CBP CBP Biometric Performance Evaluation and Testing 1 — Questions and Answers
Question 1: What does FMR (False Match Rate) measure in a biometric system?
- The rate at which genuine users are rejected
- The rate at which impostors are incorrectly accepted as genuine (Correct answer)
- The rate at which the sensor fails to capture a sample
- The rate at which templates fail to enroll
Correct answer: The rate at which impostors are incorrectly accepted as genuine
FMR (False Match Rate), also known as False Accept Rate (FAR), measures the frequency at which an impostor's biometric sample is incorrectly matched to another person's enrolled template.
Question 2: What is the FNMR (False Non-Match Rate) in biometric system evaluation?
- The probability that an impostor is accepted
- The probability that a genuine user's sample fails to match their enrolled template (Correct answer)
- The rate of sensor hardware failures
- The proportion of users who cannot enroll
Correct answer: The probability that a genuine user's sample fails to match their enrolled template
FNMR (False Non-Match Rate) is the probability that a genuine user's presented biometric sample fails to match their stored template, causing a false rejection.
Question 3: On an ROC (Receiver Operating Characteristic) curve for a biometric system, what trade-off is being visualized?
- Enrollment time vs. matching speed
- FMR vs. FNMR across different decision thresholds (Correct answer)
- Template size vs. storage cost
- Sensor resolution vs. matching accuracy
Correct answer: FMR vs. FNMR across different decision thresholds
A biometric ROC curve plots FMR against FNMR (or 1-FNMR) at varying decision thresholds, showing the trade-off between security and user convenience.
Question 4: The Equal Error Rate (EER) is the point on the ROC curve where:
- Throughput equals enrollment speed
- FMR equals FNMR (Correct answer)
- The system achieves 99% accuracy
- False rejects equal the number of enrollments
Correct answer: FMR equals FNMR
The Equal Error Rate (EER) is the operating point where FMR equals FNMR, and is commonly used as a single-figure summary of biometric system accuracy.
Question 5: What does the 'Failure to Enroll' (FTE) rate measure?
- The proportion of enrolled users who forget their PIN
- The proportion of individuals whose biometric samples cannot be successfully enrolled (Correct answer)
- The number of times a system reboots during enrollment
- The rate at which templates expire and must be re-enrolled
Correct answer: The proportion of individuals whose biometric samples cannot be successfully enrolled
FTE (Failure to Enroll) rate measures the proportion of users for whom the system cannot create a usable biometric template during the enrollment process.
Question 6: In biometric testing, what is a 'technology evaluation' as opposed to an 'operational evaluation'?
- Technology evaluation tests hardware; operational evaluation tests software
- Technology evaluation tests algorithms on archived data; operational evaluation tests complete systems in real deployment conditions (Correct answer)
- Technology evaluation is done by vendors; operational evaluation is done by regulators
- Technology evaluation measures speed; operational evaluation measures accuracy
Correct answer: Technology evaluation tests algorithms on archived data; operational evaluation tests complete systems in real deployment conditions
A technology evaluation tests biometric algorithms on archived datasets in controlled conditions, while an operational evaluation tests the complete system in a real or simulated live deployment environment.
CBP CBP Biometric Performance Evaluation and Testing 1
What does FMR (False Match Rate) measure in a biometric system?