JP2000011142A - Fingerprint image pickup device and fingerprint collating device using the same device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fingerprint image detecting device for which an optical member whose degree of freedom of structure is relatively high can be used, and a fingerprint collating device using this device. SOLUTION: This fingerprint collating device is provided with an optical means 1 having a plane part 1a with which a finger 2 is brought into contact, light source means 2 for irradiating the finger 2 brought into contact with the plane part 1a with a light, image pickup means 3 for image picking-up a reflected light due to the projection and recession of the fingerprint of the finger 2, signal processing means 6 for adding a signal processing necessary for the fingerprint collation to the image signal of the fingerprint image picked-up by the image pickup means 3, and fingerprint judging means 7 for judging whether or not the person is the person himself, or detecting the penitent person from among plural registered persons based on the image signal of the fingerprint outputted from the signal processing means 6. The optical means 1 has a structure in which plural prisms whose cross-section shapes are isosceles triangles which are sufficiently smaller than the finger 2 of a human body are arranged like an array so that the finger 2 can be brought into contact with the area only necessary for the fingerprint collation at the plane part 1a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a fingerprint collating device used as a means for personal identification for security and the like, and a configuration including an optical system in a fingerprint image capturing device used therefor.

[0002]

2. Description of the Related Art FIG. 14 shows, for example, the Transactions of the Institute of Electronics and Communication Engineers, "Fingerprint Information Detection Method Using Prisms-Comparison between Total Reflection Method and Optical Path Separation Method": Shimizu et al., March 1985, vol. J68-D no. .3.P
P.414-415. 1 is an example of a total reflection type fingerprint collating apparatus in the related art in which an optical unit for imaging a fingerprint is described. In the fingerprint matching device shown in FIG.
Is a finger to be detected, 3 is a light source means, 4 is a lens, 5 is an imaging means for receiving reflected light, 6 is a signal processing means, 7 is a fingerprint discriminating means, and 20 is a prism.

[0003] The operation of the fingerprint collation apparatus configured as described above will be described. The light emitted from the light source means 3 is radiated from one of the ridges of the prism toward the human finger 2 to be detected. Light incident from one side of the prism 20 is reflected on the bottom surface of the prism 20, that is, the surface in contact with the finger, and the reflected light exits from another edge of the prism 20. The light emitted from the prism 20 is condensed by the lens 4 and imaged by the imaging means 5.

FIG. 15 is a diagram for explaining the principle of fingerprint detection. Lights emitted from the light source means 3 are A and B. The human finger 2 has irregularities due to fingerprints, of which the convex surface contacts the bottom surface 20a of the prism 20, and the concave surface does not. Then, light A and B emitted from the light source means 3
Is diffused (light B) at a contact portion (that is, a convex portion) on the bottom surface 20a of the prism 20, and a non-contact portion (that is, a light B).
(Light A). Therefore, the totally reflected light A is reflected as reflected light A1 as shown in the figure, and the diffused light B is reflected as scattered light B1 to the imaging means 5, respectively. Therefore, in the imaging means 5, an image having a higher luminance value in the concave portion of the fingerprint than in the convex portion is obtained.

The image of the finger 2 detected by the imaging means 5 is adjusted by the signal processing means 6 to adjust the image level,
Signal processing, such as digitization, is added to make it easier to detect for fingerprint collation. Further, the fingerprint discriminating means 7 registers, from the fingerprint image obtained from the signal processing means 6, whether or not the person is to be detected by a detection algorithm for fingerprint collation, and the fingerprint collated person is registered. It detects who is among the plurality of persons and outputs the result of the determination. Algorithms for fingerprint detection are described in, for example, "Image Processing Handbook", Morio Onoe (Shokodo) Chapter 24.3 pp.579-5
82. Various discriminating methods are also described in Mitsubishi Electric Technical Report "Fingerprint Discriminating Device" pp.40-43, vol.72, no.5 (1998). An example is given in such as.

In the above-mentioned conventional fingerprint collating apparatus, 1
One large right angle prism 20 is used. Since the size of the prism 20 is determined by the size of the human finger to be detected, the area at the contact portion needs to be a certain value or more. Therefore, it was difficult to reduce the size of the prism.

Further, since the optical path in the prism 20 is relatively long in the distance between the light source means 3 and the imaging means 5 and the ratio of the optical path in the air to the optical path in the prism, the image to be imaged changes due to heat or the like. , And changes in optical constants. Therefore, a material having a low coefficient of thermal expansion, such as glass, must be used as a material for forming the prism, and it has been difficult to form the prism from a material such as plastic, which is lighter than conventional glass.

In order to solve these problems, reduce the volume of the optical member that comes into contact with the finger, and reduce the size and weight, the inventor has previously described the invention shown in FIG.
Invention described in US Pat. No. 157,734). Hereinafter, FIG.
The invention shown in FIG. 6 will be described.

In FIG. 16, steps 2 to 7 are the same as those shown in FIG. Reference numeral 21 denotes a prism array which is an optical member having a shape in which a plurality of small prisms each having a substantially right-angled triangular cross section are arranged in an array, and other than two ridge surfaces sandwiching a substantially right-angled portion (end portion) 21b of each prism. The common plane portion 21a is formed by connecting the surfaces. And
The flat portion 21a has an area where the human finger 2 to be collated can contact. At the time of fingerprint collation, the finger 2 is brought into contact with the bottom surface 21a.

The light source means 3 is configured to irradiate light to the human finger 2 as a detection target, and irradiates the human finger 2 via the prism array 21. Then, the light source means 3 converts the incident light into the flat portion 21 a of the prism array 21.
Is positioned so as to hit at an angle of 45 degrees.

Light incident from one of the ridges of the prism array 21 by the light source means 3 is reflected on the bottom surface of the prism array 21, that is, the flat portion 21 a where the finger contacts, and the reflected light is reflected on the other ridge of the prism. Emitted from The light emitted from the prism array 21 is condensed by the lens 4 and imaged by the imaging means 5.

The principle of collecting a fingerprint image is the same as that shown in FIG. 15, and the convex surface of the fingerprint contacts the flat portion 21a of the prism array and the concave surface does not. The light emitted from the light source means 3 and incident on the finger 2 from one of the ridge faces of the prism array 21 is reflected by the prism array plane portion 21 with which the finger 2 contacts.
In a, the light is diffused at the contact portion and totally reflected at the non-contact portion. Therefore, the reflected light from the prism array 21 is imaged by the imaging means 5 as an image having a higher luminance value in the concave portion of the fingerprint than in the convex portion, and a fingerprint image of the finger 2 can be obtained.

The fingerprint image obtained by the imaging means 5 is input to a signal processing means 6. The signal processing unit 6 includes the imaging unit 5
A fingerprint discriminating unit 7 at the next stage, such as performing correction processing such as blurring and adhesion of the image of the finger 2 captured by the camera, adjusting the image level, adjusting the contrast, aperture processing, and removing illumination unevenness and density unevenness. Signal processing is applied to the input fingerprint image in order to obtain a fingerprint image adapted to the fingerprint collation algorithm in.

FIG. 17 is a view showing a fingerprint image picked up by the image pickup means 5, and FIG. 18 is an enlarged view of a main part of FIG. As shown in FIGS. 17 and 18, since the end 21b of the prism array 21 forms an image as a plurality of lines 22, the signal processing unit 6 also deletes the plurality of lines 22 corresponding to the end 21b. Signal processing must be performed as described above.

The fingerprint discriminating means 7 detects a characteristic point of the fingerprint from the fingerprint image obtained from the signal processing means 6 and determines whether or not the person is to be detected by a detection algorithm for fingerprint collation. In addition, the fingerprint collation is performed to determine who is among the registered humans, and the result of the determination is output.

[0016]

As described above, in the fingerprint image pickup apparatus and the fingerprint collation apparatus using the same in the earlier application, as an embodiment thereof, a technique in which the prism array 21 is constituted by a substantially right-angle prism is used. Was disclosed,
In the case where such a configuration is adopted, processing accuracy is required to make the angle between the ridge faces located on the opposite side to the plane portion 21a a right angle.

Further, since the end portion 21b of the substantially right-angle prism forms an image on the image pickup means 5, an image of a plurality of lines 22 caused by the unnecessary end portion 21a of the right-angle prism is deleted from the taken fingerprint image. It was necessary to perform signal processing.

Furthermore, a lens 4 for condensing the reflected light is required for imaging, and there is a problem that the number of components is large.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a fingerprint image detecting device capable of forming an optical member with a prism array having a relatively high degree of freedom in structure, and a fingerprint matching device using the same. And

[0020]

SUMMARY OF THE INVENTION A fingerprint image pickup apparatus according to the present invention is an optical device having a structure in which a plurality of prisms having a triangular cross section are arranged in an array, each of which has a flat portion with which a human finger having irregularities comes into contact. A member, light source means for irradiating light to a finger in contact with the flat part of the optical member, and a condenser lens and an imaging means for obtaining a fingerprint image by imaging light reflected by the unevenness of the fingerprint, The triangle which is the cross-sectional shape of each prism is a substantially isosceles triangle, and the angle between two sides of equal length is substantially a right angle or an obtuse angle.

Also, an optical member having a planar portion in contact with an uneven human finger and having a structure in which a plurality of prisms having a triangular cross section are arranged in an array, and a finger in contact with the planar portion of the optical member. Light source means for irradiating light, and a condensing lens and an imaging means for obtaining a fingerprint image by imaging reflected light due to the unevenness of the fingerprint. The width of the prism is smaller than half of the distance between the concave portions of the fingerprint, and the pitch of the prism is smaller than the width of each pixel constituting the imaging means.

Further, the flat part of the optical member is formed in a spherical shape so that the image of the human finger reflected from the optical member is directly formed on the image pickup means without passing through the condenser lens. It is characterized by having.

The fingerprint collating apparatus according to the present invention comprises: the above fingerprint image capturing apparatus; signal processing means for performing signal processing required for fingerprint collation on an image signal of a fingerprint image obtained by the fingerprint image capturing apparatus; A fingerprint discriminating unit for discriminating whether or not the person is a person based on an image signal of the fingerprint image output from the signal processing unit, or detecting a corresponding person from among a plurality of registered persons. It is a feature.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a fingerprint image capturing apparatus and a fingerprint matching apparatus using the same according to the present invention will be described.
This will be described with reference to FIGS. 1 to 13, the same reference numerals as those used in the conventional technology denote the same components.

Embodiment 1 FIG. 1 is a configuration diagram showing a first embodiment of the fingerprint matching device according to the present invention. 1 is a prism array, 2 is a finger including a fingerprint to be collated, 3 is a light source unit, 4 is a lens, 5 is an imaging unit that obtains a fingerprint image by imaging reflected light from the light source unit, and 6 is an imaging unit 5 The signal processing means 7 for processing the fingerprint image output from the signal processing means 6 performs the signal processing on the fingerprint image obtained by the signal processing means 6 by using a detection algorithm for fingerprint collation, The fingerprint discriminating means detects a person whose fingerprint has been collated and who is registered, and outputs the discrimination result.

FIG. 2 is an enlarged view of a cross section of the prism array 1 shown in FIG. The prism array 1 is an optical member having a shape in which a plurality of small prisms having a cross-sectional shape in a direction perpendicular to the arrangement direction and a substantially isosceles triangle are arranged in an array, and surfaces other than the ridge surface corresponding to the isosceles of each prism. Form a common plane part 1a. And
The flat portion 1a has an area where the human finger 2 to be collated can contact. Further, both angles θ1 and θ2 of each prism of the prism array 1 are substantially equal, and the angle θ3 sandwiched between both sides is an obtuse angle larger than 90 degrees or almost a right angle.

Here, the optical member 1, the light source means 3,
It is also possible to manufacture and sell a part of the fingerprint collation device including the lens 4 and the imaging means 5 as a single device. A device capable of obtaining a fingerprint image of a human finger is called a fingerprint image imaging device. It shall be.

The operation of the fingerprint collation apparatus configured as described above will be described. The light source means 3 is configured to irradiate light to the human finger 2 as a detection target, and irradiates the human finger 2 via the prism array 1. As shown in FIG. 2, the prism array 1 is formed by connecting small prisms sufficiently smaller than the human finger 2 in a row (array), and the area of the plane portion 1a is the size required for detection. Of the finger 2 can be contacted.

FIG. 3 is a sectional view of the prism array 1 showing the principle of capturing a fingerprint, and FIG. 4 is a perspective view of the outer shape of the prism array 1. As shown in the figure, the bottom surface of the prism array 1 is a flat surface, and a human finger 2 to be detected is placed on the flat surface 1a.
Contact. Light incident at an angle φ1 from one of the ridges of the prism array 1 by the light source means 3 is refracted at an angle φ2 according to Snell's law. Further prism array 1
Is reflected by the bottom surface of the prism, that is, the plane portion 1a where the finger contacts, and the reflected light is emitted from another ridge surface of the prism. At this time,
The relationship between the refractive index of the prism array and the angle of the incident light from the light source means 3 satisfies an angle such that the light refracted at the angle φ2 and incident on the prism array 1 is totally reflected at the bottom surface 1a. It is stipulated that

The reflection at the bottom surface 1a of the prism array is totally reflected at the concave portion of the fingerprint and scattered at the convex portion. Light emitted from the prism array 1 is collected by the lens 4 and imaged by the imaging means 5. The reflected light from the prism array 1 is imaged by the imaging means 5 as an image having a higher luminance value in the concave portion of the fingerprint than in the convex portion, and a fingerprint image can be obtained.

FIG. 5 shows an example of the image pickup means 5. The imaging means 5 includes an image sensor 8 for detecting the light reflected from the prism array 1 on the image plane via the lens 4 and a driving means 9 for driving the image sensor 8.

The fingerprint image obtained by the imaging means 5 is input to the signal processing means 6. The signal processing unit 6 includes the imaging unit 5
A fingerprint discriminating unit 7 at the next stage, such as performing correction processing such as blurring and adhesion of the image of the finger 2 captured by the camera, adjusting the image level, adjusting the contrast, aperture processing, and removing illumination unevenness and density unevenness. Signal processing so as to obtain a fingerprint image adapted to the fingerprint collation algorithm in. Also, depending on the algorithm, it is necessary to perform a binarization process.

The fingerprint discriminating means 7 detects a characteristic point of the fingerprint from the fingerprint image obtained from the signal processing means 6, and determines whether or not the person is to be detected by a detection algorithm for fingerprint collation. Then, a person whose fingerprint has been collated is determined to be any of the registered persons, and the result of the determination is output.

As described above, in the present embodiment, it is not necessary to limit the shape of the prism to only a right-angle prism, and the prism array 1 can be constituted by a combination of triangular prisms having a relatively high degree of freedom.

Further, the prism array 1 of the present invention
In addition to the configuration shown in FIG. 1, the configuration example of the fingerprint collation device using the image sensor 5 is provided in the same direction as the light source unit as shown in FIG. It is needless to say that a similar effect can be obtained even if the configuration is adapted to an optical path separation method for obtaining a fingerprint image. However, in this case, it is necessary to prevent the reflection by painting the ridge surface 1c of the prism array 1 on the side opposite to the side where the light from the light source means 3 is incident, in black.

Embodiment 2 The present embodiment is different from the first embodiment in that an image sensor 8
The feature is that the relationship between the size of each pixel and the distance between the concave portions of the fingerprint, and the relationship between the size of each pixel and the pitch between each prism of the prism array are respectively defined. Is the same as in the first embodiment.

FIG. 7 is a cross-sectional view showing the optical member itself in Embodiment 2 of the fingerprint collating apparatus according to the present invention. In FIG. 7, reference numeral 10 denotes an optical member, which is a prism array in which substantially isosceles triangular prisms are formed in an array in the same manner as in the first embodiment, and the angle at the end 10b sandwiched between the isosceles is substantially a right angle or an obtuse angle. I just want it. The prism array 10 can be used in place of the prism array 1 in FIGS. 1 and 6 to constitute a fingerprint matching device.

Here, similarly to the first embodiment, the fingerprint collation device including the prism array 10, the light source means 3, the imaging device 5, and the lens 4 may be manufactured and sold as a single device. A device that is capable of obtaining a fingerprint image of a human finger is referred to as a fingerprint image capturing device.

In the present embodiment, similarly to the first embodiment, the irradiation light emitted from the light source 2 is applied to the finger 2 via the prism array 10. Since the imaging of the light reflected by the finger 2 by the imaging means 5 and the fingerprint discrimination is performed in the same manner as in the first embodiment, the description thereof is omitted.

FIG. 7 is a sectional view of the prism array 10 and has a structure in which a person's finger 2 to be collated with the flat portion 10a is pressed. In FIG. 7, Dpa is the size of the prism array 10, and Dp is a distance indicating the pitch of the triangular prisms of the prism array. FIG. 8 is an enlarged cross-sectional view of the fingerprint portion of the finger 2 to be detected. In FIG. 8, Dfa represents the size of the finger required for detection, and Df represents the distance between the valleys (recesses) of the fingerprint. . FIG. 9 is an enlarged view of the image sensor 8 which is a component of the imaging unit 5,
In FIG. 9, Dsah and Dsav indicate the vertical and horizontal sizes of the image sensor 8, and Dsh and Dsv indicate the size of each pixel constituting the image sensor 8.

In each of the components formed as described above, the size Dpa of the prism array 10 is determined by the finger 2 to be detected.
And the size Dfa of the finger 2 necessary for detection is in a relationship such that an image is formed in Dsah and Dsav of the image sensor 8.

Now, assuming that Dfa is imaged to the size of Dsah and Dsav, in order to clearly capture the fingerprint image of the finger 2, the size Dsh and Dsv of each pixel of the image sensor 8 is required. From 1 / Df <1 / (2 × Dsh) and 1 / Df <1 / (2 × Dsv), Dsh <Df / 2 and Dsv <Df /, so as to satisfy the Nyquist frequency for the fingerprint pitch. It is necessary to satisfy 2-(1) at the same time. The present embodiment is also designed to satisfy such a relationship.

Here, the expression (1) is obtained by comparing Dsh and Dsv
The reason for simultaneously specifying each of
On the other hand, the fingerprint must be detected two-dimensionally in both the vertical and horizontal directions of the image sensor 8, and therefore it is necessary to simultaneously define both the vertical and horizontal directions.

In addition, in the present embodiment, in particular, the pitch Dp between the prisms of the prism array 10 satisfies the relationship of Dp <Dsh or Dp <Dsv-(2). A prism array 10 is formed. Here, the equation (2) is different from the equation (1) as long as the relationship shown in the equation is satisfied only in one direction in the vertical or horizontal direction.
This is because the arrangement direction of the prisms in the prism array 10 and the installation state of the image sensor 8 do not change arbitrarily, and the installation state is kept constant.

The prism array 1 satisfies the expression (2).
0, a plurality of lines 2 corresponding to the end 10b of the prism array formed on the image sensor 8 are formed.
2 will disappear from the fingerprint image. This is because, when the pitch between the ends 10b of the prism array is smaller than the pixel pitch Dsh or Dsv as shown in Expression (2), the end 10b can be resolved at a resolution determined from the pixel pitch of the image sensor 8. It is because it disappears.

FIG. 10 shows an example of a captured fingerprint image. Dotted lines described in the fingerprint image are a plurality of lines 22 corresponding to the end 10b of the prism lens. Although the dotted line is shown here for easy understanding, the plurality of lines 22 themselves do not appear on the formed image because the pixel pitch is smaller than the pixel pitch resolvable by the image sensor 8.

As described above, by forming the optical member of the fingerprint collating apparatus with the prism array 10 satisfying the above-mentioned relationship, it is possible to cope with unnecessary ends 10b from a fingerprint image taken as in the prior art. A fingerprint image used for fingerprint collation can be obtained without deleting a plurality of lines 22.

Embodiment 3 The structure of the fingerprint matching device according to the present embodiment is the same as that of the first embodiment except that the structure of the optical member is different.

FIG. 11 is a diagram showing a fingerprint image capturing device in the fingerprint matching device according to the third embodiment of the present invention. In FIG. 11, reference numeral 11 denotes an optical member, which is the first embodiment.
A spherical surface formed by arranging a plurality of substantially isosceles triangular prisms as shown in FIG. 11c in an array and forming a surface 11a in which surfaces other than the ridge surface corresponding to the isosceles of each prism are spherical. It is a prism array. Here, of course, the angle sandwiched by the isosceles sides may be a substantially right angle or an obtuse angle. Reference numeral 3 denotes a light source unit, and 5 denotes an imaging unit.

In the present embodiment, the irradiation light emitted from the light source means 3 is transmitted through the finger 2 through the spherical prism array 11.
Is irradiated. The spherical prism array 11 is a triangular prism, as in the first embodiment. Each of the prisms is a triangular prism, but the surface 11a with which the finger 2 contacts is formed in a spherical shape. The reflected light is configured to form an image on the imaging unit 3 without passing through the condenser lens.

FIG. 12 is a cross-sectional view of the spherical prism array 11, showing a state where the finger 2 is pressed against a person to be collated with the spherical surface 11a. The human finger 2 is soft, and even if the portion to be contacted is a spherical surface, the fingerprint can be brought into contact with the finger, and there is no lack of unevenness of the fingerprint by pressing. The incident light from the finger in contact with the spherical prism array 11 is totally reflected by the concave portion and diffused by the convex portion as described in the first embodiment, and the reflected light is imaged by the imaging means 5 to form a fingerprint image. Obtainable. The fingerprint image obtained by the imaging unit 5 is compared with the fingerprint by the signal processing unit 6 and the fingerprint discrimination unit 7 in the same manner as in the first embodiment, and the description is omitted.

As described above, since the optical member is constituted by the spherical prism array 11, the lens 4 (see FIG. 1) for condensing an image on the image pickup means 5 is omitted, and the structure of the entire apparatus is simplified. Becomes possible.

Further, even if each of the spherical prism arrays 11 does not accurately make the shape of the triangular prism as shown in FIG. 11, the entire bottom surface of the spherical prism array 11 has a gentle spherical surface as shown in FIG. It goes without saying that the same effect can be obtained even if the shape is in the form. Here, FIG. 13A is a sectional view of a principal part showing another example of the prism array 11, and FIG. 13B is a sectional view of FIG.
It is an enlarged view of (a).

[0054]

According to the present invention, there is provided a fingerprint image capturing apparatus, comprising: an optical member having a planar portion in contact with an uneven human finger and having a structure in which a plurality of prisms having a triangular cross section are arranged in an array; Light source means for irradiating light to a finger in contact with the flat portion of the optical member, a condenser lens for imaging reflected light due to the unevenness of the fingerprint to obtain a fingerprint image, and an imaging means; The triangular shape is a substantially isosceles triangle, and the angle between two sides having the same length is characterized by being a substantially right angle or an obtuse angle, so that the optical member is not limited to a right-angle prism alone. The degree of freedom can be improved, and the production of the optical member can be facilitated, and the production yield is improved,
The manufacturing cost of the device can be reduced.

Further, an optical member having a structure in which a plurality of prisms having a triangular cross section are arranged in an array and having a flat portion with which a human finger having irregularities comes into contact, and a finger in contact with the flat portion of the optical member. Light source means for irradiating light, and a condensing lens and an imaging means for obtaining a fingerprint image by imaging reflected light due to the unevenness of the fingerprint. Since the width is smaller than half the distance between the concave portions of the fingerprint, and the pitch of the prism is smaller than the width of each pixel constituting the imaging means, a plurality of lines corresponding to the prism end portions are It is possible to obtain an image of only the fingerprint without appearing in the image.
Therefore, there is no need to perform signal processing for deleting the plurality of lines, and when applied to fingerprint matching, the time required for fingerprint matching is reduced.

Further, the flat portion of the optical member is formed in a spherical shape so that the image of the finger reflected from the optical member is directly formed on the image pickup means without passing through a condenser lens. Therefore, there is no need to specially prepare an imaging lens, and the optical member itself serves as both a prism and a lens. Simplification can be achieved.

The fingerprint collating apparatus according to the present invention comprises: the above fingerprint image capturing apparatus; signal processing means for performing signal processing required for fingerprint collation on an image signal of a fingerprint image obtained by the fingerprint image capturing apparatus; A fingerprint discriminating unit for discriminating whether or not the person is a person based on an image signal of the fingerprint image output from the signal processing unit, or detecting a corresponding person from among a plurality of registered persons. Therefore, fingerprint collation can be realized with a small device.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of a fingerprint matching device according to the present invention.

FIG. 2 is a cross-sectional view of a main part of the optical member according to the first embodiment of the fingerprint matching device according to the present invention.

FIG. 3 is a diagram for explaining the principle of collecting a fingerprint image in the fingerprint matching device according to the first embodiment of the present invention.

FIG. 4 is a perspective view showing an outer shape of a prism array in the fingerprint matching device according to the first embodiment of the present invention.

FIG. 5 is a configuration diagram of an imaging unit in the fingerprint matching device according to the first embodiment of the present invention.

FIG. 6 is a configuration diagram showing another example of the fingerprint matching device according to the first embodiment of the present invention.

FIG. 7 is a cross-sectional view illustrating an optical member according to a second embodiment of the fingerprint matching device according to the present invention.

FIG. 8 is an essential part cross-sectional view showing the size of a fingerprint of a finger and the pitch of unevenness.

FIG. 9 is a diagram illustrating the size and pixel pitch of an image sensor.

FIG. 10 is an enlarged view of a main part of a fingerprint image picked up by an image pickup unit.

FIG. 11 is a diagram illustrating a fingerprint matching device according to a third embodiment of the present invention.
FIG. 3 is a configuration diagram illustrating a main part in FIG.

FIG. 12 is a diagram illustrating a fingerprint matching device according to a third embodiment of the present invention.
5 is a cross-sectional view of a main part in which a finger is brought into contact with an optical member.

FIG. 13 is a diagram illustrating a fingerprint matching device according to a third embodiment of the present invention.
It is a principal part sectional view which shows the other Example of the optical member in FIG.

FIG. 14 is a configuration diagram illustrating an example of a fingerprint matching device according to the related art.

FIG. 15 is a diagram for explaining the principle of fingerprint detection by a fingerprint matching device according to a conventional technique.

FIG. 16 is a configuration diagram showing a fingerprint collation device according to the earlier invention made by the inventor.

17 is a diagram illustrating a fingerprint image captured by an imaging unit of the fingerprint matching device illustrated in FIG. 16;

FIG. 18 is an enlarged view of a main part of FIG. 17;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Prism array (optical member), 1a flat part, 1b end part, 1c Ridge surface opposite to the side where light enters, 2 fingers, 3 light source means, 4 lens,
Reference Signs List 5 imaging means, 6 signal processing means, 7 fingerprint discriminating means, 8 image sensor, 9 driving means, 10 prism array (optical member), 10b end, 11 spherical prism array, 20 prism, 21 prism array, 22 plural lines .

Claims (4)

[Claims] 1. An optical member having a structure in which a plurality of prisms having a triangular cross-section are arranged in an array and having a flat portion with which a human finger having irregularities contacts, and a finger in contact with the flat portion of the optical member Light source means for irradiating light, and a condensing lens and an image pickup means for obtaining a fingerprint image by imaging reflected light due to the unevenness of the fingerprint. The triangle having a cross-sectional shape of each prism is a substantially isosceles triangle. Wherein the angle between two sides of equal length is substantially a right angle or an obtuse angle. 2. An optical member having a planar portion in contact with an uneven human finger and having a structure in which a plurality of prisms having a triangular cross section are arranged in an array, and a finger in contact with the planar portion of the optical member. Light source means for irradiating light, and a condensing lens and an imaging means for obtaining a fingerprint image by imaging reflected light due to the unevenness of the fingerprint. A fingerprint image capturing apparatus, wherein the width is smaller than half of the distance between the concave portions of the fingerprint, and the pitch of the prisms is smaller than the width of each pixel constituting the image capturing means. 3. The fingerprint image pickup apparatus according to claim 1, wherein the image of the human finger reflected from the optical member is directly imaged on the flat part of the optical member without passing through a condenser lens. A fingerprint image pickup device, which is formed in a spherical shape so as to form an image thereon. 4. A fingerprint image capturing apparatus according to claim 1, further comprising: a signal for performing signal processing required for fingerprint collation on an image signal of a fingerprint image obtained by the fingerprint image capturing apparatus. Processing means, based on an image signal of a fingerprint image output from the signal processing means, determines whether or not the person is a fingerprint, or detects a corresponding person from among a plurality of registered persons. And a fingerprint collation device.