influence of height and angle on fingerprint collections
DESCRIPTION
Charles Sheppard. Influence of Height and Angle on Fingerprint Collections. Question by US-VISIT. Given current surface heights, what is the “best” angle?. Heights. Reported Height Frequencies less 6”. Heights. Choose three heights 39” 45” Practical Midpoint 49”. 49”. 45”. 39”. - PowerPoint PPT PresentationTRANSCRIPT
Biometrics and Usability
Influence of Height and Angle on Fingerprint Collections
Charles Sheppard
Biometrics and Usability
22
Given current surface heights, what is the “best” angle?
Question by US-VISIT
Biometrics and Usability
33
Heights
3033353637.5
38394346474849
0
20
40
60
80
100
Reported Height Frequencies less 6”
3033353637.5
38394346474849
0
20
40
60
80
100
Biometrics and Usability
44
Choose three heights◦ 39”◦ 45” Practical Midpoint◦ 49”
Heights
39”45”
49”
Biometrics and Usability
55
Selected Range of Angles◦ Flat◦ 10 °◦ 20 °◦ 30 °
Angles
Flat 10° 20° 30°
Adjustable Table Angle Adjustment
Equipment
Biometrics and Usability
77
Data
× 4 angles = 48 prints/height
12 prints/angle
× 20 people = 960 prints per height
× 3 heights = 2,880 prints/scanner
× 2 scanners = 5,760 total prints
(120 people total)
Biometrics and Usability
88
Given current surface heights, what is the “best” angle?
Best = ◦ Efficient —Timing — Time to complete task◦ Effective — Quality — How good were the prints◦ Satisfaction — Comfort — Questionnaire
Question
Demographics
Biometrics and Usability
1010
• Age• Height• Gender• Handedness
Test population was representative of the user population with respect to:
EfficiencyTiming
Biometrics and Usability
1212
Timing
12
Opportunity (“please place your hand on the scanner”)
System starts capture
Capture
System ends capture (“Please remove hand from scanner”)
Capture thresholding
Time
System
Participant presentsAttempt starts
Attempt
Attempt ends
Next attempt(acceptable
attempt)
Participant
Scanner A
Biometrics and Usability
1313
Timing
13
Opportunity (“please place your hand on the scanner”)
Capture
System ends Attempt (“Please remove hand from scanner”)
Capture thresholding
Time
System
Participant presentsAttempt starts
Attempt
Attempt ends
Next attempt(acceptable
attempt)
Participant
Scanner B
Timing — Median Times per Slap
0 10 20 309.00
9.50
10.00
10.50
11.00
Median Time Per Task vs. Angle
(across all heights and tasks)
Angle
Tim
e
39 45 499.00
9.50
10.00
10.50
11.00
Median Time Per Task by Counter Height
(across all angles and tasks)
Table Height
Tim
e
Scanner A
Neither height nor angle is significant
Timing — Median Times per Slap
Scanner B
39 45 4916.0016.1016.2016.3016.4016.5016.6016.7016.8016.9017.00
Median Time Per Task by Counter Height
(across all angles and tasks)
Counter Height
Tim
e
Flat 10 20 3016.00
16.20
16.40
16.60
16.80
17.00
Median Time Per Task vs. Angle(across all heights and table
heights
Angle
Tim
e
Neither height nor angle is significant
Biometrics and Usability
1616
No significant affect due to angle or height
Timing
EffectivenessQuality
Biometrics and Usability
1818
NIST Fingerprint Imaging Software◦ Segmentation◦ Image Quality
Quality Measures
Biometrics and Usability
1919
Two levels of analysis1. Individual finger NFIQ — Medians2. Individual finger NFIQ frequencies
Quality Analysis - Angle
No significant affect due to angle
Biometrics and Usability
2121
Two levels of analysis1. Individual finger NFIQ — Medians2. Individual finger NFIQ frequencies
Quality Analysis - Height
Significant differences were found across different counter heights, the effect of which appears to be scanner dependent
Finger #
Task #
Table Height
2 1 39”>45”. 45”<49”3 1 39”>454 1 39”>45”5 1 39”>45”7 3 39”>45”8 3 39”>49”9 3 39”>45”
10 3 +. 39”>451 2 39”>45”. 45”<49”6 4 -
11 5 -12 5 -
1
2345
6
7 8 910
1112
Quality Analysis – Median NFIQ per Finger
Finger #
Task #
Table height
2 1 -3 1 *39”>45”4 1 39”<45”. 45”<49”5 1 -7 3 -8 3 -9 3 -10 3 39”<45”. 45”<49”1 2 39”>45”. 45”<49”6 4 -11 5 -12 5 _
Scanner A Scanner B
Biometrics and Usability
2424
US visit quality scoring.
NFIQ 1 or 2
NFIQ 1 or 2 or 3
Biometrics and Usability
2525
US visit quality scoring.
Right Slap Right Thumb Left Slap Left Thumb Both Thumbs
57.58%
82.20%
54.92%
71.21% 70.83%
63.23%
80.35%
59.83%
79.39%
60.17%
Scanner A Scanner B
satisfactionMost and Least Comfortable
Angle
Biometrics and Usability
2727
0 deg 10 deg 20 deg 30 deg None0
2
4
6
8
10
12Scanner B
39
45
49
Parti
cipa
nt C
ount
Scanner A39
45
49
Most Comfortable Angle
Biometrics and Usability
2828
0 deg 10 deg 20 deg 30 deg02468
10121416
Scanner B
39
45
49.
0 deg 10 deg 20 deg 30 deg none02468
10121416
Scanner A39
45
49
Parti
cipa
nt C
ount
Least Comfortable Angle
satisfactionThumb Preference
Biometrics and Usability
3030
Both Single
No Answer
0
2
4
6
8
10
12Scanner B
39
45
49
Coun
t of P
artic
ipan
ts
02468
1012141618 Scanner A
39
45
49
Parti
cipa
nt C
ount
Thumb Preferences
Observations
6’6” Individual having to bend knees to position hand comfortably.
39” 30°
5’2” individual having to stand on toes to reach scanner.
49” 0°
5’2” individual not having to stand on toes to reach scanner.
49” 30°
Biometrics and Usability
3535
ConclusionsAngles have no impact on performance Height does affect qualityParticipants when given a choice start with
their right hand
Participants preferred 20° and 30° angles as counter height increased
Shorter participants struggled less at the taller counter heights when scanner was angled