JPH05174134A - Optical device - Google Patents

Abstract

PURPOSE:To reduce the size and cost of device by converting light received with a light receiving means arranged along the longitudinal direction of a subject to be checked into a 1-dimensional image in the longitudinal direction of a finger by means of the successive addition of a 'black' part in the shorter direction of a finger. CONSTITUTION:By making a finger 6 contact with the contact surface between a prism 5 and the finger 6 so that approximate center of a nail can coincide with a mark, an image diffusedly reflected by the finger 6 on the contact surface between the prism 5 and the finger 6 is formed on a line sensor 9 via a cylindrical lens 10. At this time, since only the reflection light in the shorter direction of the finger 6 is collected on the line sensor 9 by the cylindrical lens 10, the light received by one element of the line sensor 9 is equivalent to a value obtained by adding the 'black' part in the shorter direction of the finger 6, for example. The light received by each element of the line sensor 9 arranged along the longitudinal direction of the finger 6 is the 1-dimensional image in the longitudinal direction of the finger which is obtained by successive adding the 'black' part in the shorter direction of the finger 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device used in a finger collation device or the like.

[0002]

2. Description of the Related Art In order to prevent leakage of corporate secrets, it is necessary to confirm the identity of a person when entering or leaving an important facility or managing access to a computer.

A finger collating device is one of the devices for confirming the person.

With the finger collating device, the fingerprint characteristics of each person are registered in advance together with the password, and the fingerprint characteristics and password of the person himself / herself are entered when entering / leaving the room, and the registered fingerprint characteristics are input. This is to check the characteristics of the fingerprint.

By the way, as a device for inputting the characteristics of a fingerprint, for example, there is a conventional finger image input device shown in FIGS. 3 and 4.

In these drawings, reference numeral 1 denotes a prism which comes into contact with a finger 2. Light is emitted from a lamp 3 from a surface facing a contact surface with the finger 2 in a direction of an angle θ larger than a critical angle of the prism 1. An image of a finger is obtained by the TV camera 4 arranged.

FIG. 5A shows such a television camera 4 as described above.
It is an image of a finger that is black-and-white inverted after being imaged by.

This finger image is a one-dimensional image in the longitudinal direction of the finger as shown in FIG. 5B by sequentially adding the "black" portions in the lateral direction of the finger.

This one-dimensional image is a characteristic of a fingerprint and is used for collation by a finger collating device. However, since such a finger image detecting device captures an image of the entire finger using a television camera, it requires a predetermined distance that is determined by the optical magnification and the focal length, which reduces the size of the device. Making it difficult.

Moreover, the television camera itself and the signal processing circuit for one-dimensional image processing have led to an increase in size and cost of the device.

[0011]

As described above, the finger image detecting device used in the finger collating device has a problem that it is large and expensive because it is premised on image processing.

The present invention has been made to solve such a problem, and an object thereof is to provide a small-sized and low-priced optical device.

[0013]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an irradiation means for irradiating a long object to be inspected with light and a longitudinal arrangement of the object to be inspected. The light receiving means for receiving the reflected light from the inspection object and the light receiving means interposed between the inspection object and the light receiving means, and only the reflected light in the lateral direction of the inspection object is received by the light receiving means. And a light collecting means for collecting light.

[0014]

In the present invention, only the light reflected in the lateral direction of the object to be inspected is focused on the light receiving means. The light received by the light receiving means corresponds to, for example, a value obtained by adding the "black" portion in the lateral direction of the finger described in the conventional example.

The light received by the light receiving means arranged along the longitudinal direction of the object to be inspected is one-dimensional in the longitudinal direction of the finger formed by sequentially adding the "black" portions in the lateral direction of the finger. It becomes an image.

Therefore, according to the present invention, the above one-dimensional image can be obtained without the television camera for picking up the image of the finger and the signal processing circuit for one-dimensional image processing.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 show an optical device according to an embodiment of the present invention.

In these figures, reference numeral 5 is a prism which comes into contact with the finger 6. A mark 7 is provided at a predetermined position on the contact surface of the prism 5 with the finger 6. The mark 7 serves as a guide when the finger 6 comes into contact with the prism 5, and the following light receiving system is provided so that an optimum image can be obtained when the finger is brought into contact so that the center of the nail coincides with the mark 7. Are arranged.

On the surface of the prism 5 facing the contact surface with the finger 6, a lamp 8 for radiating light toward the contact surface with the finger 6 is arranged.

In the direction of an angle θ larger than the critical angle of the prism 5, a contact type line sensor 9 for receiving the reflected light from the contact surface with the finger 6 is arranged along the longitudinal direction of the finger 6. The resolutions of the line sensor 9 in the longitudinal direction and the lateral direction are determined by the accuracy required for collating the finger images.

Between the prism 5 and the line sensor 9,
A cylindrical lens 10 that focuses only the light reflected in the lateral direction of the finger 6 on the line sensor 9 is inserted.

The line sensor 9 and the cylindrical lens 10 have a length up to the knee of the finger 6 in the longitudinal direction or a length longer than that.

Further, the left slope of the prism 5 in FIG. 1 is subjected to antireflection treatment. This is because on the contact surface of the prism 5 with the finger 6, the light is totally reflected at the portion where the finger 6 does not contact, and the line sensor 9 receives the light from the left slope of the prism 5 in FIG.

Next, the operation of the optical device constructed as described above will be described.

On the contact surface of the prism 5 with the finger 6,
The finger 6 is brought into contact so that the center of the nail coincides with the mark 7.

Then, the image diffusely reflected by the finger 6 on the contact surface of the prism 5 with the finger 6 is formed on the line sensor 9 via the cylindrical lens 10.

At this time, since only the light reflected in the lateral direction of the finger 6 is focused on the line sensor 9 by the cylindrical lens 10, the light received by one element of the line sensor 9 is, for example, a conventional example. This corresponds to the value obtained by adding the “black” portion in the lateral direction of the finger described in 5. That is, finger 6
The total length of the convex portions of the fingerprint in the short-side direction is output as a voltage value from one element of the line sensor 9.

The light received by each element of the line sensor 9 arranged along the longitudinal direction of the finger 6 is obtained by sequentially adding the "black" portions in the lateral direction of the finger 6 to the longitudinal direction of the finger. It becomes a one-dimensional image in the direction.

Therefore, in this optical device, the television camera for picking up the image of the finger and the signal processing circuit for one-dimensional image processing are eliminated, and the one-dimensional direction of the finger in the longitudinal direction shown in FIG. 5B is shown. An image is obtained.

[0031]

As described above, according to the present invention, a television camera for picking up an image of a finger and a signal processing circuit for one-dimensional image processing are eliminated, so that a one-dimensional image in the longitudinal direction of the finger can be obtained. It is possible to reduce the size and cost of the device.

[Brief description of drawings]

FIG. 1 is a front view of an optical device according to an embodiment of the present invention.

FIG. 2 is a perspective view of FIG.

FIG. 3 is a side view of a conventional finger image input device.

FIG. 4 is a front view of FIG.

FIG. 5 is a diagram showing outputs of respective units of a conventional finger image input device.

[Explanation of symbols]

5 ... Prism, 6 ... Finger, 8 ... Lamp, 9 ... Line sensor, 10 ... Cylindrical lens.

Claims (2)

[Claims] 1. An irradiation unit for irradiating a long-shaped object to be inspected with light, and a light-receiving unit arranged along the longitudinal direction of the object to be inspected for receiving reflected light from the object to be inspected. An optical device, which is interposed between the object to be inspected and the light receiving means and condenses only the light reflected in the lateral direction of the object to be inspected on the light receiving means. apparatus. 2. A finger collation device for collating registered fingerprint features with inputted fingerprint features, wherein the optical device according to claim 1 inputs the fingerprint features. .