brian stanton, mary theofanos, shahram orandi, ross micheals, nien-fan zhang these tests were...

Effects of Scanner Height on Fingerprint

CaptureBrian Stanton, Mary Theofanos,

Shahram Orandi, Ross Micheals, Nien-Fan Zhang

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.

HFES October 5, 2007

Biometrics and Usability


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HFES October 5, 2007Biometrics and Usability

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Current US Entry Fingerprint Procedures

• Current US VISIT Procedure – 2 Index Prints• Future US VISIT Procedure – All 10• Little, if any, previous usability work has been done

USV ISITnited

tates

isitor

and

mmigrant

tatus

ndicator

echnology


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4 fingerprint scanner heights◦ Work Table : 26”◦ Desk: 32”◦ Counter: 36”◦ Standing Counter: 42”

5 tasks:◦ Right Slap (Index, Middle, Ring, and Little)◦ Left Slap (Index, Middle, Ring, and Little)◦ Both thumbs at once◦ Individual Thumbs

Experimental Design

26”

32”

36”

42”


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4


26”

Right Slap

Left Slap

Right Thumb

Left Thumb

Both Thumbs

32”

Right Slap

Left Slap

Right Thumb

Left Thumb

Both Thumbs

36”

Right Slap

Left Slap

Right Thumb

Left Thumb

Both Thumbs

42”

Right Slap

Left Slap

Right Thumb

Left Thumb

Both Thumbs

Experimental Design 4 × 5 factorial design Each participant did

each task at every height

Height and task order was counterbalanced and randomly assigned.


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Equipment Rack with a movable shelf 6” tall electronic fingerprint scanner

capable of taking a four finger image. PC system with custom software to control

the order of tasks/heights and to record timing data and fingerprint images


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Participants

• 75 NIST employees • 17 to 67 years and were distributed fairly normally across the age ranges. • 41 men and 34 women• 83% right handed, while 17% were either left-handed or ambidextrous.• Participants ranged from 5 feet (152 cm) to 6 feet 5 inches (196 cm).


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Effectiveness – Fingerprint Quality Efficiency – Timing User Satisfaction – Questionnaire

Measures


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NIST Fingerprint Image Quality Software 2

Breaks slap into individual fingers

1: Best quality – 5: Worst quality

Counted frequencyof scores for each finger at each height

Effectiveness - Quality

Index

Middle

Ring

Little

1 2 3 4 50

5

10

15

20

25

42"36"32"26"


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1 2 3 4 50

5

10

15

20

25

42"36"32"26"

Add all 1’s and 2’s and 4’s and 5’s

Look at the amount of change at each height

Determine if change is significant

Effectiveness - Quality

Good Poor05

10152025303540

42"36"32"26"

Index


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The right index finger had no significant changes with height

Left hand was more sensitive to height Generally, quality improved as height reduced For left slap and both thumbs quality was best

at 26” and 32”.

Effectiveness - QualityRight Hand

42” à 36”

42” à 32”

42” à 26”

36” à 32”

36” à 26”

32” à 26”

Thumb Solo

ê ê é é é

Thumb Duo

é é é

Index

Middle ê é é

Ringer ê é

Little é é

Left Hand

42” à 36” 42” à 32” 42” à 26” 36” à 32” 36” à 26” 32” à 26”

Thumb Solo

é é é

Thumb Duo

é é é é

Index ê é

Middle é é é é é

Ring é é é é

Little é é é


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Total time for each task◦ Right Slap◦ Left Slap◦ Right Thumb◦ Left Thumb◦ Both Thumbs

Friedman’s two-way non-parametric test showed the medians for Right Slap were not the same, p < 0.05.

Effeciency – Task Time


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Effeciency – Task Time

Right Slap Box plot of task times 26” vs. 36” p<.01 with

participants being faster at 36”

Overall, 36” had the smallest means smallest

standard deviations, smallest medians andsmallest interquartile ranges


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(1) Which scan height did you find most comfortable? ◦ 41% - 32”◦ 40% - 36”

(2) Which scan height did you find most uncomfortable? ◦ 68% - 42”

(3) Please rank the heights in order of preference: 1 is most preferred, 4 is least preferred.

1. 32” (4) When prompted for your thumbs, which method

did you prefer? ◦ No significant difference

(5) Did you have difficulty positioning yourself for any of the trials? ◦ 45/75 said both thumbs at 42” was difficult

User Satisfaction

26”

32”

36”

42”


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Assuming that all five fingerprint images are collected for a given user, the results can be summarized by the following recommendations for a ten-print capture sequence with a six inch high sensor:

a counter height of 42 inches (1067 mm) or higher does not satisfy the efficiency, effectiveness, nor satisfaction requirements.

a counter height of 36 inches (914 mm) gives the fastest performance

a counter height of 32 or 36 inches (813 mm or 914 mm) is the most comfortable for users

a counter height of 26 inches (660 mm) gives the highest quality performance

starting a capture sequence with the right slap was most efficient

capturing individual thumb prints yields higher quality images than capturing simultaneous thumb prints

Summary

26”

32”

42”

36”

brian stanton, mary theofanos, shahram orandi, ross micheals, nien-fan zhang these tests were...

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