JPH0648494B2 - Uneven surface information input device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] There is a case in which it is erroneously determined that information input in a fingerprint sensor for collating / identifying an individual is distorted. Therefore, a spherical protrusion is provided in the portion where the finger is brought into close contact with the finger to reduce the distortion generated in the fingerprint image when the finger is moved.

[Industrial application field]

The present invention relates to an individual collation system for collating / identifying individuals based on irregular surface information such as fingerprints, and more particularly to an irregular surface information input device that reduces distortion occurring in an input image and facilitates discrimination of imitation products.

In recent years, computers have been introduced into a wide range of social systems, and along with this, attention has been focused on how to secure system security. For example, many questions have been raised in terms of ensuring security for the ID cards and passwords that have been used so far as means for verifying the identity when entering a computer room or using terminals. On the other hand, fingerprints, which have the two major characteristics of universality and invariability throughout life, are considered to be the most effective means for identifying an individual, and much research and development has been conducted on a simple personal identification system using fingerprints.

However, the fingerprint image formed on the soft skin may be deformed when the skin is pulled in one direction, and the shape of the fingerprint image or the interval between stripes showing the characteristics may be different from the original shape. The fingerprint image input in this state is different from the fingerprint image registered in advance,
As a result of collating the two fingerprint images, it is determined that they are completely different fingerprints, which causes an erroneous determination.

Further, the fingerprint image can be directly copied from the already registered fingerprint image of the individual, and a finger imitation product can be easily formed by using gypsum or resin. It is also possible to indirectly form a replica of a finger from a fingerprint image or the like registered in advance.

There is no deformation in the input fingerprint image,
Moreover, it is desired to develop an uneven surface information input device capable of easily discriminating imitation products.

[Conventional technology]

FIG. 3 is a principle diagram showing a conventional example of an uneven surface information input device, and FIG. 4 is a principle diagram showing another conventional example of an uneven surface information input device.

The uneven surface information input device shown in FIG. 3 has an information input unit 2 for bringing the subject 1 into contact with it, a light source 3 for irradiating the subject 1 via the information input unit 2, and an object input from the information input unit 2. The information input unit 2 includes an image pickup device 4 for converting an uneven surface image of the specimen 1 into an electric signal.
And a hologram 23 that guides an uneven surface image of the subject 1 propagating through the transparent flat plate 22 to the outside of the transparent flat plate 22.

When the subject (finger) 1 is brought into contact with the input surface 21 with an appropriate pressing force, the convex portion 11 directly comes into contact with the input surface 21, but the concave portion 12 and the input surface 21.
An air layer is present between 21. Therefore, the light that has passed through the transparent flat plate 22 from the light source 3 and reaches the recess 12 is reflected by the recess 12 and re-enters the transparent flat plate 22 from the input surface 21, and then from the surface opposite to the input surface 21 according to Snell's law. Emit to the air layer.

On the other hand, the light reaching the surface with which the convex portion 11 abuts is scattered at the corresponding contact interface, and a part of the reflected light is emitted from the surface on the reflection side of the input surface 21 to the air layer. The light incident on the interface between the transparent flat plate 22 and the air layer is totally reflected at the interface, propagates inside the transparent flat plate 22, and is guided to the outside by the hologram 23. The image composed of the reflected light that is guided to the outside via the hologram 23 is an image representing the convex portion 11, that is, a fingerprint image, and the fingerprint image can be input by capturing the image with the imaging element 4.

In addition, the uneven surface information input device shown in FIG. 4 is derived from the information input unit 2 that abuts the subject 1, the light source 3 that illuminates the subject 1 via the information input unit 2, and the information input unit 2. The information input unit 2 is composed of a transparent prism 25 having an input surface 21 with which the subject 1 is brought into contact with the image pickup device 4 for converting an uneven surface image of the subject 1 into an electric signal.

When the subject (finger) 1 is brought into contact with the input surface 21 with an appropriate pressing force, the convex portion 11 directly comes into contact with the input surface 21, but the concave portion 12 and the input surface 21.
An air layer is present between 21. In this state, the light that has passed through the transparent prism 25 from the light source 3 and reached the surface with which the convex portion 11 is in contact is absorbed by the contact surface of the convex portion 11 and is not reflected toward the image pickup element 4. On the other hand, the light that has reached the interface between the air layer interposed between the recess 12 and the input surface 21 and the transparent prism 25 is totally reflected at the interface and guided to the image pickup device 4.
The image composed of the reflected light led out from the transparent prism 25 is an image representing the concave portion 12, that is, a fingerprint image, and the fingerprint image can be input by capturing the image with the image pickup device 4.

[Problems to be solved by the invention]

FIG. 5 is a diagram showing a problem in the conventional uneven surface information input device.

In the conventional concave-convex surface information input device, the input surface 21 of the transparent flat plate 22 on which the subject 1 is brought into contact is flat, and the subject 1 can be shifted to the left or right while the subject 1 is brought into contact with it. However, the fingerprint image formed on the flexible skin is deformed when the skin is pulled in one direction, and for example, the fingerprint image originally having the shape shown in Fig. 5 (a) is shown in Fig. 5 (b) or 5 ( It becomes the shape shown in c). Therefore, the fingerprint image input in this state is different from the fingerprint image registered in advance, and causes an erroneous determination such as being determined as another person by collation. Even if the subject 1 is an imitation product having no elasticity unlike a finger, if the same fingerprint image as the already registered personal fingerprint image is formed on the surface, the input fingerprint image is an imitation product. There was a problem that it was difficult to determine what was there.

[Means for solving problems]

FIG. 1 is a principle view showing an uneven surface information input device of the present invention.

The above-mentioned problems are caused by the information input unit 2 that brings the subject 1 into contact,
A light source 3 for irradiating the subject 1 via the information input unit 2 and an image sensor 4 for converting an uneven surface image of the subject 1 derived from the information input unit 2 to an electric signal and outputting the electrical signal. ,
Moreover, the input surface 21 of the information input section 2 for contacting the subject 1
In addition, the uneven surface information input device of the present invention, which is formed by forming the spherically-shaped protrusions 24, is solved.

[Action]

In FIG. 1, an information input unit 2 for contacting the subject 1
By forming the spherically-shaped protrusion 24 on the input surface 21, even if the subject 1 is brought into contact with the protrusion 24 and is displaced to the left or right, the portion that is in contact with the protrusion 24 is deformed. The fingerprint image on the outer side of the part, which is in contact with the protrusion 24, is not deformed. Therefore, it is possible to eliminate erroneous determination such as determination as another individual by collation. Further, when the subject 1 is an imitation product having no elasticity like a finger, even if a fingerprint image is formed on the surface, the input fingerprint image is different from the original one and the imitation subject 1 can be easily manufactured. Can be determined.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to FIG. Note that FIG. 2 is a principle view showing another embodiment of the present invention, and the same object is denoted by the same symbol throughout the drawings.

The uneven surface information input device according to the present invention shown in FIG. 1 is different from the uneven surface information input device shown in FIG. 3 in that the uneven surface information input device according to the present invention is applied to the subject 1 of the information input unit 2. This is because the input surface 21 to be brought into contact is formed with a spherical projection 24. By thus forming the spherically-shaped protrusion 24 having a size of sinking the subject 1 on the input surface 21 with which the subject 1 is abutted, the subject 1
The position on the input surface 21 for contacting the
Opportunity to shift left and right with abutting is reduced.

Further, when the projection 24 sinks into the test object 1, the test object 1 that is in contact with the projection 24 is stretched, and appropriate stress is applied to the skin of the part in advance, so that the test surface is in contact with the input surface 21. Even if the subject 1 is shifted to the left or right, what is deformed is the fingerprint image outside the portion in contact with the protrusion 24.
The fingerprint image of the portion in contact with the protrusion 24 is not deformed.

Further, when the subject 1 is a dummy product that is not elastic like a finger, the protrusions 24 do not sink into the subject 1 even if a fingerprint image is formed on the surface thereof, and therefore the input fingerprint image is originally Different from the above, the imitation subject 1 can be easily discriminated.

The uneven surface information input device according to the present invention shown in FIG. 2 is different from the uneven surface information input device shown in FIG. 4 in that the uneven surface information input device according to the present invention is applied to the subject 1 of the information input unit 2. This is because the input surface 21 to be brought into contact is formed with a spherical projection 24. By forming the spherically-shaped protrusion 24 having a size that sinks into the subject 1 on the input surface 21 with which the subject 1 is brought into contact, the uneven surface information input device shown in FIG. You can get exactly the same effect.

〔The invention's effect〕

As described above, according to the present invention, it is possible to provide a concavo-convex surface information input device in which distortion generated in an input image is reduced and discrimination of an imitation product is facilitated.

[Brief description of drawings]

1 is a principle view showing an uneven surface information input device of the present invention, FIG. 2 is a principle view showing another embodiment of the present invention, FIG. 3 is a principle view showing a conventional example of an uneven surface information input device, FIG. 4 is a principle view showing another conventional example of the uneven surface information input device, and FIG. 5 is a diagram showing problems in the conventional uneven surface information input device. In the figure, 1 is a subject, 2 is an information input section, 3 is a light source, 4 is an image sensor, 11 is a convex section, 12 is a concave section, 21 is an input surface, 22 is a transparent flat plate, 23 is a hologram, 24 is a protrusion, 25 Represents a transparent prism, and, respectively.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hiroyuki Ikeda 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited (72) Inventor, Yushi Inagaki 1015, Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited

Claims (3)

[Claims] 1. An information input unit (2) for contacting a subject (1)
A light source (3) for irradiating the subject (1) through the information input unit (2), and an uneven surface image of the subject (1) derived from the information input unit (2) to the outside. Is provided with an image pickup device (4) for converting into an electric signal and outputting the signal, and the input surface (21) of the information input part (2) to which the subject (1) is abutted is raised in a spherical shape. An uneven surface information input device, characterized in that the projections (24) are formed. 2. A transparent flat plate (22) having a hologram (23) as means for deriving an uneven surface image of a subject (1) to the outside, as an information input unit (2). The uneven surface information input device described. 3. The uneven surface information input device according to claim 1, wherein the transparent prism (25) is used as the information input section (2).