JPH04134583A - Paper money discriminator - Google Patents

Abstract

PURPOSE:To stably perform discrimination for authenticity by taking a difference between a detection signal with a detecting means and a prescribed first reference value with a reference pattern generating means by a subtraction means, eliminating the DC component of the difference with a conversion means, and discriminating the truth/falsehood of a note based on the output of the conversion means. CONSTITUTION:The detecting means 8 sends the detection signal by detecting an optical or magnetic pattern from the paper money, and the subtraction means 12 takes the difference between the detection signal and the prescribed first reference value by the reference pattern generating means 10, 11, and the conversion means 13 eliminates the DC component of the difference. Comparing means 14, 15 outputs a comparison result by comparing a signal obtained based on the output of the conversion means 13 with a prescribed second reference value, and a deciding means 16 discriminates the authenticity of the paper money based on the output from the comparing means 14, 15. Thereby, it is possible to stably perform the discrimination for the authenticity without being affected by the stain of the paper money, temperature change in the detecting sensitivity of the detecting means 8, and secular change.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a banknote discriminating device that detects an optical or magnetic pattern on a banknote and determines the authenticity of the banknote.

(Prior Art) When a banknote is inserted by a customer into an automatic teller machine, vending machine, etc., a process is performed to determine the denomination and authenticity of the banknote. A banknote discriminator is used for this process.

A banknote discrimination device detects optical or magnetic patterns such as reflected light and transmitted light from the patterns and shapes of the inserted banknote, and compares this with a preset reference value to determine the authenticity of the banknote. was being carried out. In this case, the detected pattern and the preset reference value can be compared by directly comparing the detected pattern and the reference value, or by integrating a portion or the entire detected pattern with the reference value. There are known methods of comparison.

An example of a conventional banknote authenticity determination device is shown in FIG. 2. In the figure, 1 is a detector placed on a banknote transport path. As this detector l, a reflected light detector, a transmitted light detector, or a magnetic detector is used, and it detects an optical pattern or a magnetic pattern from the pattern or figure of the banknote being conveyed on the conveyance path, and takes appropriate action. outputs an electrical signal. Reference numeral 2 denotes an amplifier circuit whose input end is connected to the output end of the detector 1, and this amplifier circuit 2 amplifies the detection signal input from the detector 1 to a predetermined voltage and outputs the amplified signal. 3 is
An analog/digital conversion circuit (referred to as an A/D conversion circuit) whose input terminal is connected to the output terminal of the amplifier circuit 2 and whose output terminal is connected to the input terminal of the register 4 that holds digital data. The A/D conversion circuit 3 converts the analog signal supplied from the amplifier circuit 2 into a digital signal and outputs the digital signal to the register 4. The input terminal of 5 is connected to the output terminal of a denomination direction discrimination circuit (not shown) which outputs the denomination direction discrimination result, and the register 4
This is a reference value storage circuit that outputs a reference value corresponding to the data held in the memory.

6 has one input end connected to the output end of register 4,
and the other input terminal is connected to the output terminal of the reference value storage circuit 5, and this comparison circuit 6 receives the digital signal f(t) inputted from these registers 4 and the reference value storage circuit 5. The reference value which is a digital signal inputted from the reference value storage circuit 5 (maximum reference value g,... (t) which is an allowable value of the reference value) and minimum reference value g-+o(t
) ), f (t) is g --- (t) 3g
1- Whether it is larger or smaller than (t), the result of the magnitude is output as a binary signal. The input terminal of the discrimination circuit 7 is connected to the output terminal of the comparison circuit 6, and based on the output from the comparison circuit 6, the detected waveform f(t) is set to the maximum reference value g□,
(1) and the minimum reference value gm+n(t). For example, as shown in Figure 3(a), the detected waveform f (t) is within the maximum reference value g□, (1). When it is within the range of the minimum reference value g1゜(1), the banknote is determined to be genuine, and the detected waveform f (t) is within the range of the maximum reference value g @, ,
(t) and the minimum reference value g□, when it is not within the range of (t),
For example, as shown in Figure (b), when the detected waveform f (t) is outside the range of the maximum reference value g ff1ax (t) and the minimum reference value g, ゎ (1) in the shaded area, the banknote is considered to be counterfeit. It is determined to be a ticket. The determination circuit 7 outputs the determination result of the authenticity of the banknote to the host device.

(Problem to be Solved by the Invention) However, in the conventional banknote discrimination device described above, the permissible value of the reference value (maximum reference value g, ax (
t) and the minimum reference value g-+o(t)) must be set large. Therefore, as shown in FIG. 3(C), even if the banknote should clearly be determined to be a counterfeit banknote, the detected waveform f (t) will change to the allowable value of the standard value ( g□, (1).

g min (t) ),
There was a risk of misjudgment, such as the bill being determined to be genuine.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned problems, and to provide a system that is not affected by dirt on banknotes or temperature changes or aging of the detection means for detecting optical or magnetic patterns on banknotes.
It is an object of the present invention to provide a bill discriminating device capable of extremely stable authenticity discrimination.

(Means for Solving the Problems) The present invention provides a banknote discriminating device that detects an optical or magnetic pattern on a banknote to determine the authenticity of the banknote.
a detection means for detecting an optical or magnetic pattern from the banknote and transmitting a detection signal; a reference pattern generation means for outputting a predetermined first reference value as an analog signal; the predetermined first
subtraction means for outputting the difference between the reference value of and the detection signal from the detection means; conversion means for removing the direct current component of the output signal of the subtraction means; a comparison means for comparing the received signal with a predetermined second reference value and outputting the comparison result; and a determination means for determining the authenticity of the banknote based on the output from the comparison means. .

(Function) In the banknote discriminating device of the present invention, the detection means detects the optical or magnetic pattern from the banknote and sends out a detection signal, and the subtraction means compares the detection signal by the detection means with the predetermined signal by the reference pattern generation means. Take the difference from the first reference value,
The converting means removes the DC component of the difference, the comparing means compares the signal obtained based on the output of the converting means with a predetermined second reference value and outputs the comparison result, and the discriminating means removes the DC component of the difference. Since the authenticity of banknotes is determined based on the output from the comparison means, extremely stable determination of authenticity can be performed without being affected by dirt on the banknotes, temperature changes in the detection sensitivity of the detection means, or changes over time. Ru.

(Example) Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a bill discriminating device according to the present invention.

In the figure, reference numeral 8 denotes an insulator detector which is a detection means of the present invention for detecting optical patterns and magnetic patterns such as reflected light and transmitted light from the patterns and figures of banknotes, and 9 a detection signal obtained by the detector 8. 10 is a reference value storage circuit that stores a reference value set in advance for each denomination direction; 11 is an analog converter of the reference value (digital signal) output from the reference value storage circuit 10; This is a digital/analog conversion circuit (hereinafter referred to as a D/A conversion circuit) that converts it into a signal. Here, the reference value storage circuit 10 and the D/A conversion circuit 11 constitute the reference pattern generating means of the present invention. 12 is the output A of the amplifier circuit 9 and the D/A conversion circuit 1.
1 is a subtraction circuit as a subtraction means of the present invention that outputs the difference between the output B and the output B of the subtraction circuit 12, and 13 is a filter circuit as a conversion means of the present invention that removes only the DC component of the output C of the subtraction circuit 12 and outputs it. , 14 is an absolute value circuit that outputs the absolute value of the output of the filter circuit 13, and 15 is a comparator that compares the output of the absolute value circuit 14 with the reference voltage VR. here,
The absolute value circuit 14 and the comparator 15 constitute the comparison means of the present invention.

Further, reference numeral 16 denotes a discriminating circuit as a discriminating means of the present invention which outputs the discriminating result to a host device (not shown) based on the output F of the comparator 15.

A second explanation of the operation of the banknote discriminating device configured as described above.
This will be explained with reference to the figures.

The output of the detector 8 with respect to the inserted banknote is sent to an amplifier circuit 9.
The detected signal is amplified by, for example, the detection signal shown in FIG. 4(a). Further, a reference value (digital signal) corresponding to the denomination direction determination result when the detection signal A is obtained, determined by a denomination direction determination means (not shown), is output from the reference value storage circuit 10, and the D/A The signal is converted into an analog signal by the conversion circuit 11, resulting in a reference pattern B shown in FIG. Here, the reference pattern B is output in synchronization with the detection signal A by banknote detection means and timing generation means (not shown). The subtraction circuit 12 receives the detection signal A
and the reference pattern B, and outputs a signal C (=A-B) as shown in FIG. The filter circuit 13 removes the DC component of the signal C and outputs the signal C. The absolute value circuit 14 takes the absolute value of the signal and outputs the signal E shown in FIG. The comparator 15 compares the magnitude of the signal E and the reference voltage vR, and if the signal E is larger than the reference voltage VR, it becomes "1", and if the signal E is larger than the reference voltage ■8, it becomes "○", and the comparison result is shown in the figure. A binary signal F as shown in (e) is output.The discrimination circuit 16 outputs a binary signal F as shown in FIG.
If there is no "1", it is determined that it is a genuine bill, and if there is a "1", it is determined that it is a counterfeit bill, and the determination result is sent to a host device (not shown).In the case of FIG. As can be seen from (e), it was determined to be a genuine note, and as shown in Figure 4 (a) above.
When Figures 5(a) to 5(e) are used instead of 5(e), the banknotes are determined to be counterfeit, as can be seen from Figure 5(e). In addition, FIGS. 5(a) to (e) are respectively similar to FIGS. 4(a) to (e).
This is another example corresponding to e).

As can be seen from the above description, in the present invention, the filter circuit 13 removes the DC component of the difference between the detection signal and the reference pattern, so that the filter circuit 13 removes the DC component of the difference between the detection signal and the reference pattern. It is possible to realize a banknote discrimination device that is not affected by change or aging and can perform extremely stable authenticity discrimination.

In this embodiment, banknotes are determined based on whether the output E of the absolute value circuit 14 exceeds the reference voltage 8, but the present invention is not limited to this.
For example, as shown in FIG. 6, the output E of the absolute value circuit 14 is integrated by an integrating circuit 17, and this integrated value is compared with a preset allowable integral value by a comparing circuit 18 to identify banknotes. You can do it like this. Here, the absolute value circuit 14, the integration circuit 17, and the comparison circuit 18 constitute the comparison means of the present invention. 6 shows another embodiment of the present invention, in which an integrating circuit 17 integrates the output E of the absolute value circuit 14, outputs the integrated value to the comparator circuit 18, and outputs the integrated value to the comparator circuit 18. The integral value from the integrating circuit 17 is compared with a preset allowable integral value, and if the integral value is larger than the allowable integral value, it is marked as "1", and if it is not larger than the allowable integral value, it is marked as "○". The comparison result is output as a binary signal to the discrimination circuit 19 as the discrimination means of the present invention, and the discrimination circuit 19 determines that it is a genuine note if the output signal from the comparison circuit 18 does not have "1". 1", the bill is determined to be a counterfeit and the determination result is sent to a host device (not shown).

In this figure, other configurations are the same as those in FIG. 1, so the same reference numerals are used and explanations are omitted.

The present invention is not limited to this embodiment, and various applications and modifications can be made without departing from the gist of the present invention.

For example, the present invention can provide a banknote discrimination device with higher accuracy by combining the embodiments shown in FIGS. 1 and 6.

(Effect of the invention) As described above, if the banknote discriminating device according to the present invention is used,
The difference between the detection signal by the detection means and the predetermined first reference value by the reference pattern generation means is calculated by the subtraction means, the DC component of the difference is further removed by the conversion means, and the difference is calculated based on the output of the conversion means. Since the authenticity of banknotes is determined, very stable determination of authenticity can be achieved without being affected by dirt on the banknotes, temperature changes in the detection sensitivity of the detection means, and changes over time.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a bill discriminating device according to the present invention, FIG. 2 is a block diagram showing an example of a conventional bill discriminating device, and FIG. 3 is for explaining the discrimination method using the device shown in FIG. FIGS. 4 and 5 are waveform diagrams for explaining the operation of FIG. 1, respectively, and FIG. 6 is a block diagram showing another embodiment of the present invention. 8...Detection circuit, 10...Reference value storage circuit, 11.
...D/A conversion circuit, 12...Subtraction circuit, 13...
Filter circuit, 14...Absolute value circuit, 15...Comparator, 16.19...Discrimination circuit, 17...Integrator circuit, 18...Comparison circuit. Waveform diagram box 3 to explain how to distinguish conventional equipment
Figure 4 Explanation of the operation in Figure 1 (In the case of a genuine note) Figure 5 Explanation of the operation in Figure 1 (In the case of a counterfeit note)

Claims (1)

[Scope of Claims] A bill discriminating device that detects an optical or magnetic pattern on a bill to determine the authenticity of the bill, comprising: a detection device that detects the optical or magnetic pattern from the bill and sends a detection signal; means, a reference pattern generation means for outputting a predetermined first reference value as an analog signal, and a difference between the predetermined first reference value output from the reference pattern generation means and the detection signal from the detection means. A subtracting means for outputting, a converting means for removing the DC component of the output signal of the subtracting means, and a signal obtained based on the output of the converting means is compared with a predetermined second reference value. A bill discriminating device comprising: a comparing means for outputting a comparison result; and a discriminating means for discriminating authenticity of the bill based on the output from the comparing means.