Method and system for adaptively varying templates to accommodate changes in biometric information

• US 7,372,979 B2
• Filed: 07/25/2006
• Issued: 05/13/2008
• Est. Priority Date: 03/05/2001
• Status: Expired due to Term

• Current Assignee: Activcard Ireland, Limited
• Original Assignee: Activcard Ireland, Limited
• Inventors: Hillhouse, Robert, Boyer, John
• Primary Examiner(s): CHAWAN, SHEELA C
• Application Number:
  US11/492,247
• Publication Number:
  US 20070110283A1
• Time in Patent Office: 658 Days
• Field of Search: 382/115, 382/124, 382/278, 382/128, 382/209, 382/312, 235/380, 235/376, 380/255, 380/258, 713/186, 713/173, 713/172, 713/182, 713/185
• US Class Current: 382/115
• CPC Class Codes: G06F 18/28 Determining representative reference patterns, e.g. by averaging or distorting; Generating dictionaries
• CPC Class Codes: G06V 40/1365 Matching; Classification

Abstract

A method and apparatus for authenticating a user In dependence upon biometric Input information is disclosed. According to the method when a user is identified, their biometric information or data derived therefrom is automatically stored. The data is then used in subsequent user identification attempts as a template. The original templates are not replaced but those templates that are automatically stored are replaced at intervals.

Claims

1. A system for identifying a user comprising:

an authentication server that stores templates relating to identifications of users; and

a processing device programmed to;

determine electronic data representing a biometric information sample from a biometric source of the user;

analyze the electronic data to compare the electronic data against stored biometric templates relating to identifications of users;

when a first threshold corresponding to a substantial match of a template is satisfied, identify the individual; and

when a difference between the electronic data and the matched template is above a predetermined second threshold, store a new biometric template in said authentication server as an adaptive enrollment for the user based on the electronic data relating to biometric information samples for said biometric source as provided by the user for use in identifying the user.

2. A system according to claim 1 wherein for every predetermined number of occurrences of a substantial match, the processing device:

stores the electronic data within a history file;

analyzes the electronic data to determine its suitability for use as the adaptive enrollment; and

when the electronic data is determined to be suitable, stores the electronic data as the adaptive enrollment.

3. A system according to claim 2 wherein the history file comprises up to N samples of electronic data and wherein an oldest sample of electronic data is deleted by the processing device when a new sample of electronic data is added to a history file containing N samples.

4. A system according to claim 3 wherein a score is stored in association with each sample electronic data within the history file indicating a suitability of the sample for use as the adaptive enrollment.

5. A system according to claim 4 wherein the score is determined by the processing device by comparing the sample electronic data against each other sample electronic data within the history file and associated with a same user identification.

6. A system according to claim 5 wherein the score is determined by the processing device by determining a composite comparison metric, M_i for each sample electronic data, i,

$m_i=\frac{\sum _{}^{}}{}$

j = 1 , j ≠

i n ⁢

c ⁡

( H i , H j ) n - 1 , i ∈

{ 1 , …

⁢

, n }

where n is the number of historical enrollments in the set and c(H_i,H_j) is the comparison metric between biometric template i and biometric template j.

7. A system according to claim 5 wherein upon deleting a sample electronic data from the history file, its effect on the scores in the history file is approximately reversed.

8. A system according to claim 7 wherein the effect is approximately reversed by said processing device by recalculating m, after the deletion of sample electronic element j according to

$m_i=m_i-\frac{c}{}$

( H i , H j ) n - 1 , i ∈

{ 1 , …

⁢

, n } , i ≠

j

where n is the number of historical enrollments in the set including historical enrollment j.

9. A system according to claim 8 wherein the effect of an added sample electronic element j is determined by the processing device by calculating m_i according to

$m_i=m_i+\frac{c}{}$

( H i , H j ) n - 1 , i ∈

{ 1 , …

⁢

, n } , i ≠

j

where n is the number of historical enrollments in the set including historical enrollment j.

10. A system according to claim 2 wherein the effect of an added sample electronic element j is determined by the processing device by calculating m_i according to

$m_i=m_i+\frac{c}{}$

( H i , H j ) n - 1 , i ∈

{ 1 , …

⁢

, n } , i ≠

j

where n is the number of historical enrollments in the set including historical enrollment j.

11. A system according to claim 2 wherein electronic data samples suitable for use as the adaptive enrollment are compared against the stored data by the processing device, and when a difference greater than a predetermined difference exists, a notification of such is generated.

12. A system according to claim 2 wherein electronic data samples are compared against the stored data by the processing device, and when a difference greater than a predetermined difference exists, the user is prompted to re-enroll in order to provide new biometric information for use in determining new stored data.

13. A system for identifying a user comprising:

an authentication server that stores templates relating to identifications of users; and

a processing device programmed to;

receive a biometric information sample from a biometric source of the user for use in identifying the user;

determine electronic data representing said biometric information sample of the user;

analyze the electronic data to compare the electronic data against stored biometric template data relating to identifications of users;

when a first threshold corresponding to a substantial match of a template is satisfied;

identify the individual;

store the electronic data in association with the user identification as further stored biometric template data; and

determine from the further stored biometric template data comparison data for use in identifying the user; and

when a difference between the electronic data and the stored biometric template data is above a predetermined second threshold, compare the electronic data against other stored biometric template data relating to biometric information samples for said biometric source as provided for use in identifying the user.

14. A system according to claim 13 wherein the further stored biometric template data relates to different features of the individual, the features for use in identifying the individual.

15. A system according to claim 13 wherein the processing device stores the electronic data in association with the user identification as further stored biometric template data by storing an electronic representation of the biometric information sample associated with the identification.

16. A system according to claim 15 wherein the processing device determines from the further stored biometric template data comparison data for use in identifying the user by:

comparing each stored electronic representation associated with the identification against a template derived from each other electronic representation associated with the identification to select at least an electronic representation that best represents the stored electronic representations associated with the identification; and

determining at least a template from the at least a selected electronic representation.

17. A system according to claim 15 wherein the processing device determines from the further stored biometric template data comparison data for use in identifying the user by:

storing with each electronic representation associated with the identification a score indicative of a quality of the stored electronic representations associated with the identification for use in generating a template;

comparing the oldest stored electronic representation associated with the identification against a template derived from each other electronic representation associated with the identification to determine the conection for the score associated with said template;

correcting each score in accordance with the determined corrections;

comparing the newest stored electronic representation associated with the identification against a template derived from each other electronic representation associated with the identification to determine a second conection for each score;

correcting each score in accordance with the determined second correction; and

selecting an electronic representation associated with a best score for use in determining a template for use as the comparison data.

18. A system for identifying a user comprising:

means for receiving a biometric information sample from a biometric source of the user for use in identifying the user;

means for determining electronic data representing said biometric information sample of the user;

means for analyzing the electronic data to extract features for comparison with stored electronic data;

means for comparing the extracted features against stored electronic data, the stored electronic data relating to identifications of users;

means for, when a substantial match is found;

identifying the individual;

determining a number of times that the user has been identified and when the number is one of at least a predetermined number;

storing the electronic data in association with the user identification as further stored data; and

determining from the further stored data comparison data for use in identifying the user; and

,

means for, when a difference between the electronic data and the stored data is above a predetermined threshold, comparing the electronic data against other stored data, the other stored data relating to additional biometric information samples for said biometric source as provided for use in identifying the user.

19. A system for identifying a user comprising:

an authentication server that stores templates relating to identifications of users; and

a processing device programmed to;

receive a biometric information sample from a biometric source of the user;

form from said biometric information sample at least a first template including biometric features for use in identifying an individual;

form a history file including a plurality of biometric information samples from said biometric source each provided by the same individual at different times for use in identifying the individual; and

form at least one adaptive enrollment template from the biometric information samples from said biometric source in the history file,

wherein an individual is identified by registering provided biometric information sample against the at least a first template and, when registration is not successful, registering the provided biometric information sample against the at least one adaptive enrollment template.

20. A system according to claim 19 wherein the at least one adaptive enrollment template is a template formed from one or more biometric information samples within the history file, the one or more biometric information samples selected through a comparison with other biometric information samples within the history file.

21. A system according to claim 20 wherein each biometric information sample stored within the history file is compared against each other biometric information sample within the history file by the processing device to determine those that are most suitable for use in determining adaptive enrollment templates.

22. A system according to claim 21 wherein the history file comprises up to N biometric information samples and wherein an oldest biometric information sample is deleted by the processing device when a new biometric information sample is added to a history file containing N samples.

23. A system according to claim 22 wherein a score is stored in association with each biometric information sample within the history file indicating a suitability of that sample for use in determining an adaptive enrollment template.

24. A system according to claim 23 wherein the score is determined by the processing device by comparing the sample electronic data against each other sample electronic data within the history file and associated with a same user identification.

25. A system according to claim 24 wherein the score is determined by the processing device by determining a composite comparison metric, M_i for each sample electronic data, i,

$m_i=\frac{\sum _{}^{}}{}$

j = 1 , j ≠

i n ⁢

c ⁡

( H i , H j ) n - 1 , i ∈

{ 1 , …

⁢

, n }

where n is the number of historical enrollments in the set and c(H_i,H_j) is the comparison metric between biometric template i and biometric template j.

26. A system according to claim 24 wherein upon deleting a sample electronic data from the history file, its effect on the scores in the history file is approximately reversed.

27. A system according to claim 26 wherein the effect is approximately reversed by the processing device by recalculating m_i after the deletion of sample electronic element j according to

$m_i=m_i-\frac{c}{}$

( H i , H j ) n - 1 , i ∈

{ 1 , …

⁢

, n } , i ≠

j

where n is the number of historical enrollments in the set including historical enrollment j.

28. A system according to claim 27 wherein the effect of an added sample electronic element j is determined by the processing device by calculating m_i according to

$m_i=m_i+\frac{c}{}$

( H i , H j ) n - 1 , i ∈

{ 1 , …

⁢

, n } , 1 ≠

j

wherein n is the number of historical enrollments in the set including historical enrollment j.

29. A system according to claim 19 wherein the effect of an added sample electronic element j is determined by the processing device by calculating m_i according to

$m_i=m_i+\frac{c}{}$

( H i , H j ) n - 1 , i ∈

{ 1 , …

⁢

, n } , i ≠

j

where n is the number of historical enrollments in the set including historical enrollment j.

30. A system according to claim 19 wherein adaptive enrollment templates are compared against the at least a first template by the processing device and, when a difference greater than a predetermined difference exists, a notification of such is generated.

31. A system according to claim 19 wherein adaptive enrollment templates are compared against the at least a first template by the processing device and, when a difference greater than a predetermined difference exists, the user is prompted to re-enroll in order to provide new biometric information for use in determining a new at least a first template.

32. A computer readable medium having executable instructions stored thereon that when read by a computer causes the computer to:

receive a biometric information sample from a biometric source of a user for use in identifying the user;

determine electronic data representing said biometric information sample of the user;

analyze the electronic data to compare the electronic data against biometric templates relating to identifications of users;

when a first threshold corresponding to a substantial match of a template is satisfied, identify the individual; and

,

when a difference between the electronic data and the matched template is above a predetermined second threshold, store a new biometric template as an adaptive enrollment for the user based on the electronic data relating to biometric information samples for said biometric source as provided by the user for use in identifying the user.

33. A computer readable medium according to claim 32 further having stored thereon executable instructions that for every predetermined number of occurrences of a substantial match, causes the computer to:

store the electronic data within a history file;

analyze the electronic data to determine its suitability for use as the adaptive enrollment; and

when the electronic data is determined to be suitable, store the electronic data as the adaptive enrollment.

34. A computer readable medium according to claim 33 wherein the history file comprises up to N samples of electronic data and wherein the computer readable medium further comprises executable instructions for causing the computer to delete an oldest sample of electronic data when a new sample of electronic data is added to a history file containing N samples.

35. A computer readable medium according to claim 34 further comprising executable instructions for causing the computer to store a score in association with each sample electronic data within the history file indicating a suitability of the sample for use as the adaptive enrollment.

36. A computer readable medium according to claim 35 further comprising executable instructions for causing the computer to determine the score by comparing the sample electronic data against each other sample electronic data within the history file and associated with a same user identification.

37. A computer readable medium according to claim 36 further comprising executable instructions for causing the computer to determine the score by determining a composite comparison metric, M_i for each sample electronic data, i,

$m_i=\frac{\sum _{}^{}}{}$

j = 1 , j ≠

i ⁢

n ⁢

c ⁡

( H i , H j ) n - 1 , i ∈

{ 1 , …

⁢

, n }

where n is the number of historical enrollments in the set and c(H_i, H_j) is the comparison metric between biometric template i and biometric template j.

38. A computer readable medium according to claim 36 further comprising executable instructions for causing the computer to, upon deleting a sample electronic data from the history file, approximately reverse the effect of the sample electronic data on the scores in the history file.

39. A computer readable medium according to claim 38 further comprising executable instructions for causing the computer to approximately reverse the effect of the sample electronic data by recalculating m, after the deletion of sample electronic element j according to

$m_i=m_i-\frac{c}{}$

( H i , H j ) n - 1 , i ∈

{ 1 , …

⁢

, n } , i ≠

j

where n is the number of historical enrollments in the set including historical enrollment j.

40. A computer readable medium according to claim 39 further comprising executable instructions for causing the computer to determine the effect of an added sample electronic element j by calculating m_i according to

$m_i=m_i+\frac{c}{}$

( H i , H j ) n - 1 , i ∈

{ 1 , …

⁢

, n } , i ≠

j

where n is the number of historical enrollments in the set including historical enrollment j.

41. A computer readable medium according to claim 33 further comprising executable instructions for causing the computer to determine the effect of an added sample electronic element j by calculating m_i according to

$m_i=m_i+\frac{c}{}$

( H i , H j ) n - 1 , i ∈

{ 1 , …

⁢

, n } , i ≠

j

where n is the number of historical enrollments in the set including historical enrollment j.

42. A computer readable medium according to claim 33 further comprising executable instructions for causing the computer to compare electronic data samples suitable for use as the adaptive enrollment against the stored data, and when a difference greater than a predetermined difference exists, generate a notification of such.

43. A computer readable medium according to claim 33 further comprising executable instructions for causing the computer to compare electronic data samples against the stored data, and when a difference greater than a predetermined difference exists, prompt the user to re-enroll in order to provide new biometric information for use in determining new stored data.

44. A computer readable medium having executable instructions stored thereon that when read by a computer causes the computer to identify a user by:

receiving a biometric information sample from a biometric source of the user for use in identifying the user;

determining electronic data representing said biometric information sample of the user;

analyzing the electronic data to compare the electronic data against stored biometric template data relating to identifications of users;

when a first threshold corresponding to a substantial match of a template is satisfied;

identifying the individual;

storing the electronic data in association with the user identification as further stored biometric template data;

determining from the further stored biometric template data comparison data for use in identifying the user; and

e) when a difference between the electronic data and the stored biometric template data is above a predetermined second threshold, comparing the electronic data against other stored biometric template data relating to biometric information samples for said biometric source as provided for use in identifying the user.

45. A computer readable medium according to claim 44 wherein the further stored biometric template data relates to different features of the individual, the features for use in identifying the individual.

46. A computer readable medium according to claim 44 wherein storing the electronic data in association with the user identification as further stored biometric template data comprises storing an electronic representation of the biometric information sample associated with the identification.

47. A computer readable medium according to claim 46 wherein determining from the further stored biometric template data comparison data for use in identifying the user includes:

comparing each stored electronic representation associated with the identification against a template derived from each other electronic representation associated with the identification to select at least an electronic representation that best represents the stored electronic representations associated with the identification; and

determining at least a template from the at least a selected electronic representation.

48. A computer readable medium according to claim 46 wherein determining from the further stored biometric template data comparison data for use in identifying the user includes:

storing with each electronic representation associated with the identification a score indicative of a quality of the stored electronic representations associated with the identification for use in generating a template;

comparing the oldest stored electronic representation associated with the identification against a template derived from each other electronic representation associated with the identification to determine the correction for the score associated with said template;

correcting each score in accordance with the determined corrections;

comparing the newest stored electronic representation associated with the identification against a template derived from each other electronic representation associated with the identification to determine a second correction for each score;

correcting each score in accordance with the determined second correction; and

selecting an electronic representation associated with a best score for use in determining a template for use as the comparison data.

49. A computer readable medium having executable instructions stored thereon that when read by a computer causes the computer to identify a user by:

receiving a biometric information sample from a biometric source of the user for use in identifying the user;

determining electronic data representing said biometric information sample of the user;

analyzing the electronic data to extract features for comparison with stored electronic data;

comparing the extracted features against stored electronic data, the stored electronic data relating to identifications of users; and

when a substantial match is found;

identifying the individual;

determining a number of times that the user has been identified and when the number is one of at least a predetermined number;

storing the electronic data in association with the user identification as further stored data; and

determining from the further stored data comparison data for use in identifying the user; and

when a difference between the electronic data and the stored data is above a predetermined threshold, comparing the electronic data against other stored data, the other stored data relating to additional biometric information samples for said biometric source as provided for use in identifying the user.

50. A computer readable medium having executable instructions stored thereon that when read by a computer causes the computer to identify a user by:

receiving a biometric information sample from a biometric source of the user;

forming from said biometric information sample at least a first template including biometric features for use in identifying an individual;

forming a history file including a plurality of biometric information samples from said biometric source each provided by the same individual at different times for use in identifying the individual; and

forming at least one adaptive enrollment template from the biometric information samples from said biometric source in the history file,

wherein an individual is identified by registering provided biometric information sample against the at least a first template and, when registration is not successful, registering the provided biometric information sample against the at least one adaptive enrollment template.

51. A computer readable medium according to claim 50 wherein the at least one adaptive enrollment template is a template formed from one or more biometric information samples within the history file, the one or more biometric information samples selected through a comparison with other biometric information samples within the history file.

52. A computer readable medium according to claim 51 further comprising executable instructions for comparing each biometric information sample stored within the history file against each other biometric information sample within the history file to determine those that are most suitable for use in determining adaptive enrollment templates.

53. A computer readable medium according to claim 52 wherein the history file comprises up to N biometric information samples further comprising executable instructions for deleting an oldest biometric information sample when a new biometric information sample is added to a history file containing N samples.

54. A computer readable medium according to claim 53 further comprising executable instructions for storing a score in association with each biometric information sample within the history file indicating a suitability of that sample for use in determining an adaptive enrollment template.

55. A computer readable medium according to claim 54 further comprising executable instructions for determining the score by comparing the sample electronic data against each other sample electronic data within the history file and associated with a same user identification.

56. A computer readable medium according to claim 55 further comprising executable instructions for determining the score by determining a composite comparison metric, M_i for each sample electronic data, i,

$m_i=\frac{\sum _{}^{}}{}$

j = 1 , j ≠

i ⁢

n ⁢

c ⁡

( H i , H j ) n - 1 , i ∈

{ 1 , …

⁢

, n }

where n is the number of historical enrollments in the set and c(H_i,H_j) is the comparison metric between biometric template i and biometric template j.

57. A computer readable medium according to claim 55 further comprising executable instructions for, upon deleting a sample electronic data from the history file, approximately reversing the effect of said sample electronic data on the scores in the history file.

58. A computer readable medium according to claim 57 further comprising executable instructions for approximately reversing the effect of the sample electronic data on the scores in the history file by recalculating m_i after the deletion of sample electronic element j according to

$m_i=m_i-\frac{c}{}$

( H i , H j ) n - 1 , i ∈

{ 1 , …

⁢

, n } , i ≠

j

where n is the number of historical enrollments in the set including historical enrollment j.

59. A computer readable medium according to claim 58 further comprising executable instructions for determining the effect of an added sample electronic element j by calculating m_i according to

$m_i=m_i+\frac{c}{}$

( H i , H j ) n - 1 , i ∈

{ 1 , …

⁢

, n } , i ≠

j

wherein n is the number of historical enrollments in the set including historical enrollment j.

60. A computer readable medium according to claim 50 further comprising executable instructions for determining the effect of an added sample electronic element j by calculating m_i according to

$m_i=m_i+\frac{c}{}$

( H i , H j ) n - 1 , i ∈

{ 1 , …

⁢

, n } , i ≠

j

where n is the number of historical enrollments in the set including historical enrollment j.

61. A computer readable medium according to claim 50 further comprising executable instructions for comparing adaptive enrollment templates against the at least a first template and, when a difference greater than a predetermined difference exists, generating a notification of such.

62. A computer readable medium according to claim 50 further comprising executable instructions for comparing adaptive enrollment templates against the at least a first template and, when a difference greater than a predetermined difference exists, prompting the user to re-enroll in order to provide new biometric information for use in determining a new at least a first template.