METHOD AND APPARATUS FOR CHOOSING AND EVALUATING SAMPLE SIZE FOR BIOMETRIC TRAINING PROCESS

• US 20100315202A1
• Filed: 08/25/2010
• Published: 12/16/2010
• Est. Priority Date: 08/10/2006
• Status: Active Grant

• Current Assignee: Louisiana Tech University Foundation Incorporated
• Original Assignee: Louisiana Tech University Foundation (Louisiana Tech University)
• Inventors: Phoha, Vir V.
• Granted Patent: US 7,986,818 B2
• Time in Patent Office: Days
• US Class Current: 340/5.83
• CPC Class Codes: G06F 18/25 Fusion techniques
• CPC Class Codes: G06V 40/70 Multimodal biometrics, e.g. combining information from different biometric modalities

Abstract

At least two biometric measurements of a person are collected, then a statistical measure based on the measurements is computed. The statistical measure is a bounded estimate of the discriminative power of a test based on the measurements. While the discriminative power is less than a target value, additional biometric measurements are collected. When enough measurements have been collected, a biometric template is constructed from the measurements and stored for use in future identifications. Systems and software to implement similar methods are also described and claimed.

Claims

1. A method comprising:

collecting a plurality of biometric measurements of a person;

computing a statistical measure based on the plurality of biometric measurements;

while the statistical measure is less than a target value, collecting a supplemental biometric measurement of the person and updating the statistical measure based on the supplemental biometric measurement;

storing a biometric template constructed from the plurality of biometric measurements and any supplemental biometric measurements; and

computing an estimate of a discriminative power associated with a certain confidence of a biometric identification system based on the plurality of biometric measurements and any supplemental biometric measurements.

2. The method of claim 1, wherein

the statistical measure comprises an upper bound for an error variance.

3. The method of claim 1, further comprising:

calculating a number of supplemental measurements likely to be required to achieve target values for false rejection rate (FRR) and false acceptance rate (FAR); and

calculating a number of supplemental measurements likely to be required to achieve target values for a certain confidence level.

4. The method of claim 1, wherein

the statistical measure is proportional to

5. The method of claim 1, further comprising:

displaying the estimate of the discriminative power.

6. The method of claim 1, further comprising:

computing an estimate of a number of supplemental biometric measurements required to complete enrollment; and

displaying the estimate to the person.

7. The method of claim 1, further comprising:

collecting a candidate biometric measurement of a candidate;

comparing the candidate biometric measurement to the biometric template; and

granting access to a resource to the candidate if the candidate biometric measurement matches the biometric template.

8. The method of claim 1 wherein each biometric measurement comprises a plurality of keystroke timing measurements collected while the person types on a keyboard.

9. A non-transitory computer-readable medium containing instructions to cause a programmable processor to perform operations comprising:

collecting a plurality of measurements of a characteristic of a user, each measurement including a plurality of scalar quantities;

adjusting the plurality of measurements to produce standard normal variables;

computing an estimate of a number of measurements required to achieve a target discriminative power associated with a certain confidence of a test for a plurality of different numbers of elements that the measurements are related to; and

while a number of the plurality of measurements is less than the estimated number of measurements for all of the a numbers of elements, collecting a supplemental measurement of the user and computing a new estimate of a number of measurements required to achieve the target discriminative power of the test based on the-standard normal variables and the supplemental measurement.

10. The computer-readable medium of claim 9, containing additional instructions to cause the programmable processor to perform operations comprising:

calculating a number of supplemental measurements likely to be required to achieve target values for false rejection rate (FRR) and false acceptance rate (FAR); and

calculating a number of supplemental measurements likely to be required to achieve target values for a certain confidence level.

11. The computer-readable medium of claim 10 wherein computing is based on the standard normal variables.

12. The computer-readable medium of claim 9, containing additional instructions to cause the programmable processor to perform operations comprising:

displaying the estimate to the user.

13. The computer-readable medium of claim 9 wherein the characteristic of the user is a typing rhythm of the user.

14. The computer-readable medium of claim 9 wherein the characteristic of the user is a measurement of at least one of a hand geometry, a fingerprint, a retina image, or a voice recording.

15. A system comprising:

an input device to measure a characteristic of an enrolling user;

biometric sample collection logic to collect a plurality of measurements from the input device;

statistical analysis logic to compute a bounded estimate of a biometric identification capability based on the plurality of measurements; and

control logic to cause the biometric sample collection logic to collect a supplemental measurement until the bounded estimate reaches a target value; and

the control to compute an estimate of a discriminative power associated with a certain confidence of a biometric identification system based on the plurality of biometric measurements and any supplemental biometric measurements.

16. The system of claim 15, further comprising:

the control to calculate a number of supplemental measurements likely to be required to achieve target values for false rejection rate (FRR) and false acceptance rate (FAR); and

the control to calculate a number of supplemental measurements likely to be required to achieve target values for a certain confidence level.

17. The system of claim 15, further comprising:

a database to store a biometric template of the enrolling user prepared from the plurality of measurements and any supplemental measurements.

18. The system of claim 17, further comprising:

access control logic to compare a biometric sample of a prospective user with the biometric template and grant access to a resource if the comparison indicates that the prospective user is identical to the enrolling user.

19. The system of claim 15 wherein the characteristic is a typing rhythm.

20. A non-transitory computer-readable medium containing instructions to cause a programmable processor to perform operations comprising:

collecting a plurality of biometric measurements of a person;

computing a statistical measure based on the plurality of biometric measurements;

while the statistical measure is less than a target value, collecting a supplemental biometric measurement of the person and updating the statistical measure based on the supplemental biometric measurement; and

storing a biometric template constructed from the plurality of biometric measurements and any supplemental biometric measurements, wherein the statistical measure is proportional to “

m”

a number of elements in one biometric measurement, is proportional to “

σ

²”

an upper bound for an error variance, and is inversely proportional to “

Δ

²”

a maximum allowable difference.

21. A system comprising:

an input device to measure a characteristic of an enrolling user;

biometric sample collection logic to collect a plurality of biometric measurements of a person from the input device;

statistical analysis logic to compute a statistical measure based on the plurality of biometric measurements, and while the statistical measure is less than a target value, collect a supplemental biometric measurement of the person and updating the statistical measure based on the supplemental biometric measurement, wherein the statistical measure is proportional to a number of elements in one biometric measurement, is proportional to “

σ

²”

an upper bound for an error variance, and is inversely proportional to “

Δ

²”

a maximum allowable difference; and

a database to store a biometric template constructed from the plurality of biometric measurements and any supplemental biometric measurements.