KR101670427B1 - High sensitive metal detecting apparatus with noise immunity - Google Patents

Abstract

The present invention relates to a high sensitive metal detector having strong noise immunity, which improves the detection sensitivity of metal foreign materials mixed in food and removes a disturbance signal. The high sensitive metal detector having strong noise immunity comprises: a transfer part which transfers a detection object; a magnetization part which is arranged in the transfer path of the detection object and magnetizes the metal foreign materials flowing into the detection object; a magnetic field detecting part which is arranged in the rear end of the magnetization part on the transfer path and has multiple magnetic field sensors for detecting the magnetic fields of the detection object passing through the magnetization part; and a control part which identifies the signal of the magnetic field sensors where the magnetic fields of the metal foreign materials are detected to remove the disturbance signal from the magnetic field signal received from the magnetic field detecting part.

Description

TECHNICAL FIELD [0001] The present invention relates to a high-sensitivity metal detector that is robust against disturbance,

More particularly, the present invention relates to a high-sensitivity metal detector which is robust against disturbance capable of removing a disturbance signal while improving detection sensitivity of a metal incorporated in a food.

The metal-water detector is a device for detecting water mixed with metal in inspection products such as foods. It is composed of an optical detection system using x-rays, an eddy current system using a high frequency magnetic field, and a method in which a metal magnetized by a magnetizing means There is an electromagnetic induction method in which the magnetic field is detected by a magnetic sensor that operates as an electromagnetic induction phenomenon.

The present invention relates to an electromagnetic induction type metal-water detector in which a magnetized metal detects the residual magnetic intensity of water with a magnetic sensor, and the technical background thereof is as follows.

Faraday's electromagnetic induction law is generalized by the formula of ε = -N (dΦ / dt) (unit: V), and the induced electromotive force (ε) is proportional to the number of turns of the coil and the rate of change of magnetic flux (Φ) with time. At this time, in order to easily detect a signal generated by the movement of water, the number of turns of the coil is unchanged. Therefore, the metal passing through the magnetic field must increase the moving speed of water or the metal must increase the degree of magnetization of water. However, since the moving speed of the metal water depends on the conveying speed of the conveyor belt, there is a practical limit to the metal moving speed of the water. Therefore, the conventional metal-oxide-water detecting device improves the detection sensitivity by a method in which metal is magnetized by water to sense a signal.

In addition, in order to detect water by a metal having a small magnetic field due to a small amount of water or a metal component, it is necessary to improve the detection sensitivity of the detection device as much as possible. When the detection sensitivity is set sensitively, , The inverter, the movement of the iron structure, etc.), the reliability of the detection apparatus is deteriorated due to frequent malfunction of the apparatus due to a significant increase in the disturbance signal.

Registration Utility Model No. 20-0269923: Metal detector

SUMMARY OF THE INVENTION The present invention has been made to overcome the problems of the conventional art, and it is an object of the present invention to provide a highly sensitive metal detector which is robust against disturbance which can remove the disturbance signal while improving the detection sensitivity of metal incorporated into food.

According to the present invention, there are provided a plurality of magnetic sensors for detecting the magnetic field of a metal, and the magnetic sensors are arranged in a line on a line coinciding with the conveying path on the magnetic detecting portion, A problem is to improve the detection sensitivity by causing the metal conveyed along the conveying path to continuously sense water and a plurality of magnetic sensors with a time difference therebetween.

The magnetic sensor of the second sensor line may be installed at the same interval as the magnetic sensors provided on the adjacent first sensor line so as to correspond to the midpoint of the sensors installed on the first sensor line. It is an object of the present invention to effectively narrow the interval of the sensor lines so as to minimize the square where the metal does not detect water.

In addition, the present invention is intended to effectively remove a disturbance signal from each magnetic sensor by determining signals commonly detected by a plurality of magnetic sensors as disturbance.

Further, the present invention aims at synchronizing the time axis of each signal value of the magnetic sensors included in each sensor line, thereby enabling the metal to amplify the magnetic field signal of the water so that the metal can more clearly identify the water.

According to an aspect of the present invention, there is provided a high-sensitivity metal detector which is robust against disturbance, comprising: a conveying unit for conveying a substance to be detected; and a control unit which is disposed on a conveyance path of the substance to be detected, And a plurality of magnetic sensors disposed at a rear end of the magnetizing unit on the conveying path for detecting a magnetic field of the object to be detected that has passed through the magnetizing unit; And a control unit for identifying a signal of the magnetic sensor in which the metal detects the magnetic field of the water by removing the disturbance signal from the signal.

Further, the magnetic sensor may be a self-resonant (Fluxgate) sensor.

A first sensor line is formed on one side of the magnetic detection unit and is provided with a plurality of magnetic sensors arranged in a line on a line coinciding with the conveyance path at a predetermined interval. And a plurality of second sensor lines formed in a line and spaced apart at regular intervals are alternately arranged.

The magnetic sensors of the second sensor line are installed at the same interval as the magnetic sensors provided on the adjacent first sensor line and are installed in correspondence with the midpoints of the sensors installed on the first sensor line have.

The control unit may exclude the disturbance signal from any of the magnetic sensors by a difference between an output value of the magnetic sensor and an average output value of the total magnetic sensor.

The control unit may further include an entry monitoring unit disposed at a front end of the magnetic detecting unit on the conveying path to detect the presence or absence of the object to be detected. The time at which the object to be detected reaches the magnetic sensor of the magnetic detection unit is calculated through the speed at which the object to be detected is conveyed and the distance between the entry monitoring unit and the magnetic detection unit.

In addition, the control unit may set the signal value of the magnetic sensor disposed at the rear end of each signal value of the magnetic sensors included in one sensor line from the magnetic sensor disposed at the topmost stage to the magnetic sensor disposed at the rear stage, And synchronizing the signal values of the magnetic sensors included in any of the sensor lines by retracting the time axis by the time during which the sensor is transported.

In addition, the control unit derives the amplified signal by summing the synchronized signal values of the magnetic sensors included in any one of the sensor lines, and when the amplified signal is equal to or greater than a preset reference value, It is judged that it has been determined that

In addition, the controller may perform A / D conversion of each synchronized signal value of the magnetic sensors included in one of the sensor lines, and then, through the learned artificial neural network, Is determined.

The high sensitivity metal detector which is robust against disturbance according to the present invention has the following effects.

First, it is possible to provide a highly sensitive metal detector which is robust against disturbance capable of removing the disturbance signal while improving the detection sensitivity of the metal incorporated into the food.

Second, a plurality of magnetic sensors for detecting the magnetic field of the metal are arranged on the magnetic detection portion, and the sensor lines are formed in a line on the magnetic detection portion on a line coinciding with the conveyance path. The metal being conveyed is caused to continuously sense the water and the plurality of magnetic sensors with a time difference, so that the metal can improve the detection sensitivity of the water.

Third, the magnetic sensors of the second sensor line are installed at the same interval as the magnetic sensors provided on the adjacent first sensor line, and are installed corresponding to the midpoints of the sensors installed on the first sensor line, The interval can be effectively narrowed to minimize the square where the metal does not detect water.

Fourth, a signal commonly detected by a plurality of magnetic sensors is determined to be disturbance, so that the disturbance signal can be effectively removed from each magnetic sensor.

Fifth, by synchronizing the time axis of each signal value of the magnetic sensors included in each sensor line, the magnetic field signal of the metal is amplified so that the metal can more clearly identify the water.

1 is a front view of a highly sensitive metal detector that is robust to disturbance according to an embodiment of the present invention.
2 is a plan view partially showing only a carry section, a magnetization section, an entry monitoring section, and a magnetic detection section of a highly sensitive metal detector which is robust against disturbance according to an embodiment of the present invention.
3A is a reference view showing a structure of a self-resonant (fluxgate) sensor and a principle of drying a magnetic body.
3B is a schematic view showing a schematic structure of a self-resonant sensor and a wavelength of input / output signals.
3C is a BH Curve graph of the self-resonant sensor.
FIG. 3D shows a signal processing process of a self-resonant sensor capable of obtaining an output proportional to the magnitude of an external magnetic field with high sensitivity.
4 is a comparative example in which (a) the magnetic sensor is arranged in a checkered pattern, and (b) the magnetic sensor is constituted by the first sensor line and the second sensor line in the magnetic detecting portion.
FIG. 5 is a block diagram illustrating a relationship among electrical configurations of a high-sensitivity metal detector that is robust against disturbance according to an embodiment of the present invention. FIG.
6A and 6B illustrate a process of synchronizing the time axis of the detection values of the magnetic sensors arranged on the sensor line based on the time at which the control unit detects the object to be detected in the entry monitoring unit.
FIG. 7 is a diagram illustrating that a metal amplifies a signal of a water by adding a detection value of a magnetic sensor with a time axis synchronized to a control unit to determine whether a metal is present or absent, according to an embodiment of the present invention. FIG.
FIG. 8 is a diagram illustrating an architecture and an algorithm of an artificial neural network for explaining how a control unit determines whether or not a metal is included in an object to be detected through a learned artificial neural network according to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of a highly sensitive metal detector which is robust against disturbance according to the present invention will be described in detail as follows.

1, a highly sensitive metal detector which is robust against disturbance according to an embodiment of the present invention includes a conveying unit 152 for conveying a substance to be detected 10, A magnetization part 120 for magnetizing the water 12 in a molten state in the object to be detected 10 and a magnetization part 120 disposed in the rear end of the magnetization part 120 on the conveyance path, A magnetic detection unit 110 including a plurality of magnetic sensors 112 for detecting a magnetic field of the water 10 and a magnetic detection unit 110 for detecting a magnetic field of the water 10 by removing a disturbance signal from a signal of a magnetic field received by the magnetic detection unit 110, And a control unit 160 (see Fig. 5) for identifying the signal of the magnetic sensor 112 that detects the magnetic field of the magnetic sensor.

The apparatus may further include an entry monitoring unit 130 disposed at the end of the magnetic detecting unit 110 on the conveying path to detect the presence or absence of the object 10 to be detected.

Here, the object 10 to be detected may be food, clothing, and the like, but is not limited thereto.

The carry section 152 has a function of transporting the object 10 in a predetermined direction, and specifically, it may be a mechanical device such as a conveyor belt. In Fig. 1, the object 10 placed on the carry section 152 is transported in the right direction. The moving speed of the detected object 10 is determined by the rotating speed of the motor that drives the carry section 152. [ The control unit 160 controls the rotation speed of the conveying motor 154 to adjust the moving speed of the object 10 placed on the conveying unit 152.

2, the magnetization part 120 is provided at a predetermined position on the conveyance path of the object 10 to be detected, and the magnetic detection part 110 is provided at the rear end of the magnetization part 120 in the conveyance path, The magnetization part 120 and the magnetic detection part 110 are disposed at a predetermined interval along the conveying direction of the magnetism detection part 152. The object 10 to be detected 10 sequentially passes through the magnetizing portion 120 and the magnetic detecting portion 110 along the conveying path of the conveying portion 152. [

The magnetization part 120 serves to magnetize the water 12 by the metal which may be mixed in the object 10 to be detected. The magnetizing portion 120 has a rim shape having a cavity region through which the carry section 152 passes and surrounds the carry section 152. [ The magnetization part 120 is formed at both the upper part and the lower part where the object 10 to be inspected passes and the metal in the object 10 passing through the magnetization part 120 can magnetize the water 12. The magnetization portion 120 may be formed of any structure other than the permanent magnet or the permanent magnet, as long as it can magnetize the metal material or the like.

When the metal contained in the object 10 to be detected is magnetized while the water 12 passes through the magnetizing portion 120, the detection sensitivity of the magnetism detecting portion 110, which is then passed through, becomes high.

The magnetic detection section 110 has a cavity area through which the carry section 152 passes.

내지

로서, 일반적으로 금속이물(12)을 검출하기 위해 이용되는 탐색코일(search coil)의 검출범위

내지

보다 우수하다.Referring to FIGS. 3A to 3D, it is preferable that the magnetic sensor 112 provided in the magnetic detection unit 110 and detecting the magnetic field of the object 10 be a self-resonant (Fluxgate) sensor having excellent detection sensitivity. The detection range (Gauss) of the self-resonance sensor is

To

The detection range of a search coil, in which metal generally is used to detect water 12,

To

.

The self-resonant sensor is also referred to as a saturated iron core type magnetometer as a magnetic sensor 112 that uses saturation characteristics of a B-H curve of a material having a high permeability. When a primary coil and a secondary coil are wound around a magnetic core having a high magnetic permeability and a sine wave current having a sufficiently large amplitude of frequency f (several hundred Hz to several kHz) is supplied to the primary coil, the secondary coil The induced voltage deviates from the sinusoidal wave. When there is no external magnetic field, the voltage waveform of the secondary coil is symmetrical between positive (+) and negative (-), and includes harmonics which are odd-numbered only. However, if an external magnetic field is added to this, the harmonic of the even-numbered harmonic is included because the symmetry is broken. Therefore, when a detector (demodulator) in the signal processing circuit detects only twice the frequency (2xf) of the excitation frequency of DDS (Direct Digital Synthesis), an output proportional to the magnitude of the external magnetic field can be obtained with high sensitivity .

The magnetic field strength of the magnetized metal diaphragm 12 varies depending on the size of the metal 12 and the amount of metal contained therein. Therefore, as the magnetic sensor 112 is used in an excellent detection range, it becomes possible to detect water 12 that is finer and various metals.

However, there is a problem that the magnetic sensor 112 frequently generates errors in a detection range exceeding a certain level due to disturbance generated in the environment. The disturbance includes a magnetic field generated by the earth magnetic field, the magnetizing portion 120 and the conveying motor 154, equipment located on the outside, belongings of the worker, and vehicles for transporting freight in the factory. Although the disturbance fixedly affects the magnetic sensor 112, since there are more factors that affect the magnetic sensor 112 due to factors such as movement or power supply, all the signal patterns of the disturbance magnetic field are stored, If the signal contains the pattern, it is virtually impossible to remove it. Therefore, there is a limit to develop a device having a detection range exceeding a certain level by applying a self-resonance (Fluxgate) sensor having an excellent detection range.

Sensitive metal detector that is robust against disturbance according to an exemplary embodiment of the present invention includes a plurality of magnetic sensors 112 as described above and detects a signal inputted in common to the magnetic sensors 112 as a disturbance, .

Referring to FIGS. 2 and 4, a first sensor line is formed on one side of the magnetic detection unit 110, and a plurality of magnetic sensors 112 are arranged in a line on the line coinciding with the conveyance path at regular intervals, The second sensor lines formed by arranging the magnetic sensors 112 in a line at regular intervals in parallel with the first sensor lines are alternately arranged.

Since the object to be detected 10 is transported only in one direction by the carry section 152, the metal contained in the object 10 to be detected 10 is also transported in the same direction. It is possible for the magnetic sensors 112 of the line on which the metal 12 is conveyed to sequentially detect the metal 12 so that the detection reliability can be improved.

Since the magnetic flux sensor itself generates a magnetic field, it is preferable to dispose the plurality of magnetic sensors 112 at a predetermined interval in order to prevent interference with each other. The magnetic sensor 112 can be disposed as many as possible in the magnetic detecting portion 110 by arranging the magnetic sensors 112 at regular intervals in the left and right direction and the vertical direction, It is possible to minimize the rectangular area in which the detection unit 12 is not detected.

In particular, the magnetic sensors 112 of the second sensor line are installed at the same intervals as the magnetic sensors 112 provided on the adjacent first sensor lines, and are disposed at the midpoints of the magnetic sensors 112 provided on the first sensor line And can be installed correspondingly. When the magnetic sensors 112 are arranged in this manner, the sensor lines can be arranged more closely in the direction of the conveying path than the magnetic sensors 112 are arranged in the form of a checkerboard while maintaining the same distance between the magnetic sensors 112 do. The magnetic sensor 112 can acquire a higher magnetic field signal as the metal is adjacent to the water 12, thereby further enhancing the ability of the metal to detect the water 12.

The magnetic sensor 110 is disposed at the upper and lower portions of the magnetic detection unit 110 to detect the detection object 10 between the upper magnetic sensor 112 and the lower magnetic sensor 112, (See FIG. 2). Particularly, the magnetic sensors 112 disposed on the upper part of the magnetic detecting part 110 are disposed at positions corresponding to the positions between the sensor lines of the lower magnetic sensor 112, And the upper magnetic sensor 112 can cover the detection of the region where the magnetic sensor 112 is not disposed in the lower portion of the magnetic detection portion 110. [

Although the magnetizing portion 120 and the magnetic detecting portion 110 are described as having a frame shape having a cavity region, they may have different shapes (for example, a cylindrical shape). That is, the upper and lower portions of the carry section 152 may be separated from each other.

The entry monitoring unit 130 is configured to detect the presence or absence of the object 10 to be detected so as to calculate the absolute time at which the object 10 to be transported reaches the respective magnetic sensors 112 of the magnetic detection unit 110 . As shown in FIG. 2, the entry monitoring unit 130 may be a photo sensor, and the light emitting unit 130b and the light receiving unit 130a may be disposed on both sides of the carry unit 152. FIG. In another embodiment, the ultrasonic sensor or the laser sensor detects the sound wave or light reflected by the object 10 to determine the presence or absence of the object 10, 10 may be applied to any of the means capable of detecting the entry of the vehicle.

In order to calculate the delay time until the object 10 detected by the entry monitoring unit 130 reaches each magnetic sensor 112, the control unit 160 is provided with an entry monitoring unit 130, It is preferable that the separation distance of the magnetic sensor 112 is stored.

5, the control unit 160 is electrically connected to the magnetic sensor 112, the entry monitoring unit 130, the conveying motor 154, and the like of the magnetic detecting unit 110, Respectively.

A disturbance magnetic field signal having a strength enough to affect the magnetic sensor 112 is detected only in the magnetic sensor 112 adjacent to the path on which the metal 12 contained in the detected object 10 is conveyed, Are commonly detected at the same time by all the magnetic sensors 112 included in the magnetic detecting unit 110. That is, excluding the signals commonly received among the signal values received from the magnetic sensors 112, the disturbance is removed from the detection value of the magnetic sensor 112 as a result.

)과 자기센서(112)의 총 개수(N)로 전체 자기센서(112)의 평균 출력 값(

)을 산출한다.Accordingly, the controller 160 may control the output value of each of the magnetic sensors 112 to remove the disturbance signal from the output values detected from the plurality of magnetic sensors 112

And the total number N of the magnetic sensors 112 and the average output value of the total magnetic sensors 112

).

[Equation 1]

)과, 전체 자기센서(112)의 평균 출력 값(

)의 차로 외란 신호가 배제된 어느 한 자기센서(112)의 출력 값(

)을 획득할 수 있게 된다.In addition, the control unit 160 determines the output value of one of the magnetic sensors 112

And the average output value of the total magnetic sensor 112

) Of the magnetic sensor 112 from which the disturbance signal is excluded

). ≪ / RTI >

&Quot; (2) "

)를 통해 피검출물(10)이 자기검출부(110)의 자기센서(112)에 도달되는 시간(

)을 산출한다.The control unit 160 controls the entrance monitoring unit 130 to detect the time T at which the detected object 10 is detected and the speed at which the conveying unit 152 returns the detected object 10 V), a distance between the entrance monitoring unit 130 and each magnetic sensor 112 of the magnetic detecting unit 110

The time at which the object 10 to be detected 10 reaches the magnetic sensor 112 of the magnetic detection unit 110

).

The magnetic sensor 112 is disposed along the conveyance path line on the magnetic detection section 110 and the object 10 to be detected 10 passes the magnetic sensors 112 at a constant speed by the conveyance section 152, 112) are able to detect the magnetic field of the water 12 in the order listed. Therefore, even if each magnetic sensor 112 detects the magnetic field of the water 12, a difference occurs in the detection time. Therefore, the time axis of the magnetic sensors 112 is adjusted .

6A and 6B, the control unit 160 compares whether or not the metal detects the magnetic field of the water 12 from the signal values of the magnetic sensors 112 included in the path through which the water 12 is transported And synchronizes the time axis of the signal values of the respective magnetic sensors 112 to judge.

Specifically, the control unit 160 determines the signal value of the magnetic sensor 112 disposed at the rear end of each of the signal values of the magnetic sensors 112 included in any one of the sensor lines, from the magnetic sensor 112 It is possible to synchronize the signal values of the magnetic sensors 112 included in any one of the sensor lines by retracting the time axis by the time during which the object 10 is conveyed to the magnetic sensor 112 disposed at the subsequent stage.

The time at which the object 10 is transported from the magnetic sensor 112 disposed at the foremost end to the magnetic sensor 112 disposed at the rear end is the time at which the object 10 is detected by the entry monitoring unit 130 And the distance between the delivery speed and the entry monitoring unit 130 and each magnetic sensor 112. [

Referring to FIG. 7, in one embodiment of determining whether a magnetic field signal of the metal 12 is included in the signal values of the synchronized magnetic sensors 112, It is possible to derive the amplified signal by summing the synchronized signal values of the magnetic sensors 112 and judge that the object 12 contains the metal in the detected object 10 when the amplified signal is not less than a predetermined reference .

The object 10 to be inspected without the metal water 12 is removed together with the inherent magnetic field generated in the product and the packaging material when the disturbance signal is removed. The magnitude of the signal to be amplified is small even if the signal values are summed up. However, the object 10 to which the object 12 contains the water is continuously connected to the magnetic sensors 112 included in at least one sensor line, Since the magnetic field of the foreign object 12 is detected, the signal value generated by the magnetic field of the metal 12 is remarkably amplified when the signal value of the magnetic sensor 112 synchronized with the time axis is added.

Referring to FIG. 8, in another embodiment, the controller 160 performs A / D conversion on each synchronized signal value of the magnetic sensors 112 included in one sensor line, It is possible to determine whether or not the metal 12 is included in the object 10 to be detected through the artificial neural network.

The discretization converts the signal value of the magnetic sensor 112 to be represented by only two values of 0 and 1.

In addition, the control unit 160 may multiply the signal value by the method of the above embodiment, and then, after digitizing the amplified signal by the method of another embodiment of the present invention, It is possible to determine whether or not the metal 12 contains the water.

The control unit 160 determines that the metal 12 is contained in the object 10 to be detected by the control unit 160. The control unit 160 detects the presence of the metal 12 in the object 12 through output means, Or physically remove the object 10 to be detected on the conveying path.

One embodiment of the present invention may further include a power switch 144 for driving the metal detector and a controller 142 for setting the conveying speed, detection sensitivity, and the like of the carry section 152.

As described above, it will be understood that the present invention is implemented in a modified form without departing from the essential characteristics of the present invention.

It is therefore to be understood that the specified embodiments are to be considered in an illustrative rather than a restrictive sense and that the scope of the invention is indicated by the appended claims rather than by the foregoing description and that all such differences falling within the scope of equivalents thereof are intended to be embraced therein It should be interpreted.

10: Detected substance 12: Metal is water
110: magnetic detection unit 112: magnetic sensor
120: Magnetization unit 130: Entry monitoring unit
140: Signal processing 142: Controller
144: Power switch 152:
154: conveying motor 160:
170: warning light

Claims (9)

A transport section for transporting the object to be detected,
A magnetized portion which is disposed on a conveyance path of the object to be detected and in which the metal incorporated in the object to be detected magnetizes water;
And a plurality of magnetic sensors disposed at a rear end of the magnetization portion on the conveyance path and detecting a magnetic field of the object to be detected that has passed through the magnetization portion;
And a control unit for identifying a signal of the magnetic sensor in which the metal detects the magnetic field of the water by removing the disturbance signal from the signal of the magnetic field received by the magnetic detection unit,
A first sensor line formed on one side of the magnetic detection section and provided with a plurality of magnetic sensors arranged in a line at regular intervals on a line coinciding with the conveyance path; And a plurality of second sensor lines arranged in a line with respect to the first sensor line,
The magnetic sensors of the second sensor line are installed at the same interval as the magnetic sensors provided on the adjacent first sensor line and are installed corresponding to the midpoints of the sensors installed on the first sensor line,
Wherein the controller excludes a disturbance signal from any of the magnetic sensors by a difference between an output value of a magnetic sensor and an average output value of the total magnetic sensor. The method according to claim 1,
Wherein the magnetic sensor is a self-resonant (Fluxgate) sensor. delete delete delete The method according to claim 1,
Further comprising an entry monitoring section arranged at the tip of the magnetic detection section on the conveyance path for detecting presence or absence of the object to be detected,
Wherein the controller is configured to control the movement of the article to be detected through the entry monitoring unit, the time at which the article to be detected is detected, the speed at which the carry unit carries the article to be inspected, Wherein the time required to reach the magnetic sensor of the high sensitivity metal detector is calculated. The method according to claim 6,
The control unit controls the signal value of the magnetic sensor disposed at the rear end of each signal value of the magnetic sensors included in any one of the sensor lines from the magnetic sensor disposed at the frontmost stage to the magnetic sensor disposed at the rear stage, And synchronizing the signal values of the magnetic sensors included in any one of the sensor lines by retracting the time axis by a predetermined time. 8. The method of claim 7,
The control unit derives the amplified signal by summing the synchronized signal values of the magnetic sensors included in any one of the sensor lines, and if the amplified signal is equal to or greater than a preset reference value, Wherein the high-sensitivity metal detector is a high-sensitivity metal detector that is robust against disturbance. 8. The method of claim 7,
The control unit performs A / D conversion of each synchronized signal value of the magnetic sensors included in one sensor line, and then determines whether or not the metal contains water in the object to be detected through the learned artificial neural network Sensitive metal detector.

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