JP5111438B2 - Biometric authentication device - Google Patents

Description

  The present invention relates to a biometric authentication apparatus, and more particularly to a biometric authentication apparatus that performs finger vein authentication.

  Normally, when biometric authentication is performed using a finger vein, a user places a finger on a portion (a transparent plate such as plastic) surrounded by a guide of the authentication device, and a predetermined light is applied to the finger from a light source provided in the guide. The light or the like is irradiated, and a camera or the like images the finger irradiated with the light. Then, the captured vein pattern of the finger is read as an image by a scanner or the like, and when the read vein pattern image matches a vein pattern registered in advance, personal authentication is performed.

  By the way, when authenticating the person by the above-described method, it is desirable that external light such as natural light such as sunlight or ambient light such as an electric light or light emitted from the light source to the finger does not enter the portion surrounded by the guide. . The reason is that these incident lights are reflected on the above-mentioned transparent plate, the reflected light is reflected on the user's finger, and the image captured by the camera becomes unclear and the accuracy of authenticating the person is lowered. It is because it ends.

  As a method for eliminating such so-called unnecessary light, for example, in Patent Document 1, unnecessary light is applied to a user's finger by providing a shading plate using a matte material or the like around a camera or the like. A technique for reducing the reflection is disclosed.

Japanese Patent Laid-Open No. 2005-253989

  However, in the technique described in Patent Document 1, the light shielding plate is arranged perpendicularly to the photographing aperture (parallel to the light from outside light) or with an inclination that substantially matches the optical axis of the light source. Therefore, only reflection by light emitted from the light source can be reduced. That is, there is a problem that the reflected light reflected on the transparent plate when the external light is reflected on the transparent plate cannot be reduced and the authentication accuracy is lowered.

  The present invention has been made in view of the above, and an object of the present invention is to provide a biometric authentication device that can reduce reflection of external light on a user's finger and prevent a decrease in authentication accuracy. .

  In order to achieve the above-described object, a biometric authentication device according to the present invention is a biometric authentication device that obtains information on a finger vein by irradiating light from a light source to a user's finger. Is formed on the surface of the guide, and an absorber that absorbs reflected light of the external light incident from above the space; A filter that is disposed at the bottom of the space and has a reflecting surface that reflects external light incident on the space in the direction of the absorber, and is disposed under the filter and receives the light emitted from the light source. An imaging unit that images the veins of the user's finger.

  ADVANTAGE OF THE INVENTION According to this invention, the biometrics apparatus which can reduce the reflection of the external light with respect to a user's finger | toe and can prevent the fall of authentication precision can be provided.

It is a figure which shows the external appearance of the biometrics apparatus concerning this embodiment. 2 is a cross-sectional view at a position L when the biometric authentication device shown in FIG. It is a figure which shows the paper which described the character string for verification. It is a figure which shows a mode that the paper shown in FIG. 3 was put on the upper end of a guide. (A) It is a figure which shows the verification result when not tilting a filter. (B) It is a figure which shows the verification result at the time of tilting a filter. It is a figure which shows the example in case the angle which a filter inclines does not satisfy | fill conditions (angle is small). It is a figure which shows the example in case the angle which a filter inclines does not satisfy | fill conditions (angle is large). It is a figure which shows the example of a finger rest part and a main-body part at the time of arrange | positioning the filter which made the shape of the filter shown in FIG. 2 the triangular prism type | mold. It is a figure which shows the specific example of the triangular prism type filter shown in FIG. It is a figure which shows the example of a finger rest part and a main-body part at the time of arrange | positioning the filter which made the shape of the filter shown in FIG. 2 polygonal prism type. It is a figure which shows the example of a finger rest part and a main-body part at the time of arrange | positioning the filter which made the shape of the filter shown in FIG. 2 a semi-elliptical type.

  Embodiments of a biometric authentication apparatus according to the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is a diagram illustrating an appearance of a biometric authentication apparatus 1000 according to the present embodiment. As shown in FIG. 1, the biometric authentication device 1000 includes a main body unit 100, a finger placement unit 200, and a connection unit 300. The connection unit 300 is a cable or the like for connecting to various devices described later.

  The main unit 100 includes an imaging unit 101 that captures an image of a finger and a control unit 102 that performs authentication using a finger vein. In addition, the finger placement unit 200 includes a guide 201 and a filter 202. Furthermore, the guide 201 includes a light absorbing sheet 2011 and a light source 2012.

  The biometric authentication device 1000 is connected to various information processing devices such as a computer (for example, a notebook personal computer) or an ATM (Automated Teller Machine) via the connection unit 300, or connected to these information processing devices. User authentication can be performed in the embedded state.

  Further, in the following description, the biometric authentication apparatus 1000 is described on the assumption that the user authentication is performed. For example, an image of the user's finger captured by the imaging unit 101 described below is used as the above-described various information. It is good also as transmitting to a processing apparatus, performing personal authentication by the information processing apparatus side, and receiving the result by the biometrics authentication apparatus 1000.

  2 is a cross-sectional view at a position L when the biometric authentication device 1000 shown in FIG. As shown in FIG. 2, the light absorbing sheet 2011 is provided on the inner surface on one side of the guide 201. In addition, the imaging unit 101 and the control unit 102 described above are included in the main body unit 100 of the biometric authentication device 1000. First, each part of the main body 100 will be described.

  The imaging unit 101 includes an imaging element such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor), and a finger placed on the finger placement unit 200 via a filter 205 of the finger placement unit 200 described later. The vein is imaged.

  As shown in FIG. 2, in the imaging unit 101, the lens is directed from the inside of the main body unit 100 to the upper outside. The imaging unit 101 images the vein of the finger F that has received light emitted from the light source 2012 embedded in a guide 201 of the finger placement unit 200 described later.

  For various controls such as the adjustment of the light amount of the light source 2033 of the finger placement unit 200, the timing of irradiating light, the timing of starting imaging of the imaging unit 101, and the like, for example, an arithmetic device such as a CPU (Central Processing Unit) This is performed by a control unit (not shown) composed of

  The control unit (not shown) compares the finger vein pattern image captured by the imaging unit 101 described above with the vein pattern image stored in advance in a storage medium such as a memory (not shown). If they match, the user is authenticated to be a valid user. As a specific authentication method, various conventionally known methods can be used. As described above, the control unit (not shown) may be configured either inside the biometric authentication device 1000 (for example, the main body 100) or the various information processing devices described above. Next, each part of the finger placement unit 200 will be described.

  The guide 201 is fixed so that the finger (reference numeral F shown in FIG. 2) placed on the finger placing unit 200 does not move left and right, and the external light incident from the lateral direction (short direction and tip direction) of the finger F. Is to block. As shown in FIG. 1, the guide 201 forms a space for the user to place his / her finger.

The light absorption sheet 2011 absorbs external light reflected by a filter 202 described later.
The light absorption sheet 2011 is made of, for example, a resin material such as polyurethane resin, and is laid on substantially the entire inner side surface of the guide 201.

  Specifically, as shown in FIG. 2, the light absorbing sheet 2011 allows external light L <b> 1 and L <b> 2 to enter from the gap between the finger F and the guide 201 and absorb the reflected light of these lights by the filter 202. Has been placed. As will be described later, in order to efficiently absorb external light, it is preferable that the absorption sheet 2011 has a length (width) in the vertical direction according to the angle at which the filter 202 is inclined.

  The light source 2012 includes, for example, a plurality of light emitting elements such as LEDs (Light Emitting Diodes), and each light emitting element is disposed at a predetermined interval in the longitudinal direction of the guide 201 and has a predetermined wavelength with respect to the finger F. (For example, near infrared light) is irradiated.

  The filter 202 is a flat plate for the user to place a finger, and is, for example, a plastic plate. The filter 202 is a material that reflects external light (for example, visible light) and has a flat plate shape, and reflects light incident from the gap between the finger F and the guide 201.

  The filter 202 is configured so that the reflected light of the external light L1 and L2 incident from above the space for the user to place a finger formed by the guide 201 is absorbed by the light absorbing sheet 2011 described above. It is tilted at a certain angle in the hand direction.

  Specifically, as shown in FIG. 2, the filter 202 is arranged to be inclined with respect to the horizontal line H by an angle α. The optimum value of the angle α is that the distance from the axis to the top end of the guide 201 (height of the guide 201: h) with the portion where the guide 201 and one side in the longitudinal direction of the filter 2011 are in contact as an axis, and the finger If the relationship of the distance between the inner surfaces in the short direction of the guide 201 located on both sides of F (width between the guides 201: w) is used, it can be expressed by the following equation.

  The filter 202 shown in FIG. 2 absorbs light at an angle α that satisfies the above-described relationship, that is, an angle at which light L1 and L2 incident from the gap between the finger F and the guide 201 is reflected by the light absorbing sheet 202. Inclined to the sheet 201 side. The direction in which the filter 202 is inclined may be the longitudinal direction of the guide 201. In this case, the light absorbing sheet 2011 needs to be laid on the inner side surface of the guide 201 located at the tip of the finger F. Become.

  In the example shown in FIG. 2, the light L1 incident from the gap between the finger F and the guide 201 is reflected by the filter 202 in a symmetric direction about the normal line V1 with respect to the filter 202, and the reflected light L1 ′ is It is shown that the light-absorbing sheet 202 proceeds in the direction in which it is disposed. Similarly, the light L2 incident on the filter 202 from the gap between the finger F and the guide 201 is reflected by the filter 202 in a symmetric direction about the normal line V2 with respect to the filter 202, and the reflected light L2 ′ is The process proceeds in the direction in which the light absorbing sheet 202 is disposed.

  3 to 5, as shown in FIG. 2, the filter 202 is arranged so that the angle with the horizontal line H satisfies the above-described condition, and the filter 202 is parallel to the horizontal line H (angle α). It is a figure which shows the result of having reflected external light in two cases when it exists in the position used as 0).

  FIG. 3 is a diagram illustrating an example in which a sheet on which a character string is written is used instead of using a finger as a living body to be verified. As shown in FIG. 3, the character string is written on the paper P2, and the paper P2 is attached to the paper P1. FIG. 4 is a diagram illustrating a state in which the above-described paper P1 is placed on the upper end of the guide 201. As illustrated in FIG. 4, the paper P <b> 1 is disposed at the upper end of the guide 201 so that the paper P <b> 2 attached to the paper P <b> 1 is positioned directly above the filter 202.

  As shown in FIG. 4, in a state where the filter 202 is arranged so as to be parallel to the horizontal line H, the external light L3 is reflected by the filter 202 and proceeds in the direction of the paper P2 as reflected light L3 '. FIG. 5A is a diagram illustrating a state in which the imaging unit 101 images a predetermined region R of the paper P2 illuminated by the reflected light L3 'that has traveled in the direction of the paper P2.

  Further, in a state where the filter 202 is disposed so as to be inclined at an angle α3 with respect to the horizontal line H, the light L4 from the outside is reflected by the filter 202 and travels in the direction of the light absorbing sheet 2011 as reflected light L4 ′. FIG. 5B is a diagram illustrating a state where the imaging unit 101 images a predetermined region R of the paper P2 when the reflected light L4 ′ travels in the direction of the light absorbing sheet 2011.

  Comparing FIG. 5 (a) and FIG. 5 (b), in the example shown in FIG. 5 (a), the predetermined range R of the paper P2 is bright, but the example shown in FIG. 5 (b). Then, it turns out that it is tinged with darkness compared with the case shown to Fig.5 (a). That is, the reflected light from the filter 202 with respect to the paper P2 is suppressed in the example shown in FIG. 5B compared to the example shown in FIG. 5A, and the reflected light of outside light is reduced in the paper P2 (user's (Finger) is reduced.

  As described above, in the biometric authentication apparatus 1000 that obtains information on finger veins by irradiating light from the light source 2012 to the user's finger, the guide 201 forms a space in which the user's finger is placed, and the side of the space. The external light incident from the direction is blocked, the absorption sheet 2011 is disposed on the surface of the guide 201, the reflected light of the external light incident from above the space is absorbed, and the filter 202 is disposed at the bottom of the space. The imaging unit 101 is disposed under the filter 202 and images the veins of the user's finger that has received the light emitted from the light source 2012. Therefore, the reflection of external light on the user's finger can be reduced, and a decrease in authentication accuracy can be prevented.

  In the present embodiment, the filter 202 has been described as being disposed at an angle α that satisfies the above-described equation. However, it is also possible to arrange the filter 202 so that the value of tan α is smaller than the value of w / h (α ′) (that is, tan α <w / h).

  However, as shown in FIG. 6, the light L1 incident on the filter 202 from the gap between the finger F and the guide 201 is reflected by the filter 202, and is reflected light L1 that travels in the direction of the finger F instead of the direction of the light absorbing sheet 2011. 'Occurs, and a portion of the finger F (range W shown in FIG. 6) is irradiated with the reflected light L1 ′, interferes with the light irradiated from the light source 2012, or the reflected light L1 ′ is reflected on the finger F. End up. Therefore, in order to effectively reduce the reflection, it is desirable to dispose the filter 202 so as to satisfy the above-described conditions.

  Further, when the filter 202 is arranged so that the value of tan α is very large (α ″) compared to the value of w / h even when the above-described conditions are satisfied, as shown in FIG. Since the light absorbing sheet 202 requires a width in the vertical direction, the height of the guide 201 is also required in accordance with the width of the light absorbing sheet 202. As a result, the overall height of the biometric authentication device 1000 increases, Therefore, it is difficult to reduce the thickness of the authentication apparatus 1000. Therefore, even when the above-described conditions are satisfied, the filter 202 is disposed at an angle α such that the values on both sides shown in the above-described equation are equal to each other. It is desirable to do.

  Furthermore, in the above-described embodiment, the filter 202 is not fixed at a position that satisfies the above-described conditions, and changes the value of the angle α according to the thickness of the finger F of the user of the biometric authentication device 1000. Also good. That is, by providing a hinge or the like that joins the filter 202 and the guide 201 and allowing the filter 202 to rotate clockwise or counterclockwise about the hinge or the like, the thickness of the finger F of the user The angle α may be adjusted according to the above.

  In addition, this invention is not limited to embodiment mentioned above, A various deformation | transformation is possible. For example, in the above-described embodiment, the light absorbing sheet 2011 is provided on substantially the inner surface of the guide 201, and the light L1 and L2 incident on the flat filter 202 from the gap between the finger F and the guide 201 are absorbed by the light absorbing sheet. It was decided to incline so as to reflect in 2011.

  However, a prismatic (for example, triangular prism) filter 212 having a central portion between the guides 201 as a vertex may be disposed. FIG. 8 is a diagram illustrating an example of the finger placement unit 400 and the main body unit 100 when a filter 212 having a triangular prism shape as the shape of the filter 202 illustrated in FIG. 2 is arranged.

  As shown in FIG. 8, the filter 212 is arranged so that the center line C between the guides 201 and the position of the apex overlap, and the light absorption sheet 2011 and the light source 2012 are arranged on both of the guides 201. In addition, each part other than these has the same configuration as the finger placement part 200 shown in FIG.

  Specifically, as shown in FIG. 9, a triangular prism type filter 212 having an angle between the filter 221 and the horizontal line H as α and a center line C as an apex is disposed. In this case, each of the lights L5 and L6 incident on the filter 212 from the gap between the finger F and the guide 201 is reflected by the filter 221 (the two surfaces above the triangular prism). Then, the reflected lights L5 'and L6' are absorbed by the respective absorption sheets 2011 arranged on substantially one surface inside the guide 2012.

  In this case, the height h can be halved compared to the flat filter 202 shown in FIG. Accordingly, the height of the guide 201 is also half that of the case shown in FIG. 2, so that the biometric authentication device 1000 can be thinned.

  Note that some users of the biometric authentication device 1000 may accidentally press the finger against the filter in the same manner as in the case of authentication by fingerprint when placing the finger. In this case, if a triangular prism type filter 212 is disposed as a filter, the user's finger touches the center line of the filter 212 (the apex portion of the filter 202). As a result, it is possible to give a sense of incongruity to the finger and call attention to the fact that the authentication method is not the fingerprint authentication but the finger vein authentication.

  Furthermore, in the example shown in FIG. 9, the triangular prism type filter 212 is arranged. However, for example, as shown in FIG. 10, a polygon type filter 222 may be arranged. In this case, external light is reflected by the surface adjacent to the upper base (upper surface) of the polygon, and the reflected light travels in the direction in which the light absorbing sheet 2011 is disposed.

  When the triangular filter 212 as shown in FIG. 9 is arranged, the above-described center line (boundary line between adjacent surfaces) may be reflected in the image captured by the imaging unit 101 in some cases. However, when the polygonal filter 222 as shown in FIG. 10 is arranged, the biometric authentication apparatus can be thinned while preventing such reflection. In this case, in order to prevent the above-described reflection, it is preferable that the width of the upper base (upper surface) of the polygon is equal to or greater than the width of the lens of the imaging unit 101.

  Further, a semi-elliptical filter 232 may be disposed instead of the triangular shape or the rectangular shape described above. FIG. 11 is a diagram illustrating an example in which a semi-elliptical filter 232 is arranged. As shown in FIG. 11, each of the light L7 and L8 incident on the filter 232 from the gap between the finger F and the guide 201 is reflected by the filter 232, and the reflected lights L7 ′ and L8 ′ are reflected by the guide 2012. It will be absorbed by each light-absorbing sheet 2011 arranged on the substantially inner surface.

  It should be noted that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

DESCRIPTION OF SYMBOLS 1000 ... Biometric authentication apparatus, 100 ... Main-body part, 101 ... Imaging part, 102 ... Control unit, 200 ... Finger placing part, 201 ... Guide, 202 ... Filter, 2011 ... Light absorption sheet, 2012 ... Light source, 300 ... Connection part.

Claims (5)

A biometric authentication device that obtains finger vein information by irradiating light from a light source to a user's finger,
A guide that forms a space in which the user's finger is placed and blocks external light incident from a lateral direction of the space;
An absorber that is disposed on the surface of the guide and absorbs reflected light of external light incident from above the space;
A filter that is disposed at the bottom of the space and has a reflection surface that reflects external light incident on the space in the direction of the absorber;
An imaging unit that is disposed under the filter and that captures a vein of the user's finger that has received the light emitted from the light source;
A biometric authentication device comprising: The filter has a flat plate shape and is inclined to the absorber.
The angle (α) at which the filter is tilted is based on the height (h) from the portion where the filter and the guide are in contact to the upper end of the guide and the width (w) of the space.

Is a range represented by
The biometric authentication device according to claim 1. The filter is prismatic, and at least two surfaces of the filter are inclined so that reflected light of external light incident on the space is reflected in the direction of the absorber.
The biometric authentication device according to claim 1, wherein the biometric authentication device is provided.   The biometric authentication device according to claim 1, wherein the filter has a semi-elliptical shape.   The biometric authentication device according to any one of claims 1 to 4, wherein the light source is disposed on an inner side surface of the guide.

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