JP6940910B1 - Magnetic Tomography System and Magnetic Tomography Method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately detect a magnetic object existing in the ground. A magnetic exploration system 1 is a magnetic sensor having a first coil 55 and a second coil 56 arranged apart from each other in the axial direction of the first coil 55 and whose winding direction is opposite to that of the first coil 55. 2 and a waveform generating unit connected to each of the plurality of magnetic sensors 2 and generating a waveform from each output of the plurality of magnetic sensors 2, and a recording device 4 for recording the waveform generated by the waveform generating unit. Each of the plurality of magnetic sensors 2 is configured so that the inter-coil distance D, which is the distance between the first coil 55 and the second coil 56, is different from each other, and can be selectively used. [Selection diagram] Fig. 1

Description

The present invention relates to a magnetic exploration system and a magnetic exploration method for exploring magnetic objects existing in the ground.

In the ground, land mines, shells, bombs, etc. used in the war may be left unexploded for some reason, and for example, some impact may occur during underground construction such as waterworks. The addition may cause unexploded ordnance to explode, causing human and material damage. Therefore, in order to proceed with underground construction safely and smoothly, it is necessary to search for the existence of magnetic objects including these unexploded ordnance in advance.

Conventionally, as a technique for exploring a magnetic object in the ground, a magnetic exploration method as disclosed in Patent Document 1 has been proposed. In the magnetic exploration method of Patent Document 1, a magnetic sensor having two sensor units provided on the same axis is used, and the difference in magnetic field strength detected by each sensor unit is output as a waveform, and the output is output. The presence or absence of a magnetic object is determined from the change in waveform.

However, magnetic objects have different sizes and different depths in the ground, and due to these differences, the magnetic exploration method as described in Patent Document 1 has a problem that the detection accuracy of magnetic objects is lowered. be.

Japanese Unexamined Patent Publication No. 2004-347533

An object of the present invention is to provide a magnetic exploration system and a magnetic exploration method capable of appropriately detecting a magnetic object existing in the ground in view of the above-mentioned problems.

The present invention comprises a magnetic sensor having a first coil, a second coil arranged apart from the first coil in the axial direction, and a second coil whose winding direction is opposite to that of the first coil, and a plurality of the plurality of magnetometers. Each of the plurality of magnetic sensors is provided with a waveform generation unit connected to each of the sensors and generating a waveform from the output of each of the plurality of magnetic sensors, and a recording unit for recording the waveform generated by the waveform generation unit. Is a magnetic exploration system and a magnetic exploration method that are configured such that the inter-coil distance, which is the distance between the first coil and the second coil, is different from each other and can be selectively used. And.

According to the present invention, a magnetic object existing in the ground can be appropriately detected.

Explanatory drawing which shows an example of the structure of the magnetic exploration system of this invention. Explanatory drawing which shows an example of the structure of a magnetic sensor. Explanatory drawing which shows an example of the structure of the amplification part. The explanatory view which shows an example of the data which is stored in the auxiliary storage part of a recording apparatus. Explanatory drawing which shows the distance between coils of each magnetic sensor. Explanatory drawing which shows an example of a magnetic exploration method. Explanatory drawing which shows the case where a magnetic sensor passes near one end (single pole) of a magnetic object. A graph showing an output waveform when a magnetic sensor passes near one end (single pole) of a magnetic object. Explanatory drawing which shows an example of the case where a magnetic sensor passes near both ends (bipolar) of a magnetic object. A graph showing an example of an output waveform when a magnetic sensor passes near both ends (bipolar) of a magnetic object. Explanatory drawing which shows another example of the case where a magnetic sensor passes near both ends (bipolar) of a magnetic object. A graph showing another example of an output waveform when a magnetic sensor passes near both ends (bipolar) of a magnetic object. Explanatory drawing which shows another example of the case where a magnetic sensor passes near both ends (bipolar) of a magnetic object. A graph showing another example of an output waveform when a magnetic sensor passes near both ends (bipolar) of a magnetic object. The flowchart which shows an example of the magnetic exploration processing of this invention. A graph showing each individual waveform and a composite waveform when a magnetic sensor passes near one end (single pole) of a magnetic object. A graph showing each individual waveform and a composite waveform when a magnetic sensor passes near both ends (bipolar) of a magnetic object. Explanatory drawing which shows an example of the case where a magnetic sensor passes near both ends (bipolar) of a magnetic object. A graph showing each individual waveform and a composite waveform when a magnetic sensor passes near both ends (bipolar) of a magnetic object. The flowchart which shows an example of the waveform output processing of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
<System configuration>

FIG. 1 is a block diagram showing an example of the system configuration of the magnetic exploration system 1. The magnetic exploration system 1 is a system for exploring (detecting) unexploded ordnance and other magnetic objects (exploration objects) existing in the ground. Unexploded ordnance is, for example, non-exploding shells, bombs, land mines or grenades. In addition, there are non-exploration objects such as H-shaped steel and sheet piles that are not exploration objects even if they are magnetic objects. Of the magnetic objects, what kind of objects are to be explored and which are not to be explored is appropriately set according to the purpose of the exploration.

As shown in FIG. 1, the magnetic exploration system 1 has a plurality of measuring units 5 and a recording device (recorder) 4. Each of the plurality of measuring units 5 has a magnetic sensor 2 and an amplification unit 3. That is, the magnetic exploration system 1 has a plurality of magnetic sensors 2 and a plurality of amplification units 3. In each measurement unit 5, the magnetic sensor 2 and the amplification unit 3 are connected via a connector cable 6. Further, the amplification unit 3 of each measurement unit 5 is connected to the recording device 4 so as to be able to wirelessly communicate with each other. The number of measurement units 5 (the number of magnetic sensors 2 and amplification units 3) included in the magnetic exploration system 1 is three in FIG. 1, but it is not particularly limited and may be two. It may be four or more.

FIG. 2 is an explanatory diagram showing an example of the configuration of the magnetic sensor 2. As shown in FIG. 2, the magnetic sensor 2 has a substantially rod shape as a whole and is a movable sensor. For example, the magnetic sensor 2 is a portable sensor that can be carried by humans.

The magnetic sensor 2 has a cylindrical main body 50 and a sensor unit 51, and is configured by inserting the sensor unit 51 into the tubular main body 50. A tip cap 52 is attached to the tip end (one end) of the tubular body 50, and a connector cap 53 is attached to the base end (the other end) of the tubular body 50. An O-ring 54, which is a rubber annular ring, is attached to the tip cap 52. A connector cable 6 for connecting to the amplification unit 3 is attached to the connector cap 53. Further, the diameter and length of the cylindrical main body 50 differ depending on the size of the sensor unit 51 (magnetic sensor 2).

The sensor unit 51 has a first coil 55 and a second coil 56. The second coil 56 is arranged so as to be separated from each other in the axial direction of the first coil 55. In the present embodiment, the first coil 55 and the second coil 56 are arranged on the same axis (the axis of the magnetic sensor 2).

The first coil 55 is wound around a first hollow member 58 inserted through a first core member 57 made of Permalloy. The number of turns of the first coil 55 was set to 40,000 turns by aligning winding using a predetermined wire rod. However, the number of turns of the first coil 55 is not limited to 40,000 turns, and may be, for example, 60,000 turns.

Further, the second coil 56 is wound around a second hollow member 60 inserted through a second core member 59 made of Permalloy. The second coil 56 was wound in an aligned manner using the same wire as the first coil 55, and the number of turns was 40,000 turns. However, the number of turns of the second coil 56 is not limited to 40,000 turns, and may be, for example, 60,000 turns. However, the number of turns of the first coil 55 and the number of turns of the second coil 56 are the same.

In the combination of the first coil 55 and the second coil 56, a coil having the same resistance value is taken out, a waveform is collected in a state where a constant current sine wave is passed through the taken out coil, and a coil having the same waveform amplitude is collected. Was set as one set. More specifically, in the first coil 55 and the second coil 56, conductors of the same material and the same thickness are all wound in a coil shape with the same radius and the same length (coil length). However, the winding directions of the first coil 55 and the second coil 56 are opposite to each other (opposite directions). Therefore, the first coil 55 and the second coil 56 have a symmetrical shape when a resistance value and a constant current sine wave are applied.

One end of the first core material 57 (the end on the tip cap 52 side) is attached to the first permalloy stopper 61A, and the other end of the first core material 57 (the end on the connector cap 53 side) is attached to the second permalloy stopper 61B. It is attached. Further, an O-ring 62, which is an annular ring made of rubber, is attached to the first permalloy stopper 61A and the second permalloy stopper 61B. Here, the first permalloy stopper 61A has an outer diameter substantially the same as the inner diameter of the tubular main body 50, and is arranged adjacent to the tip cap 52. Further, the second permalloy stopper 61B also has an outer diameter substantially the same as the inner diameter of the tubular main body 50.

Further, the first color material 63 is arranged so as to be inserted through the first core material 57 and adjacent to both the first permalloy stopper 61A and the first coil 55. Further, the second color material 64 is arranged so as to be inserted through the first core material 57 and adjacent to both the first coil 55 and the second permalloy stopper 61B.

One end of the second core material 59 (the end on the tip cap 52 side) is attached to the third permalloy stopper 61C, and the other end of the second core material 59 (the end on the connector cap 53 side) is attached to the fourth permalloy stopper 61D. It is attached. Further, an O-ring 62, which is an annular ring made of rubber, is attached to the third permalloy stopper 61C and the fourth permalloy stopper 61D.

Here, the third permalloy stopper 61C has an outer diameter substantially the same as the inner diameter of the tubular main body 50. Further, the fourth permalloy stopper 61D also has an outer diameter substantially the same as the inner diameter of the tubular main body 50, and is arranged adjacent to the connector cap 53.

Further, the third color material 65 is arranged so as to be inserted through the second core material 59 and adjacent to both the third permalloy stopper 61C and the second coil 56. Further, the fourth color material 66 is arranged so as to be inserted through the second core material 59 and adjacent to both the second coil 56 and the fourth permalloy stopper 61D. Further, the second permalloy stopper 61B and the third permalloy stopper 61C are connected by an aluminum pipe 67.

In the magnetic sensor 2 configured in this way, when a magnetic object (exploration object) approaches the first coil 55 and the second coil 56 within a predetermined distance, the magnetic flux density in the coil increases, and the magnetic flux density in the coil increases. An induced electromotive force is generated that generates a magnetic flux in a direction that hinders the increase. On the other hand, when the exploration target moves away from the first coil 55 and the second coil 56 from the state where the distance between the first coil 55 and the second coil 56 and the exploration object is short, the magnetic flux density in the coil decreases and the coil Induced electromotive force is generated in the direction of increasing the magnetic flux density. Since the induced electromotive force increases or decreases according to the amount of change in the magnetic flux density per unit time, the induced electromotive force increases as the moving speed of the magnetic sensor 2 increases, and the moving speed of the magnetic sensor 2 decreases. The induced electromotive force becomes smaller. Further, the induced electromotive force increases or decreases depending on the strength of the magnetic field (magnetic flux density) of the exploration object, and the magnetic flux density of the exploration object is inversely proportional to the cube of the distance.

Therefore, when the magnetic sensor 2 is moved and approaches or moves away from the object to be searched, the induced current flowing by the induced electromotive force according to the change in the distance to the object to be searched (change in magnetic flux density) is generated by the magnetic sensor 2. It is output from (first coil 55 and second coil 56) to the amplification unit 3.
<Structure of amplification unit 3>

FIG. 3 is an explanatory diagram showing an example of the configuration of the amplification unit 3. As shown in FIG. 3, the amplification unit 3 includes a preamplifier 31, a noise removal unit 32, a signal amplification unit 33, and an A / D conversion unit 34. The amplification unit 3 may be configured as one amplifier including the preamplifier 31, the noise removal unit 32, the signal amplification unit 33, and the A / D conversion unit 34.

Further, the amplification unit 3 has a first amplification unit 3a connected to the first coil 55 and a second amplification unit 3b connected to the second coil 56. The first amplification unit 3a includes a preamplifier 31a, a noise removal unit 32a, a signal amplification unit 33a, and an A / D conversion unit 34a. The second amplification unit 3b includes a preamplifier 31b, a noise removal unit 32b, a signal amplification unit 33b, and an A / D conversion unit 34b. However, the preamplifier 31a and the preamplifier 31b have the same configuration, the noise removing unit 32a and the noise removing unit 32b have the same configuration, the signal amplification unit 33a and the signal amplification unit 33b have the same configuration, and the A / D conversion unit 34a and Since the A / D conversion unit 34b has the same configuration, they may be referred to as a preamplifier 31, a noise removal unit 32, a signal amplification unit 33, and an A / D conversion unit 34, respectively, when it is not necessary to distinguish them. ..

The preamplifier 31 is a preamplifier for converting an induced current generated by an induced electromotive force in the first coil 55 or the second coil 56 into a voltage (voltage value). The preamplifier 31 may perform an amplification process that amplifies the voltage value when it is converted into a voltage value.

The noise removing unit 32 performs a noise removing process for removing noise from the voltage value converted by the preamplifier 31. For example, the noise removal process in the noise removal unit 32 is a process for removing noise caused by an environmental magnetic field other than the object to be searched included in the voltage value converted by the preamplifier 31. For example, the noise removing unit 32 has a low-pass filter, a high-pass filter, and the like, and noise caused by an environmental magnetic field is removed by these.

The signal amplification unit 33 performs an amplification process for amplifying the voltage value that has been subjected to the noise removal process by the noise removal unit 32. The A / D conversion unit 34 performs an A / D conversion process of converting the input signal amplified by the signal amplification unit 33 into a digital signal (digital value) in a predetermined cycle (sampling cycle). The sampling period is set in the range of, for example, 2 ms to 10 ms, and is preferably 4 ms or less. An output signal (sensor value) corresponding to the digital value after the A / D conversion process is transmitted to the recording device 4.

In the present embodiment, an output signal (first individual signal) corresponding to the induced current generated in the first coil 55 is transmitted from the first amplification unit 3a to the recording device 4, and in response to the induced current generated in the second coil 56. The output signal (second individual signal) is transmitted from the second amplification unit 3b to the recording device 4. That is, the first individual signal and the second individual signal are individually transmitted to the recording device 4.
<Configuration of recording device 4>

Returning to FIG. 1, the recording device 4 is composed of a general-purpose computer (terminal) such as a tablet PC, a desktop PC, a notebook (laptop) PC, or a smartphone, and records an output signal transmitted from the amplification unit 3. belongs to.

The recording device 4 includes a control unit 41, an input unit 42, a display unit 43, a communication unit 44, and an auxiliary storage unit 45. Each of the input unit 42, the display unit 43, the communication unit 44, and the auxiliary storage unit 45 is connected to the control unit 41 via a communication line.

The control unit 41 includes a calculation unit (processor) 46 and a main storage unit 47, and executes various calculations and control operations in the recording device 4. The calculation unit 46 is a calculation processing unit including a CPU, an MPU, and the like. The main storage unit 47 includes a RAM (DRAM), a ROM, and the like. The RAM is used as a work area and a buffer area of the calculation unit 46. The ROM stores default values and the like for the boot program and various information.

The input unit 42 includes an input component that receives an operation input of an operator (user) of the recording device 4, and an input detection circuit that is interposed between the input component and the calculation unit 46. The input component is, for example, a keyboard and / and a computer mouse, and when the input component is a keyboard, a hardware operation button or operation key (hardware key) is included. Further, a touch panel may be used as the input component. As the touch panel, any type such as a capacitance type, an electromagnetic induction type, a resistance film type, and an infrared type can be used. When the input component is a touch panel, operation keys (software keys) reproduced by software are included. The input detection circuit outputs an operation signal or operation data corresponding to the operation of each input component to the calculation unit 46.

The display unit 43 includes a display and a display control circuit interposed between the display and the calculation unit 46. As the display, for example, an LCD (liquid crystal display) or an organic EL display can be used. The display control circuit includes GPU, VRAM and the like. Under the instruction of the calculation unit 46, the GPU generates display image data for displaying various screens on the display using the image generation data stored in the RAM in the VRAM, and displays the generated display image data. Output to. For example, a recording screen or the like including a waveform (output waveform) based on an output signal output from the measurement unit 5 (amplification unit 3) is output (displayed) on the display. When the input component is a touch panel, the touch panel is provided on the display surface of the display, and the software keys are displayed on the display surface of the display.

The auxiliary storage unit 45 is composed of other non-volatile memories such as an HDD, SSD, flash memory, and EEPROM, and the arithmetic unit 46 stores a control program for controlling the operation of the recording device 4, various data, and the like. The data of the output signal transmitted from the amplification unit 3 is automatically stored (stored) in the auxiliary storage unit 45.

Further, the auxiliary storage unit 45 stores the control program 48 for executing various operations of the recording device 4 in the magnetic exploration system 1 and the exploration data (recorded data) 49 required for using this system. There is. The control program 48 and the exploration data 49 are read out from the auxiliary storage unit 45 and stored (expanded) in the main storage unit 47 (RAM) as needed.

The control program 48 includes a reception program (acquisition program) for receiving (acquiring) an output signal transmitted from the amplification unit 3, a waveform generation program that generates a waveform (output waveform) from the received output signal, and output waveform data. A storage program (recording program) for storing (recording) (output waveform data) in the auxiliary storage unit 45 is included. That is, the operation (recording operation) in which the recording device 4 records the output waveform data is realized by the arithmetic unit 46 executing the control program 48 expanded in the main storage unit 47 (RAM).

However, in the present embodiment, the receiving program individually receives the first individual signal transmitted from the first amplification unit 3a and the second individual signal transmitted from the second amplification unit 3b. Further, the waveform generation program generates a first individual waveform from the first individual signal, generates a second individual waveform from the second individual signal, and further synthesizes a first individual waveform and a second individual waveform (composite waveform). Differential amplitude waveform) is generated. Furthermore, the storage program stores the data of the first individual waveform (first individual waveform data), the data of the second individual waveform (second individual waveform data), and the data of the composite waveform (composite waveform data) in the auxiliary storage unit 45. (See Fig. 4). That is, the first individual waveform is generated from the induced current generated in the first coil 55, the second individual waveform is generated from the induced current generated in the second coil 56, and the composite waveform is generated in the first coil 55. It is generated from the induced current generated by the second coil 56 and the induced current generated by the second coil 56.

The composite waveform is an amplified waveform when the amplitudes of the first individual waveform and the second individual waveform are both positive amplitudes or both negative amplitudes, and the first individual waveform and the second individual waveform are the amplified waveforms. When one of the amplitudes of the individual waveforms is the amplitude on the plus side and the other is the amplitude on the minus side, the waveform is attenuated (cancelled). Therefore, in the composite waveform, even if a wave due to noise caused by the environmental magnetic field is generated in each of the first individual waveform and the second individual waveform, the wave due to noise is attenuated, so that the influence of noise caused by the environmental magnetic field is affected. It can be suppressed or prevented.

FIG. 4 is an explanatory diagram showing an example of exploration data 49 stored in the auxiliary storage unit 45 of the recording device 4. As shown in FIG. 4, the exploration data 49 includes the output waveform data 49a, and the output waveform data 49a includes the first individual waveform data 49b, the second individual waveform data 49c, and the composite waveform data 49d. The output waveform data 49a is generated or stored each time magnetic exploration is performed, and is stored separately from other output waveform data 49a. Further, each of the first individual waveform data 49b, the second individual waveform data 49c, and the composite waveform data 49d included in the same output waveform data 49a are associated with each other. For example, the first individual waveform data 49b, the second individual waveform data 49c, and the composite waveform data 49d are stored so that they can be output (displayed) in a state where their time axes are aligned with each other.

The configuration of the amplification unit 3 and the recording device 4 shown in FIG. 1 is merely an example, and the configuration is not limited to this. For example, the recording device 4 may be a so-called pen recorder that draws and records an output waveform with ink on paper such as roll paper. Further, each amplification unit 3 and the recording device 4 may be connected by wire.

In the magnetic exploration method in the conventional magnetic exploration system, the magnetic sensor 2 is moved horizontally or vertically, and the presence or absence of the exploration object is determined from the change in the output waveform. However, magnetic objects have different sizes and different depths in the ground, and due to these differences, the length of the object to be explored with respect to the distance between the first coil 55 and the second coil 56. If (the length in the axial direction of the magnetic sensor 2) is too short or the length of the exploration object is too long, there is a problem that the correct waveform is not output and the detection accuracy of the exploration object is lowered.

Therefore, in the present invention, a plurality of magnetic sensors 2 having different distances between the first coil 55 and the second coil 56 are prepared so that the plurality of magnetic sensors 2 can be selectively used. Further, in the present invention, the first individual waveform data 49b, the second individual waveform data 49c, and the composite waveform data 49d are recorded in association with each other, and the first individual waveform, the second individual waveform, and the composite waveform are individually recorded. Can be referenced or compared with.

FIG. 5 is an explanatory diagram showing the distance D between the coils of each magnetic sensor 2 included in the magnetic exploration system 1. As shown in FIG. 5, each of the magnetic sensors 2 is configured such that the inter-coil distance D, which is the distance between the first coil 55 and the second coil 56, is different from each other. The inter-coil distance D is the distance between the center position of the first coil 55 in the longitudinal direction (axial direction) and the center position of the second coil 56 in the longitudinal direction.

The inter-coil distance D of each magnetic sensor 2 may be appropriately set according to the size of the object to be searched. For example, when the object to be explored is an unexploded ordnance (shell or bomb), the distance D between the coils of each magnetic sensor 2 is 0.3 m to 2.0 m so as to correspond to unexploded ordnance of various bullet lengths. Set between.

In the example shown in FIG. 5, five magnetic sensors 2a to 2e are prepared. The coil-to-coil distance D of the magnetic sensor 2a is 1.6 m, the coil-to-coil distance D of the magnetic sensor 2b is 1.0 m, the coil-to-coil distance D of the magnetic sensor 2c is 0.7 m, and the coil of the magnetic sensor 2d. The distance D is 0.5 m, and the distance D between the coils of the magnetic sensor 2e is 0.3 m. The magnetic sensor 2a having a distance D between coils of 1.6 m has been widely used in the horizontal magnetic exploration method. The magnetic sensor 2b having a distance D between coils of 1.0 m has been conventionally used mainly in a vertical magnetic exploration method.
<Example of magnetic exploration method>

Hereinafter, an example of a method for exploring an exploration object existing in the ground will be described. FIG. 6 is an explanatory diagram showing a horizontal magnetic exploration method which is an example of the magnetic exploration method. As shown in FIG. 6, an exploration survey line map in which exploration lateral lines at predetermined intervals (for example, intervals of 0.5 m to 1 m) are set in an area (exploration area) for exploring an exploration object is created. Next, in accordance with the set exploration side line, a rope or other object that serves as a mark for the exploration survey line is installed on the ground of the exploration area. A plurality of exploration lateral lines are installed, and unique identification information (for example, a number or the like) for identifying each exploration lateral line is assigned to each of the plurality of exploration lateral lines.

Then, the magnetic sensor 2 is moved by walking along the exploration survey line with the magnetic sensor 2 suspended and supported by two explorers. When an object to be searched exists in the ground, an induced electromotive force is generated in the first coil 55 or the second coil 56 of the magnetic sensor 2, and an output signal corresponding to the induced electromotive force is output from the amplification unit 3. When the recording device 4 receives the output signal, the waveform (output waveform) generated from the output signal is displayed on the display of the display unit 43. The scorer determines the presence or absence of the search target from the change in the output waveform displayed on the display of the display unit 43.

However, the magnetic sensor 2 is supported so that the ground height is a predetermined height (0.05 m to 0.15 m, preferably 0.1 m) and has a predetermined moving speed (0.8 m / sec to 1.2 m). It is moved at / sec, preferably 1 m / sec).

Hereinafter, a plurality of examples in which the magnetic sensor 2 passes in the vicinity of the object to be searched and the output waveform (composite waveform) in each case will be described with reference to FIGS. 7 to 10. The examples shown in FIGS. 7 to 10 use the horizontal magnetic exploration method. Further, the exploration object shown in FIGS. 7 to 10 is a cylindrical magnetic object having a longitudinal direction and a lateral direction, assuming an unexploded ordnance.
<Detection example 1>

FIG. 7A is a front view explanatory view showing a detection example 1 (an example of passing through a single pole) in which the magnetic sensor 2 passes near one end (single pole) of the object to be searched. That is, the exploration object buried in a standing state is illustrated. FIG. 7B is a graph showing the output waveform AW in the case of FIG. 7A.

In the graph of the output waveform shown in FIG. 7B, the horizontal axis is time and the vertical axis is the sensor value (digitally converted voltage value, that is, the intensity of the output signal). Further, of the vertical axis, the upper part of the paper surface is the plus side, and the lower part of the paper surface is the minus side. These things are the same in the graphs shown in FIGS. 8B, 9B, and 10B, which will be described later.

As shown in FIG. 7A, in the detection example 1, the longitudinal direction of the object to be searched is substantially perpendicular to the moving direction of the magnetic sensor 2 (horizontal direction in this detection example). In this case, when the magnetic sensor 2 passes near the exploration object, one end P1 in the longitudinal direction of the exploration object approaches the magnetic sensor 2, but the other end P2 in the longitudinal direction of the exploration object is It remains away from the magnetic sensor 2. Therefore, only the magnetic field of one end P1 of the object to be searched acts on the magnetic sensor 2, and the magnetic field of the other end P2 of the object to be searched hardly acts on the magnetic sensor 2. Therefore, the output waveform in the case of passing through a single pole as shown in FIG. 7A is mainly a wave due to an induced electromotive force generated by one end P1 (single pole) of the object to be searched.

Specifically, when the first coil 55 first approaches and separates from one end P1 of the object to be searched, a positive or negative induced electromotive force is generated in the first coil 55. Then, after a lapse of a predetermined time, the second coil 56 approaches and separates from one end P1 of the object to be searched, so that a positive or negative induced electromotive force is generated in the second coil 56. Therefore, as shown in FIG. 7B, the output waveform (combined waveform) AW obtained by combining the first individual waveform and the second individual waveform is a wave in one direction corresponding to the induced electromotive force generated in the first coil 55. A (first wave) CA1 and a unidirectional wave (second wave) CA2 corresponding to the induced electromotive force generated in the second coil 56 appear.

As described above, the winding directions of the first coil 55 and the second coil 56 are opposite to each other. Therefore, in the detection example 1, the first wave CA1 and the second wave CA2 are waves having the same amplitude and opposite directions (waves in which plus and minus are opposite). Further, since the waves in the opposite directions appear with a predetermined time difference, the output waveform AW of Detection Example 1 has a waveform similar to a sine wave.

In such an output waveform AW, the presence or absence of an object to be searched is determined by reading and analyzing the distance (inter-peak distance) PD between the peak of the first wave CA1 and the peak of the second wave CA2. It can be performed. For example, the distance D between the coils is 1.0 m, the moving speed of the magnetic sensor 2 is 1.0 m / sec, the amplitude of the first wave CA1 and the amplitude of the second wave CA2 are equal, and When the inter-peak distance PD on the output waveform AW corresponds to 1.0 m (for example, when the horizontal axis of the output waveform AW is 1 cm / sec and the inter-peak distance PD is 1 cm), the first It can be estimated that the coil 55 and the second coil 56 are reacting to an object having the same magnetic flux density at the same position, that is, the same object. Therefore, the position of the peak of the first wave CA1 (or the peak of the second wave CA2) (that is, the position of the first coil 55 and the second coil 56 where the peak appears is directly below the position at the peak time). It can be determined (estimated) that one exploration object exists (underground).

As described above, when a waveform similar to a sine wave (waveform in the case of passing through a single pole) appears independently in the output waveform AW, the first coil 55 and the second coil 56 of the magnetic sensor 2 are used. It can be determined that the reaction is occurring at one end (single pole) of the same exploration object. That is, it can be determined that there is an object to be searched whose longitudinal direction is substantially perpendicular to the moving direction of the magnetic sensor 2.
<Detection example 2>

FIG. 8A is an explanatory diagram showing a detection example 2 (an example of bipolar passage) in which the magnetic sensor 2 passes near both ends (bipolar) of a magnetic object. FIG. 8B is a graph showing an example of the output waveform AW in the case of FIG. 8A.

As shown in FIG. 8A, in the detection example 2, the longitudinal direction of the object to be searched is parallel to the moving direction of the magnetic sensor 2 (horizontal direction in this detection example). In this case, when the magnetic sensor 2 passes near the exploration object, after one end P1 in the longitudinal direction of the exploration object approaches the magnetic sensor 2, the other end P2 in the longitudinal direction of the exploration object is moved. Approach the magnetic sensor 2. Therefore, when the magnetic sensor 2 passes near both ends (bipolars) of the magnetic object, both the magnetic field of one end P1 and the magnetic field of the other end P2 act on the magnetic sensor 2. ..

However, in each of the first coil 55 and the second coil 56, between the wave due to the induced electromotive force due to one end P1 of the exploration object and the wave due to the induced electromotive force due to the other end P2 of the exploration object. , There is a time difference determined by the distance between one end P1 and the other end P2 (length L of the object to be searched), the moving speed of the magnetic sensor 2, and the distance D between the coils. Therefore, the output waveform AW in this case is a waveform in which the wave due to the induced electromotive force due to one end P1 of the exploration object and the wave due to the induced electromotive force due to the other end P2 of the exploration object appear with a predetermined time difference. Become.

Specifically, the first coil 55 first approaches and separates from one end P1 of the exploration object to generate an induced electromotive force in the first coil 55, and then the first coil 55 moves to the exploration object. An induced electromotive force is generated in the first coil 55 by approaching and separating from the other end P2. Further, after the first coil 55, the second coil 56 approaches and separates from one end P1 of the object to be searched, so that an induced electromotive force is generated in the second coil 56, and then the second coil 56 searches. An induced electromotive force is generated in the second coil 56 by approaching and separating from the other end P2 of the object.

However, the magnetic poles of the one end P1 and the other end P2 are opposite to each other. For example, if one end P1 is the S pole, the other end P2 is the N pole. These things are the same in the detection example 3, the detection example 4, the detection example 6, and the detection example 7 which will be described later. Therefore, the positive and negative sides of the induced electromotive force generated in the vicinity of one end P1 and the induced electromotive force generated in the vicinity of the other end P2 are opposite. Therefore, although not shown, in the case of bipolar passage, the waveform of the induced electromotive force generated in the first coil 55 (first individual waveform) and the waveform of the induced electromotive force generated in the second coil 56 (second individual waveform) In each case, the opposite waves appear with a predetermined time difference, so that the waveform resembles a sine wave.

Therefore, as shown in FIG. 8B, the output waveform (composite waveform) AW obtained by synthesizing the first individual waveform and the second individual waveform is the wave (first wave) CA1 by one end P1 in the first individual waveform. And the wave by the other end P2 in the first individual waveform and the wave by the one end P1 in the second individual waveform (second wave) CA2 and the wave by the other end P2 in the second individual waveform. (Third wave) CA3 appears.

In this detection example 2, the distance D between the coils of the magnetic sensor 2 and the length L of the object to be searched (distance between the one end P1 and the other end P2) L are equal. Therefore, in the detection example 2, the wave due to the other end P2 in the first individual waveform and the wave due to the one end P1 in the second individual waveform appear almost at the same time.

Further, in the detection example 2, the winding directions of the first coil 55 and the second coil 56 are opposite to each other, and the magnetic poles of the one end P1 and the other end P2 have opposite polarities. Therefore, the first wave CA1 and the third wave CA3 are waves in the same direction (plus and minus are the same). On the other hand, the wave due to the other end P2 in the first individual waveform and the wave due to the one end P1 in the second individual waveform are waves in the same direction, respectively, and the first wave CA1 and the third wave CA3 Is a wave in the opposite direction. That is, in the second wave CA2, the wave by the other end P2 in the first individual waveform and the wave by the one end P1 in the second individual waveform, which are waves in the same direction, are combined. Therefore, the wave becomes amplified, and the amplitude becomes larger than that of the first wave CA1 and the third wave CA3.

Therefore, the output waveform AW in Detection Example 2 is an M-shaped waveform in which three waves CA1 to CA3 in which the positive and negative directions are alternately reversed appear (W-shaped waveform when the polarities of the exploration object are opposite). ), And the amplitude of the second wave CA2 is larger than the amplitude of the first wave CA1 and the amplitude of the third wave CA3.

As described above, when an M-shaped or W-shaped waveform appears in the output waveform AW, the first coil 55 and the second coil 56 of the magnetic sensor 2 are at both ends of the same search object ( It can be determined that it is reacting to (bipolar). That is, it can be determined that there is an object to be searched whose longitudinal direction is substantially perpendicular to the moving direction of the magnetic sensor 2. Further, since the amplitude of the second wave CA2 in the output waveform AW is larger than the amplitude of the first wave CA1 and the amplitude of the third wave CA3, the wave due to the other end P2 in the first individual waveform and the second wave. It can be seen that the wave due to the one end P1 in the individual waveform appears at the same time. That is, it can be seen that the length L of the object to be searched is equal to the distance D between the coils of the magnetic sensor 2.
<Detection example 3>

FIG. 9A is an explanatory diagram showing another detection example 3 (example of bipolar passage) in which the magnetic sensor 2 passes near both ends (bipolar) of the magnetic object. FIG. 9B is a graph showing an example of the output waveform AW in the case of FIG. 9A.

As shown in FIG. 9A, in the detection example 3, the distance D between the coils of the magnetic sensor 2 and the length L of the object to be searched are different, and the length L of the object to be searched is larger than the distance D between the coils. It's getting shorter. For example, the length L of the object to be searched is 1/10 to 1/2 of the distance D between the coils.

Since this detection example 3 is also a case of bipolar passage, the basic configuration of the output waveform AW is similar to the waveform of detection example 2 (waveform shown in FIG. 8B). However, in the detection example 3, since the length L of the object to be searched is shorter than the distance D between the coils, the wave due to the other end P2 in the first individual waveform and the wave due to the one end P1 in the second individual waveform There is a time lag.

Therefore, as shown in FIG. 9B, in the detection example 3, the first wave CA1 by the one end P1 in the first individual waveform and the third wave CA3 by the other end P2 in the second individual waveform clearly appear. However, the wave due to the other end P2 in the first individual waveform and the wave due to the one end P1 in the second individual waveform are attenuated at the time of synthesis. That is, the amplitude of the second wave CA2 between the first wave CA1 and the third wave CA3 becomes small. At least, the amplitude of the second wave CA2 is equal to or less than the amplitude of the first wave CA1 and the third wave CA3. Therefore, the ideal second wave CA2 as shown in FIG. 2B may not appear, and the second wave CA2 may not be recognized.

Further, the waveform Z1 over the first half of the first wave CA1 and the second wave CA2 and the waveform Z2 over the second half of the second wave CA2 and the third wave CA3 are each in the case of unipolar passage. It is similar to the waveform of (single pole waveform). That is, in Detection Example 3, it can be said that a plurality of unipolar waveforms appear.

As described above, when the second wave CA2 between the first wave CA1 and the third wave CA3 is not an ideal waveform as the output waveform AW, it is known that the search object exists. However, there is a possibility that one bipolar has passed, and each of the first wave CA1 and the third wave CA3 may have passed through a single pole (passed through two single poles). .. That is, the length L or the number of objects to be explored is undetectable (unknown).

Therefore, even though there is one exploration object whose longitudinal direction is substantially perpendicular to the moving direction of the magnetic sensor 2, the longitudinal direction is substantially perpendicular to the moving direction of the magnetic sensor 2. There is a possibility of misidentifying that there are two exploration objects that are oriented in a substantially vertical direction.

Here, if the magnetic sensor 2 having a shorter coil-to-coil distance D than the magnetic sensor 2 used when obtaining the output waveform AW of FIG. 9B is used, the coil-to-coil distance D of the magnetic sensor 2 and the object to be searched are used. The difference from the length L can be reduced, and in some cases, the distance D between the coils of the magnetic sensor 2 can be made to match the length L of the object to be searched. If the difference between the distance D between the coils of the magnetic sensor 2 and the length L of the object to be searched becomes small, the output waveform AW becomes a shape closer to the waveform shown in FIG. 8B. Therefore, by using the magnetic sensor 2 having a shorter distance D between the coils than the magnetic sensor 2 used when obtaining the output waveform AW of FIG. 9B, the longitudinal direction is substantially vertical. It is possible to detect the existence of an exploration object. That is, the exploration target can be appropriately detected.
<Detection example 4>

FIG. 10A is an explanatory diagram showing another detection example 4 (example of bipolar passage) in which the magnetic sensor 2 passes near both ends (bipolar) of a magnetic object. FIG. 10B is a graph showing an example of the output waveform AW in the case of FIG. 10A.

As shown in FIG. 10A, in the detection example 4, the distance D between the coils of the magnetic sensor 2 and the length L of the object to be searched are different, and the length L of the object to be searched is larger than the distance D between the coils. It's getting longer. For example, the length L of the object to be explored is 1.5 times or more the distance D between the coils.

Since this detection example 4 is also a case of bipolar passage, the basic configuration of the output waveform AW is similar to the waveform of the detection example 2 (waveform shown in FIG. 8B). However, in the detection example 4, since the length L of the object to be searched is longer than the distance D between the coils, the wave due to the other end P2 in the first individual waveform and the wave due to the one end P1 in the second individual waveform There is a time lag.

Therefore, as shown in FIG. 9B, in the detection example 4, the first wave CA1 by the one end P1 in the first individual waveform and the third wave CA3 by the other end P2 in the second individual waveform clearly appear. However, the wave due to the other end P2 in the first individual waveform and the wave due to the one end P1 in the second individual waveform are attenuated at the time of synthesis. That is, the amplitude of the second wave CA2 between the first wave CA1 and the third wave CA3 becomes small. Further, a wave (fourth wave) CA4 having the same direction as the first wave CA1 and the third wave CA3 is generated between the first wave CA1 and the third wave CA3, although the amount is small. That is, in the detection example 4, five continuous waves in which the positive and negative directions are alternately reversed are generated. Therefore, the ideal second wave CA2 as shown in FIG. 2B may not appear, and the second wave CA2 may not be recognized. Further, in the detection example 4, the waveform Z1 and the waveform Z2 similar to the unipolar waveform appear. That is, it can be said that in the detection example 4, a plurality of unipolar waveforms appear.

In this case as well, since the second wave CA2 between the first wave CA1 and the third wave CA3 is not an ideal waveform, it is possible to know that the exploration object exists, but one bipolar pole. It is also possible that it has passed through two or more unipolar poles. That is, the length L or the number of exploration objects is unknown.

Here, if the magnetic sensor 2 having a longer coil-to-coil distance D than the magnetic sensor 2 used when obtaining the output waveform AW of FIG. 10B is used, the coil-to-coil distance D of the magnetic sensor 2 and the object to be searched are used. The difference from the length L can be reduced, and in some cases, the distance D between the coils of the magnetic sensor 2 can be made to match the length L of the object to be searched. If the difference between the distance D between the coils of the magnetic sensor 2 and the length L of the object to be searched becomes small, the output waveform AW becomes a shape closer to the waveform shown in FIG. 8B. Therefore, by using the magnetic sensor 2 having a longer distance D between the coils than the magnetic sensor 2 used when the output waveform AW of FIG. 10B is obtained, the object to be searched can be appropriately detected.

FIG. 11 is a flowchart showing an example of the magnetic exploration process of the present invention. Hereinafter, the flow of the magnetic exploration process will be described with reference to FIG. First, one of the plurality of magnetic sensors 2 is selected (step S1), magnetic exploration is performed (step S2), and the output waveform generated by the magnetic exploration is displayed (step S3).

Subsequently, from the output waveform displayed in step S3, it is determined whether or not it can be determined that the bipolar passage has passed (step S4). Here, it is an M-shaped or W-shaped waveform in which three waves CA1 to CA3 in which positive and negative are alternately reversed appear, and the amplitude of the second wave CA2 is the amplitude of the first wave CA1 and the first wave. It is determined whether or not the waveform is larger than the amplitude of the wave CA3 of 3.

If it can be determined that the bipolar passage has passed (step S4: YES), the bipolar passage is detected (step S5), and the magnetic exploration process ends. That is, it detects an exploration object buried in the ground in a substantially horizontal direction. At this time, the length L of the object to be searched is also detected from the distance D between the coils of the magnetic sensor 2 used in step S2.

On the other hand, if it cannot be determined that the bipolar passage has passed (step S4: NO), it is determined whether or not a plurality of unipolar waveforms continuously appear in the output waveform displayed in step S3 (step S6).

When a plurality of unipolar waveforms do not appear continuously in the output waveform, that is, when the unipolar waveforms appear independently (step S6: NO), the unipolar passage is detected (step S7). End the magnetic exploration process. Detects exploration objects buried in the ground in a nearly vertical orientation.

On the other hand, when a plurality of unipolar waveforms appear continuously in the output waveform (step S6: YES), five or more consecutive waves in which the positive and negative directions are alternately reversed in the output waveform displayed in step S3. It is determined whether or not there is (step S8). The wave is a wave having an amplitude exceeding a predetermined threshold value, and does not include fine waves due to noise.

If there are five or more consecutive waves in which the positive and negative directions are alternately reversed (step S8: YES), the magnetic sensor 2 having a longer coil-to-coil distance D than the magnetic sensor 2 used immediately before is selected (step S9). , Return to step S2. On the other hand, if there are no continuous five or more waves in which the positive and negative directions are alternately reversed (step S8: NO), the magnetic sensor 2 having a shorter coil-to-coil distance D than the magnetic sensor 2 used immediately before is selected (step S8: NO). S10), the process returns to step S2.

As described above, in this magnetic exploration system 1, a plurality of measuring units 5 can be selectively used. That is, in the magnetic exploration system 1, a plurality of magnetic sensors 2 having different coil-to-coil distances D can be selectively used.

Therefore, as shown in Detection Examples 1 to 4, the waveform detected for each magnetic sensor 2 of the magnetic exploration system 1 differs depending on the distance D between the coils and the size (length) and direction of the exploration object. Then, by utilizing this, when the number and length of the exploration object are unknown from the output waveform, the number and length of the exploration object are re-explored by using another magnetic sensor 2. May become clear.

With the above configuration and operation, magnetic objects existing in the ground can be appropriately detected. More specifically, the search target is detected along the search side line using one magnetic sensor 2, and the search target is confirmed by confirming which of the detection examples 1 to 4 the obtained waveform corresponds to. It detects that it is an object and its size (length), or re-searches its position with another magnetic sensor 2 that has a different distance D between coils to determine that it is an object and its size (length). It can be detected, and the object to be explored and its size (length) can be detected accurately.

Further, since the magnetic sensor 2 has the first coil 55 and the second coil 56, it is possible to detect the object to be searched by both the first coil 55 and the second coil 56 and improve the detection accuracy. Further, since the first coil 55 and the second coil 56 are arranged so that the axial core directions are aligned and the directions of the coils are opposite to each other, the object to be searched is detected by each of the first coil 55 and the second coil 56. The waveform can be the opposite waveform, and noise can be removed to perform accurate detection.

Further, since each magnetic sensor 2 has a configuration in which the first coil 55 and the second coil 56 are the same but the distance D between the coils is different, it is easy to compare the detected waveforms and another magnetic sensor. By re-exploring using 2, it becomes easy to appropriately determine whether or not the object is an exploration object, and it becomes easy to detect the size (length) of the exploration object.

For example, a magnetic sensor 2a having a coil-to-coil distance D of 1.6 m, which has been widely used in the past, could properly detect an object to be searched with a projectile length of 0.6 m or more, but the projectile length. There is a problem that it is difficult to find an exploration object with a distance of less than 0.6 m. Therefore, for exploration objects with a projectile length of less than 0.6 m, the exploration objects should be appropriately detected by using magnetic sensors 2c to 2e with a coil-to-coil distance D of 0.3 m to 0.7 m. Can be done. As described above, the magnetic sensors 2c to 2e having a coil-to-coil distance D of 0.3 m to 0.7 m prepared in the present embodiment are suitable for exploration of relatively small unexploded ordnance, and are particularly common in past wars. It is suitable for exploration of the used 5-inch shell (body length 0.526 m).

On the other hand, for an exploration object with a projectile length of 1.0 m or more, the exploration object can be appropriately detected by using magnetic sensors 2a and 2b having a coil-to-coil distance D of 1.0 m to 1.6 m. can.
<Detection example 5>

FIG. 12 is a graph showing individual waveforms and composite waveforms of another example (detection example 5) in which the magnetic sensor 2 passes near one end (single pole) of a magnetic object. Since the detection example 5 is an example of passing through a single pole, the longitudinal direction of the object to be searched is substantially perpendicular to the moving direction of the magnetic sensor 2 as in the detection example 1 (for example, FIG. 7A). reference).

As described in Detection Example 1, in the case of unipolar passage, the output waveform (composite waveform) AW has a waveform similar to a sine wave. However, in Detection Example 5, as shown in FIG. 12, the composite waveform AW is not a beautiful sine wave even in the case of passing through a single pole. In such a case, although it is known that the exploration object exists, it becomes difficult to detect (determine) whether the object is unipolar or bipolar, and the number or length L of the exploration object can be determined. There is a possibility of misunderstanding.

Here, in the present invention, the first individual waveform data 49b and the second individual waveform data 49c associated with the composite waveform data 49d are recorded. That is, the first individual waveform IW1 shown by the first individual waveform data 49b and the second individual waveform IW2 shown by the second individual waveform data 49c can be referred to.

Looking at the first individual waveform IW1, a wave (first wave) CA1 in one direction appears, and when looking at the second individual waveform IW2, a wave (second wave) CA2 in one direction appears. There is. The first wave CA1 and the second wave CA2 are waves having the same amplitude and opposite directions, and are represented by a predetermined inter-peak distance PD. In this case, when the inter-coil distance D and the inter-peak distance PD correspond, it can be seen that the passage is unipolar.

As described above, in the detection example 5, the first individual waveforms IW1 and the first individual waveforms IW1 and the first individual waveforms IW1 and the first when the existence of the exploration object (magnetic object) is detected from the composite waveform AW and the number of the exploration objects is unknown. 2 By referring to the individual waveform IW2, the number of exploration objects can be appropriately detected.
<Detection example 6>

FIG. 13 is a graph showing individual waveforms and composite waveforms of detection example 6 (example of bipolar passage) in which the magnetic sensor 2 passes near both ends (bipolar) of a magnetic object. Since the detection example 6 is an example of bipolar passage, the longitudinal direction of the object to be searched is parallel to the moving direction of the magnetic sensor 2 (see, for example, FIG. 8A).

As described in Detection Example 2, in the case of bipolar passage, the output waveform (composite waveform) AW is an M-shaped or W-shaped waveform in which three waves CA1 to CA3 in which the positive and negative directions are alternately reversed appear. The waveform is such that the amplitude of the second wave CA2 is larger than the amplitude of the first wave CA1 and the amplitude of the third wave CA3. However, in Detection Example 6, as shown in FIG. 13, the waveform is not ideal in the case of bipolar passage, and a large number of waves appear. For example, when the length L of the object to be searched is shorter than the distance D between the coils of the magnetic sensor 2, the waveform is as shown in FIG. In such a case, although it is possible to know that the exploration object exists, it is difficult to determine whether it is a plurality of unipolar passages or bipolar passages, and there is a possibility of misidentifying the number of exploration objects. be. In addition, it is difficult to accurately detect the length L of the exploration object in the case of bipolar passage, and there is a possibility that the length L of the exploration object may be misidentified.

Here, also in the detection example 6, as in the case of the detection example 5, the first individual waveform IW1 shown by the first individual waveform data 49b and the second individual waveform IW2 shown by the second individual waveform data 49c are referred to. be able to. Looking at the first individual waveform IW1, a wave similar to a sine wave (first wave CA1) appears, and looking at the second individual waveform IW2, a wave similar to a sine wave (second wave CA1) appears. Wave CA2) is appearing. That is, looking at each individual waveform, the first wave CA1 resembling a sine wave and the second wave CA2 resembling a sine wave appear with a predetermined time difference. From these characteristics, it can be seen that the passage is bipolar. Further, the length L of the exploration object can be detected from the inter-peak distance PD of the first wave CA1 and the inter-peak distance PD of the second wave CA2.

As described above, in the detection example 6, when the existence of the exploration object (magnetic object) is detected from the composite waveform AW and the length L or the number of the exploration objects is unknown, the first individual By referring to the waveform IW1 and the second individual waveform IW2, the length L or the number of objects to be searched can be appropriately detected.
<Detection example 7>

FIG. 14A is an explanatory diagram showing another example (detection example 7) in which the magnetic sensor 2 passes near both ends (bipolar) of two magnetic objects. FIG. 14B is a graph showing each individual waveform and a composite waveform in the case of FIG. 14A.

As shown in FIG. 14A, in the detection example 7, the magnetic sensor 2 passes near the bipolar of two magnetic objects. However, one of the two magnetic objects is an exploration target, and the other is a non-exploration target magnetic object (non-exploration object). Further, the length L1 of the exploration object is a length equal to or less than the inter-coil distance D, and the length L2 of the non-exploration object is longer than the inter-coil distance D. That is, the length L1 of the exploration object is shorter than the length L2 of the non-exploration object. In addition, the exploration object and the non-exploration object exist so as to be arranged substantially in parallel, and the exploration object is located at a position (non-exploration object) aligned with the central portion in the longitudinal direction (axial direction) of the non-exploration object. It exists in a position that fits within the longitudinal range of the object).

In this detection example 7, the magnetic sensor 2 (first coil 55 and second coil 56) has one end P3 of the non-exploration object, one end P1 of the exploration object, and the other end P2 of the exploration object. It passes in the order of the other end P4 of the non-exploration object. In this case, as shown in FIG. 14B, the output waveform (composite waveform) AW is a waveform in which many large and small waves appear. In such a composite waveform AW, although it is possible to know that the object to be searched exists, it is not only difficult to determine whether the object is unipolar or bipolar, but also the length L1 of the object to be searched is determined. It is also difficult to detect accurately. Therefore, there is a possibility of misidentifying the number of exploration objects or the length L1 of the exploration object.

On the other hand, looking at the first individual waveform IW1, a wave in one direction (first wave CA11), a wave similar to a sine wave (second wave CA12), and a wave in one direction (third wave). CA13) appears with a predetermined time difference. Looking at the second individual waveform IW2, a wave in one direction (first wave CA21), a wave similar to a sine wave (second wave CA22), and a wave in one direction (third wave). CA23) appears with a predetermined time difference. However, the second wave CA12 resembling a sine wave and the second wave CA22 resembling a sine wave appear in a predetermined inter-peak distance PD. From this feature, it can be seen that the second wave CA12 and the second wave CA12 are bipolar passing waveforms. Therefore, even if a long non-exploration object is near the exploration object, it can be seen that it is a bipolar passage. Further, the length L1 of the exploration object can be detected from the relationship between the peak distance PD between the second wave CA12 and the second wave CA22 and the coil distance D of the magnetic sensor 2 used. ..

FIG. 15 is a flowchart showing an example of the waveform output process of the present invention. Hereinafter, the flow of the waveform output processing will be described with reference to FIG. First, magnetic exploration is performed (step S21), and it is determined whether or not to output a composite waveform as an output waveform (step S22). That is, it is determined whether to output the composite waveform or the individual waveform. Whether to output the composite waveform or the individual waveform may be set in advance.

When the composite waveform is output (step S22: YES), the composite waveform is output (step S23), and it is determined whether the number of exploration objects or the length of the exploration object can be determined from the composite waveform (step S24). .. If the number of objects to be searched or the length of the objects to be searched can be determined from the composite waveform (step S24: YES), the waveform output process is terminated. On the other hand, if it is not possible to determine the number of objects to be searched or the length of the objects to be searched from the composite waveform (step S24: NO), an individual waveform is output (step S25), and the waveform output process is terminated.

When the individual waveform is output in step S22 (step S22: NO), the individual waveform is output (step S26), and it is determined whether the number of exploration objects or the length of the exploration object can be determined from the individual waveforms. (Step S27). If the number of objects to be searched or the length of the objects to be searched can be determined from the individual waveforms (step S27: YES), the waveform output process is terminated. On the other hand, if the number of objects to be searched or the length of the objects to be searched cannot be determined from the individual waveforms (step S27: NO), the composite waveform is output (step S28), and the waveform output process is terminated. The case where the number of objects to be searched or the length of the objects to be searched cannot be determined from the individual waveforms is, for example, a case where the influence of noise is large. This is because, as described above, the composite waveform is less susceptible to noise, whereas the individual waveform is more susceptible to noise.

In this magnetic exploration system 1, not only the composite waveform but also the first individual waveform and the second individual waveform can be referred to. Therefore, as described in Detection Example 5 to Detection Example 7, even if the length or number of the objects to be searched is unknown only by referring to the composite waveform, the first individual waveform and the second individual waveform can be obtained. By referring to it, the length or number of exploration objects can be appropriately detected. Further, even if the length or number of the exploration objects is unknown only by referring to the first individual waveform and the second individual waveform, the length or number of the exploration objects can be determined by referring to the composite waveform. It can be detected properly.

The first coil of the present invention corresponds to the first coil 55 of the above embodiment, the second coil corresponds to the second coil 56, the magnetic sensor corresponds to the magnetic sensor 2, and the waveform generator corresponds to the waveform. The recording unit corresponds to the generation program and the control unit 41 (calculation unit 46) that operates according to the generation program, and the recording unit corresponds to the recording device 4, but the present invention is not limited to the present embodiment and can be various other embodiments. .. Further, the specific configuration and the like given in the above-described embodiment are examples, and can be appropriately changed according to the actual product. For example, in the above-described embodiment, the horizontal magnetic exploration method has been described as an example of the magnetic exploration method, but the present invention can also be applied to the vertical magnetic exploration method.

In the above-described embodiment, the magnetic sensor 2 is moved by walking while being suspended and supported by an explorer, but is moved by an autonomous vehicle, a robot, a drone, or the like, or is moved by a ropeway or the like. It may be moved by the device.

Further, in the above-described embodiment, the magnetic exploration system 1 is provided with a plurality of measuring units 5, but the magnetic exploration system 1 may be provided with one measuring unit 5. That is, the magnetic exploration system 1 may include one magnetic sensor 2.

Further, in the above-described embodiment, the first individual waveform data, the second individual waveform data, and the composite waveform data are stored in the auxiliary storage unit 45, but only the composite waveform data is stored in the auxiliary storage unit 45. You may do so.

Furthermore, in addition to the configuration of the above-described embodiment, the amplification unit 3 may perform a walking noise removal process for continuously removing the walking noise of the explorer in real time. The specific content of the walking noise removal process is described in, for example, Japanese Patent No. 683396, and detailed description thereof will be omitted here. Briefly, the vertical shaking at both ends of the magnetic sensor 2 in the horizontal direction is defined as walking noise, and the range of the frequency band corresponding to the walking noise in the digital value converted by the A / D conversion unit 34 is defined as the noise range. Of the digital values converted by the A / D conversion unit 34, walking noise can be removed from the digital values by attenuating the noise range. The output signal corresponding to the digital value after the noise removal processing processed in this way is transmitted to the recording device 4. In this way, the influence of walking noise of the explorer can be suppressed or prevented, and the detection accuracy of the magnetic object (exploration object) can be further improved.

The present invention can be used in industries such as exploring unexploded ordnance and other magnetic objects such as structures existing in the ground.

1 ... Magnetic exploration system 2 ... Magnetic sensor 55 ... 1st coil 56 ... 2nd coil 3 ... Amplification unit 3a ... 1st amplification unit 3b ... 2nd amplification unit 4 ... Recording device 45 ... Auxiliary storage unit 49 ... Exploration data 49a ... Output waveform data 49b ... First individual waveform data 49c ... Second individual waveform data 49d ... Synthetic waveform data

Claims (4)

A magnetic sensor having a first coil and a second coil arranged apart from each other in the axial direction of the first coil and having a winding direction opposite to that of the first coil.
A waveform generator that is connected to each of the plurality of magnetic sensors and generates a waveform from the output of each of the plurality of magnetic sensors.
A recording unit for recording the waveform generated by the waveform generation unit is provided.
A magnetic exploration system in which each of the plurality of magnetic sensors is configured such that the distance between the coils, which is the distance between the first coil and the second coil, is different from each other, and can be selectively used. The magnetic exploration system according to claim 1, wherein the distance between the coils of each of the plurality of magnetic sensors is 0.3 m or more and is set within a range of 2.0 m or less. The magnetic exploration system according to claim 2, wherein one of the plurality of magnetic sensors is set within a range in which the distance between the coils is 0.6 m or less. It has a first coil and a second coil that is arranged apart from each other in the axial direction of the first coil and whose winding direction is opposite to that of the first coil, and is between the first coil and the second coil. A magnetic sensor configured so that the distance between the coils, which is the distance between the coils, is different from each other, a waveform generator connected to each of the plurality of magnetic sensors and generating a waveform from the output of each of the plurality of magnetic sensors, and a waveform. A magnetic exploration method for exploring a magnetic object in the ground in a magnetic exploration system including a recording unit that records the waveform generated by the generation unit.
Magnetic tomography was performed using one of the plurality of magnetic sensors.
When the presence of a magnetic object is detected from the waveform obtained in the magnetic exploration and the length or number of the magnetic objects is unknown, magnetism is performed by magnetic exploration using another magnetic sensor. Exploration method.

Images