WO2015051681A1 - Ultrasonic detection device and detection method for adhesive-tape and overlapped banknotes in processing of banknotes - Google Patents

Abstract

An ultrasonic detection device and method for adhesive-tape and overlapped banknotes in the processing of banknotes (33). The device comprises: an ultrasonic wave transmitting unit and an ultrasonic wave receiving unit, wherein the ultrasonic wave receiving unit comprises a first circuit board (1) and an ultrasonic wave receiving sensor (3) fixed onto the first circuit board (1) via a first bracket (2); and the ultrasonic wave transmitting unit comprises a second circuit board (5) and an ultrasonic wave transmitting sensor (4) fixed onto the second circuit board (5) via a second bracket (2), and the ultrasonic wave transmitting unit corresponding to the ultrasonic wave receiving unit. The method comprises: an ultrasonic wave transmitting unit transmitting ultrasonic waves which pass through banknotes (33), and an ultrasonic receiving unit receiving an attenuated signal average value for analysis processing, so as to recognize adhesive-tape and overlapped banknotes (33). The method has the advantages of a rapid detection speed, high accuracy and no contact between banknotes (33). The intensity of the received signal is only related to banknotes (33) passing between the receiving sensor and the transmitting sensor, and is not affected by factors such as whether adhesive tapes reflect light, etc.

Description

 Ultrasonic detecting device and detecting method for rubber strip and double sheet in banknote processing

 The present invention relates to a banknote processing apparatus, and more particularly to a banknote detecting and recognizing apparatus for a banknote processing machine and a detecting method thereof. Background technique

 In industrial and agricultural production and people's commercial activities, banknotes are extremely vulnerable to damage in the circulation field. People generally use damaged paper sheets for pasting and then continue to use them. There are also unscrupulous traders who use stitching and pasting to make counterfeit coins. In the processing of banknotes, there is often a re-folding that affects the counting accuracy during the processing of banknotes. When the financial department clears the banknotes, it is necessary to accurately and effectively distinguish the banknotes with the rubber strips or the double-drawn banknotes. The ultrasonic inspection device can quickly and accurately detect and identify single banknotes, glue banknotes or heavy banknotes.

 The existing banknote processing equipment mainly has two methods for detecting the multi-sheet and the glue banknotes. One is to use a mechanical detecting method, and the banknote passes between two metal rollers that are close together, one of which is non-rigid Installed, due to the thickness of the banknotes, the displacement of the non-rigid mounting shaft will vary depending on the thickness of the banknotes. With this different displacement, the strips or sheets can be detected. The disadvantages of this type of mechanical testing device are that it is bulky, bulky, and noisy. The grease stain on the roller surface has a serious influence on the measurement accuracy. Another method is to use the attenuation characteristic of the banknote to transmit infrared light to detect the multi-sheet. The disadvantage of this method is that the degree of soiling of the banknote has a great influence on the detection result, and the glue banknote cannot be detected. Summary of the invention

 In view of the deficiencies of the prior art, it is an object of the present invention to provide a detecting device and a detecting method thereof for detecting a rubber strip banknote or a multi-sheet banknote by using ultrasonic waves passing through different media to attenuate different principles.

 The technical solution adopted by the present invention to achieve the above object is:

 The ultrasonic detecting device for the strip processing and the multi-sheet in the banknote processing comprises: an ultrasonic transmitting unit and an ultrasonic receiving unit; the ultrasonic receiving unit comprises a first circuit board and an ultrasonic receiving sensor fixed on the first circuit board by the first bracket The ultrasonic transmitting unit includes a second circuit board and an ultrasonic transmitting sensor fixed to the second circuit board by the second bracket; the ultrasonic transmitting unit and the ultrasonic receiving unit are correspondingly disposed.

 The first circuit board and the second circuit board are parallel and the ultrasonic receiving sensor and the ultrasonic transmitting sensor are oppositely disposed, and the axes of the ultrasonic receiving sensor and the ultrasonic transmitting sensor are coincident, and the angle formed by the normal line of the banknote is 15 ~20 degrees.

The opposite surfaces of the ultrasonic receiving sensor and the ultrasonic transmitting sensor are parallel and have a pitch of 15 to 20 mm. The ultrasonic wave transmitting sensor is connected to an ultrasonic wave transmitting circuit provided on the second circuit board; the ultrasonic wave transmitting circuit includes a CPU and an ultrasonic signal driver connected thereto, and the ultrasonic signal driver is connected to the ultrasonic wave transmitting sensor. The ultrasonic signal driver uses a triode; the two input terminals are respectively connected to the CPU; the first input terminal is sequentially connected to the base of the triode Q1 through the resistor R1, the capacitor C1, and the resistor R2, and the emitter of the triode Q1 is connected to the power source, and the resistor R3 The other end is connected to the power supply, the other end is connected to the junction of the capacitor C1 and the resistor R2, the collector is grounded through the resistor R4, and the diode is connected between the collector and the emitter; the second input terminal sequentially passes through the resistor R5, the capacitor C2, and the resistor R6. Connected to the base of transistor Q2, the emitter of transistor Q2 is connected to the power supply, the resistor R7 is connected to the power supply, the other end is connected to the junction of capacitor C2 and resistor R6, and the collector is grounded via resistor R8. Collector and emitter A diode is connected between them; an ultrasonic emission sensor is connected between the collector of the transistor Q1 and the collector of the Q2.

 The second circuit board is provided with a plurality of ultrasonic signal drivers respectively connected to the plurality of ultrasonic wave transmitting sensors, the input ends of which are connected to the CPU; the first circuit board (1) is provided with the second circuit board (5) The ultrasonic emission sensor has the same number of ultrasonic receiving sensors.

 The ultrasonic detecting method for the strip and the double sheet in the banknote processing includes the following steps:

 The CPU disposed on the second circuit board outputs multiple ultrasonic signals, and each ultrasonic signal driver converts the ultrasonic signal into an ultrasonic scanning driving signal, and drives the corresponding ultrasonic transmitting sensor to emit ultrasonic waves;

 The plurality of ultrasonic receiving sensors on the first circuit board respectively receive the ultrasonic waves passing through the banknotes and convert them into electrical signals, and are amplified by the corresponding ultrasonic signal amplifiers, and are subjected to rectification and filtering by the ultrasonic signal rectifying filter to obtain the banknotes. Attenuated multiple sets of analog signals;

 The single-chip microcomputer on the first circuit board receives the analog signal, and after each set of analog signals is respectively A/D converted into a digital signal and processed, if at least one of the processing results is a strip or a double sheet, the banknote is glued. Strip or double; If the result of the multiplexing is a single banknote, the banknote is a single banknote.

 The ultrasonic signals are two complementary pulse signals having a pulse frequency of 300 kHz; respectively driving the two transistors Q1 and Q2 of the ultrasonic signal driver.

 The ultrasonic scan driving signal is a plurality of sets of pulse signals, each set of pulse signals includes six pulses; and is outputted in a scanning manner with a scanning frequency of 1.25 kHz.

 The performing A/D conversion to a digital signal and processing includes the following steps:

 After A/D conversion of the set of analog signals, a set of digital signals is collected within the width range of the scanned banknotes; if a single sheet or a multi-sheet banknote is detected, the average method is adopted, that is, the two ends of the set of digital signals are first removed. Data, the average value is calculated for the remaining data; when the average value is greater than the set threshold, the banknote is re-tensioned, otherwise it is a single sheet;

 If a single sheet, strip, or multi-sheet is detected, the sheet is recognized by the average method according to the previous step, and the slip sheet is identified by the sliding filter method, that is, a group collected within the range of the scanned bill. In the digital signal, the number of points that are continuously lower than the threshold is found. When the number of consecutive points is greater than the threshold, the banknote is considered to be a strip of banknotes, otherwise it is not a strip of banknotes.

 The invention has the following beneficial effects and advantages:

1. The invention has high detection speed and high accuracy. Since the invention works by the principle that the signal intensity is attenuated differently when the ultrasonic waves pass through different media, and there is no contact between the banknotes, the received signal strength is only related to the banknote passing between the transceiving sensors, and is not affected by the reflective strips, etc. The impact of factors. 2. Since the invention has no mechanical device, energy saving during operation, no noise, no influence on the surface of the banknote, no banknote or banknote, improving the stability and reliability of the banknote processing system; facilitating popularization and application .

 3. The present invention is simple in structure, and the entire circuit components of the ultrasonic transmitting unit (portions of Figs. 4a to 4c) are mounted on a 177 mm*17 mm PCB board, and only two wires of the power source are connected to the mother machine. The whole circuit components of the ultrasonic receiving unit (parts of Figure 6a to Figure 6b) are also mounted on another 177mm*17mm PCB board. In addition to the power supply line, there are two left and right ultrasonic signal output lines, four in total. Line; therefore, the wiring is convenient, easy to install, and can be installed in various types of banknote processing machines.

 4. The present invention provides flexibility in the final data processing, since instead of a switching quantity, a set of (about 77) data representing the ultrasonic attenuation characteristics can be used to process the data. Method, sliding filter extremum method and other methods to process these data, in order to finally get the correct results. The data processing process of the method is simple, the calculation speed is fast, and the accuracy is high. DRAWINGS

 Figure la is a schematic structural view of an ultrasonic transmitting and receiving portion of the present invention;

 Figure lb is a structural diagram of the ultrasonic sensor of the present invention;

 Figure 2 is a schematic view of the shield cover and installation method;

 Figure 3 is a block diagram of the ultrasonic transmitting circuit;

 Figure 4a is a circuit diagram of the ultrasonic signal driver;

 Figure 4b is a circuit diagram of the ultrasonic transmitting unit single chip microcomputer;

 Figure 4c is a power conversion circuit diagram of the ultrasonic transmitting unit;

 Figure 5 is a block diagram of the ultrasonic receiving circuit;

 Figure 6a is an analog signal processing circuit diagram of the ultrasonic receiving unit;

 Figure 6b is a power conversion circuit diagram of the ultrasonic receiving unit;

 Figure 7 is a waveform diagram of the ultrasonic drive signal;

 Figure 8 is a waveform diagram of the ultrasonic scan driving signal;

 Figure 9 is a schematic diagram showing the test output voltage difference of a single banknote, a glue banknote, and a double banknote;

 Figure 10 is a schematic view showing the structure of the ultrasonic array detecting device installed on the banknote sorting machine;

 Figure 11 is a partial enlarged view of Figure 10;

 Figure 12 is a schematic structural view 1 of the ultrasonic array detecting device;

 Figure 13 is a schematic structural view 2 of the ultrasonic array detecting device;

Among them, 1 first circuit board, 2 brackets, 3 ultrasonic receiving sensors, 4 ultrasonic transmitting sensors, 5 second circuit boards, 6 shields, 7 grounding terminals, 8 positive terminals, 9 center lines, 10 clearing machines The device, 11 ultrasonic signal generator, 12 ultrasonic signal conditioner, 13 ultrasonic signal driver, 14 ultrasonic signal amplifier, 15 ultrasonic signal rectification filter, 16 A/D converter, 17 signal processor, 18 ultrasonic sensor lead hole, 19 locating pin, 21 signal A, 22 signal B, 31 on the wheel, 32 on the wheel, 33 banknotes. detailed description

 The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

 The present invention is a banknote detecting device attached to a banknote processing machine such as a banknote sorting machine or a money counter, and this embodiment is attached to a banknote sorting machine as an embodiment.

 The detecting device of the invention is installed in the banknote processing machine and has two parts: transmitting and receiving. The transmitting and receiving sensors are coaxially mounted, and the coaxiality deviation is 1 mm; the end faces of the two sensors are 15 to 20 mm apart; the axes of the two sensors are The angle of the plane normal of the banknote is about 15 to 20 degrees; the resonant frequency of the ultrasonic sensor is 300 KHz; the terminals of the transmitting and receiving sensors are connected to the signal processing circuit.

 The signal processing circuit includes circuits for transmitting and receiving two portions, which are respectively disposed on a circuit board of the transmitting portion and a circuit board of the receiving portion. The transmitting part is responsible for the generation, processing, amplification and output driving of the 300KHz ultrasonic signal; the receiving part is to amplify the 300KHz ultrasonic signal attenuated by the banknote, and after rectifying and filtering, it is sent to the A/D conversion circuit, and the analog quantity is converted into a digital quantity for the ARM single chip pair. Signal analysis processing, resulting in a single banknote, a strip of banknotes or a double banknote.

 When the device is installed in the banknote sorting machine, the two circuit boards are fixed to the detection box of the banknote sorting machine, the emitting portion is fixed to the lower measuring box, and the receiving portion is fixed to the upper measuring box. A pair of wheel sets are mounted on both sides of the ultrasonic detecting device. When working, the wheel group drives the banknotes on one hand, and on the other hand, the movement track of the banknotes is fixed by the wheel sets, so that the movement track of the banknotes is located on the center line of the ultrasonic detecting device. Referring to Fig. 10, the circled portion 10 in Fig. 10 is the apparatus of the present invention. Figure 11 is a partial enlarged view of Figure 10, 31 is the upper wheel, 32 is the lower wheel, 3 is the ultrasonic receiving sensor, 4 is the ultrasonic transmitting sensor, 33 is the detected banknote, and the banknote is moved by the wheel.

 As shown in FIG. 1a, FIG. 1a is a schematic structural view of an ultrasonic transmitting and receiving portion. The whole device is composed of an ultrasonic transmitting unit and an ultrasonic receiving unit. During operation, the banknote passes through the center line 9 of the ultrasonic transmitting unit and the ultrasonic receiving unit in a horizontal manner (ie, two The center line of a parallel board). The ultrasonic detecting device is composed of a PCB circuit board 1 (first circuit board), 5 (second circuit board), a bracket 2, an ultrasonic wave receiving sensor 3 having a resonance frequency of 300 kHz, and an ultrasonic wave transmitting sensor 4; two of the brackets are triangular type , the structure is the same shape, see Figure lb. In Figure lb, 18 is the ultrasonic sensor lead hole, 19 is the positioning pin, and the inclination angle must be guaranteed from 15 to 20 degrees. The role of the bracket is to form an angle between the ultrasonic sensor and the PCB board. The angle between the ultrasonic transducer unit and the ultrasonic sensor receiving unit forms an angle A with the normal of the banknote. To ensure that between 15 and 20 degrees, the purpose of designing this angle is to prevent the ultrasonic signal from being repeatedly reflected between the banknote and the ultrasonic sensor, and affecting the received signal; in order for the ultrasonic wave passing through the banknote to be a beam, Ensure that there is a certain distance B between the two ultrasonic sensors, and the distance B is between 15 and 20 mm. In order to ensure that the ultrasonic sensor receives a certain sensitivity, the maximum deviation of the ultrasonic transmitter and the ultrasonic receiver should be 1 mm.

As shown in Figure 2, in order to ensure that the ultrasonic sensor is not affected by the surrounding environment and electromagnetic field, a shield cover is required. The shield is 0.2~0.3mm copper beryllium wrapped around the outer side of the sensor, and the joint of the shield 6 is not closed. The grounding terminal 7 of the shield and the ultrasonic sensor is connected to the signal ground of the PCB; the positive terminal 8 of the ultrasonic sensor is a signal output terminal, and is connected to the input end of the ultrasonic signal amplifier 14. In order to avoid the generation of ultrasonic transmitting units to the surrounding circuits In effect, the ultrasonic transducer of the transmitting part also needs to be equipped with a shield, which is connected to the signal reference ground point on the circuit board, that is, the GND end.

 As shown in FIG. 3, FIG. 3 is a circuit block diagram of an ultrasonic transmitting unit, which is disposed on the second circuit board 5, mainly by an ultrasonic signal generator 11, an ultrasonic signal conditioner 12, an ultrasonic signal driver 13, and an ultrasonic transmitting sensor ( Ultrasonic transducer) 4 composition.

 4 is a schematic diagram corresponding to FIG. 3, as shown in FIGS. 4a, 4b, and 4c, the ultrasonic signal generator 11 and the ultrasonic signal conditioner 12 are completed by the single chip STC12C5412, and the waveform of the ultrasonic signal outputting 300 kHz is shown in FIG. Complementary control signal, the advantage of this driving method is to eliminate the DC component at both ends of the ultrasonic transducer, prevent the metal plating on the surface of the ultrasonic transducer resonating device from falling off, and prolong the service life of the ultrasonic transducer. The signal A21 is The output of pin 5 of the single chip microcomputer is connected to the base of the driving circuit Q1. The signal B22 is output by the pin 6 of the single chip microcomputer, and is connected to the base of the driving circuit Q2. The driving circuit Ql, Q2 completes the work of driving the ultrasonic transmitter UT5. The electrical signal of 300KHz is converted into an acoustic signal by the UT5; the ultrasonic driving signal is output by scanning, as shown in Fig. 8, each group of 6 pulses, the scanning frequency is 1.25KHz, due to the particularity of the operation of the ultrasonic device, when it is applied When the driving signal is continuous, the resonant device of the ultrasonic transducer will quickly enter the fatigue state. The sensitivity of the transmission and reception is reduced. The advantage of the scanning mode drive is that it overcomes this shortcoming and ensures the highest sensitivity of the ultrasonic transmitting and receiving sensors. The ultrasonic signal driver 13 is completed by a triode Q1 and a triode Q2. The DC/DC converter LT3580 in Fig. 4c converts the +5V power supply into a +9V power supply to the ultrasonic transducer, and the ultrasonic transducer converts the 300KHz electrical signal into Acoustic signals of the same frequency are transmitted. The LT3580 boosts the 5V DC supply to 9V for use in the driver circuit as well as Q1 and Q2.

 5 is a circuit block diagram of the ultrasonic receiving unit, which is disposed on the first circuit board 1, mainly by an ultrasonic receiving sensor (ultrasonic transducer) 3, an ultrasonic signal amplifier 14, an ultrasonic signal rectifying filter 15, A/D conversion The signal processor 16 is composed of a signal processor 17, wherein the A/D converter 16 and the signal processor 17 are implemented by a single chip microcomputer.

 Fig. 6 is a schematic diagram of an analog signal processing circuit of the ultrasonic receiving unit, as shown in Figs. 6a and 6b. Figure 6a shows the ultrasonic receiving amplifier circuit. The DC/DC converter LT3580 in Figure 6b converts the +5V supply of VCC to a voltage of -5V and supplies the amplifier with a -5V supply. The ultrasonic transducer URA1 converts the 300KHz acoustic signal after the banknote is attenuated into a corresponding electrical signal, and is coupled to the fourth pin of the U1 input terminal of the 3-stage integrated amplifiers U1, UA2A, and UA2B via the capacitor CA1. This electrical signal is weak. After 38800 times of comprehensive amplification, it is output by the 7th pin of the integrated amplifier UA2B, and is connected to the half-wave rectification filter circuit composed of DA1, DA2, RA13, RA14, CA11 through the coupling capacitor CA10. The average value of the signal after attenuation of a banknote, a strip of paper, or a double banknote. The single banknote has less attenuation on the ultrasonic wave, and the obtained signal voltage is relatively higher; the rubberized banknote increases the thickness of the strip portion relative to the single banknote, and the attenuation of the ultrasonic wave is larger, and the obtained signal voltage is smaller than that of the single banknote. The signal is smaller; the double banknote is the overlap of two banknotes, and the attenuation of the ultrasonic signal is larger than that of the glue banknote. The obtained signal voltage is smaller than the signal of the plastic banknote, and the whole test signal is in a ladder state. See Figure 9. This signal is sent to the AIN input terminal of the MCU in the ultrasonic receiving unit, converted into a digital signal by the A/D converter in the chip, and analyzed by the CPU to identify a single sheet, a strip of glue or a multi-sheet.

After the CPU of the ultrasonic receiving unit receives the signal after the banknote is attenuated, the analysis process includes the following steps: (1) A/D conversion is performed on the received signal, and a set of digital signals relative to the analog signal is acquired within the width of the scanned banknote. For example, for a RMB with a denomination of 100 yuan, the RMB width of a 100-yuan denomination is 77 mm. When collecting one data per 1 mm, at least 75 valid digital signal quantities can be collected. The data near the edge is not necessarily accurate, so give up.

 (2) processing the digital semaphore according to the selected algorithm;

 (2-1) If only a single sheet or a multi-sheet is detected, the average method can be used. Since the front edge of the banknote enters the detection zone and the rear edge leaves the detection zone, it is an excessive zone, and the detected value error is large. In order to ensure the accuracy of detection, firstly, some data near the front and rear edges are removed (determined according to actual use conditions). The number, in this embodiment, the front edge removes 20 data points, the trailing edge removes 10 data points), and the average value is calculated for the remaining data; if the average value is greater than the set threshold, the banknote is re-tensioned, otherwise For a single sheet;

 (2-2) If it is necessary to detect a single sheet, a strip, or a multi-sheet, for the detection of a multi-sheet, the method of (2-1), that is, the average method can be used. For the detection of rubber strips, the average method is not applicable. Here, a sliding filtering method can be used, that is, within a valid data range (within the banknote range), a continuous number of points below the threshold is found, and when the continuous number of points is greater than a certain set value, the banknote is considered to be a glue. Coin. For the ECB (European Central Bank) standard, the minimum strip that can be detected is 10mm*40mm. Considering the error of the front and back edges of the strip, when the number of consecutive points is greater than 6 points, it can be judged as strip. currency.

 (3) Determination of the threshold in system detection. This threshold needs to be determined according to the actual situation of different currencies (the method for determining the threshold of rubber and re-dollars is the same). For the RMB, it is necessary to use the new RMB as the standard currency, and repeatedly collect the ultrasonic waves. The attenuation value, which is stored as the standard deviation of the standard currency for later use. When it is necessary to detect the glue or the coin, add a certain offset to the difference (according to the actual situation) In this embodiment, the actual offset is +10) as the threshold. According to the threshold, the glue or the coin can be detected by the above method (1) or (2).

 The above steps are data processing steps of a pair of transmitting or receiving ultrasonic units. When multiple pairs of transmitting or receiving ultrasonic units are used, when the detection result of at least one pair of transmitting or receiving ultrasonic units is a strip or a double sheet, the banknote is a strip or Re-stocking banknotes; if the detection results of multiple pairs of transmitting or receiving ultrasonic units are normal banknotes, the banknotes are normal banknotes.

 Example 1

 In the application of this embodiment, the focus is on the detection of the multi-banknotes. Such an application can satisfy the requirements by using two pairs of ultrasonic sensors, and the specific structure is shown in Fig. 12. The two transmitting or receiving ultrasonic sensors are spaced apart by a length of the banknote, and the long side of the banknote is laterally moved by an array of two pairs of ultrasonic sensors.

 The signal terminals of the two ultrasonic transducers of the ultrasonic transmitting unit are connected to the respective two ultrasonic transmitting driving circuits; the signal terminals of the two ultrasonic transducers of the ultrasonic receiving unit are connected to the signal input ends of the two ultrasonic signal amplifiers After the amplified signals are smoothed by the respective rectifying and filtering circuits, they are connected to the CPU of the ultrasonic receiving unit (here, the CPU with the A/D is selected).

The ultrasonic transmitting unit works under the coordination of the single chip microcomputer (STC12C5412 in this embodiment), the single chip microcomputer completes the generation of the ultrasonic signal, the synthesis of the scanning signal, etc., and the scanning signal is output from the 5th and 6th pins, and is connected to each channel. The base of the driving transistor is driven in the driving circuit, and the ultrasonic wave is emitted through the driving circuit and the ultrasonic transducer. The two ultrasonic sensors in the ultrasonic receiving unit send the two signals to the input end of the two integrated amplifiers, and after being amplified, smoothed and smoothed, they are sent to the ultrasonic receiving unit, that is, the main single chip microcomputer (STM32F207VGT6 in this embodiment). /D Revenue end AIN1 ~ AIN2, A/D conversion of the analog signal, data analysis processing, and finally the desired result, that is, the normal single banknote or the heavy banknote is judged.

 Example 2

 In the application of this embodiment, not only the multi-sheet banknotes but also the tape banknotes need to be detected, so that it is necessary to scan the entire banknotes. In order to achieve this, the ultrasonic transmitting group consists of 15 ultrasonic transmitting units to form a transmitting array. Similarly, the ultrasonic receiving group consists of 15 receiving units to form a receiving array, as shown in Fig. 13, the two rows of corresponding ultrasonic transmitting units and ultrasonic receiving units are parallel. In this way, all banknotes in the current commercial circulation area can be covered. The signal terminals of the ultrasonic transducers of the ultrasonic transmitting unit are connected to respective 15-way ultrasonic transmitting and driving circuits; the signal terminals of the ultrasonic transducers of the ultrasonic receiving unit are connected to the signal input terminals of the 15 ultrasonic signal amplifiers, and amplified. The subsequent signals are smoothed by the corresponding 15-way rectifying and filtering circuits, and then connected to the CPU of the ultrasonic receiving unit (here, the CPU with the A/D is selected).

 The ultrasonic transmitting unit works under the coordination of the single chip microcomputer (STC12C5412 in this embodiment), the single chip microcomputer completes the generation of the ultrasonic signal, the synthesis of the scanning signal, etc., and the scanning signal is output from the 5th and 6th pins, and is connected to each driving. The base of the triode is driven in the circuit, and the ultrasonic wave is emitted through the driving circuit and the ultrasonic transducer. The 15-channel ultrasonic sensor in the ultrasonic receiving unit sends 15 signals to the input end of the 15-channel integrated amplifier, and after being amplified, smoothed and smoothed, it is sent to the ultrasonic receiving unit, that is, the main single-chip microcomputer (STM32F407VFT6 in this embodiment). /D income terminal AIN1 ~ AIN15, A / D conversion of the analog signal, data analysis and processing, and finally get the desired result, that is, to determine the normal single banknote, the glue banknote or the heavy banknote.

Claims

& 禾U ΐ

1. An ultrasonic detecting device for strips and sheets in banknote processing, characterized by comprising: an ultrasonic transmitting unit and an ultrasonic receiving unit; the ultrasonic receiving unit comprises a first circuit board (1) and through the first bracket (2) An ultrasonic receiving sensor (3) fixed to the first circuit board (1); the ultrasonic transmitting unit includes a second circuit board (5) and an ultrasonic wave fixed to the second circuit board (5) by the second bracket (2) The transmitting sensor (4); the ultrasonic transmitting unit and the ultrasonic receiving unit are correspondingly disposed.

 2. The ultrasonic detecting device for strips and sheets in banknote processing according to claim 1, wherein: the first circuit board (1) and the second circuit board (5) are parallel and the ultrasonic waves The receiving sensor (3) and the ultrasonic transmitting sensor (4) are disposed opposite to each other, and the axes of the ultrasonic receiving sensor (3) and the ultrasonic transmitting sensor (4) coincide with each other, and form an angle of 15 to 20 degrees with the normal line of the banknote.

 3. The ultrasonic detecting device for strips and sheets in banknote processing according to claim 1, wherein: the surfaces of the ultrasonic receiving sensor (3) and the ultrasonic transmitting sensor (4) are parallel and spaced apart It is 15~20mm.

 4. The ultrasonic detecting device for strips and sheets in banknote processing according to claim 1, wherein: the ultrasonic wave transmitting sensor (4) is connected to an ultrasonic wave transmitting circuit provided by the second circuit board (5) The ultrasonic transmitting circuit includes a CPU and an ultrasonic signal driver (13) connected thereto, and the ultrasonic signal driver (13) is connected to the ultrasonic transmitting sensor (4).

 The ultrasonic detecting device for processing a strip in a banknote processing according to claim 4, wherein: the ultrasonic signal driver (13) adopts a triode; and the two input ends are respectively connected to the CPU; The input terminal is connected to the base of the transistor Q1 through the resistor R1, the capacitor C1, and the resistor R2 in sequence. The emitter of the transistor Q1 is connected to the power source, the resistor R3 is connected to the power source, and the other end is connected to the junction of the capacitor C1 and the resistor R2. The electrode is grounded through a resistor R4, and a diode is connected between the collector and the emitter; the second input terminal is sequentially connected to the base of the transistor Q2 through a resistor R5, a capacitor C2, and a resistor R6, and the emitter of the transistor Q2 is connected to the power source, and the resistor R7 The other end is connected to the power supply, the other end is connected to the junction of the capacitor C2 and the resistor R6, the collector is grounded through the resistor R8, and the diode is connected between the collector and the emitter; the ultrasonic transmission is connected between the collector of the transistor Q1 and the collector of the Q2 Sensor (4).

 The ultrasonic detecting device for strips and sheets in banknote processing according to claim 1, wherein: the second circuit board (5) is provided with a plurality of ultrasonic signal drivers (13), respectively a plurality of ultrasonic transmitting sensors (4) are connected, the input ends of which are connected to the CPU; the first circuit board (1) is provided with the same number of ultrasonic receiving sensors as the ultrasonic transmitting sensor (4) of the second circuit board (5) (3).

 7. Ultrasonic detecting method for strips and re-tensioning in banknote processing, characterized in that the following steps are included: The CPU provided on the second circuit board (5) outputs multiple ultrasonic signals, and each ultrasonic signal driver (13) The ultrasonic signal is converted into an ultrasonic scanning driving signal, and the corresponding ultrasonic transmitting sensor (4) is driven to emit ultrasonic waves; the plurality of ultrasonic receiving sensors (3) on the first circuit board (1) respectively receive the ultrasonic waves passing through the banknotes and are converted The electrical signal is amplified by the corresponding ultrasonic signal amplifier (14), and is rectified and filtered by the ultrasonic signal rectifying filter (15) to obtain a plurality of sets of analog signals after the banknote is attenuated;

 The single chip on the first circuit board (1) receives the analog signal, and after each set of analog signals are respectively A/D converted into digital signals and processed, if at least one of the processing results is a strip or a double sheet, the banknote That is, the strip or the double sheet; if the result of the multi-path processing is a single banknote, the banknote is a single banknote.

 8 . The ultrasonic detecting method for strips and sheets in banknote processing according to claim 7 , wherein: the ultrasonic signals are two complementary pulse signals ( 21 , 22 ), and the pulse frequency is 300 kHz; The two transistors Q1 and Q2 of the ultrasonic signal driver (13) are driven separately.

9. The ultrasonic detecting method for strips and sheets in banknote processing according to claim 7, wherein: The ultrasonic scan driving signal is a plurality of sets of pulse signals, each set of pulse signals includes six pulses; and is outputted in a scanning manner, and the scanning frequency is 1.25 KHz.

 10 . The ultrasonic detecting method for strips and sheets in banknote processing according to claim 7 , wherein: performing the A/D conversion into a digital signal and performing the processing comprises the following steps:

 After A/D conversion of the set of analog signals, a set of digital signals is collected within the width range of the scanned banknotes; if a single sheet or a multi-sheet banknote is detected, the average method is adopted, that is, the two ends of the set of digital signals are first removed. Data, the average value is calculated for the remaining data; when the average value is greater than the set threshold, the banknote is re-tensioned, otherwise it is a single sheet;

 If a single sheet, strip, or multi-sheet is detected, the sheet is recognized by the average method according to the previous step, and the slip sheet is identified by the sliding filter method, that is, a group collected within the range of the scanned bill. In the digital signal, the number of points that are continuously lower than the threshold is found. When the number of consecutive points is greater than the threshold, the banknote is considered to be a strip of banknotes, otherwise it is not a strip of banknotes.