A magnetic total field vertical gradient data processing method and device and related equipment

Abstract

The application discloses a magnetic total field vertical gradient data processing method and device and related equipment, and the method comprises the following steps: acquiring two-dimensional magnetic total field gradient data collected by two magnetic total field sensors vertically arranged in a detection area, and the recording points of the two-dimensional magnetic total field gradient data are uniformly distributed in the detection area; based on this, first horizontal distribution data of the modulus of the two-dimensional magnetic total field gradient on each group of unit orthogonal bases is acquired, the unit orthogonal bases are obtained by decomposing the two-dimensional magnetic total field gradient data generated by the magnetic dipole of a target body at an arbitrary height; based on the first horizontal distribution data, second horizontal distribution data of the energy of the two-dimensional magnetic total field gradient in a two-dimensional space formed by the unit orthogonal bases is acquired; and based on the second horizontal distribution data, the horizontal coordinate of the target body is determined. The application can improve the signal-to-noise ratio of data, effectively improve the accuracy of target detection, and determine the horizontal coordinate of the target, thereby realizing the positioning of the target in the horizontal direction.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of magnetic exploration, more particularly to a magnetic total field vertical gradient data processing method and device and related equipment. BACKGROUND

[0002] Magnetic anomaly detection (MAD) is one of the most suitable geophysical techniques for locating and mapping the distribution of ferromagnetic metal objects, and has a wide range of applications in the fields of resource exploration, unexploded ordnance detection, underwater submarine detection, archaeology, and other fields related to national economic security and cultural construction. The most common way to implement magnetic anomaly detection is to measure one-dimensional or two-dimensional magnetic total field. One-dimensional magnetic total field data can only be used for target detection, but cannot determine the precise location of the target. Two-dimensional magnetic total field data can not only achieve target detection, but also can locate the target. Among them, the total field measurement mode of a single sensor needs to set up a separate geomagnetic diurnal station to correct the data for diurnal variation, which greatly reduces the efficiency of magnetic exploration in the field. Gradient measurement mode solves this problem well. By simultaneously collecting magnetic fields with two or more magnetic total field sensors, the obtained magnetic total field gradient data is not affected by the geomagnetic diurnal variation.

[0003] Magnetic total field gradient data often contains various noises, making it particularly difficult to detect gradient anomaly signals. Currently, the signal processing method of one-dimensional orthonormal basis function (OBF) decomposition is mainly used to improve the signal-to-noise ratio of one-dimensional data in practical applications. However, the research on two-dimensional gradient anomaly signal detection is still in the academic research stage. At the same time, the method of locating the target from two-dimensional data starts from the original data with low signal-to-noise ratio, which is easily affected by noise, thereby reducing the accuracy of target detection. SUMMARY

[0004] Therefore, the present application provides a magnetic total field vertical gradient data processing method, device and related equipment to improve the accuracy of target detection.

[0005] To achieve the above purpose, the first aspect of the present application provides a magnetic total field vertical gradient data processing method, comprising:

[0006] Obtaining two-dimensional magnetic total field gradient data, the two-dimensional magnetic total field gradient data being collected by two magnetic total field sensors vertically deployed in a detection area, and the recording points of the two-dimensional magnetic total field gradient data being uniformly distributed in the detection area;

[0007] Based on the two-dimensional magnetic total field gradient data, first horizontal distribution data of the modulus of the two-dimensional magnetic total field gradient on each group of unit orthogonal bases is obtained, the unit orthogonal bases being obtained by decomposing the two-dimensional magnetic total field gradient data generated by the magnetic dipole of the target body at an arbitrary height;

[0008] Based on the first horizontal distribution data, second horizontal distribution data of the energy of the two-dimensional magnetic total field gradient in the two-dimensional space spanned by the unit orthogonal bases is obtained;

[0009] Based on the second horizontal distribution data, the horizontal coordinate of the target body is determined.

[0010] Preferably, the process of obtaining the two-dimensional magnetic total field gradient data comprises:

[0011] The magnetometer is used to record the magnetic total field data of the two magnetic total field sensors and the recording point along the preset scanning path, and a plurality of data items are obtained, each data item comprising the first magnetic total field data, the second magnetic total field data and the recording point;

[0012] For each data item, the difference between the first magnetic total field data and the second magnetic total field data is calculated, and the magnetic total field gradient data of each data item is obtained by dividing the difference by the distance between the two magnetic total field sensors;

[0013] Based on the magnetic total field gradient data and the recording point of each data item, the magnetic total field gradient data at each grid point of a grid is obtained by using a preset interpolation method, the grid being uniformly distributed in the detection region;

[0014] The two-dimensional magnetic total field gradient data is composed of the magnetic total field gradient data at each grid point and the coordinates of each grid point.

[0015] Preferably, the unit orthogonal bases comprise:

[0016]

[0017] Each unit orthogonal base satisfies the following equation:

[0018]

[0019] wherein (x, y) is the horizontal coordinate of the recording point, z1 and z2 are the vertical coordinates of the two magnetic total field sensors, respectively, and C1(z1, z2) and C2(z1, z2) are constant coefficient expressions composed of z1 and z2, respectively.

[0020] Preferably, based on the two-dimensional magnetic total field gradient data, the process of obtaining the first horizontal distribution data of the modulus of the two-dimensional magnetic total field gradient on each group of unit orthogonal bases comprises:

[0021] each group of unit orthogonal bases to obtain a plurality of orthogonal base window functions;

[0022] performing inner product calculation on the two-dimensional magnetic total field gradient data at each grid point by using each orthogonal base window function to obtain first horizontal distribution data of the modulus of the two-dimensional magnetic total field gradient on each group of unit orthogonal bases.

[0023] Preferably, the process of performing inner product calculation on the two-dimensional magnetic total field gradient data at each grid point by using each unit orthogonal base window function to obtain first horizontal distribution data of the modulus of the magnetic total field gradient on each group of unit orthogonal bases comprises:

[0024] the first horizontal distribution data of the modulus of the two-dimensional magnetic total field gradient on each group of unit orthogonal bases is calculated by using the following equation n (x,y):

[0025]

[0026] wherein I and J are the sizes of the window in the x direction and the y direction respectively, dΔT(x i ,y j ) is the magnetic total field gradient data of the grid point at (x i ,y j ).

[0027] Preferably, the process of obtaining second horizontal distribution data of the energy of the two-dimensional magnetic total field gradient in the two-dimensional space spanned by each group of unit orthogonal bases based on the first horizontal distribution data comprises:

[0028] the energy horizontal distribution data E(x,y) of the two-dimensional magnetic total field gradient in the two-dimensional space spanned by each group of unit orthogonal bases is calculated by using the following equation:

[0029]

[0030] wherein α n (x,y) is the first horizontal distribution data of the modulus of the two-dimensional magnetic total field gradient on the nth group of unit orthogonal bases;

[0031] performing normalization processing on the energy horizontal distribution data to obtain second horizontal distribution data of the energy of the two-dimensional magnetic total field gradient in the two-dimensional space spanned by each group of unit orthogonal bases.

[0032] Preferably, the process of determining the horizontal coordinates of the target object based on the second horizontal distribution data comprises:

[0033] determine a target sub-region in the detection region where a ferromagnetic target exists based on the second horizontal distribution data, the second horizontal distribution data of the target sub-region having a value greater than a preset threshold value;

[0034] determine the horizontal coordinate of the point with the maximum value of the second horizontal distribution data in each target sub-region as the horizontal coordinate of the target.

[0035] The second aspect of the present application provides a magnetic total field vertical gradient data processing device, comprising:

[0036] a data acquisition unit configured to acquire two-dimensional magnetic total field gradient data, the two-dimensional magnetic total field gradient data being collected by two magnetic total field sensors vertically arranged in a detection region, and the recording points of the two-dimensional magnetic total field gradient data being uniformly distributed in the detection region;

[0037] a module calculation unit configured to acquire first horizontal distribution data of the module of two-dimensional magnetic total field gradient on each set of unit orthogonal bases based on the two-dimensional magnetic total field gradient data, the unit orthogonal bases being obtained by decomposing the two-dimensional magnetic total field gradient data generated by the magnetic dipole of a target at an arbitrary height;

[0038] an energy calculation unit configured to acquire second horizontal distribution data of the energy of two-dimensional magnetic total field gradient in a two-dimensional space spanned by each set of unit orthogonal bases based on the first horizontal distribution data;

[0039] a coordinate determination unit configured to determine the horizontal coordinate of the target based on the second horizontal distribution data.

[0040] The third aspect of the present application provides a magnetic total field vertical gradient data processing device, comprising a memory and a processor;

[0041] the memory is configured to store a program;

[0042] the processor is configured to execute the program to realize each step of the magnetic total field vertical gradient data processing method.

[0043] The fourth aspect of the present application provides a storage medium having a computer program stored thereon, the computer program being executed by a processor to realize each step of the magnetic total field vertical gradient data processing method.

[0044] It can be known from the technical solution that the two-dimensional magnetic total field gradient data is acquired first, wherein the two-dimensional magnetic total field gradient data is collected by two magnetic total field sensors which are vertically arranged in a detection area, and the record points of the two-dimensional magnetic total field gradient data are uniformly distributed in the detection area to form the two-dimensional magnetic total field gradient data in a grid. Then, based on the two-dimensional magnetic total field gradient data, the first horizontal distribution data of the modulus of the two-dimensional magnetic total field gradient on each group of unit orthogonal bases is acquired, wherein the unit orthogonal bases are obtained by decomposing the two-dimensional magnetic total field gradient data generated by the magnetic dipole of the target body at any height. Next, based on the first horizontal distribution data, the second horizontal distribution data of the energy of the two-dimensional magnetic total field gradient in a two-dimensional space formed by the unit orthogonal bases is acquired. It can be understood that, compared with the first horizontal distribution data, the second horizontal distribution data in the two-dimensional space has a higher signal-to-noise ratio, and the area with relatively strong energy, that is, the area with a higher value of the second horizontal distribution data, means that the ferromagnetic target is more likely to exist. Finally, based on the second horizontal distribution data, the horizontal coordinate of the target is determined. The two-dimensional magnetic total field gradient data is converted into the two-dimensional energy distribution in the application, which can improve the signal-to-noise ratio of the data, effectively improve the accuracy of target detection, and determine the horizontal coordinate of the target to realize the positioning of the target in the horizontal direction. BRIEF DESCRIPTION OF DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of the provided drawings.

[0046] Figure 1 A schematic diagram of the magnetic total field vertical gradient data processing method disclosed in the embodiments of the present application;

[0047] Figure 2 A two-dimensional survey line distribution diagram disclosed in the embodiments of the present application is illustrated;

[0048] Figure 3 A two-dimensional magnetic total field gradient surface diagram obtained after Kriging interpolation provided by the embodiments of the present application is illustrated;

[0049] Figure 4 Two-dimensional unit orthogonal base surface diagrams calculated by the first and second group of unit orthogonal base functions provided by the embodiments of the present application are illustrated;

[0050] Figure 5 Two-dimensional unit orthogonal base surface diagrams calculated by the third and fourth group of unit orthogonal base functions provided by the embodiments of the present application are illustrated;

[0051] Figure 6 A two-dimensional unit orthogonal base surface graph calculated by the unit orthogonal base functions of the 5th and 6th groups is shown as an example;

[0052] Figure 7 A two-dimensional unit orthogonal base surface graph calculated by the unit orthogonal base functions of the 7th and 8th groups is shown as an example;

[0053] Figure 8 A two-dimensional unit orthogonal base surface graph calculated by the unit orthogonal base functions of the 9th and 10th groups is shown as an example;

[0054] Figure 9 An energy distribution curve graph is shown as an example;

[0055] Figure 10 A schematic diagram of the magnetic total field vertical gradient data processing device disclosed in the embodiments of the present application is shown;

[0056] Figure 11 A schematic diagram of the magnetic total field vertical gradient data processing device disclosed in the embodiments of the present application is shown. DETAILED DESCRIPTION

[0057] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0058] The magnetic total field vertical gradient data processing method provided by the embodiments of the present application will be described below. Please refer to Figure 1 The magnetic total field vertical gradient data processing method provided by the embodiments of the present application can include the following steps:

[0059] In step S101, two-dimensional magnetic total field gradient data is acquired.

[0060] The two-dimensional magnetic total field gradient data is collected by two magnetic total field sensors vertically arranged in a detection area, and the record points of the two-dimensional magnetic total field gradient data are uniformly distributed in the detection area.

[0061] Specifically, after the detection area is determined, the magnetometer mounting platform (flight platform, water platform or handheld type, etc.) reciprocally moves along several parallel lines, two magnetic total field sensors are vertically arranged in the detection area, the magnetometer records the magnetic total field data and coordinate information of the two magnetic total field sensors in an interval sampling manner, and the two-dimensional magnetic total field gradient data is calculated in combination with the distance between the two magnetic total field sensors.

[0062] For example, the following can be adopted: Figure 2 The two-dimensional survey line distribution map shown is used to collect the magnetic total field data of these two magnetic total field sensors. The survey line runs due north-south, with a distance of 0.1m between adjacent measuring points and a distance of 1m between adjacent survey lines. The bottom magnetic total field sensor is 0.5m above the ground, and the top sensor is 1m above the ground. Five magnetic anomalies are buried underground within the detection area, with spatial coordinates (6,7,-0.5), (14,20,-0.5), (15,10,-0.5), (5,16,-0.5), and (8,25,-0.5), each with a magnetic moment of 1 Am. 2 The magnetic moment inclination angle is 5° and the deflection angle is -10°; the background geomagnetic field inclination angle is 30° and the deflection angle is 0°. Magnetic total field data from these two magnetic field sensors are acquired at each measuring point. The magnetic field data from these two sensors are then differentially processed to obtain two-dimensional magnetic total field gradient data for each measuring point. Finally, interpolation is used to obtain two-dimensional magnetic total field gradient data uniformly distributed across each recording point in the detection area. In the practical application of this application, the magnetic total field data at each measuring point is collected using equipment such as a magnetometer. During the algorithm verification stage, the magnetic total field anomaly data at each measuring point can be directly calculated using simulation calculations, and Gaussian white noise with a preset signal-to-noise ratio (e.g., 0dB) is added to simulate the actual observation data.

[0063] Step S102: Based on the two-dimensional magnetic total field gradient data, obtain the first horizontal distribution data of the modulus of the two-dimensional magnetic total field gradient on each set of unit orthogonal bases.

[0064] Among them, each set of orthonormal bases is obtained by decomposing the two-dimensional magnetic total field gradient data generated by the magnetic dipole of the target body at any height; the modulus of the two-dimensional magnetic total field gradient on a set of orthonormal bases is defined as the projection of the two-dimensional magnetic total field gradient on the set of orthonormal bases.

[0065] Step S103: Based on the first horizontal distribution data, obtain the second horizontal distribution data of the energy of the two-dimensional magnetic total field gradient in the two-dimensional space spanned by each set of unit orthogonal bases.

[0066] This energy is defined as the square of the modulus value. By squaring the modulus value of the two-dimensional magnetic field gradient, the difference between the two-dimensional magnetic field gradients at each recording point within the detection area is amplified, thereby improving the signal-to-noise ratio.

[0067] Step S104: Determine the horizontal coordinates of the target body based on the second horizontal distribution data.

[0068] The application first acquires two-dimensional magnetic total field gradient data, wherein the two-dimensional magnetic total field gradient data is collected by two magnetic total field sensors vertically arranged in a detection area, and the recording points of the two-dimensional magnetic total field gradient data are uniformly distributed in the detection area to form grid two-dimensional magnetic total field gradient data. Then, based on the two-dimensional magnetic total field gradient data, first horizontal distribution data of the modulus of the two-dimensional magnetic total field gradient on each group of unit orthogonal bases is acquired, wherein the unit orthogonal bases are obtained by decomposing the two-dimensional magnetic total field gradient data generated by the magnetic dipole of the target body at any height. Next, based on the first horizontal distribution data, second horizontal distribution data of the energy of the two-dimensional magnetic total field gradient in a two-dimensional space spanned by each group of unit orthogonal bases is acquired. It can be understood that, compared with the first horizontal distribution data, the second horizontal distribution data in the two-dimensional space has a higher signal-to-noise ratio, and the area with relatively strong energy, that is, the area with a higher value of the second horizontal distribution data, means that the ferromagnetic target is more likely to exist. Finally, based on the second horizontal distribution data, the horizontal coordinates of the target are determined. The application converts the two-dimensional magnetic total field gradient data into two-dimensional energy distribution, which can improve the signal-to-noise ratio of the data, effectively improve the accuracy of target detection, and determine the horizontal coordinates of the target to realize the positioning of the target in the horizontal direction.

[0069] In some embodiments of the application, the process of acquiring two-dimensional magnetic total field gradient data in step S101 can include:

[0070] S1, using a magnetometer, recording the magnetic total field data of the two magnetic total field sensors and the recording points along the preset scanning path to obtain a plurality of data items.

[0071] Each data item includes first magnetic total field data, second magnetic total field data and recording points. It can be understood that the first magnetic total field data and the second magnetic total field data are the magnetic total field data of the two magnetic total field sensors detected; and the recording points are the detection positions when the data is detected.

[0072] S2, for each data item, calculating the difference between the first magnetic total field data and the second magnetic total field data, and dividing the difference by the distance between the two magnetic total field sensors to obtain the magnetic total field gradient data of each data item.

[0073] S3, based on the magnetic total field gradient data and the recording points of each data item, using a preset interpolation method to acquire the magnetic total field gradient data at each grid point of the grid.

[0074] In actual magnetic detection tasks, the distance between measurement points is usually not equal to the distance between measurement lines, for example, Figure 2In the shown two-dimensional survey line distribution map, the survey point spacing is much smaller than the survey line spacing, thus, the survey line coverage area needs to be gridded, and the obtained grid is uniformly distributed in the detection area, so as to obtain grid partition data with the same size in two horizontal directions (i.e. horizontal transverse and longitudinal). Commonly used two-dimensional gridding methods include bilinear interpolation, bicubic interpolation, spline interpolation, minimum curvature interpolation, Kriging interpolation and the like. For two-dimensional magnetic total field gradient data, the Kriging interpolation method can be used. Figure 3 The two-dimensional magnetic total field gradient surface map obtained after Kriging interpolation provided by the embodiment of the present application has a relatively high level of random noise due to the existence of large detection interference and errors, and thus the magnetic total field gradient has a relatively low signal-to-noise ratio.

[0075] At this point, the magnetic total field gradient data at each grid point (recorded point) and the coordinates of each grid point are obtained, and thus the magnetic total field gradient data at each grid point and the coordinates of each grid point constitute two-dimensional magnetic total field gradient data.

[0076] In some embodiments of the present application, the unit orthogonal basis mentioned in the above step S102 can be expressed as the following 10 groups of unit orthogonal basis functions:

[0077]

[0078] Each unit orthogonal basis satisfies the following equation:

[0079]

[0080] where (x, y) is the horizontal coordinate of the recorded point, z1 and z2 are the vertical coordinates of the two magnetic total field sensors, respectively, and C1(z1, z2) and C2(z1, z2) are constant coefficient expressions composed of z1 and z2. Exemplarily, Figures 4-8 A two-dimensional unit orthogonal basis surface map calculated from each group of unit orthogonal basis functions is provided.

[0081] In some embodiments of the present application, the process of obtaining the first horizontal distribution data of the modulus of the two-dimensional magnetic total field gradient on each group of unit orthogonal bases based on the two-dimensional magnetic total field gradient data in the above step S102 can include:

[0082] S1, each group of unit orthogonal bases is intercepted by using a window with a preset size, to obtain a plurality of orthogonal basis window functions.

[0083] S2, the inner product calculation of the two-dimensional magnetic total field gradient data is performed by using each orthogonal basis window function, grid by grid, to obtain the first horizontal distribution data of the modulus of the two-dimensional magnetic total field gradient on each group of unit orthogonal bases.

[0084] Since the two-dimensional magnetic total field gradient data is discretely distributed in space, a numerical calculation formula of inner product in the discrete case is needed to calculate the first horizontal distribution data.

[0085] Based on this, in some embodiments of the present application, the process of S2 using each orthogonal basis window function to calculate the inner product of the two-dimensional magnetic total field gradient data grid by grid to obtain the first horizontal distribution data of the modulus of the two-dimensional magnetic total field gradient on each group of unit orthogonal bases can include:

[0086] The first horizontal distribution data of the modulus of the two-dimensional magnetic total field gradient on each group of unit orthogonal bases is calculated by the following equation n (x,y):

[0087]

[0088] where I and J are the sizes of the window in the x direction and the y direction respectively, dΔT(x i ,y j ) is the magnetic total field gradient data of the grid point at (x i ,y j ).

[0089] In some embodiments of the present application, the process of S103 obtaining the second horizontal distribution data of the energy of the two-dimensional magnetic total field gradient in the two-dimensional space spanned by each group of unit orthogonal bases based on the first horizontal distribution data can include:

[0090] S1, the energy horizontal distribution data E(x,y) of the two-dimensional magnetic total field gradient in the two-dimensional space spanned by each group of unit orthogonal bases is calculated by the following equation:

[0091]

[0092] where α n (x,y) is the first horizontal distribution data of the modulus of the two-dimensional magnetic total field gradient on the nth group of unit orthogonal bases.

[0093] S2, the energy horizontal distribution data is normalized to obtain the second horizontal distribution data of the energy of the two-dimensional magnetic total field gradient in the two-dimensional space spanned by each group of unit orthogonal bases.

[0094] The normalization process can exclude the influence of the magnetic moment size of the target body, facilitating subsequent data processing. For example, Figure 9The second horizontal distribution data (i.e., the energy distribution graph) is provided, and it can be seen from the graph that the second horizontal distribution data greatly distinguishes the energy difference at different grid points. In the simulation experiment of the present application, the signal-to-noise ratio of the E surface is about 17.4 dB, which is improved by 17.4 dB compared with the signal-to-noise ratio of 0 dB of the simulation observation data.

[0095] In some embodiments of the present application, the process of determining the horizontal coordinates of the target body based on the second horizontal distribution data in the above step S104 can include:

[0096] S1, determining a target sub-region in which the ferromagnetic target body exists in the detection region based on the second horizontal distribution data.

[0097] Since the energy horizontal distribution data has been normalized in the foregoing step, the energy value in the detection region is between 0 and 1. According to the overall energy distribution, a suitable threshold is selected, and the region with energy higher than the threshold is identified as the target sub-region in which the ferromagnetic target exists. As shown in Figure 9 , assuming that the threshold is 0.5, five target sub-regions are easily obtained.

[0098] S2, determining the horizontal coordinates of the point with the maximum value of the second horizontal distribution data in each target sub-region as the horizontal coordinates of the target body.

[0099] As shown in the second horizontal distribution data Figure 9 , the horizontal coordinates of the energy maximum points of each target sub-region are read as (5.9, 7), (14, 20), (15.1, 10.1), (5, 16), and (8, 25), respectively. It can be seen that the maximum horizontal positioning error is about 0.1 m, and in actual application, the positioning accuracy can be further improved by encrypting the grid at the cost of reducing the operation efficiency.

[0100] The magnetic total field vertical gradient data processing device provided by the embodiments of the present application is described below. The magnetic total field vertical gradient data processing device described below can be correspondingly referred to the magnetic total field vertical gradient data processing method described above.

[0101] Please refer to Figure 10 , the magnetic total field vertical gradient data processing device provided by the embodiments of the present application can include:

[0102] The data acquisition unit 21 is configured to acquire two-dimensional magnetic total field gradient data, the two-dimensional magnetic total field gradient data being collected by two magnetic total field sensors vertically arranged in a detection region, and the recording points of the two-dimensional magnetic total field gradient data being uniformly distributed in the detection region.

[0103] The modulus calculation unit 22 is configured to obtain first horizontal distribution data of modulus of the two-dimensional magnetic total field gradient on each group of unit orthogonal bases based on the two-dimensional magnetic total field gradient data, the unit orthogonal bases being obtained by decomposing the two-dimensional magnetic total field gradient data generated by magnetic dipoles of the target object at an arbitrary height;

[0104] The energy calculation unit 23 is configured to obtain second horizontal distribution data of energy of the two-dimensional magnetic total field gradient in a two-dimensional space spanned by the unit orthogonal bases based on the first horizontal distribution data;

[0105] The coordinate determination unit 24 is configured to determine the horizontal coordinate of the target object based on the second horizontal distribution data.

[0106] In some embodiments of the present application, the data acquisition unit 21 obtains the two-dimensional magnetic total field gradient data in the following manner:

[0107] The magnetometer records the magnetic total field data of the two magnetic total field sensors and the recording positions along the preset scanning path, thereby obtaining a plurality of data items, each data item including first magnetic total field data, second magnetic total field data and a recording position;

[0108] For each data item, the difference between the first magnetic total field data and the second magnetic total field data is calculated, and the magnetic total field gradient data of each data item is obtained by dividing the difference by the distance between the two magnetic total field sensors;

[0109] Based on the magnetic total field gradient data and the recording positions of the data items, a preset interpolation method is used to obtain the magnetic total field gradient data at each grid point of a grid, the grid being uniformly distributed in the detection region;

[0110] The two-dimensional magnetic total field gradient data is composed of the magnetic total field gradient data at each grid point and the coordinates of each grid point.

[0111] In some embodiments of the present application, the modulus calculation unit 22 obtains the first horizontal distribution data of modulus of the two-dimensional magnetic total field gradient on each group of unit orthogonal bases based on the two-dimensional magnetic total field gradient data in the following manner:

[0112] A plurality of orthogonal base window functions are obtained by using a preset size window to intercept each group of unit orthogonal bases;

[0113] The two-dimensional magnetic total field gradient data is calculated by inner product for each grid point using each orthogonal base window function, thereby obtaining the first horizontal distribution data of modulus of the two-dimensional magnetic total field gradient on each group of unit orthogonal bases.

[0114] The function expression of the unit orthogonal bases is consistent with the 10 groups of unit orthogonal base functions described above.

[0115] In some embodiments of the present application, the modulus calculation unit 22 utilizes each orthogonal basis window function to perform inner product calculation on the two-dimensional magnetic total field gradient data grid by grid, to obtain the process of the first horizontal distribution data of the modulus of the two-dimensional magnetic total field gradient on each set of unit orthogonal bases, comprising:

[0116] The first horizontal distribution data of the modulus of the two-dimensional magnetic total field gradient on each set of unit orthogonal bases is calculated by using the following equation n (x,y):

[0117]

[0118] Wherein, I and J are the size of the window in x direction and y direction respectively, dΔT(x i ,y j ) is the magnetic total field gradient data of the grid point at (x i ,y j ).

[0119] In some embodiments of the present application, the energy calculation unit 23 obtains the second horizontal distribution data of the energy of the two-dimensional magnetic total field gradient in the two-dimensional space spanned by each set of unit orthogonal bases based on the first horizontal distribution data, comprising:

[0120] The energy horizontal distribution data E(x,y) of the two-dimensional magnetic total field gradient in the two-dimensional space spanned by each set of unit orthogonal bases is calculated by using the following equation:

[0121]

[0122] Wherein, α n (x,y) is the first horizontal distribution data of the modulus of the two-dimensional magnetic total field gradient on the nth set of unit orthogonal bases;

[0123] The energy horizontal distribution data is normalized to obtain the second horizontal distribution data of the energy of the two-dimensional magnetic total field gradient in the two-dimensional space spanned by each set of unit orthogonal bases.

[0124] In some embodiments of the present application, the coordinate determination unit 24 determines the horizontal coordinates of the target body based on the second horizontal distribution data, which can include:

[0125] Based on the second horizontal distribution data, a target sub-region in which a ferromagnetic target body exists in the detection region is determined, and the value of the second horizontal distribution data of the target sub-region is greater than a preset threshold value;

[0126] The horizontal coordinates of the point with the maximum value of the second horizontal distribution data in each target sub-region are determined as the horizontal coordinates of the target body.

[0127] The magnetic total field vertical gradient data processing device provided by the embodiments of the present application can be applied to a magnetic total field vertical gradient data processing device, such as a computer. Figure 11 The hardware structure block diagram of the magnetic total field vertical gradient data processing device is shown, and the hardware structure of the magnetic total field vertical gradient data processing device can include at least one processor 31, at least one communication interface 32, at least one memory 33 and at least one communication bus 34. Figure 11

[0128] In the embodiments of the present application, the number of the processor 31, the communication interface 32, the memory 33 and the communication bus 34 is at least one, and the processor 31, the communication interface 32 and the memory 33 complete the communication with each other through the communication bus 34.

[0129] The processor 31 can be a central processing unit CPU, or a specific integrated circuit ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the embodiments of the present application, etc.

[0130] The memory 33 can include a high-speed RAM memory, and can also include a non-volatile memory, such as at least one disk memory.

[0131] The memory 33 stores a program, and the processor 31 can call the program stored in the memory 33, and the program is used for:

[0132] Obtaining two-dimensional magnetic total field gradient data, the two-dimensional magnetic total field gradient data is collected by two magnetic total field sensors vertically arranged in a detection area, and the recording points of the two-dimensional magnetic total field gradient data are uniformly distributed in the detection area;

[0133] Based on the two-dimensional magnetic total field gradient data, first horizontal distribution data of the modulus of the two-dimensional magnetic total field gradient on each group of unit orthogonal bases is obtained, the unit orthogonal bases are obtained by decomposing the two-dimensional magnetic total field gradient data generated by the magnetic dipole of the target body at any height;

[0134] Based on the first horizontal distribution data, second horizontal distribution data of the energy of the two-dimensional magnetic total field gradient in the two-dimensional space spanned by each group of unit orthogonal bases is obtained;

[0135] Based on the second horizontal distribution data, the horizontal coordinates of the target body are determined.

[0136] Optionally, the detailed functions and extended functions of the program can refer to the description above.

[0137] ​The embodiment of the present application further provides a storage medium which can store a program suitable for processor execution, and the program is used for:

[0138] acquiring two-dimensional magnetic total field gradient data collected by two magnetic total field sensors vertically arranged in a detection area, and record points of the two-dimensional magnetic total field gradient data are uniformly distributed in the detection area;

[0139] based on the two-dimensional magnetic total field gradient data, acquiring first horizontal distribution data of a modulus of two-dimensional magnetic total field gradient on each group of unit orthogonal bases, the unit orthogonal bases being obtained by decomposing two-dimensional magnetic total field gradient data generated by a magnetic dipole of the target body at an arbitrary height;

[0140] based on the first horizontal distribution data, acquiring second horizontal distribution data of energy of two-dimensional magnetic total field gradient in a two-dimensional space spanned by the unit orthogonal bases;

[0141] based on the second horizontal distribution data, determining a horizontal coordinate of the target body.

[0142] Optionally, the detailed functions and extended functions of the program can refer to the description above.

[0143] In summary:

[0144] The embodiment of the present application first acquires two-dimensional magnetic total field gradient data, wherein the two-dimensional magnetic total field gradient data is collected by two magnetic total field sensors vertically arranged in a detection area, and record points of the two-dimensional magnetic total field gradient data are uniformly distributed in the detection area, forming grid two-dimensional magnetic total field gradient data. Then, based on the two-dimensional magnetic total field gradient data, first horizontal distribution data of a modulus of two-dimensional magnetic total field gradient on each group of unit orthogonal bases is acquired, wherein the unit orthogonal bases are obtained by decomposing two-dimensional magnetic total field gradient data generated by a magnetic dipole of the target body at an arbitrary height. Next, based on the first horizontal distribution data, second horizontal distribution data of energy of two-dimensional magnetic total field gradient in a two-dimensional space spanned by the unit orthogonal bases is acquired. It can be understood that, compared with the first horizontal distribution data, the second horizontal distribution data in the two-dimensional space has a higher signal-to-noise ratio, and a region with relatively strong energy, that is, a region with a higher value of the second horizontal distribution data, means that there is more likely to be a ferromagnetic target. Finally, based on the second horizontal distribution data, a horizontal coordinate of the target is determined. The embodiment of the present application converts two-dimensional magnetic total field gradient data into two-dimensional energy distribution, which can improve the signal-to-noise ratio of the data, effectively improve the accuracy of target detection, and determine the horizontal coordinate of the target, realizing the positioning of the target in the horizontal direction.

[0145] Finally, it should be noted that the terms "first", "second", and the like, herein do not denote any order, quantity, combination, or importance, but rather are used to distinguish one element from another, and are not intended to denote the presence of any such actual relationship or order. Moreover, the terms "include", "have", or any other variant thereof are intended to encompass non-exclusive inclusions, such that processes, methods, articles, or apparatuses that comprise a list of elements are not required to comprise only those elements in the list, but can include other elements not expressly listed, or also include elements inherent in such processes, methods, articles, or apparatuses. Without additional restrictions, an element preceded by "comprises... a" does not exclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the stated element.

[0146] The various embodiments in the specification are described in progressive order with each embodiment building on one or more of the previous embodiments, however the order of the embodiments presented is not intended to be construed as a requirement or limitation for these embodiments. Any one or more of the embodiments described herein are possible embodiments, which can be combined with each other in any way. The same reference numerals in different drawings represent the same or similar elements.

[0147] The above description of disclosed embodiments provides enabling teaching for a person skilled in the art to realize or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Therefore, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A magnetic total-field vertical gradient data processing method, characterized by, The method comprises the following steps: acquiring two-dimensional magnetic total field gradient data collected by two magnetic total field sensors vertically arranged in a detection area, and recording points of the two-dimensional magnetic total field gradient data are uniformly distributed in the detection area; based on the two-dimensional magnetic total field gradient data, acquiring first horizontal distribution data of a modulus of two-dimensional magnetic total field gradient on each set of unit orthogonal bases, the unit orthogonal bases being obtained by decomposing two-dimensional magnetic total field gradient data generated by a magnetic dipole of a target body at an arbitrary height; the modulus of the two-dimensional magnetic total field gradient on a set of unit orthogonal bases is a projection of the two-dimensional magnetic total field gradient on the set of unit orthogonal bases; based on the first horizontal distribution data, acquiring second horizontal distribution data of energy of the two-dimensional magnetic total field gradient in a two-dimensional space spanned by each set of unit orthogonal bases; based on the second horizontal distribution data, determining a horizontal coordinate of the target body; wherein, based on the two-dimensional magnetic total field gradient data, the process of acquiring the first horizontal distribution data of the modulus of the two-dimensional magnetic total field gradient on each set of unit orthogonal bases comprises: using a window of a preset size to intercept each set of unit orthogonal bases to obtain a plurality of orthogonal base window functions; using each orthogonal base window function, performing inner product calculation on the two-dimensional magnetic total field gradient data grid by grid to obtain the first horizontal distribution data of the modulus of the two-dimensional magnetic total field gradient on each set of unit orthogonal bases; wherein, the unit orthogonal bases comprise: ； each unit orthogonal base satisfies the following equation: ； wherein denotes the set of orthonormal bases, denotes the set of orthonormal bases, is the horizontal coordinate of the recording point, , is the vertical coordinate of the two magnetic total field sensors, , are composed of and constant expression.

2. The method of claim 1, wherein, the process of acquiring the two-dimensional magnetic total field gradient data comprises: using a magnetometer to record magnetic total field data and recording points of the two magnetic total field sensors along a preset scanning path to obtain a plurality of data items, each data item comprising first magnetic total field data, second magnetic total field data and recording points; for each data item, calculating a difference value of the first magnetic total field data and the second magnetic total field data, and dividing the difference value by a distance between the two magnetic total field sensors to obtain magnetic total field gradient data of each data item; based on the magnetic total field gradient data and the recording points of each data item, using a preset interpolation method to acquire magnetic total field gradient data at each grid point of a grid, the grid being uniformly distributed in the detection area; the two-dimensional magnetic total field gradient data is composed of the magnetic total field gradient data at each grid point and coordinates of each grid point.

3. The method of claim 1, wherein, the process of using each unit orthogonal base window function to perform inner product calculation on the two-dimensional magnetic total field gradient data grid by grid to obtain the first horizontal distribution data of the modulus of the two-dimensional magnetic total field gradient on each set of unit orthogonal bases comprises: The first horizontal distribution data of the modulus of the two-dimensional magnetic total field gradient on each set of unit orthogonal bases is calculated using the following equation : ； where I, J are the size of the window in x and y direction, respectively, denotes the grid point in x direction of the window, denotes the grid point in y direction of the window, is the magnetic total field gradient data of the grid point at .​​ 4. The method of claim 3, wherein, based on the first horizontal distribution data, the process of acquiring the second horizontal distribution data of energy of the two-dimensional magnetic total field gradient in the two-dimensional space spanned by each set of unit orthogonal bases comprises: The energy level distribution data of the two-dimensional magnetic total field gradient in the two-dimensional space spanned by the orthogonal bases of each group is calculated using the following equation : ； wherein is the first horizontal profile data of the modulus of the two-dimensional magnetic total field gradient on the n-th set of orthogonal bases; normalizing the energy horizontal distribution data to obtain the second horizontal distribution data of energy of the two-dimensional magnetic total field gradient in the two-dimensional space spanned by each set of unit orthogonal bases.

5. The method according to any one of claims 1 to 4, characterized in that, the process of determining the horizontal coordinate of the target body based on the second horizontal distribution data comprises: determining a target sub-region in the detection region where a ferromagnetic target exists based on the second horizontal distribution data, the value of the second horizontal distribution data of the target sub-region being greater than a preset threshold value; determining the horizontal coordinate of a point with the maximum value of the second horizontal distribution data in each target sub-region as the horizontal coordinate of the target.

6. A magnetic total-field vertical gradient data processing device, characterized by Comprising: a data acquisition unit configured to acquire two-dimensional magnetic total field gradient data, the two-dimensional magnetic total field gradient data being collected by two magnetic total field sensors vertically arranged in a detection region, and the recording points of the two-dimensional magnetic total field gradient data being uniformly distributed in the detection region; a modulus calculation unit configured to acquire first horizontal distribution data of the modulus of two-dimensional magnetic total field gradient on each set of unit orthogonal bases based on the two-dimensional magnetic total field gradient data, the unit orthogonal bases being obtained by decomposing the two-dimensional magnetic total field gradient data generated by a magnetic dipole of a target at an arbitrary height; and the modulus of the two-dimensional magnetic total field gradient on a set of unit orthogonal bases being the projection of the two-dimensional magnetic total field gradient on the set of unit orthogonal bases; an energy calculation unit configured to acquire second horizontal distribution data of the energy of the two-dimensional magnetic total field gradient in a two-dimensional space spanned by each set of unit orthogonal bases based on the first horizontal distribution data; a coordinate determination unit configured to determine the horizontal coordinate of the target based on the second horizontal distribution data; wherein the process of acquiring the first horizontal distribution data of the modulus of the two-dimensional magnetic total field gradient on each set of unit orthogonal bases based on the two-dimensional magnetic total field gradient data in the modulus calculation unit comprises: cutting each set of unit orthogonal bases using a window of a preset size to obtain a plurality of orthogonal base window functions; performing inner product calculation on the two-dimensional magnetic total field gradient data using each orthogonal base window function to obtain the first horizontal distribution data of the modulus of the two-dimensional magnetic total field gradient on each set of unit orthogonal bases; wherein the unit orthogonal bases comprise: ； each unit orthogonal base satisfies the following equation: ； wherein denotes the group of unit orthogonal bases, denotes the group of unit orthogonal bases, is the horizontal coordinate of the recording point, , is the vertical coordinate of the two magnetic total field sensors respectively, , are respectively composed of and constant expression.

7. A magnetic total-field vertical gradient data processing device, characterized by Comprising: a memory and a processor; the memory is configured to store a program; the processor is configured to execute the program to implement each step of the magnetic total field vertical gradient data processing method according to any one of claims 1-5.

8. A storage medium having stored thereon a computer program, characterized in that The computer program is executed by the processor to implement each step of the magnetic total field vertical gradient data processing method according to any one of claims 1-5.

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