JPS6028038B2 - Banknote identification device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a banknote discriminating device, and in particular to a banknote discriminating device that irradiates a running banknote with light, detects the transmitted light and reflected light, and distinguishes between this detection amount and a reference banknote. Detected amount (reference amount) in case of
This invention relates to a device for determining whether a banknote is correct or not by comparing the banknotes.

In recent years, automatic transaction machines for automating bank transactions have become popular. For example, in the automatic teller machine shown in FIG. 1, one of the important functions is to determine the authenticity of banknotes inserted by a customer. However, although various devices have been proposed for determining the authenticity of banknotes, most of them are based on optical methods.

As an example, we focus on a specific part of the pattern printed on a banknote, detect the reflectance, transmittance, color, etc. at that part, and check whether the detected value matches the standard value. Alternatively, there is a method of checking whether the pattern when replaced with "0" or "1" signals matches the reference pattern. However, since this method temporarily stops the banknotes in transit and shines light on specific areas during that period, not only does it take a long time to identify them, but the banknotes that are being transported automatically If there is a positional shift or twist in the position, there will be a positional shift between the detection position (the location where light is irradiated) and the specific location, making accurate discrimination impossible.

Furthermore, according to this method, even if the bank note itself is normal, if there is dirt or wrinkles in the specific areas mentioned above, the entire bank note is judged based on the information from that part only, so the bank note is rejected as abnormal. There's something so captivating about it. As described above, the above-mentioned method has the disadvantage that the discrimination accuracy is affected by the conveyance conditions, local dirt on the banknote, etc. Further, as another example of a slave discriminating device, the one shown in FIG. 1 is known.

This device consists of a detection section and a signal processing section, and the detection section includes a weight 1, a light source 2, a reflector 3, a lens 4, a transparent partition plate 5,
It is composed of a photoelectric conversion element 6. Then, the bank note a runs at a constant speed inside the dark space inside the weight body 1. light source 2
The light emitted from the banknote A travels upward in the drawing by the reflecting mirror 3, and uniformly illuminates the bank note a in the width direction (direction perpendicular to the running direction) through the lens 4 and the slit 8. The light transmitted through the bank note a is then guided to the photoelectric conversion element 6 via the slit 9 and converted into an electrical signal. Therefore, in this configuration, when the bank note a passes through the upper part of the slit 8, a distorted wave of a time function corresponding to the pattern written on the bank note is obtained from the optical force conversion element 6. In order to recognize the entire surface of banknote a, the signal processing section shown in FIG. 1b is provided with an integrator.

That is, the electrical signal obtained by the photoelectric conversion element 6 is amplified by the amplifier 11, and then passed through the plurality of band filters 1.
2, 12', 12... in parallel, and some specific frequency sine wave components 13, 13', 13...
..., and then each leaker 12, 12', 12
to the integrators 14, 14', 14 connected to...
...is integrated during the running period, and the electric quantity is 15,15',
15''... When the banknote a completely leaves the slit 8, the switches 16, 16'...
. . , a comparator 19 compares the quantity of electricity 18 corresponding to a normal banknote previously stored in the storage section 17 with the output of the integrator, and a determination signal 20 is output. According to the counterfeit system shown in FIG.
, 12'' to divide it into a plurality of sine wave components, these are integrated by integrators 14, 14', 14'' over the scanning period, and banknotes are discriminated based on the amount of integration. It is. Therefore, according to this method, the time required for discrimination is short, and even if the banknotes being conveyed are misaligned or twisted, they can be accurately discriminated. strong. However, the secondary device shown in FIG. 1 has the following drawbacks. That is, the pattern signal amplified by the amplifier 11 is a distorted wave depending on the pattern, but it is difficult to increase the resolution because the moving banknote is recognized through a wide slit. be. Therefore, the distorted wave does not strictly represent the characteristics of the banknote pattern, but is a so-called large pattern converted into an electrical quantity. Then, the apparatus shown in FIG. 1 applies the distorted waves to a plurality of wave leakers to extract only the alternating current component of the distorted waves. As a result, when a banknote with a pattern made by a copying machine etc. is passed through this device, the pattern of the normal one and the simulated one is almost the same, so the amount of electricity obtained from each Obijo waver is equal to the normal one. The result is almost the same as in the case of banknotes, making it difficult to accurately discriminate the above-mentioned simulated banknotes. In other words, the device shown in FIG. 1 is advantageous in cases where there are differences in patterns over the entire surface of banknotes, such as in determining the type of banknote, in determining locally similar items, and in determining local defects, but it is not effective in determining overall banknotes. The discrimination accuracy is extremely low for simulated banknotes with the same pattern added to them. Furthermore, according to the device shown in FIG. The amount of electricity that is stored is the amount of electricity obtained from each integrator when a normal bank note is passed in advance. and the actual conveyance speed of the banknote under test.

If the conveying speed or the direction of the banknote is not constant due to the presence or absence of skew, the pattern signal obtained from the amplifier changes and the amount of electricity obtained from each leaker changes. Therefore, the output of the integrator also changes, resulting in an error in the comparison value by the comparator 19. Therefore, in the apparatus shown in FIG. 1, the comparator 1
Although it is necessary to widen the allowable value of the comparison limit in 9, widening the allowable value means lowering the discrimination accuracy on the other hand. The present invention was made in order to solve the problems of conventional devices, and is capable of accurately distinguishing even fake banknotes made by copying machines, etc., and also so that the discrimination results are not affected by the conveyance speed of the banknotes. The purpose of the present invention is to provide a discriminating device based on the

Hereinafter, one embodiment of the present invention will be described based on FIGS. 2 to 5.

FIG. 2 shows an automatic teller machine in which banknotes are inserted all at once, and its configuration will be described in detail in order to make it easier to understand the requests to the discriminator. In the figure, 31 is a crab body, and this cone body 3
1 is provided with a deposit slot 34 consisting of a rotatable cover 32 and a storage box 33, and the customer stands the banknotes a all at once in the storage box 33 in the east direction. It is designed to be inserted in the same position. At the rear of the storage box 33, the inserted banknotes a are sequentially transferred one by one to a pulley 35 and an endless annular belt 36.
. . . A take-in rotor 38 is provided for taking in the material into a conveyance path 37 constituted by .

That is, a suction member 38a that is suitable for a vacuum source (not shown) is bored on the outer peripheral surface of the intake rotor 38, and as the rotor 38 rotates counterclockwise as indicated by the arrow, the banknotes a... The sheets are vacuum-suctioned and taken in one by one, starting from the earliest one. Further, a detection device 39 consisting of a light projecting section 39a and a light receiving element section 39b is arranged in the middle part of the transport section 37, and a detection device 39 is arranged in the middle of the transport section 37.
It performs ticket type determination, counting, and authenticity determination.

Further, the conveyance section 37 is divided into a main conveyance path 40a and a branch conveyance path 40b, and a rotatable division gate 41, which is driven by, for example, a rotary solenoid, is provided at the branch point.

That is, the control unit (
(not shown) to guide a valid banknote to the main conveyance path 40a, and to guide a fraudulent banknote to a branch conveyance path 40b. In this way, the correct banknotes a fed into the main conveyance path 40a are horizontally stacked in the deposit box 42 provided at the terminal end. Note that 43 is a vertically movable back-up plate on which the banknotes a conveyed to the safe 42 are placed, and is supported at one end of the shaft 44 so as to be lowered sequentially according to the amount of banknotes a accumulated. controlled.

On the other hand, the fraudulent banknote a sent to the branch conveyance path 40b
is a return port 4 whose terminal end faces the front of the body 31.
5, and the fraudulent banknote a is returned to the customer. Next, FIG. 3 is a diagram showing an embodiment of the configuration of the discriminating device of the present invention.

In Figure 3a, 51a, 51b and 51'a, 5
1'b is a conveyor belt 52... is a rotating loaf for driving each belt, and the bank note a is held between the conveyor belts 51a, 51b and 51'a, 51'b as shown by the arrow. conveyed in the direction. An illumination unit 56 composed of an illumination light source 53, a condensing lens 54, and a transparent guide 55 functioning as a slit uniformly illuminates a predetermined area in the width direction of the banknote a being conveyed. The light receiving unit 57 is composed of a diffuser/transparent guide plate 58, a reflective guide plate 59, a plurality of transmitted light receivers 60, 60', and a reflected light receiver 60'', and receives the banknote a. The transmitted light is transmitted to the plurality of light receivers 60, 60', 60''...
・The light is received at Here, each light receiver has a different wavelength sensitivity and receives transmitted light and reflected light in multiple bands. FIG. 4 shows an example of the wavelength sensitivity of each light receiver when the number of light receivers is three, for example. In FIG. 4, curve A shows the spectral sensitivity of the first light receiver 60, curve B and curve C show the spectral sensitivities of the second and third light receivers 60' and 60'', respectively.These spectral sensitivities A photoreceiver can be easily realized, for example, by combining a silicon photodiode with a suitable colored glass filter. Fig. 5 is a diagram showing the relationship between the illumination and light-receiving area and the running position of the banknote. It is.

In the figure, a indicates a banknote, and 61 indicates an illumination and light receiving area, that is, an area of the transparent guide 55 and the diffuser plate 58 in FIG. 3a. In this figure, the bank note a is conveyed in the direction of the arrow across the illumination and light-receiving area 61, but the area 61 is set as wide as necessary so that the bank note a does not run outside the area 61. By doing this, it is possible to eliminate the influence of shift or skew in the conveyance position of the bank note a. In this way, bank note a passes through 61,
When transmitted light and reflected light are received by the plurality of light receivers, the light receiver outputs are sent to a signal processing section.

The signal processing section will be explained with reference to FIG. 3b. The electrical signals obtained by the photodetectors 60, 60', 60''... are sent to the front layer amplifiers 62, 62', 62'', respectively.
... is amplified to a voltage signal of an appropriate zero level and becomes signals 63, 63', 63'', etc. These signals are then applied to integrators 64, 64', 64'', etc. . Further, 65 is a photo switch which detects the leading edge of the banknote being conveyed and generates a leading edge signal 66. This signal 66 is sent to a timing circuit 67, which receives this signal 66 and generates a timing signal for controlling the integration timing of each integrator. The integration time is the time from when the bank note a reaches the illumination and light receiving area 61 to when it completely passes through. The signals integrated for a predetermined period of time by the various separators are V, V2, V3, . . . .

The signals V,, V2, and V3 are then sent to an adder 6, which is an adding means.
Adder 68, which is added to 8, adds signals V, , V2, and V3 and outputs signal Y. A divider 69 serving as a dividing means divides the signal V by the signal Y to obtain a signal v, and a divider 69' divides the signal V2 by the signal Y to obtain a signal v2. When the signals v,, v2... are obtained in this way, these signals v,, v2 are sent to the comparators 70, 70' which are the second comparison means, and the signal Y is sent to the first comparison means. A reference voltage setting circuit 71 is guided to a comparator 70r which is a means.
, 71', . . . , 71''. The reference voltage setting circuits 71, 71', . . .
Each reference voltage set to 71" is determined in advance by passing normal banknotes through the system of the present invention. After multi-banding as described above, the ratio of each band output is taken. This is to eliminate the effects of partial dirt, damage, overall dirt, and changes in conveyance speed on banknotes.

In other words, in the distribution process of securities, etc., in addition to partial damage and stains, overall stains occur, and when considering unused banknotes as a standard, those that have been used for a long time have a lower light transmittance throughout. decreases to 70% to 65%. This fact means that a normal determination cannot be made simply by detecting the amount of transmitted light or the amount of reflected light, but the problem can be solved if the determination is made using the relative value of the multiband output as described above. Furthermore, since the signals v, , v2 are completely independent of the transport speed, the permissible comparison limit in the comparators 70, 70' can be minimized.

Each comparator compares the input signal and the reference signal and outputs a signal "1" if the difference between the two is within a predetermined range, and outputs a signal "0" if it is outside the range.

Each of these outputs is then led to an AND circuit 72, and if the AND condition of the circuit 72 is satisfied, the output Vo becomes "1", and it is determined that the insurance banknote is normal, and Vo becomes "0". ”, it is determined that the banknote under test is not normal. Now, regarding a certain standard bank note, the outputs of the light receiving system in three bands are V,, V2, and V3, and the fluctuation rates of the transmittance and reflectance of each band of an arbitrary bank note are K,, K2, respectively. , K3, then Y=K. V, 10K2V
20K3V3 v. =K,V. /Y v2=K2V2/Y.

Except in special cases, even if the transmittance and reflectance change due to overall dirt, no spectral deviation will be observed. That is, except for special cases, it can be said that K,≠K2±K3=K.

Therefore, each value above becomes as follows. Y=K(
V, 10V20V3) = KY.

v,≠KV,/KY.

=V. , V2±KV2/KY.

However, Yo, vo, vo2 of dV are values related to the standard bank note.

Therefore, since vl and v2 are values from which fluctuation factors occurring during the distribution process have been removed, the dispersion of detected values is reduced by 4.0, and a narrow tolerance range can be set, allowing for highly accurate identification. In the above equation, the three outputs V, , V2, V
Since the outputs V, , V2 are obtained by dividing each output by the sum Y of 3, overflow of the divider (in case the numerator is larger than the denominator) is completely prevented. Divider over
When there are no hard constraints such as flow, v,′:V.
A similar effect can be obtained by determining the output ratio by /V3, v2'=V2/V3, etc., and making the determination based on v, , v2', V3. As explained above, the present invention receives light from banknotes using a plurality of light receivers, amplifies the signals obtained by these light receivers, and then adds the outputs of these amplifiers to generate an electric signal. Since the amount of electricity is compared with the amount of electricity of a standard banknote, for example, the paper quality of the simulated banknote in a color copier is significantly different from that of a normal banknote, so the output of transmitted light is abnormal, and it cannot be used in a regular black-and-white copier. Since the reflected light of simulated banknotes is abnormal, this device can reliably detect simulated banknotes.

[Brief explanation of the drawing]

Figures 1a and b are block diagrams showing a conventional discrimination device;
The figure is a longitudinal cross-sectional view of an automatic teller machine using the device of the present invention.
Figures a and b are block diagrams of a discriminating device showing one embodiment of the present invention, Figure 4 is a spectral characteristic diagram of a plurality of light receivers used in the device of the present invention, and Figure 6 is a diagram of banknote identification in the device of the present invention. FIG. 3 is a schematic plan view for explaining the relationship between the conveyance state and the irradiation area. a... Bank note, 53... Light source, 60, 60', 6
To 0...Receiver, 62, 62', 62''...Amplifier,
68... Adder (adding means), 70, 70',
70＾・・・Comparator (shark means). Soup 2 diagram O J diagram * Soup 3 diagram O 4 diagram

Claims (1)

[Claims] 1. A light source that illuminates banknotes being transported, a plurality of light receivers that receive transmitted light from the banknotes that are irradiated by this light source, and electrical signals obtained by these light receivers, respectively. A plurality of integrators for integrating, an adding means for adding the outputs of these integrators, and a first comparing means for comparing the output obtained by the adding means with a reference signal in the case of a reference banknote. and a division means for dividing the output of each integrator by the output of the addition means, and a second comparison means for comparing the output of the division means with a reference signal in the case of a reference banknote. A banknote discrimination device characterized by: