JPS59142675A - Information input device of rougged face - Google Patents

Abstract

PURPOSE:To store the rugged face information of a fingerprint, an impression of a seal, or the like in a memory as the information of a distortionless orthoscopic image by using a prism, a lens system, and a detector which can pick up the image formed by this lens system. CONSTITUTION:The light irradiated from a light source 1 strikes the face 2A of a prism 2, and the information of only the contacting part of the fingerprint is inputted to the lens system 3. The image formed by the lens system 3 is focused on a screen 5. It is necessary that the screen 5 is inclined as the same angle as the face 2A of the prism 2. Thus, the distortion due to the difference of distance of the picture on the face 2A can be corrected by the inclnation of the screen 5. Consquently, the image is transduced photoelectrically by the detector such as a television camera or the like in the direction vertical to the screen 5 and is inputted as the distortionless orthoscopic image to a computer or the like.

Description

[Detailed Description of the Invention] This invention verifies the appearance of objects with uneven shapes such as fingerprints and seal stamps, and inputs them to a processing system using only a simple optical system without using ink or ink. The present invention relates to an uneven surface information input device.

Conventionally, items with uneven shapes such as fingerprints and seals are input to the processing system by recording them on paper using ink or ink, and then using a flying spot scanner (F).
The method used is to manually capture images using MS) and image sensors.

For example, in cases where fingerprints, seals, etc. are used to control entry and exit, or when qualifications are identified in cash services at banks, etc., a large number of unspecified inputs are handled, and economic efficiency and functionality are required. For such uses, this method of using ink or ink every time the user makes an input is not effective.

Particularly in the case of fingerprints, there is a need for a method for inputting data without soiling the hands.

The applicant has proposed using a prism or the like as an optical input device (see Japanese Patent Application No. 57-26154).
This has the disadvantage that when a lens system is used to penetrate the inside of the detector, the distance to the lens system is different, and when the image is captured by the detector, the image is distorted.

The optical input device proposed earlier will be further explained with reference to FIGS. 1 and 2. FIG. 1 shows an example in which a triangular prism-shaped garum like a prism is used as an object that refracts light, and a fingerprint is input as an object having uneven surface information.

In FIG. 1, 1 is a light source, 2 is a prism, 3 is a lens system, and 4 is a detector. Here, a chimp camera is used as an example. 6 is an object having uneven surface information, and a finger is shown as an example.

According to this configuration, since the surface 2A of the prism 20 is inclined, the distance to the chimp camera 4 is l between the upper and lower parts.
.

This invention aims to solve these drawbacks. The present invention will be described in detail below with reference to the drawings.

FIG. 3 is a configuration diagram showing an embodiment of the present invention. In this figure, numerals 1 to 4.6 are the same as in FIG. 1, and 5 is a screen.

Next, the operation will be explained. The light emitted from the light source 1 hits the surface 2AK of the prism 20, and only information about the contact portion of the fingerprint enters the lens system 3.

Note that this point will be discussed later.

The image created by the lens system 3 is focused on a screen 5. It is preferable that the inclination of the screen 5 is set to the same angle θ as the inclination of the two faces of the prism 20, as shown in FIG. By doing so, it is possible to correct the distortion caused by the difference in distance of the image (60 fingerprints) on the surface 2A of the prism 20 by tilting the screen 5.

In other words, when viewed from the lens system 3, the distance to the uneven surface such as a fingerprint is different at the top and bottom of the prism 2, as indicated by a and a'. If placed parallel, the image will be distorted. Therefore, by tilting the screen 5 by the same angle θ as b' and b when viewed from the lens system 3 for two people on the prism 20 surface, the image seen from the direction perpendicular to the screen 5 will be a correct image without distortion. Become a statue. Therefore, by photoelectrically converting the image from a direction perpendicular to the screen 5 using a detector such as a camera 4 as shown in FIG. 3, it becomes possible to input the image to a computer or the like in a normal image state without image distortion.

The focal length of the lens system 3 is f, the distance from the lens system 3 to the uneven surface such as a fingerprint, that is, the surface 2A is a, 'a' is the distance from the screen 5 to the lens system 3,
If b′, it can be expressed as follows.

(3) By tilting the screen 5, the magnifications n and n' become different.

When formula (3) is modified, the problem with the magnification of the present invention can be solved by increasing the distance from the prism 2 to the lens system 3.

The fingerprint information input method using the prism 2 is described in detail in Japanese Patent Application No. 57-26154 filed by the present applicant, so the principle will be explained here with reference to FIGS. 5 and 6. do.

In FIG. 5, Pa e pb and Pa indicate the vertices of the triangular surface of the prism 2, and R and Q indicate the surface 2. of the prism 2, respectively. This is a point that conceptually shows the touching and non-contacting parts of the unevenness of the fingerprint of finger 6 (Fig. 4) that is in contact with point A, and Indicates the point of incidence. θ1゜θ again!・θ3・θq is an angle indicating the angle of refraction of light from point Q. θ indicates the angle of the vertex P.

In Figure 5, if the refractive index of prism 2 is n when the refractive index of air is 1, then according to Skill's law, point Q
When light from is incident on prism 2 at an angle of 01, nainθ2-sinθ1,°, θ1 = 5in-'(-sinθr)
・・' ”・(41n Next, the angle θ when this light exits from inside prism 2 into the air
, is n sin (θ, −θ,) wsinθ3, “, θg=
sin-" (n sin (θ, -02))...
...(5) By equations (4) and (5), θB-ain-'(n sin (θ,-ain-'
(-!-5inθ,))]・・・・・・・・・(6) As can be seen from equation (6), the incident light from point Q enters the prism 2 from the air and enters the air again. The angle θ3 at which the light exits is determined by the refractive index n of the prism 2, the angle of incidence θ1, and the angle θ of the apex P.

Here, if θ1−(rad) and θ are the critical angle, then if 03 at this time is θ3Y1i, then the (6th)
From the formula, θB, 1- ain-' (nsin (θ,-5in
-"-))--(Force On the other hand, the light from point R passes through the prism 2 and exits into the air, so nainθ, = sin aB, °, θB=sin-' (nsinθ4)・・・・・・・
(8) Here, considering PeP and the plane as a reference, θ1 is the angle of the emitted light from point Q, θ is the angle of the emitted light from point R, and θ, 10, 1. −≦−θ,・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・(9) θ, −6−
θ、・・・・・・・・・・・・・・・・・・・・・
There is a relationship of (To).

From Equation (9), the light from point Q will not reach a place at an angle smaller than θ, 101 m1 m.

Now, n=1.5. When we actually calculate this angle as θ-45°, we get θ, 10amla-45°+ain-' (1,5X
gin (45°-5in-'-)) is 49.8°5. In other words, the light does not reach the region where θ<49.8°. All the symbols in the formulas up to this point correspond to those in FIG.

Here, if X→P in FIG. 5, the image of the non-contact portion cannot be seen at all in the region R4 shown by diagonal lines in FIG. 6. All other symbols in FIG. 6 are the same as in FIG. On the other hand, from equation (7), the light from the contact part (point R) in FIG. 5 is determined only by θ1, that is, the position of the chimp camera 4 and the angle θ of the vertex P1, so There are no unreachable areas in R1. Therefore, if a chimp camera 4 is provided within the region R1 as shown in FIG. 6, only the light from the contact portion (point R) can be detected.

As described above, in the uneven surface information input device of the present invention, distortion can be removed by using a prism and a lens system, and a detector capable of capturing an image formed by the lens system. Therefore, information on uneven surfaces such as fingerprints and seals is stored in the memory of a computer, etc., as information on a normal image without distortion. Fig. 1 is a schematic diagram of the configuration for explaining the optical input device proposed earlier, Fig. 2(a), (b) is a front view of a normal image and a distorted image for explaining the operation of FIG. 1, FIG. 3 is a schematic configuration diagram showing an embodiment of the present invention, and FIG. 4 is a detailed explanation of the present invention. Figure 5.

FIG. 6 is a diagram for explaining the principle of an optical input method using a prism.

In the figure, 1 is a light source, 2 is a prism, 3 is a lens system, 4 is a camera, 5 is a screen, and 6 is a finger.

Claims (1)

[Claims] A prism that inputs and inputs the uneven surface information by pressing an object having the uneven surface information onto the surface; a light source that makes light enter the prism; and a light source that emits light from the prism and includes the uneven surface information to a certain position. An uneven surface information input device comprising a lens system that forms an image, and a detector that picks up an image from an angle that allows the formed image to be viewed as a normal image.