JPS61233889A - Paper money discriminator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention 1] The present invention relates to a banknote inspection device that determines the integrity of banknotes.

[Technical background of the invention and its problems] In general, inspection of banknotes involves determining the type of banknote to determine the type of banknote, authenticity determination to determine whether the banknote is genuine or not, and whether the banknote can be recirculated. There is a fitness determination method that determines whether a bill is genuine or a soiled, unfit bill that cannot be recirculated. Conventionally, these distinctions have been made manually, but recently a banknote inspection device that automatically makes these distinctions has been developed and is in actual use.

Among these types of discrimination, a method using transmitted light as shown in FIG. 10 is conventionally known as one means of determining whether the product is good or not. In the figure, 1 is a banknote to be inspected, 2 is a light source, 3 is a light receiving element, and 4 is a discrimination section. A portion of the light irradiated onto the banknote 1 from the light source 2 passes through the banknote 1 and enters the light receiving element 3 . The light receiving element 3 outputs an electric signal S depending on the intensity of the incident light. That is, if the banknote 1 is not soiled, the transmitted light will be strong and the output signal S will be large; on the other hand, if the banknote 1 is soiled, the transmitted light will be weak and the output signal S will be small. The determining unit 4 estimates the degree of dirt on the banknote 1 by looking at the magnitude of the output signal S of the light receiving element 3, and determines whether the banknote is good or not.

Furthermore, as another means, a method using reflected light as shown in FIG. 11 is known. This method uses the same principle as the method using transmitted light in Figure 10, except that the intensity of reflected light from the banknote 1 changes depending on the degree of dirt on the banknote 1. It is for making a judgment.

However, in these systems, the intensity of transmitted light and reflected light not only changes depending on the dirt on the banknote, but also changes depending on the thickness of the banknote and the thickness of the banknote paper. especially,
This tendency is remarkable in transmitted light. Therefore, if there are variations in the thickness of banknotes, changes due to dirt will be buried under changes due to thickness, making it difficult to accurately determine whether the banknotes are good or not.

[Object of the Invention] The present invention has been made in view of the above-mentioned circumstances, and its purpose is to be able to perform highly accurate fitness determination that is not affected by thickness, and at the same time to be able to perform thickness determination. It is an object of the present invention to provide a banknote inspection device that can perform the following operations.

[Summary of the Invention] In order to achieve the above object, the present invention uses a plurality of light rays with different wavelengths, and determines the degree of dirt, thickness, etc. of a banknote from the difference in the physical characteristics of the banknote paper with respect to those light rays. It is composed of

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

In the present invention, the conventional measurements shown in FIGS. 10 and 11 are simultaneously performed using a plurality of light beams having different wavelengths. Now, when performing measurements based on the present invention, the wavelength is λA.

It is assumed that two types of light rays are used, λB (λA≠λB). First, measurement is performed using the apparatus shown in FIG. 10 using a light source that emits a light beam of wavelength λA. At this time, the thickness of the banknote 1 and the degree of dirt are known in advance, and the thickness t of the banknote is taken on the horizontal axis and the degree of dirt d is taken on the H axis.
Points (t, d) on the graph having the same photodetector output SN
), Figure 1 is obtained. That is, the first
The graph in the figure represents a group of equal transmission light quantity curves for a light beam of wavelength λA. In Figure 1, S^=SA1°SA2
, SA3 are shown, but the light receiving element output S
Considering that SA1, SA2, and S become smaller when the thickness t is large and when the degree of dirt d is large,
The magnitude relationship of As is SAI<SA2<SAs.

Next, similar measurements are performed on a light source that emits a light beam of wavelength λB, and FIG. 2 is obtained. The graph in Figure 2 shows the wavelength λB
represents a group of equal transmission light quantity curves for the light rays. As in FIG. 1, Sol<SB2<SB:l. Since the wavelength characteristics of the banknote 1 are different, the graphs in FIG. 1 and FIG. 2 are different.

Finally, similar measurements are performed on a banknote whose thickness and degree of dirt are unknown using a light source that emits two types of light beams with wavelengths λA and λB. If the output of the light receiving element for a light beam of wavelength λA is SAO, then from the group of curves in Fig. 1, SA
= SAO is selected. Similarly, if the light-receiving element output of the light beam of wavelength λB is SBO, the curve 5B=SBO is selected from the group of curves shown in FIG. FIG. 3 shows these two selected curves drawn on the same graph. These curves always intersect at one point, and the coordinates (to
, do) represent the thickness and degree of staining of the banknote to be measured. This means that t and d are determined independently of each other. This is a mapping from the two measured values SA and SB to (t, d), using the function f (t, d) = f (SA, 8B>...
1). Here, the function f is uniquely determined by the two graphs in FIG. 1 and FIG. 2.

FIG. 4 shows one embodiment implementing the invention.

In the figure, 2A and 2B each represent a wavelength λA.

A light source 3A emits a light beam of λB (λA≠λB).

3B are emitted from the lights aif2A and 2n, respectively, and the banknote 1
5 is a light receiving element 3A that receives the light beam transmitted through the
, 3B is a converting section that converts the outputs SA, SB into signals of t and d, and 6 is a discriminating section that discriminates whether it is normal or not and whether it is genuine or false. The conversion unit 5 performs conversion based on the conversion formula shown in equation (1) above.

The operation of this device is as described above.

FIG. 5 shows another embodiment of the invention. In the figure, 7 is a light source that emits light beams containing at least two types of wavelengths λA and λB, and 8 is a half mirror 19A that reflects and transmits the light beams that have passed through the banknote 1.
An optical filter 9B passes only the light beam A, and an optical filter 9B passes only the light beam of wavelength λB that has passed through the half mirror 8.The other parts are the same as in FIG.

FIG. 6 shows yet another embodiment of the invention. While FIG. 4 uses transmitted light, FIG. 6 uses reflected light.

FIG. 7 shows one simplified embodiment of the invention. In the figure, 21R is an infrared light source, 2BL is a blue light source, and 3
1R is an infrared light receiving element, 3BL is a blue light receiving element, 10
1 is a converting section, and 11 is a discriminating section. Infrared and blue light are the 8th
It exhibits the characteristics shown in the figure, with a large response to dirt in blue light and a small response to infrared light. However, similar characteristics (inclination in FIG. 8) are shown for the thickness of banknotes. Conversion part 1
0, each output 5IRISB of the light receiving elements 31R and 3BL
Calculate 5=SBL/SIR by L. Figure 9 is the 8th
It shows the SBL/SIR characteristics obtained from the figure. S does not vary greatly with changes in banknote thickness. Therefore, it can be used in cases where the thickness of banknotes varies and there is no need to measure the thickness, and the converter 10 can be realized with a simple configuration.

With this configuration, it is possible to perform highly accurate fitness determination that is not affected by the thickness of the banknote, and also to determine the thickness at the same time as the fitness determination.
Effects such as the ability to use the determination results to determine authenticity can be obtained.

In addition, in the above embodiment, only the combination of two types of light beams was explained, but it goes without saying that by using three or more types of light beams, it is possible to perform a more accurate fitness/failure determination. That's true.

[Effects of the Invention] As detailed above, according to the present invention, there is provided a banknote inspection device which is capable of performing highly accurate determination of whether or not it is unaffected by thickness, and which is also capable of determining thickness at the same time. can be provided.

[Brief explanation of drawings]

1 to 4 are for explaining one embodiment of the present invention. FIG. 1 is a characteristic diagram showing a group of equal transmission light quantity curves for a light beam of wavelength λ^, and FIG. A characteristic diagram showing a group of equal transmission light quantity curves for light rays, Fig. 3 shows the coordinates to
, and FIG. 4 is a block diagram showing one embodiment of the present invention. FIGS. 5 and 6 are block diagrams showing other embodiments of the present invention, and FIG. 7 is a configuration diagram showing one simplified embodiment of the present invention, FIGS. 8 and 9 are characteristic diagrams for explaining the embodiment of FIG. 7,
FIG. 10 and FIG. 11 are configuration diagrams for explaining a conventional banknote inspection device, respectively. 1...Banknote, 2A, 2s, 7.21R, 2BL
・・・・・・Light source, 3A', 3e, 31R, 3BL...
. . . Light receiving element, 5.10 . . . Conversion unit, 6.
11...discrimination section, 8...half mirror
19A, 9B... Optical filter. Agent Patent Attorney Noriyuki Chika (and 1 other person) Figure 6 Figure 10 Figure 11 r! A. Procedural amendment (spontaneous) 1. Indication of the case Patent Application No. 1987-73419 2. Name of the invention paper customary examination device 3. Person making the amendment Relationship with the case Patent applicant (307) Toshiba Corporation 4 , Agent Address: Toshiba Corporation Head Office, 1-1 Shibaura-chome, Minato-ku, Tokyo 105 (1) Column 6 of the detailed explanation of the invention in the specification, Contents of the amendment (1) Page 5 of Mei II Book Lines 12 to 18 [
Now, according to the present invention, the thickness of banknotes is changed to ``2 types of light beams are used to measure the thickness of banknotes based on the present invention, and the wavelengths of these light beams are λ^, λB (λ^ ≠λB)
Assume that First, the measurement using the apparatus shown in Fig. 10 is carried out at wavelength λ.
Use a light source that emits ^ rays. This is done on a large number of banknotes whose thickness and degree of dirt are known in advance. The horizontal axis is the thickness of the banknote]. (2) Click "Then, Figure 1" in the first line of page 6. As a result, Figure 1 is corrected. (3) Page 6, line 4 [Three cases are shown,
" is corrected to "Although only three cases are shown, in reality there are countless curves." (4) Correct "thing" in the 20th line of page 6 and the 3rd line of page 7 to be "curve". (5) rs on page 9, line 5 = sa t /St t
Correct J as [r −3a L /St tt J. (6) In the seventh line of the same line, "S is a graph that indicates.""r" is corrected. (7) Correct the "thickness" in the 12th line of page 9 and the 2nd line of page 10 by "change in thickness." (8) Figure 9 of the drawings shall be amended as shown in the attached sheet. that's all

Claims (7)

[Claims] (1) A light source that irradiates a banknote with a plurality of light beams of different wavelengths, a plurality of light receiving elements that respectively receive each light beam from the banknote and convert it into an electrical signal, and an output signal of each of these light receiving elements 1. A banknote inspection device characterized by comprising a discriminating means for determining the degree of dirt, thickness, etc. of a banknote. (2) The banknote inspection device according to claim 1, wherein there are two light sources, one of which emits infrared rays and the other light source emits visible rays. (3) The banknote according to claim 1, wherein there are two light sources, one of which emits infrared light, and the other light source emits light with a shorter wavelength among visible light. Inspection equipment. (4) The banknote inspection device according to claim 1, wherein each of the light-receiving elements receives transmitted light from a banknote. (5) The discrimination means determines, based on the output signal of each light-receiving element,
5. The banknote inspection device according to claim 4, wherein the degree of dirt on the banknote is determined by determining the ratio or difference in the transmittance of the banknote to each light beam. (6) The banknote inspection device according to claim 1, wherein each of the light-receiving elements receives reflected light from a banknote. (7) The discrimination means is configured to:
7. The banknote inspection device according to claim 6, wherein the degree of dirt on the banknote is determined by determining the ratio or difference in the reflectance of the banknote to each light beam.