WO2001018741A1 - Systeme d'imageur d'empreintes a prisme mince - Google Patents

Systeme d'imageur d'empreintes a prisme mince Download PDF

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Publication number
WO2001018741A1
WO2001018741A1 PCT/US2000/024669 US0024669W WO0118741A1 WO 2001018741 A1 WO2001018741 A1 WO 2001018741A1 US 0024669 W US0024669 W US 0024669W WO 0118741 A1 WO0118741 A1 WO 0118741A1
Authority
WO
WIPO (PCT)
Prior art keywords
prism
sensing
light
exit
fingeφrint
Prior art date
Application number
PCT/US2000/024669
Other languages
English (en)
Inventor
Alexander Ivanisov
Kenneth Brownlee
Original Assignee
Digital Persona, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Digital Persona, Inc. filed Critical Digital Persona, Inc.
Priority to AU73597/00A priority Critical patent/AU7359700A/en
Publication of WO2001018741A1 publication Critical patent/WO2001018741A1/fr

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Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
    • G06V40/00—Recognition of biometric, human-related or animal-related patterns in image or video data
    • G06V40/10—Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
    • G06V40/12—Fingerprints or palmprints
    • G06V40/13—Sensors therefor
    • G06V40/1324—Sensors therefor by using geometrical optics, e.g. using prisms

Definitions

  • the present invention relates to biometric detection, and more specifically, to fingerprint sensors.
  • FIG. 1 shows a prior art fingerprint sensing system using a single prism with three functional surfaces — the sensing surface 110, the entrance surface 120, and the exit surface 130.
  • a finger 140 is placed on the sensing surface of the prism 100.
  • An extended light source 150 provides illumination for the entrance surface 120.
  • the angle of incidence at the entrance surface 120 is typically at about 90 degrees, and the angle of incidence at the sensing surface 110 is about 45 degrees, which is larger than the critical angle of the prism 100.
  • One portion of the incident radiation at the sensing surface 110 is reflected through total internal reflection, and another portion is not. Where ridges on the finger 140 are in contact with the sensing surface 110, light will be transmitted into or absorbed by the finger 140.
  • the incident light is reflected from the sensing surface 110 through total internal reflection.
  • the reflected light emits from the exit surface and is focused by a lens 160 to create a fingerprint image, which is dark where there are ridges and bright where there are grooves or where the finger is not in contact with the sensing surface.
  • the lens 160 focuses the fingerprint light pattern onto an electronic detector array 170, such as a CCD camera.
  • the single prism system creates a good image of a fingerprint.
  • it is not applicable to many applications. For example, if the system is for replacing a mechanical key for a door, the system is best mounted inside the door. For such an application, in order to fit within the wooden surface of the door, the system has to be thin and flat. Due to the bulkiness of the prism, the single prism system occupies too much space for such applications. It should be apparent from the foregoing that there is still a need for a fingerprint sensing system that is of similar accuracy as the single prism system, but does not occupy as much space.
  • a prism for a fingerprint sensor comprises a rectangular prism.
  • the prism includes a sensing surface defining a normal.
  • the prism further includes a bottom surface parallel to the sensing surface, and a reflective surface, the reflective surface at an angle slightly less than ninety degrees from the normal, the reflective surface for reflecting light rebounding from the sensing surface.
  • the prism further includes an exit surface perpendicular to the sensing surface and the bottom surface, the exit surface for permitting the reflected light to exit from the prism.
  • Figure 1 is a prior art fingerprint recognition system.
  • Figure 2 is one embodiment of a fingerprint recognition system according to the present invention.
  • Figure 3 illustrates one embodiment of the prism 210 of Figure 2.
  • Figure 4 is another embodiment of the fingerprint recognition system.
  • Figure 5 illustrates one embodiment of the prism 410 of Figure 4.
  • Figure 6 shows another embodiment of the fingerprint recognition system.
  • Figure 7 illustrates one embodiment of the prism 610 of Figure 6.
  • Figure 8 illustrates an exemplary prism showing relative dimensions.
  • a fingerprint sensor having a new type of prism is described.
  • the prism has a small footprint, permitting the sensor to be small.
  • FIG. 2 shows a fingerprint sensing system using the thin prism of the present invention.
  • a finger 280 is placed on the sensing surface of the prism 200.
  • An extended light source 250 provides direct illumination for the entrance surface 220.
  • the angle of incidence at the entrance surface 220 is typically at about 90 degrees.
  • One portion of the incident radiation at the sensing surface 210 is reflected through total internal reflection, and another portion is not.
  • ridges on the finger 280 are in contact with the sensing surface 210, light will be transmitted into or absorbed by the finger 280.
  • contacts are not made with the sensing surface 210, and the incident light is reflected from the sensing surface 210 through total internal reflection.
  • the reflected emits from the exit surface 230 and is focused by a lens 260 ⁇ create a fingerprint image, which is dark where there are ridges and bright where there are grooves or where the finger is not in contact with the sensing surface 210.
  • the lens 260 focuses the fingerprint light pattern onto an electronic detector array 270, such as a charged coupled device (CCD) camera.
  • CCD charged coupled device
  • the lens 260 is a corrective lens.
  • the fingerprint image received by the detector 270 is compressed.
  • this compression is at least partially corrected by the lens 260.
  • further image correction is done by the detector 270.
  • the correction may be done during processing, or not done at all, if the same type of sensor is used for registration and matching.
  • FIG 3 illustrates one embodiment of the prism 200 of Figure 2.
  • the prism 200 includes sensing surface 210, entrance surface 220, exit surface 230, and reflective surface 240.
  • a light source (not shown) shines a diffuse light 310 at the bottom, or entrance surface 220.
  • the light 310 impacts the sensing surface 210, which has a finger on it. As discussed above, those portions of the light which do not impact the finger, are reflected, 320.
  • This reflected light 320 is bounced back to the entrance surface 220, and is reflected as light 330.
  • the light 330 is reflected by the reflecting surface 240, and exits the prism 200 through the exit surface 230. In this way, the light travels around the prism, and produces an image of the fingerprint placed on the sensing surface 210.
  • Side view 300 shows multiple light waves reflecting in the prism 200.
  • the dimensions of prism 200 can vary, and sizing may be traded off for distortion.
  • the actual dimensions are chosen based on the location — if having a thin prism is a vital concern, a thinner prism may be used than if the thinness is of less importance.
  • the balancing factors are the level of distortion versus the thinness of the prism.
  • the sensing surface 210 and the bottom surface 220 are 17 mm wide, the bottom surface 220 is 40.9 mm long, the prism 200 is 5.4 mm high, and the reflecting surface 240 is 82.28 degrees from the normal, defined by the plane of the sensing surface 210.
  • the ratio between the length and height of the prism is between 7 and 8, when the angle of the reflecting surface 240 is between 75 and 85 degrees.
  • the relationship between the height and width of the prism and the angle of the working surface is defined by the ratio, shown in Figure 8,
  • Y is the length of the image capture region, or linear field of view.
  • Y is 20 mm.
  • FIG. 4 is another embodiment of the fingerprint recognition system.
  • a finger 480 is placed on the sensing surface 410 of the prism 400.
  • An light source 450 provides diffuse illumination, from the first surface 430.
  • One portion of the incident radiation at the sensing surface 410 is reflected through total internal reflection, and another portion is not.
  • ridges on the finger 480 are in contact with the sensing surface 410, light will be transmitted into or absorbed by the finger 480.
  • contacts are not made with the sensing surface 410, and the incident light is reflected from the sensing surface 410 through total internal reflection.
  • the lens 460 focuses the fingerprint light pattern onto an electronic detector array 470, such as a charged coupled device (CCD) camera.
  • CCD charged coupled device
  • Figure 5 illustrates one embodiment of the prism 400 of Figure 4.
  • View 505 is a side view of prism 400, while view 507 is a top view of the prism 400.
  • Diffuse light is provided by light sources 550.
  • light sources 550 are a plurality of light emitting diodes (LEDs).
  • LEDs light emitting diodes
  • light guide tape (not shown) may be used with the diffuse surface lighting 550.
  • Figure 6 shows another embodiment of the fingerprint recognition system.
  • a finger 680 is placed on the sensing surface of the prism 600.
  • An light source 650 provides illumination through the reflective surface 640. For one embodiment, this light source 650 points downward, as is shown by the illustration of the light path in Figure 7.
  • One portion of the incident radiation at the sensing surface 610 is reflected through total internal reflection, and another portion is not. Where ridges on the finger 680 are in contact with the sensing surface 610, light will be transmitted into or absorbed by the finger 680. On the other hand, where there are grooves on the finger 680, contacts are not made with the sensing surface 610, and the incident light is reflected from the sensing surface 610 through total internal reflection.
  • the reflected emits from the exit surface 630 and is focused by a lens 660 to create a finge ⁇ rint image, which is dark where there are ridges and bright where there are grooves or where the finger is not in contact with the sensing surface 610.
  • the lens 660 focuses the finge ⁇ rint light pattern onto an electronic detector array 670, such as a charged coupled device (CCD) camera.
  • CCD charged coupled device
  • Figure 7 illustrates one embodiment of the prism 600 of Figure 6.
  • the light source 650 provides a light 710 at the reflective surface 640.
  • the reflective surface 640 is a cylindrical mirror for distortion correction.
  • Side view 703 shows one embodiment of the reflective surface 640.
  • the light 710 from the light source 650 is reflected from the first surface 630.
  • the first surface 630 for one embodiment, is also a cylindrical mirror.
  • the first surface 630 and reflective surface 640 are identical.
  • the first surface 630 and reflective surface 640 may differ slightly. Cut-away views A-A and B-B show the spherical surfaces 630 and 640 as well.
  • the light 720 reflected from first surface 630 is reflected from the bottom surface 620.
  • the bottom surface 620 is mirrored, or its reflective ratio is enhanced in another way.
  • the light 730 reflected from the bottom surface 630 is reflected to the sensing surface 610.
  • the finge ⁇ rint image is picked up.
  • the light 740 reflected from the sensing surface 610 is again reflected from the bottom surface 630.
  • the light 750 is reflected by the reflecting surface 640, to the lens 660.
  • the prism 600 transmits an image of the finge ⁇ rint on the sensing surface 610 to the lens.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Human Computer Interaction (AREA)
  • General Physics & Mathematics (AREA)
  • Multimedia (AREA)
  • Theoretical Computer Science (AREA)
  • Image Input (AREA)
  • Optical Elements Other Than Lenses (AREA)

Abstract

L'invention porte sur un prisme mince destiné à être utilisé avec un capteur d'empreintes. Ce prisme comprend une surface (210) de détection formant une perpendiculaire et une surface (220) inférieure parallèle à la surface de détection, ainsi qu'une surface (240) réfléchissante formée au niveau d'un angle de la perpendiculaire légèrement inférieur à 90°. Cette surface réfléchissante permet à la lumière de rebondir depuis la surface de détection. Le prisme comprend également une surface de sortie (230) perpendiculaire à la surface de détection et à la surface inférieure, cette surface de sortie permettant à la lumière réfléchie de sortir du prisme.
PCT/US2000/024669 1999-09-08 2000-09-07 Systeme d'imageur d'empreintes a prisme mince WO2001018741A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU73597/00A AU7359700A (en) 1999-09-08 2000-09-07 A thin prism fingerprint imager system

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US39222899A 1999-09-08 1999-09-08
US09/392,228 1999-09-08

Publications (1)

Publication Number Publication Date
WO2001018741A1 true WO2001018741A1 (fr) 2001-03-15

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2000/024669 WO2001018741A1 (fr) 1999-09-08 2000-09-07 Systeme d'imageur d'empreintes a prisme mince

Country Status (2)

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AU (1) AU7359700A (fr)
WO (1) WO2001018741A1 (fr)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002052491A1 (fr) * 2000-12-22 2002-07-04 Fingerpin Ag Dispositif pour enregistrer les sillons papillaires d'un doigt
WO2003063065A1 (fr) * 2002-01-18 2003-07-31 Qinetiq Limited Detecteur biometrique optique a guide d'ondes planaire
EP2039292A1 (fr) * 2006-07-10 2009-03-25 Pavel Anatolievich Zaitsev Procede d'enregistrement d'images de dessins papillaires des doigts
US8131477B2 (en) 2005-11-16 2012-03-06 3M Cogent, Inc. Method and device for image-based biological data quantification
CN102486826A (zh) * 2010-12-06 2012-06-06 一品国际科技股份有限公司 一种指纹影像撷取装置
US8275179B2 (en) 2007-05-01 2012-09-25 3M Cogent, Inc. Apparatus for capturing a high quality image of a moist finger
US8379982B2 (en) 2004-11-12 2013-02-19 3M Cogent, Inc. System and method for fast biometric pattern matching
US8411916B2 (en) 2007-06-11 2013-04-02 3M Cogent, Inc. Bio-reader device with ticket identification

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5596454A (en) * 1994-10-28 1997-01-21 The National Registry, Inc. Uneven surface image transfer apparatus
US5621516A (en) * 1994-02-04 1997-04-15 Fujitsu Limited Optical device for forming an image of an uneven surface

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5621516A (en) * 1994-02-04 1997-04-15 Fujitsu Limited Optical device for forming an image of an uneven surface
US5596454A (en) * 1994-10-28 1997-01-21 The National Registry, Inc. Uneven surface image transfer apparatus

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002052491A1 (fr) * 2000-12-22 2002-07-04 Fingerpin Ag Dispositif pour enregistrer les sillons papillaires d'un doigt
US7315632B2 (en) 2000-12-22 2008-01-01 Fingerpin Ag Device for imaging the papillary lines of a finger
WO2003063065A1 (fr) * 2002-01-18 2003-07-31 Qinetiq Limited Detecteur biometrique optique a guide d'ondes planaire
US8379982B2 (en) 2004-11-12 2013-02-19 3M Cogent, Inc. System and method for fast biometric pattern matching
US8131477B2 (en) 2005-11-16 2012-03-06 3M Cogent, Inc. Method and device for image-based biological data quantification
EP2039292A1 (fr) * 2006-07-10 2009-03-25 Pavel Anatolievich Zaitsev Procede d'enregistrement d'images de dessins papillaires des doigts
EP2039292A4 (fr) * 2006-07-10 2010-01-27 Pavel Anatolievich Zaytsev Procede d'enregistrement d'images de dessins papillaires des doigts
US8275179B2 (en) 2007-05-01 2012-09-25 3M Cogent, Inc. Apparatus for capturing a high quality image of a moist finger
US8411916B2 (en) 2007-06-11 2013-04-02 3M Cogent, Inc. Bio-reader device with ticket identification
CN102486826A (zh) * 2010-12-06 2012-06-06 一品国际科技股份有限公司 一种指纹影像撷取装置

Also Published As

Publication number Publication date
AU7359700A (en) 2001-04-10

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