BEST PRACTICES FOR CROSSMATCH L-SCAN GUARDIAN TEN-PRINT DEVICE

The purpose of this study is to create a set of best practices to capture fingerprints using an Crossmatch L-scan Guardian ten-print device. A program was used to capture user errors due to placement of fingers on the platen. User error results were analyzed based on data obtained from the created program, during user interaction. Based on the results of this research we were able to create a set of user-friendly best practices to assist in Crossmatch L-scan Guardian ten-print scanning.

Tenesha Coleman, Arielle Mabon, Katie Lawson, Michael Brockly, Stephen Elliott

Overview

Data from the scanner displayed in Figure 1.1 & Figure 1.2 were analyzed to determine what finger showed the most error.

Figure 1.1 Displays error in index and pinky fingers.

Figure 1.2 Displays results free from error

Data obtained from NISTIR7403 Ability Testing of Ten-Print Fingerprint Capture, determined that video accompanied with audio instructions was easier for users to understand than only audio instructions. Even in some instances, just video instructions (no audio) was also more effective than audio or visual (poster) instructions. This data was obtained from user interaction in different situations and the efficiency of each interaction was analyzed. Some users were only provided with audio instruction, some video (with or without audio), and other visual (poster) instruction. It was also found that operators are critical to the fingerprint acquisition process. The ten-print scanner in Figure 1.3 was used in the research conducted by NIST.

Research

Conclusion Based on the research analyzed, a program was used to identify what finger(s) may have caused the most errors when gathering data from the ten-print finger scanner. The fingers that were identified to cause the most errors were the outer most fingers (pinky and index finger). The program was designed by a student to detect when the colored bars changed, identifying and error or correcting one. Each color was designated a code to identify the level or type of error. By establishing the best practices for a ten-print scanner and providing video instructors, the need for an operator’s assistance to code errors is eliminated. Eliminating the operator helps to lower labor costs and can make the ten-print scanning process of large groups happen more quickly and efficiently.

User Interaction The ten-print scanner generates user fingerprints by reflecting light off the platen to the ridges and valleys of the users’ fingers, as seen in Figure 1.3. It displays four different colored bars depending on the interaction between the system and the user; which range from red (worst quality), orange, and green (best quality). Feedback can also consist of a non-colored bar indicating no data was captured. The program also recorded when arrows were displayed as feedback to make position changes with outside fingers.

Previous Research from NIST

Theofanos, M., Stanton, B., Orandi, S., Micheals, R., Zhang., N. F. (2007). NISTIR 7403 Usability Testing of Ten-Print Fingerprint Capture. Information Access Division Information Technology Laboratory.

Figure 1.3. NIST ten-print scanner

Best Practices • Visual and audio instructions are the most accurate way to present instructions to

the user. • When using the ten-print scanner be mindful of positioning the outer most fingers

(pinky and index finger). • The feedback display will aid in repositioning fingers to obtain accurate readings. • Use the colors in the feedback display to gauge user accuracy of attempt. Examples

can be seen under the Research section.