WO1998044447A1

WO1998044447A1 - Low-cost biometric identification system and method

Info

Publication number: WO1998044447A1
Application number: PCT/US1998/006089
Authority: WO
Inventors: James S. Bianco
Original assignee: Bianco James S
Priority date: 1997-03-31
Filing date: 1998-03-28
Publication date: 1998-10-08
Also published as: AU6781998A

Abstract

In a preferred embodiment, a biometric identification device (302), comprising a finger receiving means into which a finger of a person (320) may be inserted a light producing means (304) disposed at a first side of said finger receiving means to illuminate a finger (320) placed in the finger receiving means and a light detecting means (340, figure 14) disposed at a second, opposite side of the finger receiving means to receive illumination from the light producing means and to provide an output representative of a profile of the finger along at least a partial length thereof.

Description

Low-Cost Biometric Identification System and Method

Technical Field

The present invention relates to identification systems generally and, more particularly, but not by way of limitation, to novel, lo-cost biometric identification system and method.

Background Art

There is a need for a low-cost, simple, rapid, biometric identification system for use in low-security applications such as authentication of amusement park tickets and access to welfare benefits, for example.

Conventional biometric identification systems include fingerprinting, retinal scanning, and handprint geometry. Such methods are relative slow and require a great deal of computing power. Additionally, some methods, such a fingerprinting are considered to be degrading to some people. Handprint geometry biometric identification can be relatively easily circumvented through the use of a cardboard hand pattern. Other biometric identification systems require that a user insert a finger into a hole in a machine. However, many people are adverse to inserting a finger into such a device. All conventional biometric identification systems are relatively expensive to implement.

Accordingly, it is a principal object of the present invention to provide system and method for biometric identification that are low-cost, simple, and rapid.

It is a further object of the invention to provide such system and method that are easily implemented. It is an additional object of the invention to provide such system and method that are relatively difficult to circumvent.

Other objects of the present invention, as well as particular features, elements, and advantages thereof, will be elucidated in, or be apparent from, the following description and the accompanying drawing figures .

Disclosure of Invention

The present invention achieves the above objects, among others, by providing, in a preferred embodiment, a biometric identification device, comprising: finger receiving means into which a finger of a person may be inserted; light producing means disposed at a first side of said finger receiving means to illuminate a finger placed in said finger receiving means; and light detecting means disposed at a second, opposite side of said finger means to receive illumination from said light producing means and to provide an output representative of a profile of said finger along at least a partial length thereof.

Brief Description of Drawings

Understanding of the present invention and the various aspects thereof will be facilitated by reference to the accompanying drawing figures, submitted for purposes of illustration only and not intended to define the scope of the invention, on which:

Figure 1 is an isometric view of the major elements of a biometric identification apparatus constructed according to the present invention.

Figure 2 is a fragmentary, side elevational view of the apparatus .

Figure 3 is a fragmentary, top plan view of the apparatus . Figure 4 is a schematic/block diagram showing part of the sensing circuitry of the apparatus.

Figures 5A, 5B, and 5C are waveforms showing the operation of the apparatus and the data obtained therefrom.

Figures 6 and 7 are exploded isometric views of an alternative embodiment of the present invention.

Figures 8 and 9 are isometric views of the alternative embodiment assembled.

Figures 10 and 11 are cut-away, side elevational views illustrating the operation of the alternative embodiment .

Figures 12-14 are a cut-away side elevational views of a further embodiment of the present invention.

Figures 15A/15B, 16A/16B, and 16A/17B are top plan/end elevational views showing the operating of the embodiment of Figures 12-14.

Figures 18A-C are waveforms showing the output of the embodiment of Figures 12-14.

Figures 19, 20, 21, 22A, and 22B, are various views of terminals showing the application of the embodiments of the present invention.

Best Mode for Carrying Out the Invention

Reference should now be made to the drawing figures, on which similar or identical elements are given consistent identifying numerals throughout the various figures thereof, and on which parenthetical references to figure numbers direct the reader to the view(s) on which the element(s) being described is (are) best seen, although the element(s) may be seen also on other views .

Figure 1 illustrates the major elements of a biometric identification apparatus, generally indicated by the reference numeral 20. Apparatus 20 includes a vertically displaceable horizontal presence sensor plate 22 on which an index finger 24 of a person to be identified can be placed. Presence sensor plate 22 is mounted on a spring 30 which has first and second downwardly formed flanges 32 and 34, respectively, arranged so make electrical contact with, respectively, first and second contacts 36 and 38 mounted on a printed circuit board 40. Fixedly disposed underneath the ends of presence sensor plate 22 are first and second stops 42 and 44.

A vertical luminescent light panel 50 is fixedly disposed adjacent the distal edge of presence sensor plate 22, generally extending the length of the presence sensor plate. Light panel 50 has placed at the distal end thereof a calibration mask 52. A vertical, horizontally movable parabolic mirror 60 is disposed at the proximal edge of presence sensor plate 22 to receive light from luminescent light panel 50 and reflect the same to a photodetector 62 attached to the mirror at its focus point.

Parabolic mirror 60 is attached to a vertical mounting bracket 70 which is fixedly attached to a horizontal drive belt 72 encircling a drive pulley 74 and an idler pulley 76. Drive pulley 74 is selectively driven clockwise or counterclockwise by an electric motor 78. Thus, operation of motor 78 will cause parabolic mirror 60 to move back and forth along the proximal edge of presence sensor plate 22.

A horizontal optical clock strip 90, having first and second end notches 92 and 94, is fixedly disposed in proximity to mounting bracket 70. Fixedly attached to mounting bracket 70 in sensing relationship with optical clock strip 90 are a notch sensor 100 and a clock sensor 102. A flat wire flexible cable 110 is attached to mounting bracket 70 to transmit signals from photodetector 62, notch sensor 100, and clock sensor 102 to control circuitry (not shown on Figure 1). Figure 2 indicates that, once spring 30 completes a circuit between first and second contacts 36 and 38 by virtue of flanges 32 and 34 engaging, respectively, those contacts, an amplifier 120 will output a START signal.

Figures 2 and 3 show an insertion detector switch 130 disposed at the proximal end of luminescent light panel 50.

Referring to Figure 4, photodetector 62 is connected to provide an input signal to an amplifier 140 which provides an input to a microprocessor 142 through an analog-to-digital converter 144. Microprocessor 142 also receives an input from notch detector 100 and a calibration voltage signal from photodetector 62 and uses the latter signal to provide and automatic gain control signal to amplifier 140.

In use, a person (not shown) whose identity is to be determined places index finger 24 on presence sensor plate 22 and presses inwardly and downwardly. This causes insertion detector switch 130 to close, spring 30 to complete an electrical circuit, and amplifier 120 to output a START signal (Figure 2). Engagement of presence sensor plate 22 with first and second stops 42 and 44 (Figure 2) and the engagement of the portion of the person's hand between the index and middle fingers (Figure 3), causing insertion detector switch 130 to close, results in the index finger being fully inserted in apparatus 20 (Figure 1) and being reproducibly vertically disposed.

Once microprocessor 142 (Figure 4) receives the START signal from amplifier 120 (Figure 2) and a signal indicating that insertion detector switch is closed, the microprocessor causes motor 78 to rotate to move parabolic mirror to a position opposite calibration mask 52, movement being terminated when notch sensor 100 senses first notch 92. Here, photodetector 62 receives light from luminescent light panel 50 through calibration mask 52 and provides a calibration voltage signal to microprocessor 142 (Figure 4) which provides an automatic gain control signal to amplifier 140. This procedure permits correction for drift and other dynamic variations in the system.

After calibration, microprocessor 142 causes motor 78 (Figure 1) to move parabolic mirror 60 along finger 24 while receiving position inputs from clock sensor 102 and voltage inputs from photodetector 62. This produces the represents the voltage waveform shown on Figure 5A which represents the light intensity along finger 24. This, then, is correlated with several positions determined by reference to optical clock 90 (Figure 1) and the resulting identification data is used to determine the identity of the person. For example, voltage VI at position PI represents one data point. Similar voltages are noted at positions P2, P3, P4, and P5. The voltage/position data constitute a profile of finger 24 and can be stored in apparatus 20 or separately apart therefrom. When apparatus 20 is subsequently used to determine the identity of the person, finger 24 is placed in the apparatus, the identicalities of the positions being assured by stops 42 and 44 and switch 130. A profile, as above, is then taken of finger 24 and the data compared with the stored identification data.

Once notch sensor 100 (Figure 1) detects second notch 94 (Figure 5B), the operation of apparatus 20 is terminated by microprocessor 142.

Referring now to Figure 6, there is illustrated an alternative embodiment of a biometric identification apparatus, generally indicated by the reference numeral 200, and constructed according to the present invention. It can be seen that apparatus 200 is considerably simplified compared with apparatus 20 (Figure 1). Apparatus 200 includes parallel, vertical first and second sidewalls 202 and 204, respectively. First side 202 has disposed therein a plurality of light sources, as at 210, each light source comprising a vertical stack of LEDs . Second side 204 has disposed therein a plurality of light detecting elements, as at 212, each light detecting element being disposed opposite a corresponding light source 210, the line of sight between one such light detecting element and one such light source being orthogonal to the axes of first and second sidewalls 202 and 204. A horizontal base panel 220 joins lower edges of first and second sidewalls 202 and 204 and has fixedly mounted thereon a switch plate 222.

A U-shaped, open-sided, finger channel 230 has a horizontal opening 232 defined therethrough for journaling of the channel on a shaft (not shown) extending between oppositely disposed holes 234 and 236 defined, respectively, in first and second sidewalls 202 and 204. A coil spring 240 having its lower end fixedly joined to the upper surface of base panel 220 is disposed near the journaled end of finger channel 230 so as to normally bias the open end of the finger channel to the position shown on Figure 7.

Figure 8 illustrates apparatus 200 in its normal position, while Figure 9 illustrates the apparatus in its finger identification position, as is described further below.

In use, and with reference first to Figure 11, a person to be identified inserts an index finger 250 into finger channel 230 and rotates the finger channel downwardly so that it engages switch plate 222, as shown on Figure 12. When finger channel 230 engages switch plate 222, an electrical circuit is closed which initiates developing a profile of finger 250 in a manner similar to apparatus 20 (Figure 1). In this case, light sources 210 are serially illuminated, so as to conserve electrical power, and light detectors 212 receive beams of light from the light sources. In the case shown, 16 analog values are obtained which are converted to 16 digital binary values and identification made or not, as with apparatus 20 (Figure 1).

Apparatus 200 is periodically automatically calibrated by scanning without a finger in place, say, every 10-20 seconds while in an idle loop mode. Calibration scanning is done with and without illumination of light sources 210. When scanned without the illumination of light sources 210, ambient light is measured, so that when a finger measurement is made the finger measurement is based on a differential. Both the profile of finger 250 and its tip are measured. To ensure that finger 250 is fully inserted in finger channel 250, an impedance measurement between the end of second sidewall 204 and a reference can be employed. An impedance measurement can also be employed to ensure that a real finger has been inserted into finger channel 250 and not just a simulation such as a cardboard finger. The latter impedance measurement can also be an element in the identification profile for a person.

Figure 12 illustrates another embodiment of a biometric identification apparatus, generally indicated by the reference numeral 300, and constructed according to the present invention. Apparatus 300 generally combines the switching and upwardly open channel arrangement of apparatus 20 (Figure 1) with the stationary light source and sensing arrangement of apparatus 200 (Figure 6), together with further refinements described below.

Apparatus 300 includes a housing 302 having therein a switch plate 322 and switch contacts 324 and 326. As shown on Figure 12, a finger 320 has been inserted in apparatus 300 but has not yet been pressed downwardly to close switch contacts 324 and 326. Figure 13 illustrates apparatus 300 with switch contacts 324 and 326 closed by downward pressure of finger 320. That figure also shows a first vertical sidewall 304 mounted thereon, similar to first sidewall 202 on apparatus 200 (Figure 6). First sidewall 304 includes mounted therein a plurality of LED's, as at 310, arranged in columns "1" through "20" each column having "A" through "G" rows of LEDs. Finger 320 shown inserted in apparatus has depressed switch plate 322 closing contacts 324 and 326 to begin the scanning process. A printed circuit board 330 mounted in housing 302 contains circuitry for controlling apparatus 300.

Figure 14 illustrates a second vertical sidewall 340 of apparatus 300, similar to second sidewall 204 of apparatus 20 (Figure 6). Mounted in second sidewall 340 are a plurality of vertically elongated photodetectors "1" through "10".

Returning to Figure 13, LED's 310 are strobed horizontally with, for example, LEDs "1" through "20" in row "A" being sequentially strobed. Then, LEds "1" through "20" in row "B" are sequentially strobed, etc. It will be understood that the LEDs can also be strobed in reverse order or the LEDs can also be strobed vertically. Sequentially strobing LEDs 310 requires the use of only one high-speed A/D converter (not shown), thus providing simplicity and reduced cost. For illustrative purposes only, six of LEDs 310 on Figure 12 are shown as being simultaneously illuminated, although in actual operation, the six LEDs would not be illuminated simultaneously.

Referring now also to Figures 15A and 15B, there is illustrated how finger 320, the position shown, blocks light from LEDs "1C" and "15C" from reaching any of photodetectors "1" through "10". As shown on Figure 15A, each of photodetectors "1" through "10" is disposed at the end of a horizontal channel, such as channel 350 associated with photodetector "10", defined through second sidewall 340 to help prevent stray ambient light from reaching the photodetector. To further limit the detected light to that produced by LEDs 310, polarized sheets 352 and 354 are placed, respectively, over the facing surfaces of first and second vertical sidewalls 304 and 340. Photodetectors "1" through "10" are arranged so that they fall between two LEDs 310. For example, photodetector "1" is aligned approximately between LEDs "1" and "2", photodetector " 2 " is aligned approximately between LEDs "3" and "4", etc.

Referring now to Figures 12, 16A, and 16B together, there is illustrated how sensors "1" and "2" receive full illumination from LED "3E" and how sensors "8" and "9" receive full illumination from LED "17E".

Figures 12, 17A, and 17B together illustrate how sensors "1" and "8" receive partial illumination, respectively, from LEDs "2D" and "16D".

On initial scanning or enrollment, the profile of finger 320 is stored as a digital signature of the finger and, therefore, of the person who has inserted the finger into apparatus 300. The storing may be locally, that is, in a memory of apparatus 300, it may be in a host computer with which apparatus 300 is associated, and/or it may be in, for example, an identification card that the person carries.

Figure 18A illustrates the six LEDs, noted above, illuminated at spaced apart times, as would be the case in normal operation of apparatus 300. Figure 18B illustrates the initial reading of the profile of finger 320. Here, a threshold of 50 percent is set, to that a partial blockage of illumination from LEDs, as illustrated on Figures 13, 17A, and 17B, will result in a "zero" being recorded if the light intensity is 50 percent or less and will result in a "one" being recorded if the light intensity is greater than 50 percent. For example, the illumination from LED "1C" is somewhat greater than 50 percent so that this point is recorded as a "one" . Similarly, the illumination from LED "16D" is somewhat less than 50 percent to that this point is recorded as a "zero". The digitized signature for the six points is then "011001". It will be understood that, in actual operation of apparatus 300, values could be assigned to all 140 points defined by combinations of LEDs 310 and photodetectors "1" through "10", although it will be apparent to those skilled in the art that various techniques may be employed to reduce the number of data points stored.

Figure 18C illustrates the validation step in the use of apparatus 300 wherein a finger 320 is placed in the same position in apparatus 300 to verify or not that the finger is the same as finger 320. If the profiles, or "signatures", match, then there is a high degree of probability that the fingers are the same. In order to avoid a large number of false rejects and compensate for slight variations in finger size, sensor calibration, etc., the threshold is varied during validation such that the threshold is raised slightly when expecting to read a "zero" and lowered slightly when expecting to read a "one". This is illustrated, for example, by the first waveform on Figure 18C for photodetector "1". Normally the threshold is 50 percent. However when it is expected that a "zero" will be read for LED "1C", the threshold is raised to 60 percent to compensate for the case in which the actual illumination received by the photodetector during validation is, say, 52 percent, due to the types of slight variation noted above. If the threshold were left at 50 percent, the reading would be "1" and result in a rejection. In this case, the actual reading is "zero" or close to "zero", so the validation value is "zero". At position "2D" on the first waveform, the threshold is lowered to 40 percent to allow for the possibility that the actual validation reading is slightly below 50 percent, again due to the types of slight variations noted above. In this case, the actual reading is above 50 percent, so the value of "1" is validated.

Figures 19, 20, 21, 22A, and 22B illustrate various types of terminals which which a biometric identification device of the present invention may be employed.

Figure 19 illustrates a terminal 400 having a channel 402 into which finger 404 may be inserted. Light receiving and producing means 406 and 408, respectively, are disposed at either side of the channel. Terminal 400 may be wall mounted or desk mounted and may include a display screen 410 and a keyboard 412. Terminal 400 may be, for example, a time and attendance terminal .

Figure 20 illustrates a terminal 500 having a finger receiving channel 502 disposed on the side of the terminal .

Figure 21 illustrates a desk mounted terminal 600 having a finger receiving channel 602 disposed generally on the upper surface thereof. Terminal 600 includes a display screen 604, a keyboard 606, and a slot 608 into which a card (not shown) bearing optically and/or magnetically coded data may be inserted for reading of the data. The data may include a finger profile encoded therein.

Figures 22A and 22B illustrate a terminal 700 having a finger receiving channel 702 disposed generally on the upper surface thereof. Terminal 700 may be of the type for verifying a ticket, for example, and includes a slot 704 defined therein for the insertion thereinto of a ticket 706. Ticket 706 includes thereon optically or magnetically encoded identification data, such as bar coder 708, which data may include finger profile information. Referring to Figure 22B, a mirror 710 reflects bar code 708 to a decoder 712 in terminal 700. In the embodiments of the present invention described above, it will be recognized that individual elements and/or features thereof are not necessarily limited to a particular embodiment but, where applicable, are interchangeable and can be used in any selected embodiment even though such may not be specifically shown.

It will thus be seen that the objects set forth above, among those elucidated in, or made apparent from, the preceding description, are efficiently attained and, since certain changes may be made in the above construction without departing from the scope of the invention, it is intended that all matter contained in the above description or shown on the accompanying drawing figures shall be interpreted as illustrative only and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween

Claims

1. A biometric identification device, comprising:

(a) finger receiving means into which a finger of a person may be inserted;

(b) light producing means disposed at a first side of said finger receiving means to illuminate a finger placed in said finger receiving means; and

(c) light detecting means disposed at a second, opposite side of said finger means to receive illumination from said light producing means and to provide an output representative of a profile of said finger along at least a partial length thereof.

2. A biometric identification device, as defined in Claim 1, wherein: said light detecting means is moved along said at least a partial length of said finger as said light detecting means provides said output.

3. A biometric identification device, as defined in Claim 1, wherein: said light detecting means comprises a plurality of elongated photodetectors having the major axes thereof disposed orthogonally to the major axis of said finger.

4. A biometric identification device, as defined in Claim 1, wherein: said light producing means comprises a light panel.

5. A biometric identification device, as defined in Claim 1, wherein: said light producing means comprises a plurality of light emitting diodes.

6. A biometric method of identifying a person, comprising:

(a) said person inserting a finger in finger receiving means;

(b) illuminating a first side of said finger placed in said finger receiving means;

(c) receiving illumination from said light producing means on a second side of said finger, providing a first output representative of a profile of said finger along at least a partial length thereof, and storing first information representative of said profile; subsequently;

(d) said person inserting said finger in said finger receiving means;

(e) illuminating a first side of said finger placed in said finger receiving means;

(f) receiving illumination from said light producing means on a second side of said finger providing a second output representative of a profile of said finger along at least a partial length thereof and storing second information representative of said profile; and

(g) comparing said first and second information to determine identity or not of said person.

7. A biometric method of identifying a person, as defined in Claim 6, further comprising: detecting said profile by moving light detecting means along said at least a partial length of said finger.

8. A biometric method of identifying a person, as defined in Claim 6, further comprising: detecting said profile by using a plurality of elongated photodetectors having the major axes thereof disposed orthogonally to the major axis of said finger.

9. A biometric method of identifying a person, as defined in Claim 6, further comprising: illuminating said first side of said finger using a light panel.

10. A biometric method of identifying a person, as defined in Claim 6, further comprising: illuminating said first side of said finger using a plurality of light emitting diodes .