Page 20 - Automated Fingerprint Identification Systems (AFIS)

INTRODUCTION 5

the world. An AFIS system can be immense, such as the 46 million records held
by the FBI, or it can be small, such as when it contains information about only
one city or county.
AFIS systems may be linked to other databases, even to other AFIS systems,
but there are also some AFIS systems that stand alone and effectively do not
communicate with any other agency. As more agencies begin working together,
the number of AFIS systems connected together will grow. Stand-alone AFIS
systems are more likely to join related systems, creating larger networks of fin-
gerprints to search. The technology and applications of AFIS systems are just
beginning to emerge from initial development. The scope of this technology
has moved from a select few uses to everyday uses. The core of AFIS technol-
ogy, the computer and related software, progresses on an almost daily basis. In
particular, the software that runs AFIS systems improves constantly as compa-
nies develop faster, more accurate programs. New markets have emerged in
AFIS-related applications as manufacturers carve out niche products. All of
these advances, however, continue to rely on a biometric that has been sys-
tematically used for over 100 years: the fingerprint.
The use of fingerprints as a biometric used for identification of large popu-
lation groups can be traced back to the 1890s, when Sir Edward Henry pro-
moted a system of classifying the curving friction ridges and the direction and
flow of ridges, patterns, and other image characteristics that allowed trained
examiners to translate these images into a set of equations that could be under-
stood by any other examiner trained in the rules of classification. The result-
ing classifications, in turn, dictated how the records were filed for future
retrieval and comparison. A new industry emerged based on the ease with which
fingerprints could be captured and a uniform method for measuring these
images and storing them for future comparisons.
AFIS systems search databases for candidates based on these image charac-
teristics. The characteristics include the points where ridges end, the points
where they split, the directions that ridges appear to flow, and even dots. The
AFIS system translates what a human sees as a picture, selects key features,
searches these features against a database, and produces the best match from
that database.
These systems are amazingly fast. It takes only a few minutes to capture the
ten finger images at a booking station. Within another few minutes, the booking
officer can send the images and arrest information to a state identification
bureau. The state can determine the identity and return the identity informa-
tion and criminal history file (known as a rap sheet) in as little as 30 minutes.
If it is the first time the subject has been fingerprinted, the event becomes the
first entry in the subject’s computerized criminal history. If the search is for a
subject charged with a criminal offense, it includes a check of all 46 million