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90 AUTOMATED FINGERPRINT IDENTIFICATION SYSTEMS

scene. The search process for latent print applications thus requires a longer
time period to complete due to the limited amount of finger image informa-
tion available to the latent print examiner.
If making identifications is the reason for purchasing an AFIS system, then
those operations that will maximize the performance of the AFIS system must
be focused on. These performance metrics may include a faster response on
routine inquiries, more accuracy in searches, fewer false positives, and fewer
false negatives (missed identifications).
Searches may be conducted on databases other than the local AFIS database.
A tenprint search of a state database, for example, may be forwarded to the
FBI’s Integrated Automated Fingerprint Identification System (IAFIS) to deter-
mine if there is an FBI number and a criminal history or warrant from another
state. These transmissions are possible because of the introduction and adop-
tion of national standards and specifications that describe what can be trans-
mitted, the format for transmission, and the method for transmissions.

5.1.1 PHYSICAL LAYOUT OF AFIS

The diagram shown in Figure 5.1 is representative of a large-scale AFIS system
configuration. This figure shows the main components of an AFIS system,
including the matchers, coders, random array of independent drives (RAID)
storage arrays, and various databases. The Ethernet connects the AFIS system
to various input and output devices at other locations. A livescan is an example
of an input device. The Ethernet also connects the AFIS system to the Com-
puterized Criminal History (CCH) file.

5.1.2 AFIS HARDWARE
A card scan takes an image of a tenprint card much like a high-quality copier,
capturing finger images for searches against the AFIS. The inquiring agency
sends the resulting electronic images to the identification bureau (see Fig. 5.2),
where they are electronically mated with the subject’s biographical information,
which was sent through the On-Line Booking System (OLBS). If the record was
sent to the bureau by livescan, the scanner station or the quality control (QC)
station, which handles records that need special processing, such as searches
with missing or bandaged fingers, transposition of hands, or mismatch of
pattern information, can be used to ensure the quality of the image. If the
image does not meet the bureau’s criteria, the bureau notifies the inquiring
agency and requests resubmission or re-roll. The arrest and OLBS information
remains captured, eliminating the need to re-enter this information.