JPS589990B2 - Banknote authenticity determination method - Google Patents

Description

[Detailed Description of the Invention] This invention is applicable to, for example, automatic currency exchange machines used in banking operations,
The present invention relates to a banknote authenticity determination method for determining the authenticity of banknotes inserted into an automatic teller machine.

Conventionally, the reading pattern of the identification pattern (printed pattern) of banknotes is to extract the brightness or magnetic distribution of banknote printing as a voltage signal, extract the difference between this voltage signal and a reference voltage of 0, and convert the pattern due to this voltage difference into a model pattern. was used for comparison.

When the reading pattern is extracted in this way, for example, if the printed pattern of banknotes is configured to be read by a photoelectric switch, if the reading voltage changes due to temperature change, aging, dust accumulation, etc., the changed voltage Since the pattern due to the voltage difference described above differs even when the same banknote is read between the normal voltage and the normal voltage, a match with the model pattern cannot be obtained, and the banknote acceptance rate decreases.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a banknote authenticity determination system that can obtain a reading pattern with a stable voltage value even if the reading voltage changes.

According to the present invention, the average value of the output level of the identification pattern of the banknote read by the detector is calculated, and the pattern of the difference between the output level of this average value and the identification pattern of the banknote is calculated. Since the pattern is compared with the model pattern, a constant reading pattern of the banknote identification pattern can be obtained even if the reading voltage of the detector decreases, and it is possible to prevent pattern mismatch due to a drop in the reading voltage. rate can be improved.

An embodiment of the present invention having such characteristics will be described in detail below with reference to the drawings.

The drawing shows how to determine the authenticity of banknotes in an automatic money changer. In FIG.
are arranged opposite to each other to sandwich the conveyance path of the banknote 1.

The photoelectric element 2 outputs the amount of light transmitted through the banknote 1 from the light source 3 as a reading signal of the identification pattern (print pattern) of the banknote 1, and the amplifier circuit 4 amplifies this.

The sampling circuit 5 samples the aforementioned read signal based on the clock pulses generated from the clock pulse generation circuit 6 being inputted via an AND gate 8 gated by the control circuit 7.

The storage circuit 9 has data areas X and Y in which addresses are designated by the control circuit 7 and data is stored therein.

Z, and the data area X is the above-mentioned sampling circuit 5.
The sampled banknote reading pattern is stored in memory, the data area Y stores a deviation value pattern of the banknote reading pattern calculated by means described below, and the data area Z stores a model pattern to be compared with the deviation value pattern described above. is stored in memory.

The average value of the reading output level of the banknote reading pattern stored in the data area X is calculated in order to extract the deviation value pattern.

That is, the output level of each sampled bit of the banknote reading pattern is input to the adder circuit 11 via the gate 10 gate-controlled by the control circuit 7.

The above-mentioned adder circuit 11 adds the output levels of all bits,
This added value is divided by the total number of bits in the division circuit 12 to calculate the average value of the output level.

The above-mentioned average value of the output level is stored in the register 14 via the AND gate 13, and the AND gate 13 is gate-controlled by the output of the delay circuit 15 controlled by the control circuit γ. The times are set so that the adder circuit 11 and the divider circuit 12 described above are delayed by the time required to complete their respective operations.

The subtraction circuit 16 calculates the deviation value of the banknote reading pattern from the average value stored in the register 14, and the banknote reading pattern is input from the data area The output deviation value pattern is stored in the data area Y of the storage circuit 9.

The comparison circuit 17 is controlled by the control circuit 7 and compares the model pattern with the deviation value pattern of data areas Y and Z stored in the storage circuit 9 for each bit, and the error judgment circuit 18 compares the model pattern with the deviation value pattern of the data areas Y and Z stored in the storage circuit 9. An OK multiplication signal is output for the matched bit.

The counter 19 counts the above-mentioned OK times signal and inputs this counted value to the control circuit 7.

The control circuit 7 determines the percentage of the number of bits that are OK based on the input count value, and determines that the banknote is genuine if the number of bits is OK, for example, 80% or more.

In addition, the above-mentioned error judgment circuit 18 outputs an NG signal for bits that do not match based on the input comparison signal, and the control circuit 7 uses the number of bits of the NG signal from the counter 19 as data for truth/false judgment. be able to.

Next, the operation will be explained with reference to the flowchart shown in FIG.

When the automatic currency exchange machine is powered on, it is checked whether each circuit device is in a standby state for operation.

Next, when the banknote 1 for exchange is inserted into the automatic exchange machine,
This banknote 1 is connected to the banknote 1 by a photoelectric element 2 and a power source 3.
The identification pattern (printed pattern) is read, and this read pattern is sampled by the sampling circuit 5 and stored in the data area X of the storage circuit 9.

Next, the gate 10 is opened, and the average output level of the bill reading pattern stored in the data area X is calculated by the addition circuit 11 and the division circuit 12. is stored in register 14.

Next, the subtraction circuit 16 calculates a deviation value pattern of the banknote reading pattern using the above average value as a reference, and this deviation value pattern is stored in the data area Y of the storage circuit 9.

For example, when the reading output level of the photoelectric element 2 described above decreases due to temperature change, aging, dust accumulation, etc., that is, when it changes from ■ to V' in FIG. 3, the output level of the bill reading pattern also changes.

Therefore, if the reference voltage is set to 0■ to output the output level of the banknote reading pattern, and this is used as a target for comparison of the model pattern, even if the same banknote is read, the level will be different between level V and ■special, so V' The current banknotes will be determined to be counterfeit banknotes.

However, as in this embodiment, the average value of the output level of the reading pattern is calculated, and this average value is used as the deviation value d1 of the reading pattern. If you take out d2..., dl', d2'..., even if the banknote reading level changes like at V and V', the pattern based on the above deviation value will be the same, and the reading level will change. Not affected by change.

Next, the model pattern and the deviation value pattern stored in the data areas Z and Y of the storage circuit 9 are compared to the comparison circuit 17.
The error determination circuit 18 outputs an OK times signal, and the counter 19 counts the OK times signal.

The control circuit 7 determines that the banknote is a genuine banknote if the count value input from the counter 19 is a predetermined number or more, and determines that the banknote is a counterfeit banknote if it is less than a predetermined number.

If the banknote is determined to be a counterfeit banknote, the banknote is returned, and if the banknote is determined to be a genuine banknote, the exchange operation proceeds to the next step.

That is, the denomination of money to be exchanged is specified, the money to be exchanged is fed out and discharged into the tray, and the inserted banknote is stored to complete one exchange operation.

In addition, although the above-mentioned embodiment described an automatic money exchange machine, this invention can be utilized for an automatic teller machine and other devices necessary for determining the authenticity of banknotes.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a control circuit block diagram of a banknote authenticity determination device, FIG. 2 is a flowchart, and FIG. 3 is an explanatory diagram showing data levels. 1... Banknote, 2... Photoelectric element, 8... Memory circuit, 11...
... Addition circuit, 12 ... Division circuit, 14 ... Register, 1
6...Subtraction circuit.

Claims (1)

[Claims] 1. In a device that reads the identification pattern of a banknote with a detector and compares it with a preset model pattern to determine the authenticity of the banknote, the average value of the output level of the banknote identification pattern read by the detector is calculated. , the difference between the output level of this average value and the identification pattern of the banknote is calculated to calculate the difference pattern, and this difference pattern is compared with the model pattern to determine the authenticity of the banknote. Discrimination method.