Adaptation method for inter-person biometrics variability

• US 7,788,101 B2
• Filed: 10/31/2005
• Issued: 08/31/2010
• Est. Priority Date: 10/31/2005
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Tavares, Clifford
• Primary Examiner(s): Dorvil; Richemond
• Assistant Examiner(s): GODBOLD, DOUGLAS
• Application Number:
  US11/263,752
• Publication Number:
  US 20070100622A1
• Time in Patent Office: 1,765 Days
• Field of Search: 704/246, 704/250, 704/273
• US Class Current: 704/273
• CPC Class Codes: G10L 17/06 Decision making techniques; Pattern matching strategies

Abstract

Embodiments of a system and method for verifying an identity of a claimant are described. In accordance with one embodiment, a feature may be extracted from a biometric sample captured from a claimant claiming an identity. The extracted feature may be compared to a template associated with the identity to determine the similarity between the extracted feature and the template with the similarity between them being represented by a score. A determination may be made to determine whether the identity has a correction factor associated therewith. If the identity is determined to have a correction factor associated therewith, then the score may be modified using the correction factor. The score may then be compared to a threshold to determine whether to accept the claimant as the identity. In accordance with a further embodiment, during enrollment of a subject in a biometric verification system, a feature may be extracted from a biometric sample captured from the subject requesting enrollment and a standard deviation for the feature may then be calculated. A determination may then be performed to determining whether the standard deviation of the feature is greater than a standard deviation of a centroid of a density function. If the standard deviation of the feature is greater than the standard deviation of the centroid, then a correction factor for the subject may be derived based on a trend line of the density function.

Claims

1. A method, comprising:

extracting a feature from a biometric sample captured from a subject requesting enrollment;

calculating a standard deviation for the feature using a microprocessor, the standard deviation calculated from the biometric sample and at least one other biometric sample;

determining whether the standard deviation of the feature is greater than a standard deviation of a centroid of a density function; and

deriving a correction factor for the subject based on a trend line of the density function if the standard deviation of the feature is greater than the standard deviation of the centroid.

2. The method of claim 1, wherein the density function comprises a match score vs. standard deviation density function of a sample population.

3. The method of claim 1, wherein the correction factor is further derived from the difference between a mean score obtained from the centroid and a score for the subject derived from the trend line.

4. The method of claim 1, further comprising determining whether the standard deviation of the feature exceeds a threshold value, and using the threshold value in place of the standard deviation of the feature to derive the correction factor for the subject if the standard deviation of the feature exceeds the threshold value.

5. The method of claim 1, further comprising storing the correction factor in correction data store.

6. The method of claim 1, wherein the biometric sample comprises speech.