Personal choice biometric signature

• US 7,013,030 B2
• Filed: 03/22/2002
• Issued: 03/14/2006
• Est. Priority Date: 02/14/2002
• Status: Expired due to Fees

• Current Assignee: Delano P. Chong, Jacob Y. Wong
• Original Assignee: Delano P. Chong, Jacob Y. Wong
• Inventors: Wong, Jacob Y., Chong, Delano P.
• Primary Examiner(s): Wu, Jingge
• Assistant Examiner(s): KIM, CHONG R
• Application Number:
  US10/102,667
• Publication Number:
  US 20030179909A1
• Time in Patent Office: 1,453 Days
• Field of Search: 382/115, 382124-127, 382/280, 356/71
• US Class Current: 382/124
• CPC Class Codes: G06V 40/1335 Combining adjacent partial images (e.g. slices) to create a composite input or reference pattern; Tracking a sweeping finger movement
• CPC Class Codes: G06V 40/1347 Preprocessing; Feature extraction
• CPC Class Codes: G07C 9/257 electronically G07C9/26 takes precedence

Abstract

A biometric method and system for personal authentication using sequences of partial fingerprint signatures provides a high security capability to various processes requiring positive identification of individuals. This approach is further enhanced by employing a frequency domain technique for calculating a Similarity Index of the partial fingerprint signatures. In a baseline usage, the sequential partial fingerprint sequence techniques augments sentinel systems for gaining access to restricted areas, and when used in combination with financial cards, offer a unique and greatly simplified means for authenticating or identifying individuals. A highly automated technique initially obtains four (illustratively) linear partial fingerprint signatures which serve as reference data against which later proffered candidate data in the form of at least two linear partial fingerprint signatures are compared for authentication. The particular two candidate signatures used and the sequence in which they are submitted are selected with the user'"'"'s consent and serve as a PIN-like unique personal code. In an advanced embodiment, the same two candidate signatures in the chosen sequence are processed in a unique FFT/DFT process to produce a highly reliable Similarity Index to authenticate or verify the identity of individuals. The use of only partial fingerprint data greatly allays the concerns of widespread fingerprint dissemination by many individuals.

Claims

1. A biometric method of authenticating the identity of an individual employing a preselected sequence of linear partial fingerprint signatures processed in the frequency domain, comprising the steps of:

(a) obtaining a reference set of linear partial fingerprint signatures from an individual and electronically performing a Fourier transform on said reference set to obtain a frequency domain reference set;

(b) storing a first electronic representation of said reference set in a comparison means, said first electronic representation selected from a group including said reference set and said frequency domain reference set;

(c) generating a candidate set of linear partial fingerprint signatures from an individual and electronically performing a Fourier transform on said candidate set to obtain a frequency domain candidate set;

(d) entering a second electronic representation of said candidate set into said comparison means, said second electronic representation selected from a group including said candidate set and said frequency domain candidate set;

(e) providing a comparison means for comparing said first and second electronic representations and

(f) calculating in said comparison means a dot product of said frequency domain reference set with the complex conjugate of said frequency domain candidate set, or alternately, a dot product of said frequency domain candidate set with the complex conjugate of said frequency domain reference set; and

(g) formulating a similarity index from said dot product calculation, said similarity index resulting in the production of a real number between 0 and 1 resulting from said formulating, whereby the identity of an individual providing said reference and candidate sets may be authenticated if said similarity index is greater than a predetermined level between 0 and 1.

2. The biometric method of claim 1 including the further step of calculating in said comparison means the normalized FFT of said frequency domain reference set and said frequency domain candidate set, by dividing each set by the square root of the dot product of itself with its complex conjugate to produce a normalized frequency domain reference set and a normalized frequency domain candidate set, and thereafter formulating said similarity index.

3. The biometric method of claim 1 wherein said generating step further includes the process wherein said candidate set is derived from at least two scans taken along predetermined paths on that individual'"'"'s fingerprint, the particular two of said at least two scans and the sequence of their application to said comparison means being selected so as to serve as a personal code.

4. The biometric method of claim 1 wherein performing said Fourier transform steps are accomplished using an FFT process.

5. The biometric method of claim 1 including the further step of establishing a first authentication level and a second authentication level within said comparison means for quantifying the similarity index formulation result, whereby the identity of an individual is authenticated if said real number is greater than said first level and the identity of an individual is non-authenticated if said real number is less than said second level.

6. The biometric method of claim 5 wherein said first authentication level is a number between 0.7 and 1 and said second authentication level is a number between 0 and 0.3.

7. The biometric method of claim 5 further including providing an output signal generator as part of said comparison means, for providing an enabling signal to an external device upon determination that the identity of an individual is authenticated by said similarity index result number exceeding said first level.

8. The biometric method of claim 1 wherein said generating step is accomplished by carrying out a timed series of sample data points to produce said candidate set of linear partial fingerprint signatures, said samples taken at uniformly spaced time intervals, whereby the number of sample data points in said candidate set may be adjusted in said comparison means to compensate for fingerprint movement speed while generating said candidate set with respect to said obtained reference set.

9. The biometric claim of claim 1 wherein said obtaining step includes producing a reference set of linear partial fingerprint signatures having a number of sample data points provided at uniformly spaced time intervals, whereby the number of sample data points in said reference set may be adjusted in said comparison means to compensate for fingerprint movement speed while obtaining said reference set with respect to said generated candidate set.

10. A biometric system for authenticating the identity of an individual employing a preselected sequence of linear partial fingerprint signatures processed in the frequency domain, comprising:

(a) means for obtaining a reference set of linear partial fingerprint signatures from an individual, said reference set derived from at least one scan taken across said individual'"'"'s finger and electronically performing a Fourier transform on said reference set to obtain a frequency domain reference set;

(b) means for storing a first electronic representation of said reference set in a comparison means, said first electronic representation selected from a group including said reference set and said frequency domain reference set;

(c) means for generating a candidate set of linear partial fingerprint signatures from an individual, said candidate set derived from at least two scans taken across predetermined bidirectional portions of said individual'"'"'s finger and electronically performing a Fourier transform on said candidate set to obtain a frequency domain candidate set,

(d) means for entering a second electronic representation of said candidate set into said comparison means, said second electronic representation selected from a group including said candidate set and said frequency domain candidate set;

(e) comparison means for comparing said first and second electronic representations;

(f) means for calculating in said comparison means a dot product of said frequency domain reference set with the complex conjugate of said frequency domain candidate set, or alternately, a dot product of said frequency domain candidate set with the complex conjugate of said frequency domain reference set; and

(g) means for formulating a similarity index from said dot product calculation, said similarity index resulting in the production of a real number between 0 and 1 resulting from said formulating, whereby the identity of an individual providing said reference and candidate sets may be authenticated if said similarity index is greater than a predetermined level between 0 and 1.

11. The biometric system of claim 10 wherein said means for obtaining includes an optical scanner for deriving said at least one scan while said individual'"'"'s finger is held stationary.

12. The biometric system of claim 10 wherein said means for generating includes a single element optical sensing device for deriving said at least two scans while said individual'"'"'s finger is moving relative to said single element optical sensing device.

13. The biometric system of claim 10 wherein said comparison means includes a microprocessor and said means for storing comprises a RAM/ROM portion of said microprocessor.

14. The biometric system of claim 13 wherein said microprocessor is embedded within an identification/credit card having a self-contained power source.

15. The biometric system of claim 14 wherein said microprocessor further includes speed compensating means for assuring that said means for obtaining and said means for generating produce sets of linear partial fingerprint signatures that temporally facilitate said similarity index formulating.

16. The biometric system of claim 10 wherein said comparison means further comprises an output circuit for providing control signals to an external control unit, said output circuit employing wired or wireless channels for said controlling.

17. The biometric system of claim 10 wherein said comparison means further comprises a visual indicator for displaying an output from said means for formulating to denote a condition where an individual'"'"'s identity is authenticated.

18. The biometric system of claim 10 wherein said comparison means further comprises a scanning device having a template with two sets of contoured and indented scanning tracks and a single optical element sensor unit located at the center of said template.

19. The biometric system of claim 18 wherein said scanning device serves as said means for generating.