CN108010185B - A kind of the detection identification device and method of banknote thickness abnormity - Google Patents

Abstract

The present invention relates to a kind of detection identification devices of banknote thickness abnormity, connect bank note conveying mechanism, and bank note conveying mechanism includes the dead axle and moving axis of the upper and lower conveying bank note that cooperates, and the side plate of installation dead axle and moving axis；Detection identification device includes the sensor installing platform part being mounted on side plate, the first sensor of detection bank note conveying mechanism and moving axis vibration, the second sensor of detection bank note conveying mechanism vibration, data transfer segment, MICROCOMPUTER PROCESSING part；First sensor and second sensor are installed in sensor installing platform part, the vibration signal that first sensor and second sensor acquire is transmitted to MICROCOMPUTER PROCESSING part by data transfer segment, and MICROCOMPUTER PROCESSING part is calculated and identified automatically according to the spacing between crest value and wave crest.Further relate to a kind of detection recognition method of banknote thickness abnormity.The present invention examine it is pseudo- at low cost, it is easy for installation, using simple, belong to paper currency detection technical field.

Description

Device and method for detecting and identifying abnormal thickness of banknotes

technical field

The invention relates to banknote detection technology, in particular to a device and method for abnormal detection and identification of banknote thickness of banknote counting and checking machines and sorting machines.

Background technique

In daily life and commercial activities, because banknotes are easily damaged in circulation, people often stick damaged banknotes with thin adhesive tape and continue to use them. In addition, due to the emergence of counterfeit money (a kind of counterfeit money, which is often connected with adhesive strips or overlapped and pasted), the financial sector needs to distinguish these paper money detection in the management of paper money. In the past, mechanical thickness measuring devices were used for sorting, and the damaged banknotes and counterfeit banknotes detected by sorting were recycled. This mechanical thickness measuring device measures the thickness of banknotes by contacting two opposite rollers, and reflects the thickness of banknotes through the mechanical distance between the two rollers. Due to the complicated structure of the mechanical thickness measuring device, And must be in contact with banknotes to measure.

Later, people used the acceleration sensor to design the thickness measurement system, and judged the thickness of the banknote by measuring the acceleration value of the vibration signal of the banknote counting machine, which solved the problem that the structure of the thickness measurement device was too complicated, but because the paste is very thin, such as The thickness of scotch tape is only about 0.1mm, and it is difficult to guarantee the accuracy of measurement by using an acceleration sensor to measure the thickness, so there are problems of poor reliability, high missed detection rate and low precision.

The existing banknote conveying mechanism is installed in money counting machines, money detectors, sorting machines and other equipment, including two roller shafts installed between the side plates, one is a fixed shaft, located on the top, and the other is a moving shaft. It is located at the bottom. In the initial state, the pressing part presses the moving shaft to the fixed shaft. When the banknote passes, the moving shaft moves down slightly. After the banknote passes, the moving shaft resets to the initial position under the action of the pressing part.

Contents of the invention

Aiming at the technical problems existing in the prior art, the object of the present invention is to provide a detection and identification method for abnormal thickness of banknotes that can quickly and accurately measure the thickness of banknotes in a non-contact manner.

In order to achieve the above object, the present invention adopts following technical scheme:

A detection and identification device for abnormal thickness of banknotes, connected to a banknote conveying mechanism, the banknotes conveying mechanism includes a fixed shaft and a moving shaft that cooperate with each other to transport banknotes up and down, and a side plate on which the fixed shaft and the moving shaft are installed; the detection and identification device includes installation on the side plate The sensor installation platform part, the first sensor to detect the vibration of the banknote conveying mechanism and the moving shaft, the second sensor to detect the vibration of the banknote conveying mechanism, the data transmission part, and the microcomputer processing part; the first sensor and the second sensor are installed on the sensor installation In the platform part, the data transmission part transmits the vibration signals collected by the first sensor and the second sensor to the microcomputer processing part, and the microcomputer processing part automatically calculates and recognizes according to the wave peak and the distance between the wave peaks.

As a preference, the sensor installation platform part includes an iron plate and an iron block, and the iron block, iron plate, and side plates are sequentially connected from the outside to the inside; a horizontal gap is provided in the middle of the iron plate, and one end of the gap extends to the iron plate The edge of the gap, the middle part of the gap is provided with a through hole for the end of the drive shaft to pass through; the middle part of the iron block is provided with a through hole for the end of the drive shaft to pass through; the first sensor is installed on the iron plate and is located in the gap On the upper side, the second sensor is installed on the iron plate and is located on the lower side of the gap.

As a preference, a square slit is provided at the end of the slit extending to the edge of the iron plate, and the width of the slit is greater than the width of the slit.

As a preference, the installation position of the first sensor is located directly above the cutout, the installation position of the second sensor is located directly below the cutout, and the two installation positions are aligned in the vertical direction.

As a preference, the distance from the first sensor to the central line of the slit is d _A , the distance from the second sensor to the central line of the slit is d _B , d _A : d _B =1:3.

As a preference, the connection point between the iron plate and the side plate is located at the lower side of the gap.

As a preference, the microcomputer processing part is equipped with software for differentially processing the signals measured by the first sensor and the second sensor, and finally displays the recognition result on the display screen.

As a preference, the width of the slit is 0.15 cm, and the side length of the incision is 0.5 cm.

A detection and identification method for abnormal thickness of banknotes, using a detection and identification device for abnormal thickness of banknotes, after the banknotes pass through, the moving shaft resets, the upper side of the end of the moving shaft drives the iron block and iron plate to vibrate, and the first sensor detects the The vibration signal of the conveying mechanism and the moving shaft, the second sensor measures the vibration signal of the banknote conveying mechanism, the two sets of signals are transmitted to the microcomputer processing part through the data transmission part, and the software performs differential processing on the signals to determine whether the thickness of the banknote is normal.

As a preference, the gap isolates the vibration of the moving shaft from the second sensor.

Generally speaking, the present invention has the following advantages: it has the advantages of strengthening banknote detection, improving sensor accuracy, and improving the ability to detect abnormal banknote thickness. It can be seen from the present invention that it includes a data transmission part, a microcomputer processing part, that is, a software differential processing part and abnormal banknote thickness discrimination. In this part, two functions have been completed: the differential noise reduction data processing function and the banknote discrimination function. According to the software differential algorithm, the data is processed to determine whether the banknote thickness is abnormal. In short:

1. Have the sensor installation platform part, as well as the determined installation point.

2. Automatically perform software differential processing and noise reduction in the microcomputer processing part.

3. Low cost of counterfeit detection, easy installation and use.

4. It only needs to be installed on the existing equipment.

Description of drawings

Fig. 1 is an installation structure diagram of the present invention and the banknote conveying mechanism.

FIG. 2 is a side view of FIG. 1 .

Figure 3 is an explanatory diagram of the test waveform.

Figure 4 is the effect diagram of software difference.

Fig. 5 is a flow chart of the procedure for judging abnormal thickness of banknotes.

Among them, 1 is an iron plate, 2 is an iron block, 3 is a gap, 4 is a cutout, 5 is a moving shaft, 6 is a side plate, 7 is the installation position of the first sensor, 8 is the installation position of the second sensor, and 9 is the The connection points between the iron plate and the side plate, 10 is a banknote, 11 is a sticker, and A-D corresponds to the edge of the sticker.

Detailed ways

The present invention will be described in further detail below.

A detection and identification device for abnormal banknote thickness, comprising a sensor installation platform part installed on a side plate, a first sensor for detecting vibration of a banknote conveying mechanism and a moving shaft, a second sensor for detecting vibration of a banknote conveying mechanism, a data transmission part, a microcomputer processing part. The detection and recognition device is connected to the banknote conveying mechanism of the banknote counter. The banknote conveying mechanism includes a fixed shaft and a moving shaft that cooperate with each other to convey banknotes up and down, and two side plates for installing the fixed shaft and the moving shaft. The moving shaft is oriented by pressing parts. axis.

The sensor installation platform part includes an iron plate and an iron block. The iron block, iron plate, and side plates are connected sequentially from the outside to the inside; there is a horizontal gap in the middle of the iron plate, and one end of the gap extends to the edge of the iron plate. The middle part is provided with a through hole for the end of the drive shaft to pass through; the middle part of the iron block is provided with a through hole for the end of the drive shaft to pass through. A square notch is provided at the end of the gap extending to the edge of the iron plate, and the width of the notch is larger than that of the gap. The installation position of the first sensor is located directly above the cutout, the installation position of the second sensor is located directly below the cutout, and the two installation positions are aligned in the vertical direction. The distance from the first sensor to the center line of the slit is d _A , the distance from the second sensor to the center line of the slit is d _B , d _A : d _B =1:3. The connection point between the iron plate and the side plate is located at the lower side of the gap. The first sensor and the second sensor are respectively connected with the data transmission part, and the data transmission part is connected with the microcomputer processing part.

Specifically, in this embodiment, the first sensor and the second sensor adopt an acceleration sensor ADXL335 chip, and its bandwidth range of the X-axis and Y-axis can reach 0.5 Hz to 1600 Hz, and the bandwidth range of the Z-axis can reach 0.5 Hz to 550 Hz. The data transmission part is the Agilent data acquisition card U2331A, which can collect 6 signal voltage inputs at the same time, ensuring that the X, Y, and Z axis signals of the two sensors can be smoothly sent to the microcomputer system for processing. Agilent measurement manager 2.2, an Agilent data acquisition software located on the microcomputer, is also used in conjunction with it, which can collect and record the signals collected by the data acquisition card, and automatically generate Excel files for further processing. In this embodiment, the processing software of the microcomputer system adopts Matlab programming to process the difference algorithm, and gives the result and conclusion.

It is necessary to paste the banknotes. First prepare the adhesive tape, cut it into a strip shape, and paste the adhesive tape on the banknote to be detected. In this embodiment, the method of sticking adhesive tape horizontally is selected to make sample banknotes to be tested. Such an implementation plan is to simulate the phenomenon that in real life, someone uses real banknotes and counterfeit banknotes to splicing and pasting to deceive the bank's money counter. It is necessary to use the combination of the acceleration sensor and the algorithm in the present invention to identify the simulated samples, and finally obtain the pasted waveform characteristics on the data waveform, and use this to pick out the problem banknotes.

Introduce the device installation of present embodiment below:

The first step is to install and splice the sensor installation platform part with the experimental banknote counter.

The sensor installation platform part is made of an iron plate with a thickness of 0.8cm. There is a 0.5cm square slit in the middle of the side of the iron plate. In the center of the slit, cut a slit with a width of 0.15cm in the middle of the iron plate, so that the upper and lower sides of the slit are separated and not completely broken. In the middle gap of the iron plate, a through hole with a diameter equal to the diameter of the end of the banknote counting motor shaft is cut, and the motor shaft passes through the through hole, using a square iron block with a thickness of 0.8cm and a through hole of the same diameter in the middle. , fix the iron block and the side plate to ensure that the vibration signal of the moving shaft can be transmitted to the iron block. There are two hexagonal nuts on the lower side of the gap on the iron plate, and two screws are used to fix the iron block and the side plate, so as to ensure that the relative positions of the iron block, the sensor and the money counter body are determined.

The second step is to install the sensor on the sensor installation platform part.

Two ADXL335 chips are used as sensors for accelerometer vibration signals. The ADXL335 module has 5 interfaces in total, which are V+, GND, Xout, Yout, and Zout. They are respectively connected to 3 signal lines, which are connected to the hub of the Agilent data acquisition card through the port for signal transmission. The chip module is fixed on the iron plate with AB glue. When fixing, adjust the X-axis direction of the sensor to the vertical direction and face upward. This standard is set to ensure that the detected data has reference. When fixing the sensor, the first sensor is located directly above the slit, and the distance between the first sensor and the center line of the gap is d _A ; the second sensor is located directly below the slit, and the distance between the second sensor and the center line of the gap is d _B . d _A and d _B satisfy the proportional relationship: 1:3. According to the transmission of the vibration signal, the first sensor and the second sensor are set so that the first sensor collects the vibration signal of the machine body and banknotes, and the second sensor only collects Based on the vibration signal of the machine body, the software differential processing can be used to eliminate the noise caused by the vibration of the banknote counter itself, and achieve the purpose of noise reduction. In addition to embodiments of the present invention, the sensor may be any other vibration sensor.

The following describes the specific implementation operations

The first step is to initialize the test system. First, connect the V+ terminal and GND terminal of the sensor to the 5V power port and the ground port respectively to ensure that the sensor is enabled and working normally; secondly, open Agilent’s serial port reading software Agilent measurement manager 2.2 on the computer side , set the data saving path, and set the bit rate to 5500 to ensure that the acquisition work is ready.

The second step is to put the banknotes to be tested into the banknote counting machine to make it work normally, pass the banknotes and twist the banknotes, and at the same time ensure that the Agilent acquisition port is working normally, and the vibration data collected are stored on the computer. The Agilent acquisition software generates execl files. Prepare for the next step of software processing.

The third step is to use matlab to program the synchronous calibration algorithm and software differential algorithm. The specific implementation procedure of software difference is as follows:

The acceleration is calculated according to the high-speed rotating machinery vibration model.

High-speed rotating machinery vibration model. The vibration model of high-speed rotating machinery is as follows:

Then by the resultant acceleration formula

Since the vibration acceleration of the first sensor includes the body itself vibrating a body and a banknote signal:

a _A = a _body + λa _{banknote signal}

Since the vibration acceleration of the second sensor only includes the body:

a _B = a _body

In the above formula, the parameters corresponding to the letters are:

a _A : refers to the vibration acceleration value measured by the first sensor; a _B : refers to the vibration acceleration value measured by the second sensor; a _combined : refers to the combined acceleration of vibration acceleration in three directions measured by the sensor; a _x : refers to the sensor Acceleration of the measured vibration signal in the x-axis direction; a _y : refers to the acceleration of the vibration signal in the y-axis direction measured by the sensor; a _z : refers to the acceleration of the vibration signal in the z-axis direction measured by the sensor; x: finger movement The vibration displacement of the axis position point; ω: refers to the angular velocity of the position of the moving axis; A: refers to the amplitude of the vibration model of the moving axis; Refers to the phase of the shaft vibration model.

In the microcomputer, the acceleration a _A and the acceleration a _B measured by the sensor are compared by software. Due to the synchronization problem of the output of the two sensors, the software needs to compare the reference point. The function of the reference point is to align the first sensor and the second sensor. The output signal of the second sensor. The software synchronizes the data of the two sensors by comparing the value at the moment when the first wave peak value exceeds the threshold, and then performs software operations to obtain the acceleration vibration waveform after noise reduction. After obtaining the acceleration vibration waveform, the software judges the effective value of the peak, and automatically distinguishes the situation where the peak value is greater than the threshold.

In this embodiment, two long strips of electrical tape with a width of 1 cm are pasted horizontally on the banknotes. When the banknotes pass through the banknote counter, the vibration signals measured by the sensors are processed to obtain waveforms. It can be seen from the figure that the edge of tape A corresponds to the rising peak at A in the waveform diagram; the edge of tape B corresponds to the falling peak at B in the waveform diagram; the edge of tape C corresponds to the rising peak at C in the waveform diagram; D The edge of the tape corresponds to the falling peak at D in the waveform diagram. Due to the differential noise reduction, in the waveform diagram, the peak situation is well distinguished from the noise peak, so the threshold is set for judgment.

Within a certain time range (the time when a banknote passes through the banknote), if there are more than 2 peaks exceeding the threshold range, it can be judged that the thickness of the banknote is abnormal, and there is a situation of pasting and folding. Using the program flow chart, the design program is stored in in the microcomputer.

The above-mentioned embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above-mentioned embodiment, and any other changes, modifications, substitutions, combinations, Simplifications should be equivalent replacement methods, and all are included in the protection scope of the present invention.

Claims (9)

1. a kind of detection identification device of banknote thickness abnormity, connects bank note conveying mechanism, bank note conveying mechanism includes phase up and down The mutually dead axle and moving axis of cooperation conveying bank note, and the side plate of installation dead axle and moving axis, it is characterised in that: detection identification device packet Include the sensor installing platform part being mounted on side plate, the first sensor of detection bank note conveying mechanism and moving axis vibration, inspection Survey second sensor, the data transfer segment, MICROCOMPUTER PROCESSING part of the vibration of bank note conveying mechanism；First sensor and the second sensing Device is installed in sensor installing platform part, and data transfer segment believes the vibration that first sensor and second sensor acquire Number it is transmitted to MICROCOMPUTER PROCESSING part, MICROCOMPUTER PROCESSING part is calculated and known automatically according to the spacing between crest value and wave crest Not；

Sensor installing platform part includes iron plate and iron block, and iron block, iron plate, side plate outside-in successively connect；Iron plate Middle part be equipped with horizontal gap, the wherein one end in gap extends to the edge of iron plate, and the middle part in gap is equipped with the end for moving axis The through-hole that portion passes through；The middle part of iron block is equipped with the through-hole passed through for the end of moving axis；First sensor is mounted on iron plate above and position In the upside in gap, second sensor is mounted on iron plate above and is located at the downside in gap.

2. a kind of detection identification device of banknote thickness abnormity described in accordance with the claim 1, it is characterised in that: the extension in gap It is equipped with a rectangular notch to the end at the edge of iron plate, the width of notch is greater than the width in gap.

3. the detection identification device of a kind of banknote thickness abnormity according to claim 2, it is characterised in that: first sensor Installation site be located at the surface of notch, the installation site of second sensor is located at the underface of notch, two installation sites It is aligned in the up-down direction.

4. a kind of detection identification device of banknote thickness abnormity described in accordance with the claim 3, it is characterised in that: first sensor Distance to the center line in gap is d_A, the distance of the center line of second sensor to gap is d_B, d_A: d_BRelationship be 1:3.

5. a kind of detection identification device of banknote thickness abnormity described in accordance with the claim 1, it is characterised in that: iron plate and side plate Tie point be located at the downside in gap.

6. a kind of detection identification device of banknote thickness abnormity described in accordance with the claim 1, it is characterised in that: MICROCOMPUTER PROCESSING portion Packing has the signal for measuring first sensor and second sensor to carry out the software of difference processing, and finally recognition result exists It is shown on display screen.

7. the detection identification device of a kind of banknote thickness abnormity according to claim 2, it is characterised in that: the width in gap For 0.15cm, the side length of notch is 0.5cm.

8. a kind of detection recognition method of banknote thickness abnormity uses a kind of thickness of bank note described in any one of any one of claims 1 to 77 Spend abnormal detection identification device, it is characterised in that: after bank note passes through, moving axis resets, the upside of moving axis end drive iron block and Iron plate vibration, first sensor measure bank note conveying mechanism and moving axis vibration signal, and second sensor measures bank note conveying mechanism Vibration signal, two groups of signals reach MICROCOMPUTER PROCESSING part through data transfer segment, carry out difference processing, judgement to signal by software Whether banknote thickness is normal.

9. a kind of detection recognition method of banknote thickness abnormity according to claim 8, it is characterised in that: gap is by moving axis Vibration be isolated with second sensor.