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Ten-Print Fingerprint Capture: Effect of Instructional Modes on User Performance. Mary Theofanos NIST 301 975-5889 [email protected]. May 23, 2007. - PowerPoint PPT Presentation
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Biometrics and Usability
HFES October 5, 2007
1
Mary TheofanosNIST
May 23, 2007
These tests were performed for the Department of Homeland Security in accordance with section 303 of the Border Security Act, codified as 8 U.S.C. 1732. Specific hardware and software products identified in this report were used in order to perform the evaluations described in this document. 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.
Ten-Print Fingerprint Capture: Effect of Instructional Modes on User Performance
Biometrics and UsabilityHFES October 5, 2007
Why perform the study?
DHS and US-VISIT are transitioning from 2 prints to 10-prints
Visitors are not familiar with the 10-print process
Throughput and image quality are critical
Biometrics and UsabilityHFES October 5, 2007
Three Goals of the study
To Understand:
1. How instructional modes affect the user performance
2. How long it takes to capture a 10-print image
3. What types of errors occur in this process
Biometrics and UsabilityHFES October 5, 2007
Experimental Design
Instructional Modes Participants Leading HandRight Left
Verbal
Poster
Video
100
100
100
50 50
50 50
50 50
Timing Data and Errors
Biometrics and UsabilityHFES October 5, 2007
Three Instructional Modes
Read by the Test Facilitator:
Step #1: When the right most light starts flashing green; place your right four fingers (demonstrate what four fingers) on the scanner and press down. Hold your fingers in place until the green light stops flashing
Step #2: When the left most light starts flashing green; place your left four fingers (demonstrate what four fingers) on the scanner and press down. Hold your fingers in place until the green light stops flashing Step #3: When the center light starts flashing green; place your 2 thumbs (demonstrate thumbs side by side) on the scanner and press down. Hold your fingers in place until the green light stops flashing. Would you like me to repeat the instructions?
1st Mode: Verbal
Biometrics and UsabilityHFES October 5, 2007
2nd Mode: Poster
Biometrics and UsabilityHFES October 5, 2007
3rd Mode: Video
Video
Biometrics and UsabilityHFES October 5, 2007
Procedure
Give papers to operator
Fingerprint Collection
Receive Instructions
Biometrics and UsabilityHFES October 5, 2007
Who were the participants?
300 Adults◦ 151 women and149 men◦ Age ranged from 18 years to 75 years old◦ 265 right handed, 31 left handed, 2 ambidextrous◦ Height ranged from 4’ 6” to 6’ 9”◦ Fingerprint experience: 70 % inked 9.7% electronically
Biometrics and UsabilityHFES October 5, 2007
Event Timeline10
Time
Participant enters room
Participant is ready
Participant places hand down
Participant removes hand
Capture initiated. Light goes on.
Scanner detects hand down
Capture repeated if needed (error)
Light goes off. Scanner looks,for hand up.
Next Hand (3X)
First image is captured.
Instructions are presented
(All times measured in seconds)
Instructions
31.27 29.60
65.34 58.84 < .01
86.93 81.05
Mean Median p
Video
Verbal
Poster p < .01
p < .01
p < .01
imeTotalT
145.67126.85
151.73129.32 < .01
163.22152.18
Mean Median p
Video
Verbal
Poster p < .01
p > .05
p < .01
p
ession EndParticipant Readyto S
114.40 91.50
86.39 65.00 < .01
76.29 65.00
Mean Median p
Video
Verbal
Poster
> .05
1st HandDowntoTask End
64.13 58.50
48.21 45.00 < .01
50.87 46.00
Mean Median p
Video
Verbal
Poster
p > .05
Biometrics and UsabilityHFES October 5, 2007
Results : Efficiency
Method Participants Mean (sec) Median (sec)
Poster 52 64.13 58.5
Verbal 85 48.21 45.0
Video 85 50.87 46.0
Time for Successful Trials
Biometrics and UsabilityHFES October 5, 2007
Results : Effectiveness
Method Participants Mean Errors Median Errors
Poster 52 64.13 58.5
Verbal 85 48.21 45.0
Video 85 50.87 46.0
Number of Errors per Instructional Method
Biometrics and UsabilityHFES October 5, 2007
Results : Satisfaction
1. The information provided was effective in helping me complete the fingerprint process.
2. The information provided clearly described the fingerprint process.
3. The information provided was confusing.4. It was clear which hand was to be scanned first.5. The order of fingerprint capture was clear.6. It was clear how to position your hand on the
sensor7. It was clear when to remove your hand.
Survey Questions included:
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HFES October 5, 2007
Instructions are significant factors for performance and quality
14
Poster Participants: took significantly longer to complete the 10-print
collection process made significantly more errors only 54% were able to successfully complete the
fingerprinting process left the poorest quality images using NFIQ.
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HFES October 5, 2007Biometrics and Usability
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HFES October 5, 2007
Verbal instructions were rated highest
Poster was rated the lowest
Verbal and video instructions performed equally well
15
Biometrics and UsabilityHFES October 5, 2007
Observations on methodsPoster:
◦ Felt poster offered too much information ◦ Common problem: removed their hand before capture had
taken place◦ Spent less time viewing the instructions than other 2
methodsVerbal:
◦ Overwhelmingly stated that clearly described the tasks ◦ Problems were due to lack of visual preparation and
difficulty with hand placement◦ Implied that the operator would assist them through the
processVideo:
◦ Generally performed well◦ Difficult to judge the timing of the lights ◦ Encouraged subjects to pay attention
"initially lights did not mean anything"
“label the lights on the
machine. Left and Right”
Should fingers be centered on the
scanner? The less you have to think
the better.
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HFES October 5, 2007
Operators were able to assist: Individuals to overcome the deficits of
the instructional materialsOn a second try with operators help: 98% of the participants who received
the poster were able to successfully complete the fingerprint process
Operators are critical to the acquisition process
17
Biometrics and UsabilityHFES October 5, 2007
Language Independence is Key In the Operational Environment
Poster is error prone and impacts quality Verbal instructions are delivered to
visitors individually Video instructions can be presented to
visitors all at once◦ Provides optimum capture times◦ Low-error incidence◦ Reasonable quality
Video my be more conducive to the operational environment
Biometrics and UsabilityHFES October 5, 2007
Check out our website:
http://zing.ncsl.nist.gov/biousa/