Page 182 - Automated Fingerprint Identification Systems (AFIS)

STANDARDS AND INTEROPERABILITY 167

compliance with the FBI’s Integrated Automated Fingerprint Identification
System image quality specifications. Such equipment includes livescan systems,
fingerprint card scan systems, fingerprint card printers (grayscale), and inte-
grated products.

8.3 WAVELET SCALAR QUANTIZATION

The Wavelet Scalar Quantization (WSQ) grayscale fingerprint image compres-
sion algorithm is the standard for the exchange of fingerprint images. The WSQ
specification defines a class of image encoders and a single-image decoder
with sufficient generality to decode compressed image data from any WSQ-
compliant encoder. This allows future development while maintaining existing
compatibility. WSQ compliance provides for interoperability between state and
local systems and between these systems and the FBI.
4
NIST has developed a range of functionality for decoders and encoders. In
order to obtain certification, a WSQ decoder must implement the full range of
functionality, including the reconstruction of images using odd and even length
filters and imbedded restart codes. These requirements are contained in Part
I of the WSQ, titled “Requirement and Guidelines.”
A WSQ-compliant encoder must meet the specific parameter values con-
tained in Part III of the WSQ specification. To test for compliance with the WSQ
specification, the output from the equipment tested is compared with the
output from a double precision reference implementation developed at NIST.
Prior to a request for testing WSQ compliance, vendors are directed to conduct
self tests on their equipment. These tests would incorporate the NIST reference
set, which can be downloaded. Following a successful self-test, the vendor may
apply to the FBI for final testing and certification. More details can be found
at the NIST WSQ web site.

8.4 MANAGEMENT CHALLENGES TO INTEROPERABILITY

State and local AFIS systems do not always directly communicate with each
other. Most AFIS systems were developed independently with the vendor’s pro-
prietary software. Some cities have AFIS systems that not only are independent
of the state system, but also are made and supported by different vendors. The
systems may differ in their hardware configurations, expectations of through-
put, staffing levels, and even hours of operations. The policies for the access
and retention of records could be different, as well as the agency with respon-
sibility for operating of the system.

4 http://www.itl.nist.gov/iad/894.03/fing/cert_gui.html.