JPH0690750B2 - Paper stain detection device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a paper sheet stain determination device for detecting stains on a paper sheet by using transmitted light or reflected light of the paper sheet.

[Prior Art] Conventionally, there is a paper sheet stain discriminating apparatus disclosed for paper money among paper sheets, which will be described below.

In recent years, automatic deposit / withdrawal machines have become popular in financial institutions such as banks. Furthermore, there is a growing demand to reduce the number of bills that can be loaded into this automatic depositing / dispensing machine as much as possible. It was

However, all the bills that the customer deposits are not all bills that are free of dirt (called genuine bills), and the bills that the customer deposits at the automatic depositing / dispensing machine are the genuine bills that can be paid again to other customers. It has become necessary to determine whether a bill is a bill that is not suitable for paying to the customer (it is called an unfit bill), and whether it is right or wrong.

Conventionally, most of this type of banknote judgment is based on the degree of dirt of a banknote by applying optical means, and one example will be described below.

That is, in such a device, light is emitted from a light source to a bill (a bill to be discriminated) whose stain is to be discriminated, and the reflected light or transmitted light is photoelectrically converted by a light receiving sensor, and the bill to be discriminated or the light receiving sensor is The bill is run in the longitudinal direction or in the direction orthogonal to the longitudinal direction, the converted electric signal is further amplified to an optimum value, sampled at the timing synchronized with the running of the bill to be discriminated or the light receiving sensor, and converted into a digital signal. The lever digital signal is integrated over the range of the fixed portion to be discriminated in scanning the bill.

On the other hand, fixed on the same scanning line as the above-mentioned discriminated banknote by using a banknote (referred to as a standard banknote) that has no dirt, wrinkles, shrinkage, or tears such as a government-sealed ticket (a banknote that has been manufactured and sealed by the Mint Bureau) in advance. The integrated value of the digital signal value in the range of points is obtained.

The allowable range is set to the integral value of the standard bill, and the integral value obtained from the discriminated bill and the allowable range of the integral value of the standard bill are compared to determine whether the bill to be discriminated is within the allowable range. It was determining the stain.

[Problems to be solved by the invention]

According to the technique described above, if a stain such as a pencil or a ballpoint pen partially stains on the scanning line at a fixed position on the scanning line of the bill to be discriminated, the discriminated bill is discriminated as an unfit bill, When the partial stain is present in the direction orthogonal to the scanning line, the area of the stain portion on the scanning line of the bill to be discriminated is small, and the difference from the standard bill is not shown. That is, there is a problem that the above-mentioned bill to be discriminated has an integral value that falls within an allowable range in which it can be discriminated as a genuine bill, and is mistakenly discriminated as a genuine bill in spite of a dirty bill.

[Means for solving problems]

In order to achieve this object, the present invention irradiates traveling paper sheets with light from a light source, receives the reflected light or transmitted light with a light receiving sensor, and outputs the light from the light receiving sensor with the output signal. In a paper sheet stain discriminating apparatus for discriminating the presence or absence of stains on a sheet, a region setting means for arbitrarily setting a detection region on a scanning line for detecting stains on the sheet, and an output signal of the light receiving sensor in the detection region. And a binarizing means for binarizing the binarized signal with an arbitrary slice value, and a first addition for performing an addition operation on the binarized signal output from the binarizing means at each standard timing synchronized with the traveling of the paper sheet. The calculation means, the second addition calculation means for performing addition calculation of the output signal of the light receiving sensor in the detection area for each reference timing synchronized with the traveling of the paper sheet, and the addition result by the first addition calculation means Foresight Compared with the first judgment reference value which does not have the allowable range obtained from the mellow paper sheet, if both are equal, there is no stain, and if they are not equal, there is partial stain in the direction orthogonal to the scanning line. It is determined and the second
The result of addition by the addition calculation means is compared with a second determination reference value having a predetermined allowable range obtained in advance using standard paper sheets, and when both are equal, no stain is found, and when they are not equal, overall stain is found. It is characterized in that it comprises a discriminating means for discriminating.

[Action]

In the present invention having such a configuration, the traveling paper sheet is irradiated with light from the light source in the detection region, the reflected light or the transmitted light is received by the light receiving sensor, and the output signal of the light receiving sensor is set to 2 After binarizing with an arbitrary slice value by the binarizing means, the binarizing signal output from the binarizing means is added by the first addition computing means at each reference timing synchronized with the traveling of the paper sheet. At the same time, the output signal of the light receiving sensor is added and calculated by the first addition calculation means at each reference timing.

Then, the discriminating means compares the addition result of the first addition computing means with a first judgment reference value which does not have an allowable range obtained in advance using standard paper sheets, and when both are equal, there is no stain and is equal. If not present, it is determined that there is partial stain in the direction perpendicular to the scanning line, and the second determination having the predetermined allowable range obtained in advance by the standard paper sheet as the addition result by the second addition calculation means. Compared with the reference value, if both are equal, it is determined that there is no stain, and if they are not equal, it is determined that there is overall stain.

〔Example〕

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

FIG. 1 is a block diagram of a paper sheet stain determination device. In the figure, 1 is a light receiving sensor, 2 is an amplifier, 3 is an A / D converter, 4 is a register, 5 is a CPU, and 6 is a reference value. Memory, 7 is a comparator, 8 is an adder which is a first addition operation means, 11 is an adder which is a second addition operation means, 12 is a register and 13 is a ROM.

Therefore, the light receiving sensor 1 irradiates the paper sheet with light emitted from a light source (not shown), receives the reflected light or the transmitted light of the light, and photoelectrically converts the light.

The amplifier 2 amplifies an electric signal, for example, a current signal from the light receiving sensor 1 into a voltage signal up to an optimum value.

The A / D converter 3 converts the voltage signal (analog signal) into a digital signal at each reference timing synchronized with the traveling of the paper sheet.

The register 4 temporarily stores the digital signal.

The CPU 5 functions as a control means for controlling the entire apparatus, and provides a first determination reference value having no allowable range and a second determination reference value having a predetermined allowable range obtained in advance with standard paper sheets. It also functions as a discriminating means for discriminating the presence or absence of stains on the paper sheets.

The reference value memory 6 stores an arbitrary slice value serving as a reference for binarizing the digital signal as a comparison reference value, and the comparator 7 compares the digital signal with the comparison reference value to obtain a binary value. It is for obtaining the digitized data.

The adder 8 adds the binarized data.

The register 9 temporarily stores the addition result.

The adder 11 adds the digital signals.

The register 12 temporarily stores the added value of the digital signal.

The RAM 10 is a memory for storing the digital signal value, binary data addition value, digital signal addition value, and the like.

The ROM 13 is a memory that stores stain determination reference values and the like.

Next, the operation of this embodiment having the above configuration will be described.

2 to 7 are output waveform diagrams.

The light emitted from the light source is applied to the paper sheet to be discriminated (hereinafter referred to as a banknote) P ₁ , and the light reflected from the banknote to be discriminated P ₁ (referred to as reflected light) or this banknote P ₁ is discriminated. The transmitted light (referred to as transmitted light) is received by the light receiving sensor 1 and photoelectrically converted. The converted electrical signal is a current signal.

Here, since the principle of operation is the same for both the reflected light and the transmitted light of the bill to be discriminated P ₁ , only the reflected light will be described below.

The current signal is converted into a voltage signal by the amplifier 2 and amplified to an optimum value, and the analog amplified voltage signal output from the amplifier 2 is an A / D converter at each reference timing synchronized with the traveling of the bill to be judged P ₁ . It is converted into a digital signal by 3.

The converted digital signal is temporarily stored in the register 4,
It is stored in the RAM 10 under the control of the CPU 5.

Here, FIG. 3 shows a digital signal waveform at each reference timing when the broken line portion of the bill to be discriminated P _{1 in} FIG. 2 is scanned.

The shaded portion in FIG. 2 indicates a black-colored printed portion, which has a low reflectance. The horizontal axis of FIG. 3 is the time axis during which the light receiving sensor 1 scans, and the vertical axis is the output value of the digital signal. That is, the digital signal value of the black-colored print portion in FIG. 2 becomes small.

Next, the comparator 7 compares the output value at each timing of the digital signal waveform V _(t) shown in FIG. 3 with the reference value V _s stored in the reference value memory 6 to convert it into binary data. This 2
The output waveform U _(t) of the digitized data is shown in FIG.

Further, addition operation is performed by the adder 8. The section in which the addition calculation is performed here is a portion in which a difference in the light receiving sensor output due to dirt such as a non-printed portion of the bill to be discriminated P ₁ or a portion in which the printing color is light appears remarkably. That is, in FIG. 3 t _a ~
It is an interval of t _b .

The stain determination section can be arbitrarily set according to the denomination and direction of the bill, and is stored in the ROM 13 in advance. That is, the output value C ₁ of the adder 8 when the object to be discriminated banknote P ₁ of genuine as shown in FIG. 2, Becomes

After the addition result C ₁ is temporarily stored in the register 9, RAM1
Stored in 0.

Further, when likewise adding operation by an adder 11 for the third view of fouling discrimination periods t _a ~t _b supra digital signal waveform V _(t), the addition result A ₁ is Becomes This addition result A ₁ is temporarily stored in the register 12 and then stored in the RAM 10.

On the other hand, FIG. 5 shows a case where a graffiti such as a pencil or a ballpoint pen exists on the scanning line of the bill to be discriminated P _{2 which} is the same as the bill to be discriminated P _{1 in} FIG. R in this Fig. 5 is a graffiti,
This graffiti R exists in the direction orthogonal to the scanning line.

The bill to be discriminated P ₂ shown in FIG. 5 is a so-called unfit bill,
The digital signal waveform V _(t) when scanning is performed by the apparatus of this embodiment in the same manner as the bill to be discriminated P ₁ is as shown in FIG.

Further, when the determined binary data output waveform U of the determination banknote P _{2 (t),} as in the case of the determination banknotes P _1, becomes as in Figure 7.

In other words, the addition result C ₂ soiling discrimination periods t _a ~t _b for the adder 8 in the determination banknotes P ₂ are Becomes Furthermore, the addition result A ₂ of the adder 11 is = V ₁ (t _b −t _a ) −V ₂ (t _d −t _c ) ... (5).

Here, the criterion for determining whether the bill to be discriminated is a genuine bill or an unfit bill is determined by the values of the addition results C and A of the adder 8 and the adder 11, respectively, but the determination is made by the CPU 5.

Further, the determination reference value of the genuine bill is C, A which is a reference bill calculated in advance by the device of the present invention, but it is well known that there are variations in printing and variations in paper quality even in what is usually called a genuine bill. The fact is, the digital output waveform of a standard bill
Since the output value of V _(t) varies in the range of V _{1 to} α to V ₁ + β even between t _{a and} t _b , the judgment reference value of the A of the genuine note has an allowable value, and It becomes like this.

(V ₁ −α) (t _b −t _a ) <A <(V ₁ + β) (t _b −t _a ) ...
(6) V ₁ + β> V ₁ > V ₁ −α> V _s (7) However, the V _s stored in the reference value memory 6 has a value that allows the above-mentioned variations in printing and variations in paper quality. Even if it is set, graffiti etc. can be detected. That is, the judgment reference value of C on a genuine note does not need to have an allowable value and is as follows.

C ≧ t _b −t _a (8) In addition, in the stain determination section of the not-shown bill P _{3 to} be discriminated, for the bill to be discriminated in which the entire area is soiled, from the equation (7), an adder is used. The addition result A _{3 of} 11 is A ₃ = (V ₁ −γ) (t _b −t _a ) <(V ₁ −α) (t _b −t _a ) ...
(9) A ₃ = (V ₁ −γ) (t _b −t _a ) ≧ V _s (t _b −t _a ) ... (10), and the to-be-determined banknote P ₃ is determined to be an unfit banknote.

That is, when a partial graffiti exists in the direction orthogonal to the scanning line like the discriminated bill P ₂ , it is determined as an unfit bill based on the binarized data addition value C, and the entire bill as the discriminated bill P ₃ is judged. With respect to the stain, the added value A determines that the bill is unfit.

Although the above-described embodiments have been described with respect to reflected light, they can be similarly applied to transmitted light as described above. In addition, although one denomination and one direction are described in the embodiment, since the reference value memory 6 is provided, it is possible to set individual reference values V _s for digital signals of a plurality of scanning lines of multiple denominations and multiple directions. is there.

Further, by providing a plurality of scanning lines, that is, a plurality of light receiving sensors, it is possible to more accurately determine the stain.

〔The invention's effect〕

As described above, according to the present invention, not only is it possible to determine the presence or absence of overall dirt and stain in the detection area, but the output signal of the light receiving sensor in the detection area is binarized by an arbitrary slice value, and the binarized data Since the added value is compared with the first determination reference value having no allowable range to determine the presence or absence of stain, it is possible to stably determine the stain such as partial graffiti orthogonal to the scanning line of the light receiving sensor. Is obtained.

Further, the present invention, since it is possible to arbitrarily set the detection area on the scanning line for detecting the stain of the paper sheet, when the paper sheet is, for example, a bill, the appearance of the stain for each denomination and the traveling direction thereof. It is possible to arbitrarily set an easy portion, and it is possible to obtain high-precision determination with a small number of sensors.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a schematic plan view of a sheet to be discriminated, FIG. 3 is a digital signal waveform diagram, FIG. 4 is a binarized data output waveform diagram, FIG. 5 is a schematic plan view of the paper to be discriminated, FIG. 6 is a digital signal waveform diagram, and FIG.
The figure is a binary data output waveform diagram. 1 ... Light receiving sensor, 3 ... A / D converter, 4 ... Register, 5 ... CPU, 6 ... Reference value memory, 7 ... Comparator,
8 ... Adder, 9 ... Register, 10 ... RAM, 11 ... Adder, 12 ... Register, 13 ... ROM

Claims (1)

[Claims] 1. A traveling light source emits light from a light source, the reflected light or transmitted light is received by a light receiving sensor, and the output signal of the light receiving sensor is used to determine whether or not the paper sheet is soiled. In the paper stain determining device for determining, an area setting means for arbitrarily setting a detection area on a scanning line for detecting the stain of the paper, and an output signal of the light receiving sensor in the detection area by an arbitrary slice value. A binarizing unit for binarizing, and a binarizing signal output from the binarizing unit is added and calculated for each reference timing synchronized with the traveling of the sheet.
Addition calculation means, second addition calculation means for performing addition calculation of the output signal of the light receiving sensor in the detection area at each reference timing synchronized with the traveling of the paper sheet, and addition by the first addition calculation means The result is compared with a first determination reference value that does not have an allowable range obtained in advance using standard paper sheets, and if both are equal, there is no stain, and if they are not equal, there is a partial direction perpendicular to the scanning line. When it is determined that there is stain, the result of addition by the second addition calculating means is compared with a second determination reference value having a predetermined allowable range obtained in advance using standard paper sheets, and when both are equal, there is no stain, A paper sheet stain discriminating apparatus comprising: a discriminating unit that discriminates that there is overall stain when they are not equal.