Magnetic exploration system

Abstract

The purpose of the present invention is to provide a magnetic exploration system (100) that can automatically and immediately identify the presence or absence of an exploration object at a field after or during exploration work without securing capable persons having expert knowledge and experience required for analysis. A magnetic sensor unit (111) has a plurality of magnetic sensors (112a, 112b) that detect magnetism at locations separated by a prescribed distance in a direction of movement of a mobile body. A data assessment part (130) of a data processing unit (120) has a region acquisition means (132) for acquiring excessive regions in waveform data that include peaks exceeding a prescribed threshold, and a grouping means (133) for counting the number of the acquired excessive regions, for extracting from the waveform data and grouping a range that includes the excessive regions if the number of said excessive regions is equal to or less than a prescribed number, and for dividing the waveform data such that the number of the excessive regions becomes equal to or less than the prescribed number if the number of the excessive regions is more than the prescribed number.

Description

Technical Field

[0001] The present invention relates to a magnetic exploration system for exploring magnetic objects buried in the ground from the difference in the strength of the magnetic field at two positions separated on a exploration line.

Background Art

[0002] When magnetically exploring exploration targets (magnetic objects) with magnetism such as unexploded ordnance and underground structures, it is generally performed to use a differential magnetic exploration device (magnetic exploration system).

[0003] A differential magnetic exploration device is a device that holds two magnetic detection coils (magnetic sensor units) for detecting the magnetism of a magnetic body at a constant interval in the internal space of a moving body, differentially connects them, and detects an exploration target from the difference in the strength of the magnetic field obtained by each magnetic detection coil.

[0004] In a uniform strong magnetic field such as the Earth's magnetic field, even if the differential magnetic exploration device sways, the signals cancel each other out and no detection signal is generated. However, when a local magnetic field exists, a difference occurs in the magnitude of the magnetic field detected by the two magnetic detection coils. The differential magnetic exploration device utilizes this magnetic field difference and is configured to send a magnetic detection signal of a predetermined magnitude to a personal computer for administrators. In general differential magnetic exploration devices, the distance between the two magnetic detection coils is set to 0.5 to 2.0 m in order to detect magnetic anomalies of about several meters to a dozen or so meters generated from unexploded ordnance in the ground.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In a known differential magnetic exploration device, it was necessary to record the magnetic detection signal over time and analyze the entire data recorded after the exploration work to identify the presence or absence of the object to be explored.

[0007] Therefore, it was difficult to make an immediate judgment at the site during the exploration work, it took time to discover the object to be explored, and it was essential to secure personnel with specialized knowledge and experience necessary for analysis.

[0008] The present invention solves such problems, and without securing personnel with specialized knowledge and experience necessary for analysis, it is possible to automatically and immediately identify the presence or absence of the object to be explored after the exploration work or at the site during the exploration work. An object of the present invention is to provide a magnetic exploration system.

Means for Solving the Problems

[0009] The magnetic exploration system of the present invention includes a moving body that moves on a straight exploration line, a magnetic sensor unit provided on the moving body, and a data processing unit that processes a detection signal from the magnetic sensor unit. The magnetic sensor unit has a plurality of magnetic sensors that detect magnetism at positions separated by a predetermined distance in the moving direction of the moving body. The data processing unit includes an inversion calculation unit that adds and outputs a detection value of one of the magnetic sensors and an inverted detection value of the other magnetic sensor, a data recording unit that acquires and records the output value of the inversion calculation unit as waveform data over time in association with the moving position, a data evaluation unit that evaluates the reliability of the waveform data acquired by the data recording unit, and an exploration judgment processing unit that judges the exploration result when it is judged by the data evaluation unit that the reliability evaluation is high. The data evaluation unit includes a threshold comparison means for detecting an excess from a predetermined threshold of the waveform data, a region acquisition means for acquiring an excess region having a peak exceeding the predetermined threshold in the waveform data, counting the number of the acquired excess regions, and if the number of the excess regions is equal to or less than a predetermined number, extracting a range including these excess regions from the waveform data and grouping ConvertGrouping means configured to be as described, the grouped waveform data, and a plurality of reference waveform data previously possessed, which are waveform data with different numbers of peaks and peak magnitudes according to conditions such as the size, orientation, and distance from the exploration line of the object to be explored. Compare with the reference waveform data, select the most approximate reference waveform data based on the number of peaks and the magnitude of the peaks of the grouped waveform data, and evaluate the reliability based on whether an approximation value, which is an index indicating the degree of approximation between the selected reference waveform data and the waveform data calculated by a known method, is within a predetermined range. And a comparison means configured as such, wherein the region acquisition means defines a continuous region from a position exceeding a predetermined threshold value of the acquired waveform data to an adjacent predetermined threshold value Return inside as the excess region, and the threshold comparison means is configured to set the predetermined threshold value of the waveform data as a predetermined value based on the moving average value of the waveform data.

[0010] Since the data evaluation unit has the threshold comparison means, noise (such as magnetism other than the magnetic body to be explored) can be excluded from the exploration target. In addition, since the data evaluation unit has a region acquisition means for acquiring an excess region and a grouping means for appropriately extracting and grouping a range including these excess regions from the waveform data, it is possible to preferably extract only the waveform due to the exploration target from the waveform data. As a result, the magnetic exploration system having the data evaluation unit can automatically identify the presence or absence of the exploration target immediately at the site after the exploration work or during the exploration work without securing personnel with specialized knowledge and experience required for analysis.

[0012] It is preferable to include distance confirmation means configured to detect that the distance between the vertices of the waveform data in the excess region acquired by the region acquisition means is between predetermined distances corresponding to the magnetic sensor Between distance.

[0013] The area acquisition means acquires, from the waveform data, waveform difference data composed of the differences between each point constituting the waveform data and its adjacent points, and acquires, as vertices, the points of the waveform data at positions corresponding to the positions where the differences are 0 in the waveform difference data. At the same time, the waveform difference data before and after the positions where the differences are 0 Tag is It is preferable that the points of the waveform data at positions where the change is equal to or greater than a predetermined value are respectively acquired as change points, and the region including these vertices and change points is defined as the excess region.

[0016] It is preferable that the predetermined number in the grouping means is 4.

[0017] The Area acquisition means Preferably detects that the change point is within a predetermined range from the position where the difference is 0 in the waveform difference data.

Advantages of the Invention

[0018] According to the magnetic exploration system of the present invention, it is possible to provide a magnetic exploration system capable of automatically identifying an object to be explored immediately at the site after or during the exploration work without securing personnel with specialized knowledge and experience required for analysis.

Brief Description of the Drawings

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Mode for Carrying Out the Invention

[0020] Hereinafter, the magnetic exploration system of the present invention will be described with reference to the drawings. (Embodiment 1)

[0021] As schematically shown in FIG. 1, the magnetic exploration system 100 includes a moving body 110 that moves on a straight exploration line, a magnetic sensor unit 111 provided on the moving body 110, and a data processing unit 120 that processes detection signals from the magnetic sensor unit 111.

[0022] The magnetic sensor unit 111 has a plurality of magnetic sensors 112 that detect magnetism at positions separated by a predetermined distance in the moving direction of the moving body 110. In the present embodiment, the magnetic sensor unit 111 has two magnetic sensors 112, namely, a magnetic sensor 112a on the front end side and a magnetic sensor 112b on the rear end side in the moving direction. The magnetic sensor 112a and the magnetic sensor 112b are provided at positions separated from each other by a predetermined distance (1 m as an example in the present embodiment) and detect magnetism at a predetermined cycle. Although both the magnetic sensors 112a and 112b detect magnetism, various parameters such as magnetic flux density and magnetic field strength vary depending on the specifications of the magnetic sensors.

[0023] The data processing unit 120 includes an inversion operation unit 121 that adds (combines) the detection values of two magnetic sensors 112a at a predetermined distance and the inverted value of the detection value of the magnetic sensor 112b and outputs the result, a data recording unit 122 that associates the output value of the inversion operation unit 121 with the position information of the magnetic sensor unit 111 and acquires and records it as waveform data over time, a data evaluation unit 130 that evaluates the waveform data, and an exploration determination processing unit 123 that determines the exploration result when it is determined by the data evaluation unit 130 that the reliability evaluation is high. The exploration determination processing unit 123 and the data evaluation unit 130 will be described later.

[0024] Hereinafter, the waveform data obtained by the data recording unit 122 based on the detection values of the two magnetic sensors 112a and 112b will be described.

[0025] FIG. 2 shows a data acquisition screen as an example of waveform data, the arrangement of exploration objects (magnetic objects) A and B in the case of such waveform data, and their magnetic field lines. The position (horizontal axis) of the waveform data coincides with the position of the object. As shown in FIG. 2, the moving body 110 is moved in the left-to-right direction of FIG. 2 on a straight exploration line. During the movement, the two magnetic sensors 112a and 112b of the magnetic sensor unit 111 provided on the moving body 110 detect magnetism, and the detection values are input to the inversion operation unit 121 of the data processing unit 120.

[0026] In the inversion operation unit 121, the inverted value of the detection value of the magnetic sensor 112b is added (combined) with the magnetic sensor 112a. As a result, at positions where the magnetism of the exploration object is not detected, the detection values depending on the geomagnetism and the environment are canceled out, so that a lot of noise is removed from the waveform data obtained by the data recording unit 122.

[0027] When the moving body 110 moves near the exploration object, the detection values of the two magnetic sensors 112a and 112b are waveform data of rising and falling, and the phases are shifted according to the physical intervals of the magnetic sensors 112a and 112b. Also, since the detection value of the magnetic sensor 112b is inverted by the inversion operation unit 121, they become waveform data with opposite plus and minus signs to each other.

[0028] Specifically, as shown in FIG. 2, when moving near a relatively small exploration object A with magnetism in a direction parallel to the moving direction of the moving body, as shown in FIG. 3, the detected value by the magnetic sensor 112a on the tip side increases on the positive side as it approaches the exploration object, and becomes a waveform having one peak on the positive side. On the other hand, since the detected value of the magnetic sensor 112b on the rear end side is inverted, after the phase is shifted by the interval, it increases on the negative side as it approaches the exploration object, and becomes a waveform having one peak with the same amplitude as the detected value by the magnetic sensor 112a on the negative side. The waveform data after calculation output from the inversion calculation unit 121 shows a waveform having one peak up and down once each.

[0029] Also, when moving near a relatively large exploration object B with magnetism in a direction perpendicular to the moving direction of the moving body, as shown in FIG. 4, the detected value by the magnetic sensor 112a on the tip side becomes a waveform having a positive peak once and then inverting to have a negative peak, and the detected value by the magnetic sensor 112b on the rear end side is inverted after the phase is shifted by the interval, so it becomes a waveform having a negative peak once and then inverting to have a positive peak. Therefore, the waveform data after calculation output from the inversion calculation unit 121 shows a waveform having two peaks upward and a large one peak downward sandwiched between them.

[0030] As a result, as shown in FIG. 2, two peaks due to the exploration object A and three peaks due to the exploration object B appear in the waveform data.

[0031] In the data recording unit 122 into which the waveform data after calculation is input from the inversion calculation unit 121, by associating with the position information for the waveform data after calculation, it is acquired as waveform data indicating the magnetic detection value with respect to the position. The obtained waveform data is evaluated for reliability by a data evaluation unit 130 (described later). When the data evaluation unit 130 evaluates that the reliability of the obtained waveform data is high, the exploration determination processing unit 123 specifies the position, size, etc. of the exploration object from the change points and vertices of the grouped waveform data extracted from the waveform data in the data evaluation unit 130.

[0032] In addition, an input / output device 140 such as a PC used for operations, displays, etc. is connected to the data processing unit 120. Note that the data processing unit 120 and the input / output device 140 may be configured as a single device as a whole, or may be separate entities. Further, each function of the data processing unit 120 may be distributed among a plurality of devices. Also, the data processing unit 120 and the input / output device 140 may all be arranged at the exploration work site, or may be arranged at different locations so as to be able to communicate wired or wirelessly.

[0033] As described above, in this embodiment, by having the data evaluation unit 130, it is possible to appropriately evaluate data at the site after or during the exploration work without securing personnel having specialized knowledge and experience required for analysis, and to immediately and automatically identify the exploration target when the data is highly reliable. Hereinafter, the data evaluation unit 130 will be described in detail.

[0034] The data evaluation unit 130 includes a threshold comparison means 131 for detecting an excess from a predetermined threshold of the waveform data input to the data evaluation unit 130, a region acquisition means 132 for acquiring an excess region having a peak exceeding the predetermined threshold in the waveform data, a grouping means 133 configured to count the number of acquired excess regions, extract and group a range including these excess regions from the waveform data if the number of excess regions is equal to or less than a predetermined number, and divide the waveform data so that the number of excess regions is within the predetermined number if the number of excess regions is more than the predetermined number, a distance confirmation means 134 for detecting that the distance between the vertices of the waveform data in the excess region acquired by the region acquisition means 132 is within a distance corresponding to a predetermined distance between the magnetic sensors 112a and b, and a comparison means 135 configured to compare the grouped waveform data with the reference waveform data previously possessed and evaluate the reliability of the acquired waveform data as high if the approximation value between the reference waveform data and the waveform data is within a predetermined range. Since the data evaluation unit 130 can appropriately group only the waveforms corresponding to the object to be explored from the data, and further evaluate the data in that case to determine whether the reliability of the waveform data is high, the exploration system of the present embodiment can automatically identify the presence or absence of the object to be explored immediately at the site after or during the exploration work without securing personnel with specialized knowledge and experience required for analysis.

[0035] The operation of the data evaluation unit 130 will be specifically described with reference to FIG. 5. A predetermined threshold of the detection value is set in the threshold comparison means 131. Note that the value of this predetermined threshold can be set as appropriate. It is considered that some magnetic object exists at a position corresponding to a portion exceeding the predetermined threshold, and when a peak of a waveform that does not exceed the predetermined threshold is detected, it is considered as noise such as geomagnetism that is not the object to be explored. Therefore, in the present embodiment, the threshold comparison means 131 determines whether the detection value of the waveform data exceeds this predetermined threshold. In the example shown in FIG. 5, since each detection value exceeds the predetermined threshold, the threshold comparison means 131 determines that the waveform data exceeds the predetermined threshold.

[0036] Next, the region acquisition means 132 detects an excess region having a peak in the waveform data where the detected value exceeds a predetermined threshold. In the present embodiment, the region acquisition means 132 first acquires the waveform difference data of the waveform data. Here, the waveform difference data is data composed of the difference between the detected values of each point constituting the waveform data and its adjacent points, that is, the difference between the detected value at a certain position n of the waveform data and the detected value at the immediately preceding position n-1 is taken as the difference value at a certain position n. Therefore, as shown in FIG. 5, in the waveform difference data, the value changes according to the rise / fall of the peak of the waveform data. The region acquisition means 132 detects the peaks (X1, X2) as the points where the detected value exceeds the predetermined threshold and the difference in the waveform difference data becomes 0 and the waveform becomes the apex.

[0037] Then, the region acquisition means 132 determines that, before and after the position where this difference becomes 0, the points corresponding to the points where the difference value of the waveform difference data exceeds the difference value threshold and the gradient of the waveform difference data changes by a predetermined value or more are the roots of the peaks (the parts with large positive / negative amplitudes) of the waveform data, and acquires them as the change points (X11, X12, X21, X22). Note that the difference value threshold of the waveform difference data can be appropriately set in consideration of environmental factors and the like. The peaks (X1, X2) and the change points (X11, X12, X21, X22) of these detected values constitute the peaks of the waveform data. The region acquisition means 132 sets the first three points as one peak (excess region), sets the next three points as another peak, and sets the excess regions Z1, Z2 including each peak. Note that this gradient can be set as appropriate.

[0038] The grouping means 133 first checks the number of these peaks, and if it is within a predetermined number (4 in the present embodiment), sets it as one group. For example, in the case shown in FIG. 5, the number of peaks is 2, so it is within the predetermined number. Therefore, these two peaks are set as one group.

[0039] If the number of peaks is greater than a predetermined number, it is considered that there are multiple objects to be explored. Therefore, the grouping means 133 checks (counts) the number of peaks, and if it exceeds the predetermined number, it groups multiple peaks together and divides them into multiple groups. For example, in the case shown in FIG. 2, the number of peaks is 5. In this case, since the number of peaks is more than the predetermined number of 4, it is divided into two groups, which corresponds to the fact that there are two objects to be explored in the case shown in FIG. 2. That is, as this predetermined number, 4 is preferably used based on the results of the following reference waveform data, etc., and if it exceeds 5, it means that there are multiple objects to be explored. By making one group represent one object to be explored in this way, it becomes possible to immediately identify the object to be explored at the site after or during the exploration work without securing personnel with specialized knowledge and experience required for analysis. Note that the division into multiple groups is manually performed in this embodiment, but it may be set to be automated.

[0040] The distance confirmation means 134 detects that the distance between the peaks of the waveform data is within a predetermined distance corresponding to the distance between the magnetic sensors. The distance between the peaks ideally matches the distance between the magnetic sensors 112a and 112b, but it is also conceivable that they do not match due to errors during measurement. Therefore, in this embodiment, as the predetermined distance, a distance that is 0.5D to 1.5D with respect to the distance D between the magnetic sensors 112a and 112b, that is, a range of plus or minus 50% of the distance D, is set as the predetermined distance corresponding to the distance between the magnetic sensors 112a and 112b. Note that the predetermined distance corresponding to the distance between the magnetic sensors 112a and 112b can be appropriately set according to the situation. Then, when the distance between the peaks of the waveform data is within the predetermined distance corresponding to the distance between the magnetic sensors, the obtained waveform data has high reliability, and when it is not within the predetermined distance, the data evaluation unit 130 evaluates that the obtained waveform data has low reliability.

[0041] The comparison means 135 compares the grouped waveform data with the reference waveform data it has in advance. The waveform data is compared with the pre-registered reference waveform data, and if there is waveform data close to the acquired waveform data, it is selected as the comparison waveform data. If the approximation value between the comparison waveform data and the waveform data is within a predetermined range, the data evaluation unit 130 determines that the waveform data is highly reliable data.

[0042] Such reference waveform data will be described below. As the reference waveform data, there are various patterns with different numbers, directions, and magnitudes of peaks according to the size, orientation, distance from the exploration line, etc. of the object to be explored.

[0043] Figures 6(1) to (3) show the case where small-sized objects to be explored (up to about 0.5 m in length) exist parallel to one moving direction. (1) shows the case where the distance from the measurement position to the object to be explored is short (less than about 0.3 m), (2) shows the case where the distance from the measurement position to the object to be explored is medium (0.3 to less than about 0.6 m), and (3) shows the case where the distance from the measurement position to the object to be explored is long (0.6 to about 1.5 m).

[0044] Figures 7(1) to (3) show the case where medium-sized objects to be explored (0.5 to less than 1.5 m in length) exist parallel to one moving direction. (1) shows the case where the distance from the measurement position to the object to be explored is short, (2) shows the case where the distance from the measurement position to the object to be explored is medium, and (3) shows the case where the distance from the measurement position to the object to be explored is long.

[0045] Figures 8(1) to (3) show the case where large-sized objects to be explored (1.5 to less than 3.0 m in length) exist parallel to one moving direction. (1) shows the case where the distance from the measurement position to the object to be explored is short, (2) shows the case where the distance from the measurement position to the object to be explored is medium, and (3) shows the case where the distance from the measurement position to the object to be explored is long.

[0046] Figs. 9(1) to (3) show the case where a small-sized object to be detected exists perpendicular to the moving direction. (1) shows the case where the distance from the measurement position to the object to be detected is short, (2) shows the case where the distance is medium, and (3) shows the case where the distance is long.

[0047] Figs. 10(1) to (3) show the case where a medium-sized object to be detected exists perpendicular to the moving direction. (1) shows the case where the distance from the measurement position to the object to be detected is short, (2) shows the case where the distance is medium, and (3) shows the case where the distance is long.

[0048] Figs. 11(1) to (3) show the case where a large-sized object to be detected exists perpendicular to the moving direction. (1) shows the case where the distance from the measurement position to the object to be detected is short, (2) shows the case where the distance is medium, and (3) shows the case where the distance is long.

[0049] From Figs. 6 to 11, it can be seen that the larger the size of the object to be detected, the larger the width of the peak of the waveform, and the farther the distance from the measurement position to the object to be detected, the smaller the amplitude of the peak. Also, when comparing Figs. 6 to 8 and Figs. 9 to 11, when the object to be detected is horizontal with respect to the moving direction, since the magnetic field lines and the moving direction coincide, there will be two peaks in the waveform data. However, when the object to be detected is perpendicular to the moving direction, since the magnetic field lines and the moving direction are perpendicular, there will be four peaks. However, as shown in Fig. 11, when the size is large, the middle two peaks overlap, resulting in three peaks.

[0050] The comparison means 135 compares the grouped waveform data with the reference waveform data it has in advance. Then, the comparison means 135 compares the waveform data with the pre-registered reference waveform data, and selects the most approximate data from whether the reference waveform data has the same number of peaks as the number of peaks in the group, the peak width, amplitude, etc. If there is waveform data close to the acquired waveform data, the comparison means 135 selects it as the comparison waveform data and determines whether the approximation value between the comparison waveform data and the waveform data is within a predetermined range. In this case, the approximation value can be calculated by a known method. If this result is within the predetermined range, the data evaluation unit 130 determines that the waveform data is reliable data. Also, if the comparison waveform data cannot be selected or the approximation value is not within the predetermined range, the data evaluation unit 130 evaluates that the waveform data is low-reliability data.

[0051] In this way, in the present embodiment, since the data evaluation unit 130 can evaluate whether the obtained waveform data is reliable, it is possible to automatically identify the object to be explored immediately at the site after or during the exploration work without ensuring personnel with specialized knowledge and experience required for analysis as long as it is determined that the data is reliable. And in this case, as in the present embodiment, in the region acquisition means 132, by accurately defining the peak using the waveform difference data, it is possible to appropriately evaluate the reliability of the waveform data. (Embodiment 2)

[0052] In the present embodiment, the region acquisition means of the data evaluation unit 130 in Embodiment 1 has a region acquisition means different in configuration and operation, and the other points are the same, so the different points will be described. In the present embodiment, the region acquisition means detects the distance from the position exceeding the predetermined threshold value of the acquired waveform data to the position of the adjacent predetermined threshold value exceeding it, and defines the region where the detected distance is continuous within the predetermined distance corresponding to the distance between the magnetic sensors as the exceeding region.

[0053] That is, as shown in FIG. 12, a continuous excess region Z3 from a position (Y1) exceeding a predetermined threshold value of the acquired waveform data to a position (Y2) exceeding an adjacent predetermined threshold value is acquired. However, in this case, it is preferable that the distance confirmation means 134 further acquires that the excess region Z3 and the adjacent excess region Z4 are within a predetermined distance corresponding to the distance between the magnetic sensors. That is, it is preferable that the region acquisition means acquires, as vertices, those having the maximum value or the minimum value in each region, and the distance confirmation means 134 is configured to detect whether the distance of this vertex is within a predetermined distance corresponding to the distance between the magnetic sensors. This is because, similar to Embodiment 1, the reliability of the acquired waveform data can be confirmed.

[0054] Then, the grouping means 133 counts the number of times of this continuous region in the same manner as the number of peaks in Embodiment 1, groups a series of data into one group if it is within a predetermined number, and divides a series of data if it exceeds the predetermined number. In this way, in this embodiment, the peaks of the waveform data can be acquired and grouped more simply than in Embodiment 1. (Other Embodiments)

[0055] Although Embodiments 1 and 2 have described the case where the detection values depending on the geomagnetism and the environment are canceled out and show a zero value at positions where the magnetism of the object to be explored is not detected, the moving average value obtained by performing a moving average operation on the waveform data may be defined as a 0 value. Even if the detection values depending on the geomagnetism and the environment are not canceled out by the inversion operation at positions where the magnetism of the object to be explored is not detected, by calculating the moving average, the detection values depending more on the geomagnetism and the environment can be suppressed, and the detection values depending more accurately on the object to be explored can be obtained. In this case, the threshold comparison means 131 may obtain the moving average value from the input waveform data and set positive and negative thresholds with respect to this moving average value.

[0056] In the above-described embodiment, the change point is obtained as the point at which the gradient of the waveform difference data before and after the difference is 0 changes to a predetermined value or more. However, in order to further improve the accuracy of detecting the change point, the data evaluation unit 130 may be configured to detect that the change point is within a predetermined range from the position where the difference in the waveform difference data is 0. This is because if the change point is not within the predetermined range, the reliability of the peak itself is considered to be low.

[0057] The processing by the exploration determination processing unit 123 may be performed for each exploration line, or may be performed collectively for each site having a plurality of exploration lines. Further, although the exploration determination processing unit 123 identifies the exploration target using the vertex and the change point obtained in the data evaluation unit 130, the present invention is not limited to this. When the waveform data is evaluated to have high reliability in the data evaluation unit 130, the exploration may be performed using the waveform data recorded in the data recording unit 122.

[0058] In the above-described embodiment, the region acquisition means 132 detected the points where the differential waveform data value becomes 0 as the vertices at each peak. However, when the peaks overlap and, for example, two peaks are continuous in the positive direction, the points where the differential waveform data value becomes 0 are detected not at the vertices but at the valleys between the peaks. That is, in this case, three points where the difference in the differential waveform data becomes 0 are detected in the region where the difference exceeds the differential value threshold. Considering such a case, the region acquisition means 132 acquires the position of the waveform data corresponding to the point that becomes 0 when the difference in the differential waveform data changes from plus to minus in the region where the waveform data exceeds the positive-side predetermined threshold and the difference in the differential waveform data exceeds the differential value threshold, and acquires the position of the waveform data corresponding to the point that becomes 0 when the difference in the differential waveform data changes from minus to plus in the region where the waveform data exceeds the negative-side predetermined threshold and the difference in the differential waveform data exceeds the differential value threshold. Further, when the peaks overlap as described above and, for example, two peaks are continuous in the positive direction, in order for the distance confirmation means 134 to confirm whether the distance between the vertices is within a predetermined distance corresponding to the distance between the magnetic sensors, it is necessary to detect peaks having the same amplitude on the positive side and the negative side. For this reason, when there are a plurality of peaks on the positive side and the negative side, the region acquisition means 132 acquires the vertex of the peak having the largest amplitude among the vertices of those peaks as the maximum vertex, and the distance confirmation means 134 detects whether the distance between the maximum vertices is within a predetermined distance corresponding to the distance between the magnetic sensors.

[0059] Furthermore, it may be performed in real time as soon as the necessary waveform data for the movement of the moving body 110 is available.

[0060] Also, the magnetic sensor 112 may be a two-dimensional or three-dimensional magnetic sensor, and the above-described operations such as calculation, grouping, and comparison may be performed in each dimension.

[0061] Note that waveform data may be experimentally acquired for known objects, and a predetermined threshold value or the like used by the threshold comparison means 131 may be set, or it may be used for collecting waveform data samples. Further, the predetermined threshold value and the predetermined distance may be set such that the input / output device 140 designates an appropriate value according to the type of the object to be explored and the conditions of the exploration site.

Explanation of Signs

[0062] 100 Magnetic exploration system 111 Magnetic sensor unit 110 Moving body 112a, 112b Magnetic sensors 112a, b Magnetic sensors 120 Data processing unit 121 Inversion operation unit 122 Data recording unit 123 Exploration judgment processing unit 130 Data evaluation unit 131 Threshold comparison means 132 Region acquisition means 133 Grouping means 134 Distance confirmation means 135 Comparison means 140 Input / output device

Claims

1. A magnetic exploration system having a moving body that moves on a straight exploration line, a magnetic sensor unit provided on the moving body, and a data processing unit that processes detection signals from the magnetic sensor unit, wherein the magnetic sensor unit has a plurality of magnetic sensors that respectively detect magnetism at positions a predetermined distance away in the moving direction of the moving body, the data processing unit includes an inversion calculation unit that adds and outputs a detection value of one of the magnetic sensors and an inverted detection value of the other magnetic sensor, a data recording unit that acquires and records the output value of the inversion calculation unit as waveform data over time in association with the moving position, a data evaluation unit that performs reliability evaluation of the waveform data acquired by the data recording unit, and an exploration judgment processing unit that judges an exploration result when it is judged by the data evaluation unit that the reliability evaluation is high, the data evaluation unit includes threshold comparison means for detecting an excess from a predetermined threshold of the waveform data, region acquisition means for acquiring an excess region having a peak exceeding the predetermined threshold in the waveform data, and grouping means configured to count the number of the acquired excess regions and, if the number of the excess regions is equal to or less than a predetermined number, extract a range including these excess regions from the waveform data and group them, comparison means configured to compare the grouped waveform data with a plurality of reference waveform data previously possessed, the reference waveform data having different numbers of peaks and peak magnitudes according to conditions such as the size, orientation, and distance from the exploration line of the exploration object, select the most approximate reference waveform data based on the number of peaks and the peak magnitudes of the grouped waveform data, and evaluate the reliability based on whether an approximation value, which is an index indicating the degree of approximation between the selected reference waveform data and the waveform data calculated by a known method, is within a predetermined range, wherein the region acquisition means is configured to define a continuous region from a position exceeding a predetermined threshold of the acquired waveform data to a position returning within a neighboring predetermined threshold as the excess region, and the threshold comparison means is configured to set the predetermined threshold of the waveform data as a predetermined value based on the moving average value of the waveform data.

2. A magnetic exploration system according to claim 1, comprising distance confirmation means configured to detect that the distance between the vertices of the waveform data in the excess area obtained by the area acquisition means is within a predetermined distance corresponding to the distance between the magnetic sensors.

3. A magnetic exploration system having a moving body moving on a straight exploration line, a magnetic sensor unit provided on the moving body, and a data processing unit that processes a detection signal from the magnetic sensor unit, wherein the magnetic sensor unit has a plurality of magnetic sensors that respectively detect magnetism at positions separated by a predetermined distance in the moving direction of the moving body, the data processing unit includes an inversion calculation unit that adds and outputs a detection value of one of the magnetic sensors and an inverted detection value of the other magnetic sensor, a data recording unit that acquires and records the output value of the inversion calculation unit as waveform data over time in association with the moving position, a data evaluation unit that performs a reliability evaluation of the waveform data acquired by the data recording unit, and an exploration judgment processing unit that judges an exploration result when it is judged by the data evaluation unit that the reliability evaluation is high. The data evaluation unit, a threshold comparison means for detecting an excess from a predetermined threshold of the waveform data, an area acquisition means for acquiring an excess area having a peak exceeding the predetermined threshold in the waveform data, and a grouping means configured to count the number of the acquired excess areas and, if the number of the excess areas is equal to or less than a predetermined number, extract and group a range including these excess areas from the waveform data. comparison means configured to compare the grouped waveform data with a plurality of reference waveform data that are previously available and have different numbers of peaks and peak magnitudes according to conditions such as the size, orientation, and distance from the exploration line of the object to be explored, select the most approximate reference waveform data based on the number of peaks and the peak magnitudes of the grouped waveform data, and evaluate the reliability based on whether an approximation value, which is an index indicating the degree of approximation between the selected reference waveform data and the waveform data calculated by a known method, is within a predetermined range. The area acquisition means acquires waveform difference data composed of the difference between each point constituting the waveform data and its adjacent point from the waveform data. Obtaining, as vertices, the points of the waveform data at positions corresponding to the positions where the difference is 0 in the waveform difference data, and respectively obtaining, as change points, the points of the waveform data at positions where the waveform difference data changes by a predetermined value or more before and after the positions where the difference is 0, A magnetic exploration system characterized in that a region including these vertices and change points is defined as the excess region.

4. The magnetic exploration system according to claim 1 or 3, characterized in that the predetermined number in the grouping means is 4.

5. The magnetic exploration system according to claim 3, characterized in that the region acquisition means detects that the change points are within a predetermined range from the positions where the difference is 0 in the waveform difference data.

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