JP3102403B2 - Fingerprint image input device and input method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fingerprint matching device for identifying an individual using a fingerprint, which is a collection of sweat glands on the surface of a human finger, and more particularly to a fingerprint for inputting a fingerprint image of a finger to a computer or the like. The present invention relates to an image input device.

[0002]

2. Description of the Related Art Conventionally, the input of an imprint fingerprint image used for fingerprint collation focuses on the difference in the reflectance due to the unevenness of the fingerprint, and obtains the unevenness of the fingerprint as a gray image by receiving the light reflected by the finger. In inputting an imprinted fingerprint image, most of the methods take in an image when a finger is rotated on a finger rest.

For example, referring to FIG. 7, which is a schematic configuration diagram of a fingerprint imaging unit of a conventional fingerprint image input device, a typical typical fingerprint image input device in a typical fingerprint matching device uses white light as a light source. A light emitting unit 701, a prism 702 that reflects white light incident from the light emitting unit 701 so as to satisfy a total reflection condition on a contact surface with the finger 704, and a fingerprint image that receives light reflected from the prism 702 and forms a fingerprint image. And an imaging element 703 to be obtained.

That is, when the finger 704 is not in contact with the prism 702, the white light incident from the light projecting unit 701 is totally reflected by the upper surface of the prism 702, and
Is bright on the entire surface. Also,
At the time of inputting a fingerprint, a finger 704 is pressed against the upper surface of the prism 702. At this time, since the skin and the prism 702 are in contact with each other at the convex part of the fingerprint, the condition for total reflection is not satisfied, and most of the white light from the light emitting unit 701 is absorbed by the skin and a part of the white light is reflected by the contact surface. Will be done. On the other hand, since the skin and the prism 702 are not in contact with each other in the fingerprint concave portion, the total reflection condition is satisfied, and the white light from the light projecting unit 701 is totally reflected by the contact surface and is incident on the image sensor 703. Will be. This makes the fingerprint recess bright,
The convex portions become dark, and a fingerprint image with contrast is obtained.

Japanese Patent Laid-Open Publication No. Sho 63-177279 discloses a technique in which a palm is brought into contact with a prism 72 to identify a position where a finger to be inputted is in contact.

Further, Japanese Patent Laid-Open Publication No. Hei 3-226888 discloses a finger guide for restricting the degree of freedom between the direction perpendicular to the axis of the finger and the lateral direction of the finger on the fingerprint imprint surface.

[0007]

A first problem of the prior art is that in a fingerprint image input device, even an image of a part other than a fingerprint is input, and the image processing storage unit and the image storage storage unit are input. That is, the capacity increases.

[0008] The reason is that since there is an individual difference in the size of the fingerprint, it is necessary to input and record an extra area other than the fingerprint to prevent the loss of the image due to the individual difference.

In the technique disclosed in Japanese Patent Application Laid-Open No. 63-177279, in which a palm is brought into contact with a prism to identify a position where a finger to be input is in contact, the position of the target finger can be identified. It is necessary to input an image of a region corresponding to the largest possible image area.

In the technique using the finger guide disclosed in Japanese Patent Application Laid-Open No. Hei 3-226888, although the contact position of the finger can be limited, it is still necessary to input an image in a region corresponding to the largest possible image area. .

The second problem is that the conventional fingerprint image input device involves an extra process of cutting out a fingerprint image from the input image.

[0012] The reason is that although the fingerprint collation requires an area of only the fingerprint image, the input image includes an extra area other than the fingerprint.

An object of the present invention is to provide a fingerprint image input apparatus and an input method which can receive an image of an area of only a fingerprint image and can compress the capacity of an image processing storage unit and an image storage storage unit.

[0014]

SUMMARY OF THE INVENTION A fingerprint image input device according to the present invention comprises a light source for irradiating a transparent polyhedron having a finger on one surface with a light beam from a predetermined direction, and a contact surface between the transparent polyhedron and the finger. A two-dimensional image sensor that directly receives the total reflected light and scattered light of the above and converts the reflected light intensity into an electric signal, and intercepts light beams emitted from both directions orthogonal to each other on a plane parallel to and close to the contact surface. Thus, the finger position detecting means installed on the transparent polyhedron so as to detect the position of the finger in contact with the transparent polyhedron, and the finger detected by the finger position detecting means among the electric signals output from the two-dimensional image sensor And a control unit that converts only the image of the area corresponding to the position where the image is placed into digital image density data and saves the digital image density data to form a fingerprint image.

[0015] Finger position detecting means are installed orthogonal to each other near the edge on the transparent polyhedron, and are configured as two sets of optical fiber bundles for irradiating light rays parallel to the contact surface. Two sets of light sources incident on the optical fiber bundle, and a plurality of light detectors installed near the edge on the transparent polyhedron so as to face the optical fiber bundle and orthogonal to each other, and detect interruption of light emitted from the optical fiber bundle by a finger. The device may include two sets of photodetectors in which the elements are arranged in a line. In addition, two sets of linear light sources installed orthogonal to each other near the edge on the transparent polyhedron, and a line near the edge on the transparent polyhedron to detect the interruption of light from the linear light source by a finger. A plurality of photodetectors arranged in a line so as to face each other in opposition to a light source, and each of the photodetectors detects only incident light from the front. Two sets of photodetectors having light-shielding walls for detection may be provided. Further, two sets of light sources that can move parallel to the edge on moving means installed orthogonal to each other near the edge on the transparent polyhedron and irradiate a light beam converging at the photodetector position, It may include a position detector for detecting the position and two sets of linear light detectors installed orthogonal to each other near the edge facing the light detector on the transparent polyhedron.

According to the fingerprint image input method of the present invention, a transparent polyhedron on which a finger is placed on one side is irradiated with a light beam from a light source in a predetermined direction, and total reflection light and scattered light from the contact surface between the transparent polyhedron and the finger are emitted. The two-dimensional image sensor directly receives the light, converts the reflected light intensity into an electrical signal, and positions the finger in contact with the transparent polyhedron in two directions perpendicular to each other on a plane parallel to and close to the contact surface. Detected by interruption by
Of the electric signals output from the three-dimensional image sensor, only the image of the area corresponding to the position of the finger detected by the finger position detecting means is converted into digital image density data and stored, and the stored digital image is stored. A fingerprint image is formed from the density data.

The finger position is detected by irradiating light rays in parallel to the contact surface from two sets of linear optical fiber bundles installed orthogonally to the edge of the transparent polyhedron, thereby forming an edge on the transparent polyhedron. Two sets of photodetectors, which are arranged orthogonal to each other in opposition to the optical fiber bundle in the vicinity of the optical fiber bundle and in which a plurality of photodetectors are arranged in a line, detect the interruption of a light beam emitted from the optical fiber bundle by a finger. It may be a method. In addition, light rays are radiated in parallel to the contact surface from two sets of linear light sources installed orthogonal to each other near the edge on the transparent polyhedron, and mutually opposed to the linear light source near the upper edge of the transparent polyhedron. Two sets of photodetectors arranged orthogonally and having a plurality of photodetectors arranged in a line, each photodetector having a light shielding wall for detecting only incident light from the front direction A method of detecting the interruption of the light beam from the linear light source by a finger using two sets of photodetectors may be used. Further, two sets of point light sources that irradiate a light beam converging on the photodetector position are moved in parallel to the edges on moving means installed orthogonally to the edges of the transparent polyhedron near the edges, respectively. A position at which the position of the light source is detected by detecting the interruption of a light beam from a point light source by a finger by two sets of linear light detectors installed orthogonal to each other near the edge facing the photodetector on the polyhedron. The region of the finger position may be detected by a combination of the position signal from the detector and the detection signal from the photodetector. By using the above-described fingerprint image input device and method, a region where light emitted from a light source is blocked by a finger can be detected two-dimensionally on a parallel plane close to a contact surface of a transparent polyhedron with a finger. Only the image information in the area can be input to the image processing storage unit or the image storage storage unit, preventing input of an image in an extra area other than the fingerprint, preventing the image processing storage unit or the image storage unit from being input. Can be reduced, and an extra process of cutting out only a fingerprint image necessary for fingerprint collation from an input image can be eliminated.

[0018]

Next, a first embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram of the fingerprint image input device according to the first embodiment of the present invention.

The fingerprint image input device according to the first embodiment of the present invention includes a light source 101 for irradiating a light ray 121 to a transparent polyhedron 102 on which a finger is placed, and a reflected light from a contact surface between the transparent polyhedron 102 and the finger. Two-dimensional image sensor 103 which directly receives light and converts reflected light intensity into an electric signal;
A linear optical fiber bundle 1 for irradiating light beams, which is installed orthogonally to the vicinity of the periphery of the transparent polyhedron 102 so as to detect the position of the finger contacting the light beam 02 by blocking light beams.
04, optical fiber bundle 105 and optical fiber bundle 10
4. Light source 10 incident on optical fiber bundle 105
8. A plurality of light sources 109, a plurality of optical fiber bundles 104, and a plurality of optical fiber bundles 105 installed near the peripheral portion on the transparent polyhedron 102 in opposition to the light emitting surface of the optical fiber bundle in order to detect interruption of light emitted from the optical fiber bundle 105 by a finger. Photodetector 1
06a arranged in a line, the photodetector 106, the photodetector 107, the optical fiber bundle 104, and the optical fiber bundle 1
The electric signal from the two-dimensional image sensor 103 is converted into digital image density data only in the area corresponding to the information of the photodetector that has detected that the linear light beam irradiated from step 05 is blocked by the finger, and the fingerprint is obtained. A control unit 110 for storing the image as an image.

Each of the photodetectors 105 and 106 is composed of a plurality of aligned photodetectors 106a and a plurality of photodetectors (not shown). The presence or absence of a finger at the position is detected and output to the control unit 110 as information.
The control unit 110 includes two orthogonal photodetectors 106 and 107.
, The fingerprint image area can be determined in two dimensions.

FIG. 2 is a schematic top view showing the positional relationship between the optical fiber bundle installed around the transparent polyhedron of the fingerprint image input device of FIG. 1 and the photodetector. FIGS. 3A and 3B are schematic top views showing the relationship between finger-blocking of light emitted from an optical fiber bundle installed around the transparent polyhedron and detection of a fingerprint area. FIG. (B) shows a state of detection of a fingerprint area corresponding to (a).

Next, the operation of the first embodiment of the present invention will be described with reference to FIGS. 1, 2 and 3. On the surface of the transparent polyhedron 102 of FIG. 2 where a finger contacts, a linear optical fiber bundle 104 gathered and gathered regularly as shown in FIG. Is irradiated with a linear parallel ray 122. Opposite and opposite ends on the transparent polyhedron 102 are regularly arranged in a linear fashion to detect a light beam 122 emitted from the optical fiber bundle 104.
Are installed. The optical fiber bundle 105 is installed at the other orthogonal end on the transparent polyhedron 2, and the linear parallel light 1 is placed on the transparent polyhedron 102.
Irradiate 22. At the opposite, opposite end of the transparent polyhedron 102, a photodetector 107 in which detection elements (not shown) are regularly arranged in a line so as to detect the light beam 122 emitted from the optical fiber bundle 105 is installed. ing.

As shown in FIG. 3A, the transparent polyhedron 10
When the finger is placed on the surface 2, the linear parallel light rays 122 from the optical fiber bundle 104 and the optical fiber bundle 105 are blocked at a portion where the finger and the transparent polyhedron 102 come into contact with each other. In the portion where the light beam 122 is blocked, the light beam 122 does not reach the light detecting element 106a of the light detector 106 and the light detecting element (not shown) of the light detector 107, and the finger is transparent with the incident light amount detected by the light detecting element. Fingerprint area 1 in contact with polyhedron 102
11 can be detected as shown in FIG.

The light beam 121 emitted from the light source 101 to the transparent polyhedron 102 is
The light is reflected on the upper surface, enters the two-dimensional image sensor 103, and is converted into an electric signal. The control unit 110 converts the electric signal into a digital signal and records it as image density value data. At this time, the photodetector 105 and the photodetector 10
The image density value data of only the fingerprint area 111 detected in step 6 is recorded to form a fingerprint image.

The operation of the control unit 110, which is a feature of the first embodiment of the present invention, will be described with reference to FIG. FIG. 4 is a flowchart of the operation of the control unit of the fingerprint image input device according to the first embodiment of the present invention.

First, input of a fingerprint image is started (S1).
01), the control unit 110 detects from the photodetector 105 the position where the light beam from the optical fiber bundle 104 is cut off when the finger is placed on the transparent polyhedron 102 (step S10).
2).

Next, the position where the light beam from the optical fiber bundle 105 is blocked is detected by the photodetector 106 (step S103).

Optical fiber bundle 104, optical fiber bundle 1
The position where each light beam is blocked out from the region 05 is defined as a fingerprint region 111 to be sampled, and only the reflected light intensity of that region is set to 2
The image is converted into an electric signal by the dimensional image sensor 103, recorded by the control unit 110 (step S104), and the operation is terminated (step 105). Here, only the reflected light intensity of the fingerprint area 111 is converted into an electric signal by the two-dimensional image sensor 103.
Then, the whole area may be converted into an electric signal, and the control unit 110 may convert only the electric signal in the fingerprint area 111 into a digital signal.

Next, a second embodiment of the present invention will be described in detail with reference to the drawings. FIG. 5 shows a second embodiment of the present invention.
FIG. 2 is a schematic configuration diagram of the fingerprint image input device according to the embodiment.

In the second embodiment of the present invention, a light source 201 for irradiating a light beam to a transparent polyhedron 202 on which a finger is placed,
A two-dimensional image sensor 203 that directly receives the reflected light from the contact surface between the transparent polyhedron 202 and the finger and converts the intensity of the reflected light into an electric signal, and detects the position of the finger in contact with the transparent polyhedron 202 by blocking the light beam. A linear light source 218 and a linear light source 219 for irradiating a light beam, which are disposed orthogonally to each other in the vicinity of the periphery of the transparent polyhedron 202, and a line light source 218, and a light beam emitted from the linear light source 219 to be blocked by a finger Light source 218 and linear light source 219 near the peripheral portion on transparent polyhedron 202 to detect
Photodetector 206, photodetector 207, and linear light source 218, 219
Control that converts the electric signal from the two-dimensional image sensor 203 of only the image corresponding to the photodetector that has detected that the light beam irradiated from the finger is blocked by the finger from the two-dimensional image sensor 203 into digital image density data and stores it as a fingerprint image Unit 210. The light detector 206 includes a plurality of aligned light detection elements 2.
The light detector 207 also includes a plurality of light detection elements (not shown), and a light shielding wall 206b for receiving only light from the front is provided on the light incident side of the light detection element 206a. It is provided parallel to the incident direction,
A light-shielding wall (not shown) for receiving only a light beam from the front also on a light incident side of a light detecting element (not shown) of the light detector 207.
Are provided in parallel to the incident direction of the light beam, and the presence or absence of a finger at that position is detected based on the amount of light from the linear light source input to each light detection element, and the control unit 21 outputs the information as information.
Output to 0. Therefore, the irradiation light from the linear light source is
It is not necessary to be a linear parallel light as in the embodiment. The control unit 210 can determine the fingerprint image area in two dimensions based on information from the two orthogonal sets of photodetection rows.

Except for the structure of the light source and the photodetector for determining the fingerprint image area, the structure is the same as that of the first embodiment, and the description is omitted.

Next, a third embodiment of the present invention will be described in detail with reference to the drawings. FIG. 6 shows a third embodiment of the present invention.
FIG. 2 is a schematic configuration diagram of the fingerprint image input device according to the embodiment.

In the third embodiment of the present invention, a light source 301 for irradiating a light beam to a transparent polyhedron 302 on which a finger is placed,
A two-dimensional image sensor 303 that directly receives the reflected light from the contact surface between the transparent polyhedron 302 and the finger and converts the reflected light intensity into an electric signal, and detects the position of the finger in contact with the transparent polyhedron 302 by blocking the light beam. Moving mechanism 32 installed orthogonal to each other near the periphery on transparent polyhedron 302
6. Transparent to detect the movement of the light source 324 and the moving light source 325 that are moved by the servo motor 328 and the servo motor 329 on the moving mechanism 327 and the interruption of the light beam emitted from the moving light source 324 and the finger by the finger. A moving light source 324, a linear light detector 306, a linear light detector 307 installed facing the light emitting surface of the moving light source 325 near the peripheral portion of the polyhedron 302, a servomotor 328 for driving the moving light source 324, The position signal of the moving light source from the servomotor 329 for driving the light source 325 and the moving light source 3
24, an electric signal from the two-dimensional image sensor 303 of only the image of the area calculated in correspondence with the detection signal of the linear photodetector that detects that the light beam emitted from the moving light source 325 is blocked by the finger Is converted to digital image density data and stored as a fingerprint image.

The moving light source 324 and the moving light source 325 are point light sources for irradiating a light beam converging at the position of the photodetector. The linear photodetectors 305 and 306 are composed of horizontally long photodetectors. Then, the intensity of light in the entire length direction is detected. The control unit 310 determines the presence or absence of a finger at the position based on the information on the positions of the two sets of moving light sources orthogonal to each other and the information on the amount of light received by the linear photodetector facing the moving light source, and determines the fingerprint image area in two dimensions. Can be determined.

Except for the structure of the light source and the photodetector for determining the fingerprint image area and the method for determining the fingerprint image area,
The description is omitted because it is the same as that of the embodiment.

Although three embodiments have been described, the finger position detecting means is not limited to this.
The present invention can be applied to any means and method that can detect the position where the irradiated light beam is blocked by the finger.

[0037]

The first effect is that the capacity of the image processing storage unit and the image storage storage unit can be reduced as compared with the conventional fingerprint image input. It can be remembered.

The reason is that the fingers are in contact with each other by two orthogonal light sources provided near the periphery of the transparent polyhedron and a photodetector for detecting the interruption of the light beam emitted from the light sources by the finger. This is because an area is detected, and image information of only this area is input to the storage unit, and an extra area is not input.

A second effect is that unnecessary image processing for cutting out a fingerprint area used for fingerprint collation from an original image, which is required in a conventional fingerprint image input device, can be eliminated.

The reason for this is that when an image is input in advance, two orthogonal orthogonal polygons provided near the periphery of the transparent polyhedron are used.
One light source and a photodetector that detects the interruption of a light beam emitted from the light source by the finger detect an area where the finger is in contact, and input image information of only this area to the storage unit, Is not entered.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a fingerprint image input device according to a first embodiment of the present invention.

FIG. 2 is a schematic top view showing a positional relationship between an optical fiber bundle installed around a transparent polyhedron of the fingerprint image input device of FIG. 1 and a photodetector.

FIG. 3 is a schematic top view showing the relationship between the interruption of a light beam emitted from an optical fiber bundle installed around a transparent polyhedron by a finger and the detection of a fingerprint area. (A) shows a state in which the light beam is blocked by a finger. (B) shows the state of detection of the fingerprint area corresponding to (a).

FIG. 4 is a flowchart of an operation of a control unit of the fingerprint image input device according to the first embodiment of the present invention.

FIG. 5 is a schematic configuration diagram of a fingerprint image input device according to a second embodiment of the present invention.

FIG. 6 is a schematic configuration diagram of a fingerprint image input device according to a third embodiment of the present invention.

FIG. 7 is a schematic configuration diagram of a fingerprint imaging unit of a conventional fingerprint image input device.

[Explanation of symbols]

 101, 201, 301 Light source 102, 202, 302 Transparent polyhedron 103, 203, 303 Two-dimensional image sensor 104, 105 Optical fiber bundle 106, 107, 206, 207 Photodetector 106a, 206a Photodetector 108, 109 Light source 110, 210 , 310 Controller 111 Fingerprint area 121, 221, 321 Ray 122 Ray 206b Shielding wall 218, 219 Linear light source 306, 307 Linear light detector 324, 325 Moving light source 326, 327 Moving mechanism 328, 329 Servo motor 701 Unit 702 prism 703 image sensor 704 finger S101 to S105 step

Claims (8)

(57) [Claims] 1. A light source for irradiating a transparent polyhedron with a finger placed on one side with light rays from a predetermined direction, and a light source for directly receiving total reflection light and scattered light from a contact surface between the transparent polyhedron and a finger. Convert reflected light intensity to electrical signal 2
A three-dimensional image sensor, on a plane parallel to and close to the contact surface, on the transparent polyhedron so as to detect the position of the finger in contact with the transparent polyhedron by intercepting light beams emitted from both orthogonal directions by the finger. And a digital image density detecting unit that detects only an image of an area corresponding to the position of the finger detected by the finger position detecting unit among the electric signals output from the two-dimensional image sensor. A fingerprint image input device comprising: a control unit that converts the data into data and stores the data to form a fingerprint image. 2. The method according to claim 1, wherein the finger position detecting means is disposed orthogonal to an edge on the transparent polyhedron so as to detect a position of the finger in contact with the transparent polyhedron by blocking light beams, Two sets of linear optical fiber bundles for irradiating light rays parallel to the above, two sets of light sources incident on the respective optical fiber bundles, and facing the optical fiber bundles near edges on the transparent polyhedron And two sets of photodetectors, which are arranged orthogonal to each other, and in which a plurality of photodetectors for detecting interruption of a light beam emitted from the optical fiber bundle by a finger are arranged in a line. 4. The fingerprint image input device according to claim 1. 3. Two sets of orthogonally disposed near edges on the transparent polyhedron so that the finger position detecting means detects a position of a finger in contact with the transparent polyhedron by blocking light rays. A line-shaped light source, and a plurality of light sources installed near the edge of the transparent polyhedron, orthogonal to each other, in the vicinity of an edge on the transparent polyhedron, in order to detect interruption of light from the line-shaped light source by a finger. Two sets of photodetectors in which the detection elements are arranged in a line,
2. The fingerprint image input device according to claim 1, wherein each of the light detection elements includes two sets of light detectors having a light shielding wall for detecting only incident light from the front direction. 4. A moving means installed orthogonally to an edge on the transparent polyhedron so that the finger position detecting means detects a position of a finger in contact with the transparent polyhedron by blocking light rays. Can be moved in parallel to the edge, and two sets of light sources that irradiate a light beam that converges on the photodetector position, a position detector that detects the position of the light source, and the photodetector on the transparent polyhedron 2. The fingerprint image input device according to claim 1, further comprising: two sets of linear photodetectors installed orthogonal to each other near the opposing edges. 3. 5. A transparent polyhedron in which a finger is placed on one side is irradiated with a light beam from a light source in a predetermined direction, and total reflection light and scattered light from a contact surface between the transparent polyhedron and a finger are directly transmitted by a two-dimensional image sensor. Receiving and converting the intensity of the reflected light into an electric signal, the position of the finger contacting the transparent polyhedron is detected by the finger blocking light beams emitted from both directions orthogonal to each other on a plane parallel to and close to the contact surface. Then, of the electric signals output from the two-dimensional image sensor, only the image of the area corresponding to the position of the finger detected by the finger position detecting means is converted into digital image density data and stored, A fingerprint image input method comprising forming a fingerprint image from stored digital image density data. 6. The method for detecting a finger position, comprising: irradiating a light beam in parallel to the contact surface from two sets of linear optical fiber bundles installed orthogonal to each other near an edge on the transparent polyhedron. The optical fiber bundle is illuminated from the optical fiber bundle by two sets of photodetectors, which are arranged near the edge on the transparent polyhedron, facing the optical fiber bundle and orthogonal to each other, and a plurality of photodetectors are arranged in a line. The fingerprint image input method according to claim 5, wherein the method is a method of detecting interruption of a light beam by a finger. 7. The method of detecting a finger position, comprising: irradiating light rays parallel to the contact surface from two sets of linear light sources installed orthogonal to each other near an edge on the transparent polyhedron; Two sets of photodetectors are provided near the upper edge and opposed to the linear light source and orthogonal to each other, and a plurality of photodetectors are arranged in a line. It is a method of detecting finger blocking of light from the linear light source by two sets of light detectors having a light shielding wall for detecting only incident light from a direction,
The fingerprint image input method according to claim 5. 8. A moving means in which two sets of point light sources for irradiating a light beam converging on a photodetector position are arranged orthogonal to each other near an edge on the transparent polyhedron. The light from the point light source is moved by two sets of line-shaped photodetectors, which are respectively arranged on the transparent polyhedron in the vicinity of the edge facing the photodetector and are orthogonal to each other. The blockage of the finger is detected, and a region of a finger position is detected by a combination of a position signal from a position detector that detects the position of the light source and a detection signal from the photodetector. Fingerprint image input method.