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(2013) Examination of Stability in Fingerprint Recognition Across Force Levels
1. BIOMETRICS LAB
Biometric Standards, Performance and Assurance Laboratory
Department of Technology, Leadership and Innovation
EXAMINATION OF STABILITY IN
FINGERPRINT RECOGNITION
ACROSS FORCE LEVELS
By: Kevin O’Connor
2. PRELIMINARY INVESTIGATION
• Builds on previously funded research by
DHS S&T Directorate
– Patent issued on force concept by previous
research
– Zoo analysis for fingerprint performance
– ROC Curves – performance analysis from a
population viewpoint
– I noticed that the zoo plots were different at
different force levels
– Wanted to know why, and then try and
quantify it
3. RESEARCH QUESTION
• Is there instability of individual’s
performance scores in a fingerprint
recognition system?
4. ZOO MENAGERIE DEFINITIONS
• G= Avg genuine performance measure
– H and L= High and Low, respectively
• I= Avg Imposter performance measure
– H and L= High and Low, respectively
12. WORKFLOW: CLEAN DATA
• 154 subjects distilled from 260
–
–
–
–
Missing prints
Wrong placement
IRB info not filled out
Subject information not listed
14. ADDITIONAL QUESTIONS
• Do animal classifications change at
different force levels for the same
subject?
• Is there a score that can be assigned an
individual to provide guidance to their
inherent variability?
20. ANIMAL CLASSIFICATION
BREAKDOWN
5 N Count
Animal Classification
7 N Count 9 N Count 11 N Count 13 N Count
Chameleons
11
16
22
15
16
Doves
5
5
9
6
6
Normal
119
114
102
119
117
Phantoms
12
16
16
13
11
Worms
7
3
5
1
4
Total
154
154
154
154
154
21. BIOMETRICS LAB
Biometric Standards, Performance and Assurance Laboratory
Department of Technology, Leadership and Innovation
INSTANCES OF
INSTABILITY FROM ZOO
PLOTS
22. BIOMETRICS LAB
Biometric Standards, Performance and Assurance Laboratory
Department of Technology, Leadership and Innovation
INSTABILITY WITHIN THE
NORMAL
CLASSIFICATION- 135RI
28. BIOMETRICS LAB
Biometric Standards, Performance and Assurance Laboratory
Department of Technology, Leadership and Innovation
INTRA-ANIMAL
INSTABILITY 34RI
34. BIOMETRICS LAB
Biometric Standards, Performance and Assurance Laboratory
Department of Technology, Leadership and Innovation
INTER-ANIMAL
INSTABILITY - 117RI
45. BIOMETRICS LAB
Biometric Standards, Performance and Assurance Laboratory
Department of Technology, Leadership and Innovation
STABILITY SCORE INDEX
46. BIOMETRICS LAB
Biometric Standards, Performance and Assurance Laboratory
Department of Technology, Leadership and Innovation
STABILITY SCORE INDEX
– 135RI
49. BIOMETRICS LAB
Biometric Standards, Performance and Assurance Laboratory
Department of Technology, Leadership and Innovation
STABILITY SCORE INDEX
– 34RI
51. BIOMETRICS LAB
Biometric Standards, Performance and Assurance Laboratory
Department of Technology, Leadership and Innovation
STABILITY SCORE INDEX
– 117RI
53. BIOMETRICS LAB
Biometric Standards, Performance and Assurance Laboratory
Department of Technology, Leadership and Innovation
STABILITY SCORE INDEX
– 178RI
55. SCATTERPLOT OF STABILITY
SCORES FOR EACH INDIVIDUAL
St abi l i t y Scor e acr oss For ce Level s
0.6
Variable
5-7N
7-9N
9-11N
11-13N
St abilit y Scor e I ndex
0.5
0.4
0.3
0.2
0.1
0.0
007RI
50
100
150
Subject I D
200
259RI
250
56. CONCLUSIONS
• Results show instability in the
performance of individuals in the right
index
– Zoo plots of 5 force levels
– Table Breakdown
– Cases of Instability
• Stability score index developed to
quantify instability
57. FUTURE WORK
• Further studies could observe other
digits of the hand (left index, left middle,
right middle, etc.)
• Future research could examine other
force levels
• Examine other matching algorithms
• Change variable (habituation, time,
multiple sensors, multiple modalities)
58. RELEVANT IMPACT
• I want to understand whether a subject is
a “poor” performer, or whether there is
something that can be done.
• If someone is stable, this helps reduce
the time for data collection.
Editor's Notes
{"49":"Instability can occur within a classification at different force levels. An individual is capable of moving ¼ of the maximum possible movement and remain in the same classification. \n","16":"-Red shaded areas change\n-means lower impostor score\n","55":"007\n0.0086 \n0.2959 \n0.1936\n0.0210 \n259\n0.1469 \n0.0110 \n0.1572 \n0.1301 \n","22":"- authors have tended to ignore instability in the normal classification. \nYager and Dunstone (2010) ignore the normal classification, referred to in their papers as the “none” classification. \nThe normal classification comprises the majority of individuals across all force levels, which creates the opportunity for the individual to move significantly without changing classification. Thus it is an important classification to examine.\nnormal classification of individuals lies in the 2nd quartile of at least one of the two performance metrics (genuine or impostor) in the dataset. \nnormal classification comprises the majority of the zoo plot, there can be some instability within this classification. \n","11":"Force collected randomly on 5 force levels 5, 7, 9, 11, and 13\n","50":"individual 34 moving within the chameleon classification. \nThe star represents the individual’s coordinates on the 7 N zoo plot. The arrow points to the coordinates on the 9 N zoo plot, which results in a stability score of 0.1296.\n","39":"normal\n","28":"- Individual 34 was classified as a chameleon across all five force levels. \nGenuine and impostor scores differ between the force levels for individual 34, but remain in the same classification. \nThis illustrates instability within the same animal classification. \n","17":"In Figure 4.4, the number of individuals in each animal classification increases or stays the same compared to the previous force levels (5 N and 7 N). Table 4.5 shows the classification data at 9 N.\n","45":"The existence of instability has been proven along with the weaknesses of the zoo menagerie plots. \nThe proposed method of being able to calculate the instability of an individual can better showcase how an individual performs on a particular biometric system. \nThe Euclidean distance formula was used in order to calculate the change of performance from one force level to the next. \nThe stability score index ranges from 0 to 1. Zero would indicate perfect stability from one zoo plot to another and 1 would indicate the maximum possible movement possible. To provide reference to this scoring methodology, the previous cases are examined.\n","34":"- The most drastic case of instability examined was the change in animal classifications. \n- Individual 117 was highlighted movement in different animal classifications. \n- First couple are classified as normal. \n- 9N and 11N the existence of inter-animal instability was proven. \n","1":"[Title]\nUsed the zoo menagerie and zoo plots that will be revisited in order to understand\nNeeds to be understood as most of my results use the graphs or are based off of them\n- It can be a bit confusing to understand so I want to revisit\n","51":"individual 117, whose classification changes from a dove to a phantom at different force levels. \n","40":"Within the zoo plots, cut-off values are visible by the shaded (red) areas for each classification. \nSome individuals miss a classification by a marginal amount as they are adjacent to the border. \nThe issue with borderline cases is they can be stable but do not reflect the characteristics of the animal classification to which they are assigned well. \n","18":"The results in Figure 4.5 show only one individual classified as a worm, 135RI. \nIn the previous three force levels, individual 135RI was classified as normal in the zoo plots.\n","46":"individual 135 was examined for instability within the normal classification. The zoo plots are shown to demonstrate how the stability score index is conceptualized. The stability score and related coordinates for the 5 N and 7 N levels for individual 135 \n","13":"154 Subjects reported gender along with having all digits on all force levels\nMale\n81\nFemale\n73\n","2":"With this slide I want to try and paint the overall picture of how I got my idea, as well as why I am doing this.\nDHS funded us for a data collection we did back in 2009 where we looked at fingerprint quality over varying force levels.\nDr Elliott, Dr. Kukula, and Dr. Modi were able to obtain a patent so you know this research was important in the eyes of the university as well as the US Patent Office\nwanted us to examine a sort of new performance analysis measurement called the biometric zoo menagerie\nzoo- a way of classifying individuals based upon how well they are matched to themselves and others in their specific dataset\nRoc curves- most used performance analysis tools- How well the system is performing as a whole\nWEAKENSSES- just a screenshot of performance\nKevin – I am trying to paint a picture for the committee, especially Dr Dyrenfurth so he can wrap his brain around it. He will get it, but you need to “tell a story” –so think 646 presentation with a bit of introduction. Dr. Sutton in my discussion with him wanted to have a “problem”, “why it is important”, and “impact” style slides, and I have tried to build this up here. Feel free to change anything here – as this is your day to shine. \nFor this slide – I thought it would be interesting to say – we have done the preliminary research – you can say you helped with this research. This gives them the impact – as if DHS has already funded preliminary work then they must think it is important. If earlier researchers got a patent on force measurements, then the university must have thought it would be important, as well as US Patent Office. I am not trying to “toot” my own horn here and show off that I have a patent, so if you want to remove it I wont be offended . I kind of put in your own words – so feel free to change, why you decided to look at this in more detail – the third and fourth indented bullets I thought would be something that you could adjust. It sets the scene on why you are interested in this, and why you have a vested interest in completing this research. \n","52":"individual 117, whose classification changes from a dove to a phantom at different force levels. For individual 117, both the zoo plots and the stability score reflect a high level of instability. \n","41":"Individual 172 has an impostor score of 9.0675, and 140 has an impostor score of 9.0661, a difference of .0014.\nIf these individuals were to take each other’s impostor scores at the next force level they would change classifications, which would not be the case if they are moving an insignificant amount. \n","58":"lousy fingerprints – how long should we take to get good images. \ngreencard fingerprints 3 times. What is the cost? What if I had a stability score – and then they would know. \nAt Global Entry a person could have a score? Is a score representative of the subject. These are what I want to investigate. \n","14":"Additional question to provide evidence for instability\n1st question answered within zoo plots\n2nd question answered in individual cases\n","53":"subject 178 was examined due to their ability to have similar performance across force levels, but classified differently. This weakness of the zoo is ignored when using the stability score index\n","42":"- Not all subjects fall into the instability cases. An example of an individual that has small deviations in instability is provided within this section. \nNo subjects were able to obtain the same genuine and impostor scores across force levels but some had significantly smaller movements in the zoo plots \nThe weakness by just examining the animal classification of this particular case is it would appear to have an unstable performance, due to being classified differently.\nIndividual 178 is relatively stable and can be shown later with a stability score.\n","31":"- Big jump from 7N to 9N\n- later examined with SSI\n","20":"change in the counts shown in the table and the shifts on the zoo plots supports the presence of instability in the dataset.\n-5n and 7n dove counts the same but not the same subjects\n","9":"Zoo Plots used for my analysis\nPoint of classifications (red shaded areas show the limits for each animal)\n","48":"- a star shows the placement of individual 135 on the 5 N force level. This shows the instability established earlier. \n- Score obtained from Euclidean distance divided by the maximum movement gives a stability score index of 0.3512\n","15":"distribution of the 5 N zoo plot. \nThis is the baseline data used for the stability scores:\nMinimum Genuine (X-axis): 44\nMaximum Genuine (X-axis): 1950\nMinimum Impostor (Y-axis): 2.4\nMaximum Impostor (Y-axis): 10.3\nThere is a dispersed population across the impostor and genuine scores, varying for each classification. \n","4":"Before I go into Results, I want to revisit some key definitions and terms\nMost of what you will see will involve the zoo plots\nWant to make sure this is understood before going into numbers\n","54":"small deviation from 7N to 9N. Regardless of how the zoo plots classified subject 178, they will still result in a stability score closer to zero, indicating stability. Inserting the coordinates into the formula, a stability score of 0.0308 was obtained. \n","21":"- different cases of instability exist across the force levels for certain individuals because some move classifications and others do not. \n- illustration cases of instability of zoo plots for certain individuals that will later be quantified\n- four cases: instability in the normal classification, intra-animal instability, inter-animal instability, and also an additional case that will examine borderline situations.\n"}