JPS63259793A - Sheet paper identifier - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a paper sheet identification device that identifies paper sheets such as banknotes by detecting their patterns.

[Conventional technology]

BACKGROUND ART In an identification device for banknotes, a plurality of magnetic sensors and optical sensors are used to detect the characteristics of a banknote as an object to be detected. In FIG. 7, 1 is this type of sensor, and the output signals of these sensors 1 are amplified to an appropriate voltage or current by an amplifier 2, and further converted into ^/D by various A/D converters 4. The above is manually inputted to the control section 5, and the authenticity of the object to be inspected is determined in the control section 5 based on the aforementioned input signal.

However, this type of equipment is often used outdoors,
Since the temperature range of the operating temperature is very wide, for example, from -lO<0>C to +60<0>C, the sensor is generally provided with a temperature compensator 3 as shown in this figure.

(Problems to be Solved by the Invention) However, in recent years, there has been an increase in demand for devices that can identify high-value banknotes such as 5,000 yen bills and 10,000 yen bills, and the following problems have arisen.

In other words, as the number of denominations to be identified has increased, it is necessary to increase the number of sensors that detect patterns, etc., and it is necessary to add temperature compensation sections to the sensors above them, resulting in a reduction in the number of parts. This has become an obstacle to lowering the price and downsizing of the entire device.

An object of the present invention is to solve the above-mentioned conventional problems and to provide a paper sheet identification device that is less expensive and smaller.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a paper sheet identification device that detects a pattern on a paper sheet and identifies the paper sheet based on the pattern detection output. , a temperature detection means for detecting the ambient temperature; a first storage means for storing the temperature detected by the temperature detection means and the value of the pattern detection output under the temperature; a second storage means storing correction coefficients for correction based on the first storage means;
and means for selecting a correction coefficient stored in the second storage means based on the detected temperature and the pattern detection output value stored in the storage means, and correcting the value of the pattern detection output using the correction coefficient. It is characterized by

[Effect]

According to the present invention, when the paper sheet to be detected is guided to the identification device, the detection values detected by the individual sensors are stored in the first storage device, and when the detection of all patterns is completed, the detection values are stored in the first storage device.
Since the detected value stored in the storage means is read out and the correction corresponding to the ambient temperature at that time is corrected according to the correction coefficient stored in the second storage means, there is no need to provide a temperature compensation circuit for each sensor. It can contribute to cost reduction and miniaturization of equipment.

(Example) Examples of the present invention will be described below in detail and specifically based on the drawings.

FIG. 1 shows an embodiment of the present invention, in which a thermistor is used as a temperature sensor. The thermistor 7 is a temperature-dependent resistor, and by connecting it in series with the resistor 6, applying a constant voltage across it, and extracting the voltage v1 at the connection point, a signal corresponding to the ambient temperature can be obtained. Therefore, by reading the voltage vl, it is possible to know the ambient temperature of an identification device such as a banknote.

The photosensor 8 ('TI NT4) is a type of phototransistor or photodiode that receives reflected light or transmitted light of the light irradiated onto the paper sheet to be detected from a light emitting element (not shown) and detects the paper sheet. An electric signal is generated from each pattern portion by voltage or current according to the reflectance or transmittance. This signal is amplified by the DC amplifier circuit 10 and inputted to the A/D conversion circuit 14 .

The magnetic sensor 9 (T5-T6) detects the
This device reads magnetic information, and the AC component of the read information is amplified to an appropriate voltage by an AC amplifier 11, and then converted to a DC signal corresponding to the magnetic information while passing through a full-wave rectifier circuit 12 and an integrating circuit 13. and is manually input to the A/D conversion circuit 14. Reference numeral 15 denotes a control unit, which controls the entire identification device for paper sheets such as banknotes according to a procedure (
program). Reference numeral 17 is a memory for temporarily storing detection values from various sensors. In the AiO conversion circuit 14, when amplified DC signals from various sensors 8 to 9 are input manually, a certain sensor system is selected according to a command from the control unit 15, and the amplified DC signal of that system is converted into a digital value. and supplies it to the control section 15.

The pattern detection operation of the present invention in the identification device configured as described above will be described in detail with reference to FIG.

First, in step 51, the presence or absence of a paper sheet in the paper insertion port is determined from the output signal of a sensor (not shown) placed in the paper sheet insertion port of the apparatus, and if it is determined that there is no paper sheet, step S2
The control branches to and instructs the A/D conversion circuit 14 to A/D convert the voltage value v1 of the temperature detection signal detected by the thermistor 7. The A/D converted value is thus stored in a specific address of the RAM 17 in step S3. Note that at this time, previously stored values are destroyed and new data is always stored.

FIG. 3 shows an example of the arrangement of information stored in the RAM 17. In an actual memory element, it is arranged one-dimensionally, but in order to make it easier to understand the meaning of each data, it is shown two-dimensionally. . Therefore, the data vl is the address (φ
, φ). That is, in this way, the ambient temperature of the apparatus when detecting the pattern on the paper sheet is first detected. Further, if it is determined in step Sl that there is a sheet of paper, a transport unit (not shown) inside the apparatus is driven to take the sheet of paper into the device, and the A/D conversion circuit 14 has six types of sheets. (corresponding to i) sensors T1 to T6 (see Figure 1) are sequentially selected, and the paper sheet is detected in each predetermined detection interval (corresponding to j) using the converted value obtained from each sensor. Find the detected value St,j (for example, the average value of multiple A/D conversion values within one section), and
17 in sequence. Note that this operation is performed in the next step S.
1 until the paper passes through the last pattern detection sensor in step 5! Although not shown, the last pattern detection sensor described above is constructed by arranging, for example, a light emitting LED and a phototransistor at opposing positions on the conveyance path.

In this manner, when the detection of the detection elements on the paper sheet is completed through each sensor TINT6, the control unit 15 calculates the temperature-corrected detection value Si' of the raw detection value Si,j for each sensor in step S6 according to the following equation (1). Convert to j.

St', j = Ai, xxSi, j --
-----(1) Here, i-1, 2, ..., [i
j=1.2. ..., 9i'=1.2. −． 6
x=1.2. ..., 10 That is, when the current ambient temperature is read from the address (φ, φ) of the RAM 17, which of the correction coefficients Ai, j for each ambient temperature is selected for each sensor Tl-T6 according to FIG. It is determined in step S6 whether A
i and x are correction coefficients set in relation to the ambient temperature for each of the sensors T1 to T6, and are stored in the ROM 16. As shown in FIG. 4, the correction coefficient layer, X, is divided into 10 representative steps of ambient temperature, and is set for each sensor for each step. Note that i of the correction coefficient Ai and x corresponds to 1 to 6 of the sensor Tl-T6, and X is the above-mentioned RAM! , 7 corresponds to temperature steps 1 to 10 at addresses 7. Also,
Although the correction coefficients At and x are shown two-dimensionally in FIG. 4 for easy understanding, they are actually stored at each address in the format shown in FIG. 5.

In addition, here, the correction coefficients At and x may be set by examining the temperature characteristics of each sensor T1 to T6, and appropriately setting the resolution and quantizing the characteristic curve. For example, in the sensor T1, it has been confirmed that the detected value V2 (see Figure 1) manually input to the D/D conversion circuit 14 has a temperature characteristic with a tendency as shown by the curve in Figure 6. In this example, since the resolution is 10 degrees, A1.1 to A1.10 can be set as shown in Table 1 below.

Table 1 □ Returning to FIG. 2 again, once the correction coefficients At, j are determined for each sensor, in step S7, the series detection value of sensor T6 is corrected according to conversion formula (1) sequentially from the series of sensor Tl. The true detected value St', J corresponding to the detected element of the paper sheet is calculated, the calculated value is stored in the RAM 17, and the identification operation is performed based on the detected value St, j.

As a result of the above, it has become possible to detect patterns on banknotes and the like with more accurate temperature compensation than before without adding a special temperature compensation circuit to each sensor.

Note that although we have explained here the case of equal resolution over a predetermined temperature range, in the case of a sensor system with nonlinear temperature characteristics, the resolution is narrower in the temperature range where temperature changes are large, and the In the moderate temperature range, the resolution can be set wide.

Note that in the conventional method using a temperature correction circuit, it is impossible to perform the above-described detection or a very large number of parts are required. In contrast, in the present invention, the number of parts can be reduced and the accuracy of temperature compensation of the sensor system can be improved.

〔Effect of the invention〕

As explained above, according to the present invention, a temperature sensor for detecting the ambient temperature is arranged in the identification device, and on the other hand, the temperature sensor is stored in a ROM etc. in advance for converting each pattern detection sensor into a true detected value for each predetermined temperature range. The correction coefficient for each pattern detection sensor is stored in memory, and each time a paper sheet is brought in, the detection value is corrected for all sensors using the correction coefficient corresponding to the temperature at that time. It is possible to compensate the temperature of each sensor system using only the calculation function without adding a special temperature compensation circuit to the system.

Therefore, in an identification device for banknotes, etc., which has many sensors for pattern detection, the number of parts is reduced compared to the conventional one (this tendency is especially noticeable in the case of sensor systems with non-linear temperature characteristics), and the temperature It has become possible to use sensors that could not be used due to their large characteristics, and it has become possible to provide a cheaper and more compact device.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the circuit configuration in an embodiment of the present invention, FIG. 2 is a flowchart showing the pattern detection procedure, and FIG. Figure 4 is an explanatory diagram of the information arrangement. Figure 4 is an explanatory diagram of the correction coefficients stored in the ROM for reading. Figure 5 is an arrangement diagram when the correction coefficients shown in Figure 4 are actually stored in the ROM. , FIG. 6 is a characteristic curve diagram showing an example of the temperature characteristics of a sensor used in the process of setting the correction coefficient, and FIG. 7 is a block diagram showing an example of the configuration of a pattern detection section in a conventional identification device. 7... Thermistor, 8 (TI-74)... Photo sensor, 9 (T5~T
l1)...Magnetic sensor, 14...A/D conversion circuit, 15...Control unit, 16...ROM. 17...RAM. Ai, x... Correction coefficient, Si, j... Sensor detection value.

Claims (1)

[Scope of Claims] A paper sheet identification device that detects a pattern on a paper sheet and identifies the paper sheet based on the pattern detection output, comprising: a temperature detection means for detecting ambient temperature; and the temperature detection means. a first storage means for storing the temperature detected by and the value of the pattern detection output under the temperature; and a correction coefficient for correcting the value of the pattern detection output based on the ambient temperature. a second storage means; and a correction coefficient stored in the second storage means is selected based on the values of the detected temperature and the pattern detection output stored in the first storage means; A paper sheet identification device comprising means for correcting a value of a detection output.