JPS5834868B2 - Identification device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for identifying printed matter by reading patterns of sheet-like printed matter such as banknotes and certificates.

Conventionally, when detecting patterns on banknotes, the signal level changes due to drift of old and new amplifier circuits, dirt, etc. of the banknote, which adversely affects denomination discrimination and authenticity discrimination.

Particularly when using optical detection means, obtaining a stable signal against such level changes has been a major problem.

An object of the present invention is to provide a device capable of determining the type or authenticity using a signal that is stable even with such level changes.

According to the present invention, the effect is particularly remarkable when a transmitted light sensor is used as the sensor, and it is also very effective when used as a reflected light sensor.

Furthermore, it is also effective when a magnetic sensor is used as the sensor.

Hereinafter, the present invention will be described in detail with reference to examples, taking banknotes as an example.

FIG. 1 is a diagram showing an example of the arrangement of sensors of the present invention.

For example, the description will be made assuming that the banknote 1 is conveyed at high speed in the lateral direction thereof, that is, in the direction of the arrow 2.

Pl p P2...yP21tPn is a pattern sensor, and the pattern due to transmitted light or reflected light is indicated by the broken line arrow 3-1.3-2.・・・・・・3 n 1
It is arranged so that it is obtained along y3 n.

From a practical point of view, the number n of sensors is n −2 to 4.
is appropriate.

As mentioned above, the sensor P1 t P2 t...
, The signal from Pn changes even in areas other than the original pattern, but the signal from each sensor uniformly increases or decreases in level in response to the difference between the old and new, and the level of the signal from each sensor uniformly increases or decreases in response to fairly large dirt. , n is around the above range, there is a high possibility that the influence of the dirt will be felt on two or more sensors.

Therefore, in order to reduce the influence of old and new sensors, drift, and such contamination, the present invention takes the difference between signals between adjacent sensors, converts the difference signal into a band signal, and then sets two appropriate thresholds. I decided to perform binarization for each.

In this way, by taking the difference between the signals from the two sensors, uniform differences between the sensors can be canceled out, and by bandpass filtering, large dirt and noise components below the fineness of the pattern can be ignored. By performing binarization, it is possible to extract only the portion where the pattern change is obvious.

FIG. 2 shows an embodiment of the present invention, and FIG. 3 shows signal waveforms from various parts in FIG.

In FIG. 2, 10-1.10-2. ......, 1
0-n are amplifier circuits for adjusting variations in sensitivity of each sensor.

The analog output waveform corresponding to sensor PiyPi+1 is shown at 20-1°20 1+1 in FIG. 3a.

As shown in Figure 3a, each waveform may have a
'1,20'-i+.

Therefore, as shown in FIG. 2, 11-1.・・・・・・+1
A difference circuit of 1nl calculates the difference between signals corresponding to adjacent sensors, and a band-completed wave circuit 12-1.・・・・・・、
12-n-〒, by converting the band original wave, Figure 3 shows 2.
Waveforms such as 1-i and 21'-i are obtained.

With this band original wave, the signal component of the pattern to be detected can be stably obtained.

As can be seen from this waveform, there are some differences in the signal level depending on whether the banknote is old or new or dirty, but if we focus only on the polarity of the signal, there is not much difference in polarity behavior between the two waveforms, and the banknote passes through. You can see that it will be close to zero at times when it is not being used.

Therefore, two threshold values with different signs, such as 24.25 in Figure 3, are set, and the signal 21-
1 is equal to or higher than the threshold value 24, "1'", threshold value 2
Two binarized signals 26-i, which are 1″ when 5 or less,
2γ-■ (Fig. 3c, d).

Each binary signal 26i, 27-i is the original signal 20i
, 20-i, each becomes 1'' only when there is a clear difference between them.

13-1, 13-2 in Figure 2. ......, 13-
n-yo is signal 21-1.21-2.・・・・・・21-
〒Yo positive side, 14-1.

14-2. . . . , 14-n- are circuits for performing negative side binarization, and the threshold generation circuit 15
．． For example, signal level 24.25 from 16 is used as a threshold value for binarization.

Incidentally, differences between old and new banknotes, drift of the amplifier circuit, dirt, etc. are separately detected and the amplifier circuit 101.10-2.
. . . 10-n, the difference circuits 11-L . . . 11-n- shown in the second diagram can be omitted.

Also, instead of the above difference circuit, adjacent signals (20-1°2
0 2), (202,2O-3), (20-"1°20
It is also effective to use a circuit or the like that takes the correlation between n).

28-1 in Figure 3e is 2', 2
This is a plot of the state at each time when 7-i is viewed as a binary number corresponding to, for example, 2°, and it can be seen that the original analog signal has been ternarized into three states.

Therefore, hereinafter, a pair of binary signals such as 26i and 27-i will be referred to as a ternary signal.

Although Q in FIG. 2 is omitted in FIG. 1, it is a conveyance pitch detection sensor attached to the banknote conveyance mechanism, which outputs a pulse every time the banknote travels a certain distance.

29 in the same figure is a circuit for shaping the output pulse from the sensor Q.

30-1°30-2. . . . , 30 nt is a register with each stage having a depth of 2 bits for storing the ternarized signal at each position, and 31 is a circuit that generates a signal 32 for controlling the operation of each register.

The register group 30 is a shift register or RAM (
Random Access Memory).

The control signal 32 is a shift clock signal if the register group 30 is a shift register, or a shift clock signal if the register group 30 is a RAM.
It consists of a signal specifying an address in the RAM, a signal instructing writing to the RAM, a strobe signal thereof, etc.

Moreover, Yp in FIGS. 1 and 2 indicates that the banknote is at the sensor P1°P2.
. . . is a sensor for detecting the passage over Po. As shown in FIG. 2, its output is waveform-shaped at 33 and then input to one input terminal of the control circuit 31.

The other input terminal of the control circuit 31 is the waveform shaping circuit 29
In order to drive the register group 30 as described above, the control signal 32 is generated in synchronization with the output from the sensor Q every time the banknote moves a certain distance, and the control signal 32 is generated at each position of the banknote. The value signal is stored in the register group 30.

34-1.34-2,...34-n in Figure 2
is a group of registers that should store data related to standard banknotes, 3
Reference numeral 5 denotes a comparison circuit, which performs authentication and denomination determination of input banknotes.

That is, the ternary pattern of the input unknown banknote is temporarily stored in the register group 30, but when an output pulse is output from the circuit for detecting the end of banknote passage in 36, the register group 30 and the register group 34-1 are stored.

34-2. ......, compared with 34-m,
The denomination with the highest degree of matching is determined, and if the denomination does not match any denomination, it is determined to be a counterfeit bill and the determination results are output from 37.

Register group 34-1.34-2. ......, 34-
The configuration of m may be the same ternary pattern as register group 30 or the register group 3 whose matching degree should be checked.
It may take the form of storing individual addresses within 0 and their states.

In addition, the number m of register groups is as follows for the current circulation ticket:
Since there are four types: 500 yen, 1,000 yen, 5,000 yen, and 10,000 yen,
It is desirable that at least m≧4.

Among the above embodiments, register group 34-1 and 34-2.

. . . 34-m and the comparison circuit 35 may be assigned to a computer such as a microcomputer, and if the banknote conveyance speed is slow, the register group 30 may also be configured using a computer. You can also do that.

Although the case where an optical sensor is used has been described above, the present invention is also effective when a magnetic sensor is used instead of the optical sensor, and in that case, the difference circuit 11-1 of the second illustrated embodiment.
11-2. . . . , 11-drunk] is omitted, and the amplifier circuits 10-1, 112 . . . . The output signal of 10-n can be directly input to the band-prepared wave circuit 12-Ll2-2゜12-W.

According to the present invention, a plurality of difference signal sequences are obtained by the n pattern sensors, and based on this, the type of printed matter and the authenticity are determined, so reliability is high.

It is clear that the number n needs to be at least three in order to use a plurality of difference signal sequences.

By performing the signal processing described above, it is possible to cancel out differences in signal levels caused by differences between new and old banknotes, drift in amplifier circuits, dirt, etc., and obtain stable signals. It is possible to provide a device that can perform discrimination and authenticity discrimination with high reliability.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of the arrangement of sensors of the present invention, FIG. 2 is a diagram showing an embodiment of the present invention, and FIG. 3 is a diagram of signal waveforms from various parts of FIG. 2. In the figure, 1 is a banknote, 10 is an amplifier circuit, 11 is a difference circuit, 12 is a band dissipation circuit, 13 and 14 are binarization circuits, 15 and 16 are threshold generation circuits, and 29 is a waveform shaping circuit. , 30 is a register group, 31 is a control circuit, 34 is a register group, and 35 is a comparison circuit.

Claims (1)

[Claims] 1 A one-dimensional object that is arranged in a second direction opposite to and perpendicular to a printed matter that is moved in a first direction, and that extends in the first direction of the printed matter due to the movement of the printed matter. Three or more detection elements each output a signal sequence representing a pattern of the area, and based on the signal sequence from each detection element and the signal sequence from an adjacent detection element, the pattern of two one-dimensional areas adjacent to each other is detected. means for obtaining a difference signal string representing a difference in the second direction for each detection element; and determining the type or authenticity of the printed matter using the obtained difference signal string corresponding to each detection element. and a means for performing the same.