JPS58144280A - Detection of projected-recessed surface information - Google Patents

Abstract

PURPOSE:To detect a projected-recessed surface without using ink or red seal-ink by pressing the projected-recessed surface into contact with an object having a refractive index different from that of air, irradiating the pressed and contacted surface from a light source and arranging a detector on the passage of light reflected from the contacted point of the projected and recessed surface. CONSTITUTION:A finger 4 as a projected-recessed surface is pressed to stick with the bottom of a triangle pole type glass 3 and the pressed and contacted surface is irradiated from a light source 1. If a point of the glass 3 with which the finger 4 is contacted and a point of the glass with which the finger 4 is not contacted are defined as R and Q respectively, an angle theta3 formed when light made incident from the point Q is penetrated from air into the glass 3 and then projected into air again is determined by the refrective index of the glass 3, incident angle theta1 and the angle theta2 of the point P2 of the triangle pole. Since light from the point R is penetrated through the glass 3 and projected into air, the passage of light from the point R is included in an area R1. When a detecting part 2 is arranged in an area R1 having the passage of light from the point R, and do not having the passage of light from the point Q to penetrate no light from the light source 1, the fingerprint of the finger 4 can be detected only by an optical means without using ink or red seal-ink.

Description

[Detailed Description of the Invention] The present invention is capable of verifying the appearance of uneven objects such as fingerprints and seals, and inputting them to a processing system using only a simple optical system without using ink or ink. The present invention relates to a method for detecting uneven surface information.

Conventionally, when inputting objects with uneven shapes such as fingerprints and seals to the processing system, they are recorded on -1 paper using ink or vermilion, and then sent to a flying spot scanner (F1).
We use the method of taking pictures using a) or an image sensor.

For example, use fingerprints, seals, etc. to check the entrance and exit points! For applications that handle a large number of indefinite inputs and require economic efficiency and functionality, such as when performing 11I or identifying qualifications for bank cash services, etc., engineering is recommended. However, it is not effective to use ink or ink every time you input data. In the case of tWIVc fingerprints,
We need a way to input data without getting our hands dirty.

In order to solve these problems, the present invention aims to detect information on an uneven surface using only a simple optical system that uses ink or ink.

This invention will be explained below.

FIG. 1 is a diagram showing an embodiment of the present invention.

Figure 1 shows an example in which a triangular prism-shaped glass like a prism is used as an object that refracts the object, and a fingerprint is input as an uneven surface. In the figure m1, 1 is a light source, 2 is a detection unit, 3 is a triangular prism-shaped glass, and 4 is a glass.

'The operation source il&- in Fig. M1 will be explained using Fig. 2.

In the JA2 diagram, Pa p Ph a Pa is the tal
R and Q are conceptually shown points of the object that is in contact with the contact i1 of the triangular prism glass 3 in Fig. 1 and the object that is not in contact with it, respectively. , X indicates the point where the light from point Q enters the triangular prism glass 3, '1 e θ■, θs, 0° indicates the angle of refraction of the light from point Q, and θ reef, θ,.

-2 indicates the angle of refraction of light from point 8. Tayshi, O,
# is the angle between plane p and a plane parallel to p, 0. indicates the vertex P and the angle. In other words, FIG. 2 is a three-dimensional model of FIG. 1.

Therefore, points R and Q model the contact portion and non-contact portion of the fingerprint when the finger 4 shown in FIG. 1 is pressed.

In the second Ill, if the refractive index of the triangular prism glass 3 is n when the refractive index of air is 1, then according to Snell's law, when the element from the point Q is incident on the triangular prism glass 3 at an angle of 51m1. =aFishl#1,",#m=5ln-" (-LainL)+++・
＋＋＋＋・ITL Cram School Next, what is the angle when this light exits from inside the triangular prism glass 3 into the air? l sin (#, -#1)=sln#s-'-#
s=sim-”(11sim(#,-(ls))-(
2) From the +1+ equation and the equation (2), θm=m1n-' (n 5Sn(θ, -*ln-"
('slnθ1)))-(:l)m (3) As can be seen from equation 5, the angle at which the incident light from point Q enters the triangular prism glass 3 from the air and exits into the air again. θ is the angle θ between the refractive index n of the triangular prism glass 3, the angle of incidence 01, and the vertex P.

Determined by K.

Here, as θ, →y(rid), if “#” is the critical angle, and θ of this meeting is Lmin, then (3)
From the formula, θmm1n=sin-'in 5in(θ, -s
ln-” ” ) ) −... (41 On the other hand,
Regarding the light from point R, it passes through the triangular prism glass 3,
Since it escapes into the air, n sin194==s1M1#.

, °, θ5=sin-'(msln θ4)
・−・−−−・−・(51 Here, considering p, p, plane as a reference, the angle of the light emitted from point Q is 0.
Letting the angle of the emitted light from point R be θ, θs +Rxm1m<θ, ・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・(6) 0, -θ, =θ,
... old... old... old... (7
).

From equation (6), the light from point Q is θ, +θmmI n
Areas with smaller angles will not be suitable for sea bream. Now, n
=115+#, =4! If we actually calculate this angle by 1 as I', then from equation (4), #, 10, m1m = 4! l'+min" (1,5
41.8 in X@1n (41S°-min-'M)
('), that is, the party must reach the region where e<49.8°. All the symbols in the formulas up to this point correspond to 〇 in the 1511th equation.

Here, if X4P is shown in FIG. 3, then in the area R and IC shown by diagonal lines in FIG. 3, the non-contact portion cannot be seen at all. All other symbols in Figure 3 are 1I1
．． This is the same as in Figure 2. On the other hand, from equation (7), the origin from the contact part (point R) in the figure is CI, that is, the position of the detection part 2 and the vertex P.

Angle 0. Since it is determined only by
There is no unreachable area in
) can only detect parties from

The problem here is the influence of the light source 1.

This will be explained using FIG. In Ma 4 figure, P,
,P,,PI indicates the position of light source 1. Now, light source 1 is P
When in position l, the fingerprint contact surface p, p.

By total reflection at plane i1, and if at position P, by total reflection at plane P, P,
In addition, when the position P is 11, the light from the light source 1 directly reaches the detection part 2, making it difficult to detect the difference in brightness between the contact part and the non-contact part.

Therefore, the light source 1 is exposed to the contact surface Ik from the same side as the detection unit 2.
It must be installed in a position where the total reflected light or the light from the light source 1 does not immediately enter the detection unit 2, and
As shown in FIG. 5, as a means to block the incidence of light from the position shown in FIG. 1, for example, P in the IK4 diagram, it is effective to paint P, P, flat black. C in FIG. S indicates a light blocking coating.

As explained above, it is dark because the light from the non-contact area cannot reach the area, the influence of the light source 1 is suppressed, and the light from the contact area is viewed from a place where it can be received. Inside, only the image of the raised part of the fingerprint appears bright and vivid. That is, by placing the detection unit 1 at this position, information about the uneven surface of the fingerprint can be obtained. By configuring the detection unit mainly using a 2v lens and an image sensor such as a CCP, high-speed imaging of this uneven surface information becomes possible.

The unevenness of the fingerprint obtained in this way is compressed in one direction. There is, and if you need correction, you can easily make corrections.

As the uneven surface, input something that is less flexible than a fingerprint, such as a seal, in row 511.The object to which the uneven surface is pressed must be made flexible to ensure contact between the protrusions. There are two possible methods for this IK. One method is to interpose a thin object such as transparent rubber-like plastic or PVC between the uneven surface and the object, as shown in Figure 6, and the other method is to press the uneven surface. The object itself is made of V-flexible material with a value of 0 or more, and in the case of a seal, the same input as a fingerprint can be made. In FIG. 6, S is a flexible material and 6 is a seal.

Regarding the shape of the object shown in the triangular prism glass 3 in Figure 1, the existence of the 1; L plane and the P, P, plane shown in Figure 2 is required, and the shape of the p, p, plane is not particularly stipulated. However, attention must be paid to the influence of the light source 1 mentioned above.

In addition, the lens shape as shown in Figures 1g7 (a) and (b) K,
Objects in the shape of a rectangular prism or a combination of these shapes can be used. All of these are designed depending on the positional relationship of the light source and the detection unit when configuring the device.

%, the object shown in FIG. 7 has the advantage of being placed above the light source.

In addition, the triangular prism-shaped glass 10 in the above embodiment has an arc-like shape or the like formed into which the finger 4 is invaginated at an appropriate position on the surface to which the finger 4 is pressed, that is, in FIG. 2, P, P, plane. If it is set, the positioning of the finger 4 becomes a tool, and the detection part 1
This means that the fingerprint image is input at the same position, which facilitates signal processing. This is also true when using the objects shown in Figure 7 (aL, (b) and K).

As described above, the present invention uses an object such as a glass body that has an optically different refractive index from air.
It is possible to input a fingerprint image using only a simple optical system. Therefore, in the case of a seal, input can be made in the same way as for a bald person.

This has the advantage of not being affected by smudges or smudges compared to conventional input using ink or vermilion, and is highly functional, compatible, and versatile, and can be used in a variety of ways. Possible Applications 6 For example, fingerprints can be combined with the research results of fingerprint fixation that have been carried out by various institutions to be used for qualification identification at immigration controls, bank online services, etc. Furthermore, with regard to seals, it is possible to streamline the process of verification and registration, and improve the identification rate.

[Brief explanation of drawings]

Fig. 1 is a diagram showing a case where a fingerprint is input using a triangular prism glass as an embodiment of the present invention, Figs. 2 and 3 are diagrams explaining the principle of this invention, and Fig. 4 is an example of the shadow of a light source. An explanatory diagram of
FIG. 5 is an explanatory diagram of the light cutting process, FIG. 6 is a diagram when a seal is used, and FIG. 7 is a diagram of an object to which an uneven surface is pressed. In the figure, 1 is a light source, 1 is a detection unit, S is a triangular prism glass, 4
is the finger, i is the flexible material, 6 is the seal, P,. pb, p is the vertex of the triangular surface of the triangular prism glass, θ1
゜θ,, θ8. θ4. o, θ1. θ1. θ, "mln is the angle of refraction of light, θ is the angle of the vertex P, R is the point where the object is in contact, Q is the point where the object is not in contact, C is the coating, Pi e Pg t p, is the position of the light source, R
1 is an area where the light from the non-contact part does not reach, and X is the point of incidence from point Q on the triangular prism glass. Figure 3 Figure 4 Figure 5 Figure 7 (a) (b)

Claims (1)

[Claims] An uneven surface as input information is pressed onto an object that transmits through the fll source and has an optical refractive index different from that of air, and a light source is used to irradiate the uneven surface. A detection unit is located in the passage of light from the part that contacts the willow arrangement body, and is not located in the passage of light from the part where the uneven surface does not come into contact with the recording object. This is a method for detecting uneven image information. (The party from zi jtfjg is the boundary between the object and the air W
Claim 1, characterized in that the light source is installed at a position where the light source does not enter the detection unit due to total reflection at the iK! [The uneven surface information detection method described in (1). (3) A method for detecting uneven surface information according to claim 11, characterized in that the light source is installed so that the source from the light source does not directly enter the detection unit. (4) Object Do not use a triangular prism-shaped object as an object! #Mold (claim 11) The method for detecting uneven surface information according to claim 11. Claim 11 (The method for detecting uneven surface information according to claim 11)