similar classification p
erformance was obtained on the NIST-9 database.