Correction method for geophysical anomaly contour graph detected by electromagnetic profiling method

Abstract

Embodiments of the present application relate to the field of geophysical data processing, and specifically to a method for correcting the geophysical anomaly isogram obtained by electromagnetic profiling method. The method includes: obtaining the original graph of the geophysical anomaly isogram obtained by electromagnetic profiling method; dividing the area of the geophysical anomaly isogram into multiple parts with the same size for each part; respectively performing interpolation processing on each divided geophysical anomaly isogram to obtain the first corrected isogram; obtaining the second corrected isogram according to the geophysical anomaly isogram and the first corrected isogram; obtaining the corrected geophysical anomaly isogram according to the divided geophysical anomaly isogram and the second corrected isogram. The method provided by the embodiments of the present application can obtain a highly accurate corrected geophysical anomaly isogram.

Description

Technical Field

[0001] Embodiments of the present application relate to the field of geophysical data processing, and more particularly to a method for correcting geophysical anomaly isogram graphs detected by the electromagnetic profiling method. Background Art

[0002] The electromagnetic profiling method is a geophysical exploration method. Those skilled in the art use the electromagnetic profiling method to obtain the electromagnetic response characteristics of the detection object for analysis.

[0003] When using the electromagnetic profiling method, abnormal data will be obtained, and this abnormal data will be saved as an isogram graph. To obtain the electromagnetic response characteristics, it is necessary to analyze these geophysical anomaly isogram graphs. However, the isograms in the unprocessed geophysical anomaly isogram graphs are irregularly distributed and cannot be directly analyzed. Instead, interpolation processing needs to be performed first so that the isograms in the irregularly distributed geophysical anomaly isogram graphs become regularly distributed isograms before further analysis.

[0004] When processing geophysical anomaly isogram graphs, when there are large blank areas or complex shapes in the geophysical anomaly isogram graphs, using conventional interpolation processing methods such as the inverse distance weighting method and the Kriging method will result in large errors, causing the geophysical anomaly isogram graphs after interpolation processing to be distorted and still unable to be used for analysis. Summary of the Invention

[0005] In view of the above problems, the technical solution of the present application is proposed to solve at least one aspect of the above problems.

[0006] Embodiments of the present application provide a method for correcting geophysical anomaly isogram graphs detected by the electromagnetic profiling method, and the method includes:

[0007] Step S101: Obtain the original graph of the geophysical anomaly isogram detected by the electromagnetic profiling method; Step S102: Divide the area of the geophysical anomaly isogram graph into multiple parts with the same size; Step S103: Perform interpolation processing on each divided geophysical anomaly isogram graph respectively to obtain the first corrected isogram graph; Step S104: Obtain the second corrected isogram graph according to the geophysical anomaly isogram graph and the first corrected isogram graph; Step S105: Obtain the corrected geophysical anomaly isogram graph according to the divided geophysical anomaly isogram graph and the second corrected isogram graph.

[0008] The correction method for the geophysical anomaly isoline graph detected by the electromagnetic profiling method provided by the embodiments of the present application can obtain a highly accurate corrected geophysical anomaly isoline graph when there are large blank areas or complex shapes in the geophysical anomaly isoline graph. Description of the Drawings

[0009] Other objects and advantages of the present application will be apparent from the following description with reference to the accompanying drawings, and will help to provide a comprehensive understanding of the present application.

[0010] Figure 1 is a flowchart of the correction method for the geophysical anomaly isoline graph detected by the electromagnetic profiling method according to the embodiments of the present application;

[0011] Figure 2 is a schematic diagram of the original geophysical anomaly isoline graph obtained after detection by the electromagnetic profiling method according to the embodiments of the present application;

[0012] Figure 3 is a schematic diagram of the corrected geophysical anomaly isoline graph in the related art;

[0013] Figure 4 is a schematic diagram of the corrected geophysical anomaly isoline graph by another method in the related art;

[0014] Figure 5 is a schematic diagram of dividing the geophysical anomaly isoline graph area into multiple parts according to the embodiments of the present application;

[0015] Figure 6 is a schematic diagram of comparing the size of any divided geophysical anomaly isoline graph with a preset graph according to the embodiments of the present application;

[0016] Figure 7 is a schematic diagram of re-dividing the geophysical anomaly isoline graph area according to the embodiments of the present application;

[0017] Figure 8 is a schematic diagram of comparing the size of any re-divided geophysical anomaly isoline graph with a preset graph according to the embodiments of the present application;

[0018] Figure 9 is a schematic diagram of the corrected geophysical anomaly isoline graph according to the embodiments of the present application.

[0019] In the Figure 2 drawings:

[0020] 1. Large blank area;

[0021] In the Figure 3 drawings:

[0022] 11. Large blank areas in the geophysical anomaly isogram graph corrected by the inverse distance weighted method;

[0023] Appendix Figure 4 In:

[0024] 12. Large blank areas corrected by the Kriging method;

[0025] Appendix Figure 6 In:

[0026] 21. Any divided geophysical anomaly isogram graph; 3. Preset graph;

[0027] Appendix Figure 8 In:

[0028] 22. Any re-divided geophysical anomaly isogram graph; 3. Preset graph;

[0029] Appendix Figure 9 In:

[0030] 13. Large blank areas corrected by the correction method according to the embodiments of the present application.

[0031] It should be noted that the accompanying drawings are not drawn to scale, and for illustrative purposes, elements with similar structures or functions are generally denoted by similar reference numerals throughout the accompanying drawings. It should also be noted that the accompanying drawings are only for facilitating the description of the preferred embodiments, rather than the present application itself. The accompanying drawings do not show every aspect of the described embodiments and do not limit the scope of the present application. Detailed implementation manners

[0032] To make the objectives, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are one embodiment of the present application, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present application without creative efforts shall fall within the scope of protection of the present application.

[0033] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in this application should have the ordinary meanings understood by those with ordinary skills in the field to which this application belongs. If descriptions such as "first", "second", etc. are involved throughout the text, then such descriptions as "first", "second", etc. are only used to distinguish similar objects, and cannot be understood as indicating or implying their relative importance, sequence, or implicitly indicating the quantity of the technical features indicated. It should be understood that the data described as "first", "second", etc. can be interchanged under appropriate circumstances. If "and / or" appears throughout the text, its meaning includes three parallel scenarios. Taking "A and / or B" as an example, it includes Scenario A, or Scenario B, or the scenario where both A and B are satisfied simultaneously.

[0034] A method for correcting the geophysical anomaly isopleth map detected by the electromagnetic profiling method provided by this application, as Figure 1 shown, includes the following steps: Step S101: Obtain the original geophysical anomaly isopleth map detected by the electromagnetic profiling method; Step S102: Divide the geophysical anomaly isopleth map area into multiple parts with the same size; Step S103: Perform interpolation processing on each divided geophysical anomaly isopleth map respectively to obtain the first corrected isopleth map; Step S104: Obtain the second corrected isopleth map according to the geophysical anomaly isopleth map and the first corrected isopleth map; Step S105: Obtain the corrected geophysical anomaly isopleth map according to the divided geophysical anomaly isopleth map and the second corrected isopleth map.

[0035] For Step S102, in some embodiments, when dividing the geophysical anomaly isopleth map area into multiple parts, the geophysical anomaly isopleth map area can be divided into multiple rectangular blocks with the same size.

[0036] In Step S103, when performing interpolation processing on each divided geophysical anomaly isopleth map respectively to obtain the first corrected isopleth map, it includes the following processing steps: Obtain the values and distributions of the isopleths in each divided geophysical anomaly isopleth map; According to the values and distributions of the isopleths in each divided geophysical anomaly isopleth map, perform interpolation processing on each divided geophysical anomaly isopleth map to obtain the first corrected isopleth map.

[0037] Among them, when interpolating each divided geophysical anomaly isoline graph, the interpolation method is used for interpolation. The interpolation method is a method of interpolating a continuous function on the basis of discrete data, so that the continuous curve of this continuous function passes through all the given discrete data points. The interpolation method includes linear interpolation method, spline interpolation method, etc. Among them, the linear interpolation method is a method of using a straight line passing through known data points to represent the line of a continuous function; the spline interpolation method is a method of making a smooth curve passing through a series of points with a variable spline, and the variable spline is composed of multiple polynomials determined by multiple groups of adjacent two discrete data points.

[0038] In step S104, when obtaining the second corrected isoline graph according to the geophysical anomaly isoline graph and the first corrected isoline graph, the following processing steps are included: obtaining the values and distributions of the isolines in the geophysical anomaly isoline graph; obtaining the values and distributions of the isolines in the first corrected isoline graph; obtaining the second corrected isoline graph according to the values and distributions of the isolines in the geophysical anomaly isoline graph and the values and distributions of the isolines in the first corrected isoline graph.

[0039] In some embodiments, the second corrected isoline graph can be obtained according to the following formula:

[0040] (W T W + βD T D)d u = W T Wd i

[0041] Among them, W is a weight matrix, and its diagonal elements are the reciprocal ratios of the distances between the points on the isoline in the second corrected isoline graph d u and the nearest points on the isoline in the geophysical anomaly isoline graph, d i is the first corrected isoline graph, W T is the transpose of W, D is the two-dimensional difference matrix of the W matrix, D T is the transpose of D, and β is a regularization factor.

[0042] When obtaining the second corrected contour graph, the second corrected contour graph can be obtained by the preconditioned conjugate gradient method. The preconditioned conjugate gradient method is the main iterative method for solving symmetric linear equations at present. When judging the number of iterations, a preset value can be set. When the number of iterations reaches the preset value, the second corrected contour graph is obtained according to the calculation result of this iteration; or an error threshold can be set, and the error generated after each iteration when the preconditioned conjugate gradient method is executed is obtained. When the error is not greater than the error threshold, the second corrected contour graph is obtained according to the calculation result of this iteration; the preset value and the error threshold can also be set at the same time, and the error generated after each iteration when the preconditioned conjugate gradient method is executed is obtained. When the number of iterations reaches the preset value, and / or the error is not greater than the error threshold, the second corrected contour graph is obtained according to the calculation result of this iteration. It can be understood that when the number of iterations reaches the preset value, and / or the error is not greater than the error threshold, the number of iterations at this time is the minimum number of iterations to obtain a sufficiently accurate second corrected contour graph, which greatly reduces the amount of calculation and improves the calculation efficiency.

[0043] In step S105, when obtaining the corrected geophysical anomaly contour graph according to the divided geophysical anomaly contour graph and the second corrected contour graph, the following processing steps are included: comparing the size of any divided geophysical anomaly contour graph with a preset graph; if the divided geophysical anomaly contour graph is smaller than the preset graph, the second corrected contour graph is the corrected geophysical anomaly contour graph; if the divided geophysical anomaly contour graph is not smaller than the preset graph, the area of the geophysical anomaly contour graph is re-divided, and interpolation processing is performed on each re-divided geophysical anomaly contour graph to obtain a third corrected contour graph. The third corrected contour graph is filled into the first corrected contour graph, step S104 is executed, the second corrected contour graph is obtained again, and then the size of any re-divided geophysical anomaly contour graph is compared with the preset graph, and the above steps are repeated until the divided geophysical anomaly contour graph is smaller than the preset graph, and the re-obtained second corrected contour graph is the corrected geophysical anomaly contour graph.

[0044] When comparing the size of any divided geophysical anomaly contour graph with the preset graph, it can be understood that when any divided geophysical anomaly contour graph is smaller than the preset graph, it means that in step S102, the geophysical anomaly contour graph is divided small enough, and the second corrected contour graph obtained after further correction is accurate enough to be used as the corrected geophysical anomaly contour graph for further processing to obtain the electromagnetic response characteristics of the detection object.

[0045] In some embodiments, when dividing the geophysical anomaly isoline graph into multiple rectangular blocks of the same size, the length and width of the geophysical anomaly isoline graph of the divided rectangular blocks can be compared with the length and width of the preset graph; if the length and width of any geophysical anomaly isoline graph divided into rectangular blocks are less than the length and width of the preset graph, then the second corrected isoline graph is the corrected geophysical anomaly isoline graph; if the length or width of any geophysical anomaly isoline graph divided into rectangular blocks is not less than the length or width of the preset graph, then the area of the geophysical anomaly isoline graph is re-divided, and interpolation processing is performed on each re-divided geophysical anomaly isoline graph to obtain a third corrected isoline graph, the third corrected isoline graph is filled into the first corrected isoline graph, step S104 is executed, the second corrected isoline graph is re-obtained, and then the length and width of any geophysical anomaly isoline graph divided into rectangular blocks are compared with the length and width of the preset graph, and the above steps are repeated until the length and width of any geophysical anomaly isoline graph divided into rectangular blocks are less than the length and width of the preset graph, and the re-obtained second corrected isoline graph is the corrected geophysical anomaly isoline graph.

[0046] When re-dividing the area of the geophysical anomaly isoline graph, the number of the geophysical anomaly isoline graphs after division should be increased under the condition that the area of the geophysical anomaly isoline graph to be re-divided remains unchanged.

[0047] In the embodiments of the present application, when dividing the geophysical anomaly isoline graph into multiple rectangular blocks of the same size, the length and / or width of each geophysical anomaly isoline graph divided into rectangular blocks can be reduced to increase the number of the geophysical anomaly isoline graphs after division.

[0048] It can be understood that when comparing the length and width of the geophysical anomaly isoline graph of the divided rectangular blocks with the length and width of the preset graph, if the length of the geophysical anomaly isoline graph of the divided rectangular block is not less than the length of the preset graph, then when re-dividing the area of the geophysical anomaly isoline graph, the length of the geophysical anomaly isoline graph of the rectangular block should be reduced; if the width of the geophysical anomaly isoline graph of the divided rectangular block is not less than the width of the preset graph, then when re-dividing the area of the geophysical anomaly isoline graph, the width of the geophysical anomaly isoline graph of the rectangular block should be reduced; if the length and width of the geophysical anomaly isoline graph of the divided rectangular block are both not less than the length and width of the preset graph, then when re-dividing the area of the geophysical anomaly isoline graph, the length and width of the geophysical anomaly isoline graph of the rectangular block should be reduced.

[0049] When interpolating each re-divided geophysical anomaly isoline graph to obtain the third corrected isoline graph, the following processing steps are included: obtaining the values and distributions of the isolines in each re-divided geophysical anomaly isoline graph; according to the values and distributions of the isolines in each re-divided geophysical anomaly isoline graph, interpolating each re-divided geophysical anomaly isoline graph to obtain the third corrected isoline graph. Among them, when interpolating each divided geophysical anomaly isoline graph, the interpolation method is used for interpolation. In some embodiments, linear interpolation method, spline interpolation method, etc. can be used.

[0050] When supplementing the third corrected isoline graph into the first corrected isoline graph, the newly obtained first corrected isoline graph can be obtained by supplementing the third corrected isoline graph on the basis of retaining the first corrected isoline graph, that is, the third corrected isoline graph can be superimposed on the original first corrected isoline graph. By supplementing the new corrected isoline graph into the first corrected isoline graph and further correcting with the newly obtained first corrected isoline graph, the corrected geophysical anomaly isoline graph can be made more accurate.

[0051] When using the interpolation method, it can be understood that the more the number of divisions of the geophysical anomaly isoline map, the greater the amount of calculation for interpolating the divided geophysical anomaly isoline graph. Therefore, in order to reduce the calculation amount, when initially dividing the geophysical anomaly isoline graph area, it should not be divided too much. It can be selected to be divided into 9 - 25, or the number of divisions can be selected according to the actual situation.

[0052] The correction method for the geophysical anomaly isoline graph detected by the electromagnetic profiling method provided by the present application can obtain a highly accurate corrected geophysical anomaly isoline graph when there is a large blank area or a relatively complex shape in the geophysical anomaly isoline graph.

[0053] The following will use Figure 2 the correction process of the geophysical anomaly isoline graph obtained by detecting with the electromagnetic profiling method shown in an embodiment as an example to describe and supplement the methods in one or more of the above-mentioned embodiments in more detail.

[0054] When using the correction method for the geophysical anomaly isoline graph detected by the electromagnetic profiling method in the present application, first, in step S101, obtain Figure 2 the geophysical anomaly isoline graph detected by the electromagnetic profiling method shown. In this embodiment, as Figure 2As shown, there is a large blank area 1. When using conventional interpolation methods, such as the inverse distance weighted method, the Kriging method, etc., large errors will occur, resulting in the distortion of the geophysical anomaly isoline graph after interpolation processing. For example, Figure 3 and 4 As shown, among them, Figure 3 is the corrected geophysical anomaly isoline graph obtained after using the inverse distance weighted method for interpolation processing in the related technology Figure 2 shown in the geophysical anomaly isoline graph detected by the electromagnetic profiling method. Figure 4 is the corrected geophysical anomaly isoline graph obtained after using the Kriging method for interpolation processing in the related technology Figure 2 shown in the geophysical anomaly isoline graph detected by the electromagnetic profiling method. It can be seen from Figure 3 and 4 that there are a large number of distorted anomaly isoline graphs, especially in the large blank area 11 corrected by the inverse distance weighted method and the large blank area 12 corrected by the Kriging method. Therefore, it still cannot be used for further analysis.

[0055] After obtaining the geophysical anomaly isoline graph shown in Figure 2 , step S102 is executed. In step S102, the geophysical anomaly isoline graph in 2 needs to be divided into multiple parts with the same size. The divided graph is as shown in Figure 5 . All the geophysical anomaly isoline graphs in Figure 5 are divided into rectangular blocks with the same size. When performing subsequent calculations, the more the number of divisions of the geophysical anomaly isoline map, the greater the computational workload for interpolating the divided geophysical anomaly isoline graph. Therefore, in order to reduce the computational workload, when dividing the geophysical anomaly isoline graph area for the first time, it can be divided into 9 - 25. In this embodiment, when dividing the geophysical anomaly isoline graph shown in Figure 2 for the first time, as shown in Figure 5 , it is divided into a geophysical anomaly isoline graph of 16 rectangular blocks.

[0056] After dividing the geophysical anomaly isoline graph shown in Figure 2 to obtain 16 rectangular block - shaped geophysical anomaly isoline graphs as shown in Figure 5 , step S103 is executed. First, obtain the values and distributions of the isolines in each of the 16 rectangular block - shaped geophysical anomaly isoline graphs with the same size, and then, according to the values and distributions of the isolines in each rectangular block - shaped geophysical anomaly isoline graph, perform interpolation processing on each rectangular block - shaped geophysical anomaly isoline graph, that is, respectively for Figure 5Each rectangular geophysical anomaly isoline graph in it was preliminarily corrected to obtain the first corrected isoline graph. The interpolation method used here is the linear interpolation method.

[0057] After obtaining Figure 2 the first corrected isoline graph of the geophysical anomaly isoline graph shown in, step S104 is executed, that is, according to the isolines and their distributions in the first corrected isoline graph, and Figure 2 the values and distributions of the isolines in the geophysical anomaly isostasy graph shown in, substitute the above values and distributions into the following formula to obtain the second corrected isoline graph:

[0058] (W T W + βD T D)d u = W T Wd i

[0059] where W is the weight matrix, and its diagonal elements are the reciprocals of the distances between the points on the isoline in the second corrected isoline graph d u and the closest points on the isolines in the geophysical anomaly isoline graph shown in, d Figure 2 is the first corrected isoline graph, W i is the transpose of W, D is the two-dimensional difference matrix of the W matrix, D T is the transpose of D, and β is the regularization factor. T is the transpose of D, and β is the regularization factor.

[0060] When solving the above formula, that is, obtaining the second corrected isoline graph d in the above formula u , it is solved by the preconditioned conjugate gradient method, setting a preset value and an error threshold, obtaining the error generated after each iteration when executing the preconditioned conjugate gradient method. When the number of iterations reaches the preset value, and / or the error is not greater than the error threshold, obtain according to the calculation result of this iteration Figure 2 the second corrected isoline graph of the geophysical anomaly isoline graph shown, that is, further correct the geophysical anomaly isoline graph shown in Figure 2 shown.

[0061] Finally, step S105 is executed to compare Figure 5 the length and width of any rectangular geophysical anomaly isoline graph in with the length and width of the preset graph. In this embodiment, as Figure 6 shown, obtain Figure 5 any divided geophysical anomaly isoline graph 21 in, compare its length and width with the length and width of the preset graph 3, and it can be obtained from Figure 4 that its length and width are not less than the length or width of the preset graph 3, then it needs to be re-divided Figure 2The geophysical anomaly isoline graphic area shown in. In the embodiments of the present application, after re - division Figure 2 The geophysical anomaly isoline graph shown in Figure 7 is as shown. The length and width of the rectangular - block - shaped geophysical anomaly isoline graph are reduced, and the number of the rectangular - block - shaped geophysical anomaly isoline graphs after division is increased.

[0062] Then, interpolation processing is respectively performed on Figure 7 each re - divided geophysical anomaly isoline graph in, to obtain a third corrected isoline graph, and the third corrected isoline graph is filled into the first corrected isoline graph. Step S104 is executed to re - obtain a second corrected isoline graph, and then compare Figure 7 the length and width of any rectangular - block - shaped geophysical anomaly isoline graph divided in with Figure 6 the length and width of the preset graph 3 in. In this embodiment, as Figure 8 shown, any re - divided geophysical anomaly isoline graph 22 in Figure 7 is obtained, and its length and width are compared with the length and width of the preset graph 3. It can be obtained from Figure 8 that both its length and width are smaller than the length or width of the preset graph 3, then the re - obtained second corrected isoline graph is the corrected geophysical anomaly isoline graph.

[0063] In this embodiment, the re - obtained second corrected isoline graph, that is, the corrected geophysical anomaly isoline graph obtained by correcting the geophysical anomaly isoline graph detected by the electromagnetic profiling method in the present application, is as Figure 9 shown. Compared with the corrected geophysical anomaly isoline graph obtained by interpolation processing using the inverse distance weighted method as shown in Figure 3 , and the corrected geophysical anomaly isoline graph obtained by interpolation processing using the Kriging method as shown in Figure 4 , the corrected geophysical anomaly isoline graph 9 obtained by correcting the geophysical anomaly isoline graph detected by the electromagnetic profiling method in the present application is more accurate. Especially for the correction of the large - area blank area 1 in Figure 2 , the large - area blank area 11 corrected by the inverse distance weighted method in Figure 3 , and the large - area blank area 12 corrected by the Kriging method in Figure 4 , all include a large number of distorted anomaly isoline graphs, while the anomaly isoline graphs in the large - area blank area 13 corrected according to the correction method of the embodiment of the present application are all corrected, with high accuracy and no distortion, and can be used for further analysis and processing to analyze the detection object.

[0064] For the embodiments of the present application, it should also be noted that, without conflict, the embodiments of the present application and the features in the embodiments may be combined with each other to obtain new embodiments.

[0065] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. The protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A method for correcting the geophysical anomaly isopleth graph detected by the electromagnetic profiling method, wherein, Including: Step S101: Obtain the original graph of the geophysical anomaly isolines detected by the electromagnetic profiling method; Step S102: Divide the geophysical anomaly isoline graph area into multiple parts with the same size for each part; Step S103: Perform interpolation processing on each divided geophysical anomaly isoline graph respectively to obtain the first corrected isoline graph; Step S104: Obtain the second corrected isoline graph according to the geophysical anomaly isoline graph and the first corrected isoline graph; Step S105: Obtain the corrected geophysical anomaly isoline graph according to the divided geophysical anomaly isoline graph and the second corrected isoline graph; The obtaining the corrected geophysical anomaly isoline graph according to the divided geophysical anomaly isoline graph and the second corrected isoline graph includes: S1051: Compare the size of any one of the divided geophysical anomaly isoline graphs with the size of a preset graph; S1052: If the divided geophysical anomaly isoline graph is smaller than the preset graph, then the second corrected isoline graph is the corrected geophysical anomaly isoline graph; S1053: If the divided geophysical anomaly isoline graph is not smaller than the preset graph, then re-divide the geophysical anomaly isoline graph area, perform interpolation processing on each re-divided geophysical anomaly isoline graph respectively to obtain the third corrected isoline graph, supplement the third corrected isoline graph into the first corrected isoline graph, execute Step S104, re-obtain the second corrected isoline graph, and then compare the size of any one of the re-divided geophysical anomaly isoline graphs with the preset graph, repeat Steps S1051 - S1053 until the divided geophysical anomaly isoline graph is smaller than the preset graph, then the re-obtained second corrected isoline graph is the corrected geophysical anomaly isoline graph.

2. The method according to claim 1, wherein, The supplementing the third corrected isoline graph into the first corrected isoline graph includes: The re-obtained first corrected isoline graph is obtained by supplementing the third corrected isoline graph while retaining the first corrected isoline graph.

3. The method according to claim 1, wherein, The dividing the geophysical anomaly isoline graph area into multiple parts with the same size for each part includes: Dividing the geophysical anomaly isoline graph into multiple rectangular blocks with the same size.

4. The method according to claim 3, wherein Including: S201: Compare the length and width of any one of the geophysical anomaly isoline graphs divided into rectangular blocks with the length and width of the preset graph; S202: If the length and width of any one of the geophysical anomaly isoline graphs divided into rectangular blocks are smaller than the length and width of the preset graph, then the second corrected isoline graph is the corrected geophysical anomaly isoline graph; S203: If the length or width of any of the geophysical anomaly isopleth maps divided into rectangular blocks is not less than the length or width of the preset map, re-divide the area of the geophysical anomaly isopleth map, perform interpolation processing on each re-divided geophysical anomaly isopleth map respectively to obtain a third corrected isopleth map, supplement the third corrected isopleth map into the first corrected isopleth map, execute step S104, re-obtain the second corrected isopleth map, and then compare the length and width of any of the geophysical anomaly isopleth maps divided into rectangular blocks with the length and width of the preset map, and repeat steps S201 - S203 until the length and width of any of the geophysical anomaly isopleth maps divided into rectangular blocks are less than the length and width of the preset map. Then, the re-obtained second corrected isopleth map is the corrected geophysical anomaly isopleth map.

5. The method according to claim 3, wherein, The re - division of the area of the geophysical anomaly isopleth map includes: Reduce the length and / or width of each geophysical anomaly isopleth map divided into rectangular blocks, and increase the number of the divided geophysical anomaly isopleth maps.

6. The method according to claim 1, wherein, The performing interpolation processing on each divided geophysical anomaly isopleth map respectively to obtain a first corrected isopleth map includes: Obtain the values and distributions of the isopleths in each divided geophysical anomaly isopleth map; According to the values and distributions of the isopleths in each divided geophysical anomaly isopleth map, perform interpolation processing on each divided geophysical anomaly isopleth map to obtain the first corrected isopleth map.

7. The method according to claim 1, wherein, The obtaining the second corrected isopleth map according to the geophysical anomaly isopleth map and the first corrected isopleth map includes: Obtain the values and distributions of the isopleths in the geophysical anomaly isopleth map; Obtain the values and distributions of the isopleths in the first corrected isopleth map; According to the values and distributions of the isopleths in the geophysical anomaly isopleth map and the values and distributions of the isopleths in the first corrected isopleth map, obtain the second corrected isopleth map.

8. The method according to claim 7, wherein, The obtaining the second corrected isopleth map according to the values and distributions of the isopleths in the geophysical anomaly isopleth map and the values and distributions of the isopleths in the first corrected isopleth map includes: (W T W+ β D T D)d u = W T Wd i Among them, W is the weight matrix, and the diagonal elements thereof are the inverse ratio of the distance between the points on the isoline in the second corrected isoline graph d u and the nearest point on the isoline in the geophysical anomaly isoline graph, d i is the first corrected isoline graph, W T is the transpose of W, D is the two-dimensional difference matrix of the W matrix, D T is the transpose of D, β is the regularization factor.

9. The method according to claim 8, wherein, The obtaining the second corrected isopleth map according to the geophysical anomaly isopleth map and the first corrected isopleth map includes: Obtain the second corrected isopleth map by the pre - conditioned conjugate gradient method.

10. The method according to claim 9, wherein, The obtaining the second corrected isopleth map by the pre - conditioned conjugate gradient method includes: When performing the pre - conditioned conjugate gradient method, when the number of iterations reaches the preset value, obtain the second corrected isopleth map according to the calculation result of this iteration.

11. The method according to claim 9, wherein, The obtaining the second corrected isopleth map by the pre - conditioned conjugate gradient method includes: Set an error threshold, obtain the error generated after each iteration when performing the preconditioned conjugate gradient method, and when the number of iterations reaches a preset value and / or the error is not greater than the error threshold, obtain the second corrected isogram according to the calculation result of this iteration.

12. The method according to claim 1, wherein, Interpolate each of the re-divided geophysical anomaly isograms to obtain a third corrected isogram, including: Obtain the values and distributions of the isograms in each of the re-divided geophysical anomaly isograms; Interpolate each of the re-divided geophysical anomaly isograms according to the values and distributions of the isograms in each of the re-divided geophysical anomaly isograms to obtain the third corrected isogram.

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