Electro-optical method and apparatus for making identifications

• US 3,944,978 A
• Filed: 09/09/1974
• Issued: 03/16/1976
• Est. Priority Date: 09/09/1974
• Status: Expired due to Term

• Current Assignee: Recognition Systems Inc
• Original Assignee: Recognition Systems Inc
• Inventors: Kasdan, Harvey L., Thomasson, James T., Jensen, Niels P.
• Primary Examiner(s): Boudreau, Leo H.
• Application Number:
  US05/504,185
• Time in Patent Office: 554 Days
• Field of Search: 340/146.3 E, 340/146.3 P, 356/71, 350/162 SF
• US Class Current: 382/127
• CPC Class Codes: A61B 5/1172 using fingerprinting
• CPC Class Codes: G06V 10/88 Image or video recognition using optical means, e.g. reference filters, holographic masks, frequency domain filters or spatial domain filters
• CPC Class Codes: G06V 40/1347 Preprocessing; Feature extraction
• CPC Class Codes: G07C 9/33 by means of a password
• CPC Class Codes: G07C 9/37 using biometric data, e.g. fingerprints, iris scans or voice recognition

Abstract

A reference diffraction pattern is generated by radiating an invariant physical characteristic such as a fingerprint with coherent light, this reference diffraction pattern being converted by a detector into a reference electrical function which is stored. A person to be identified then has a corresponding invariant physical characteristic such as his fingerprint radiated by coherent light to cause generation of a sample diffraction pattern. The frequency domain of the entire sample diffraction pattern is detected simultaneously to provide a sample electrical function. The reference electrical function in storage is then compared with the sample electrical function and if a correlation exists within a given tolerance, it is known that the person from which the sample electrical function is derived corresponds to the person from which the reference electrical function was derived. The invariant physical characteristics may be fingerprints as mentioned, or signatures, or combinations of both.

Claims

1. A method of verifying a person'"'"'s identity comprising the steps of:

a. storing a reference electrical function corresponding to a reference diffraction pattern formed by radiating with coherent light an invariant physical reference characteristic of a given person by detecting the referenced diffraction pattern by means of a solid state detector made up of semi-circular ring segments and radially extending wedge segments to provide ring reference signals and wedge reference signals simultaneously;

b. positioning an invariant physical sample characteristic of a person for radiation by coherent light to cause generation of a sample diffraction pattern of said characteristic;

c. detecting the frequency domain of the entire sample diffraction pattern simultaneously to provide a sample electrical function thereof by means of a solid state detector made up of semi-circular ring segments and radially extending wedge segments to provide ring sample signals and wedge sample signals simultaneously;

d. maintaining said solid state detector centered relative to said sample diffraction pattern by providing means on said solid state detector for generating error signals in response to an off-centering of the diffraction pattern and utilizing the error signals to center said solid state detector to assure that the same conditions exist as when said referenced diffraction pattern was detected; and

e. comparing said reference electrical function to said sample electrical function by correlating the reference and sample ring signals together and cross-correlating the reference and sample wedge signals together so that the resulting correlation is rotationally invariant whereby if a correlation exists within a given tolerance it is known that the person from which the sample electrical function is derived corresponds to said given person.

2. The method of claim 1, in which said invariant physical characteristic constitutes a fingerprint.

3. The method of claim 1, in wich said invariant physical characteristic constitutes handwriting.

4. The method of claim 1, in which said invariant physical characteristic constitutes a combination of a finger-print and handwriting.

5. An apparatus for verifying a person'"'"'s identity comprising, in combination:

a. a coherent light source;

b. positioning means for positioning an invariant physical characteristic of a person to be identified for radiation by coherent light from said source to form a sample diffraction pattern of said physical characteristic;

c. detector means comprising a solid state detector made up of a plurality of segments arranged to define semi-circular ring shaped segments circumferentially extending over one half the surface of said solid state detector and wedge shaped segments radially extending over the other half of said surface upon which said entire diffraction pattern is projected to provide simultaneously ring sample signals and wedge sample signals constituting a sample electrical function of said sample diffraction pattern;

d. centering means including a central ring in said solid state detector with four conductors attached respectively to each of four quadrants of the ring;

servo means for translating said solid state detector; and

centering signal detecting means responsive to signals generated in said conductors connected to said servo means and responsive to error signals resulting from an off-centering of said solid state detector relative to said sample diffraction pattern for energizing said servo means to recenter said solid state detector; and

e. comparator means receiving said sample electrical function for comparison with a stored reference electrical function including ring reference signals and wedge reference signals derived in a similar manner from a given person, said comparator means correlating the sample and reference ring signals together and cross-correlating the sample and reference wedge signals together so that the resulting correlation is rotationally invariant, and providing a verification signal if a correlation of said sample electrical function with said reference electrical function exists within a given tolerance.

6. An apparatus according to claim 5, in which said positioning means includes at least one right angle prism;

and film means in surface contact with the exterior diagonal surface of said prism, said invariant physical characteristic being impressed against the exterior of said film means, coherent light from said source entering one side surface of the prism to internally reflect from said diagonal surface and pass out the other side surface of the prism for detection by said solid state detector, whereby after a diffraction pattern has been generated and detected, said film means may be moved to position a fresh film portion against the exterior diagonal surface of the prism preparatory to receiving a next invariant physical characteristic whereby said exterior diagonal surface of the prism is kept clean.

7. An apparatus for verifying a person'"'"'s identity comprising, in combination:

a. a coherent light source;

b. positioning means for positioning an invariant physical characteristic of a person to be identified for radiation by coherent light from said source to form a sample diffraction pattern of said physical characteristic;

c. detector means comprising a solid state detector made up of a plurality of segments upon which said entire diffraction pattern is projected to provide simultaneously a plurality of signals constituting a sample electrical function of said sample diffraction pattern; and

d. comparator means receiving said sample electrical function for comparison with a stored reference electrical function derived in a similar manner from a given person, said comparator means providing a verification signal if a correlation of said sample electrical function with said reference electrical function exists within a given tolerance said positioning means including at least one right angle prism with film means in surface contact with the exterior diagonal surface of the prism, said invariant physical characteristic being impressed against the exterior of said film means, coherent light from said source entering one side surface of the prism to internally reflect from the diagonal surface and pass out the other side surface of the prism for detection by said solid state detector, whereby after a diffraction pattern has been generated and detected, said film means may be moved to position a fresh film portion against the exterior diagonal surface of the prism preparatory to receiving a next invariant physical characterstic so that the external diagonal surface of the prism is kept clean, and an additional right angle prism with its exterior diagonal surface spaced from the exterior diagonal surface of the first mentioned prism, said coherent light passing through said additional right angle prism prior to entering said first mentioned prism whereby an additional invariant physical characteristic may be positioned for detection relative to said additional prism to provide a sample diffraction pattern combining both of said physical characteristics.

8. An apparatus according to claim 7, including a transparent film with an adhesive surface positioned against the exterior diagonal surface of said additional prism for receiving said additional invariant physical characteristic, said film then being peeled from said exterior diagonal surface, the adhesive thereon pulling free any particles so that said additional diagonal surface is maintained clean.