Information Technology Reference
In-Depth Information
MATERIALS 1
We used a CrossMatch Guardian Fingerprint scanner as
used by US-VISIT. Specifications include 500 ppi resolu-
tion, effective scanning area 3.2″ × 3.0″ (81 × 76 mm),
single prism, single imager, uniform capture area. The sys-
tem runs on an Intel core 2 CPU 4300 @1.8-GHz proces-
sor PC, with 3.23 GB RAM and a 20-inch LCD monitor.
Figure 10.5 shows the experiment configuration: scan-
ner on a height-adjustable table with height set to 39 inches
(common counter height at US-VISIT facilities). The scan-
ner was placed at the recommended 20° angle ( Theofanos
et al., 2008 ). A webcam was mounted on the ceiling above
the scanner to record participants' hand movements.
PROCEDURE
Each participant was instructed to perform two self-
capture tasks using on-screen instructions. Participants
were informed verbally that both tasks required them
to capture four fingerprint images following the same
sequence: right slap (RS), right thumb (RT), left slap
(LS), and left thumb (LT).
Figure 10.5 Experimental setup.
The test scenario is described in Figure 10.6 : task 1
includes the overlay and task 2 includes the nonoverlay. Half of the participants
were assigned randomly to start without an overlay, followed by a task with the
overlay. The other half of the participants received the reverse.
When the participant was ready, a generic fingerprint capture symbol as in
Figure 10.7 was displayed, marking the start of the process.
Participants filled out a post-task questionnaire and discussed their overall
impressions with the test administrator.
RESULTS
Applying the ISO (1998) definition of usability—“the extent to which a prod-
uct can be used by specified users to achieve specified goals with effectiveness,
efficiency and satisfaction in a specified context of use”—we measured effective-
ness, efficiency, and user satisfaction. The α of all tests for statistical significance
was set to 0.05. Data were not distributed normally; thus, a nonparametric test
of difference, the Wilcoxon matched-pairs signed-ranks test, was used on all sta-
tistical within-subject comparisons.
1 Specific products and/or technologies are identified solely to describe the experimental proce-
dures accurately. In no case does such identification imply recommendation or endorsement by the
National Institute of Standards and Technology, nor does it imply that the products and equipment
identified are necessarily the best available for the purpose.
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