A method for analyzing changes in mountain volume and for calculating explosive equivalent.

Abstract

This invention proposes a method for analyzing the volume change of a mountain and a method for analyzing explosive equivalent. The method utilizes DEM data to establish an initial three-dimensional model of the target mountain; it uses InSAR to acquire at least three pairs of SAR images of the target mountain from different line-of-sight directions, forming at least three interferograms; it reads the coordinate information of each pixel in the difference result corresponding to each interferogram, obtaining three displacement vector matrices for each direction; it calculates the deformation component of each pixel in the spatial rectangular coordinate system for each value in the displacement vector matrix; it establishes a new three-dimensional model of the target mountain based on the deformation component of each pixel in the spatial rectangular coordinate system; and it calculates the difference between the initial three-dimensional model and the new three-dimensional model of the target mountain to obtain the volume change of the target mountain. This invention overcomes the problem of traditional methods failing to clearly distinguish the boundaries of the blast range.

Description

Technical Field

[0001] This invention relates to the field of microwave remote sensing technology, specifically to a method for analyzing changes in mountain volume and a method for analyzing explosive equivalent. Background Technology

[0002] Currently, InSAR methods are commonly used to study surface subsidence changes. While InSAR technology can achieve millimeter-level accuracy when processing high-quality microwave remote sensing imagery, researchers can only obtain surface changes along the image's direction. This data cannot replace standardized engineering techniques such as elevation, horizontal displacement, and volumetric changes. For example, when analyzing the explosive yield of a bomb, if the bomb is detonated on a target mountain, although InSAR can calculate the deformation of each surface unit along the image's direction, it cannot effectively represent the horizontal displacement and vertical subsidence caused by the explosion. Therefore, when determining the impact area of ​​a nuclear test, it is difficult to clearly distinguish the boundaries of the blast zone and estimate the volumetric changes caused by the explosion. Summary of the Invention

[0003] In order to overcome the defects existing in the prior art, the purpose of this invention is to provide a method for analyzing changes in mountain volume and a method for analyzing explosive equivalent.

[0004] To achieve the above-mentioned objectives of this invention, this invention provides a method for analyzing changes in mountain volume, comprising the following steps:

[0005] An initial three-dimensional model of the target mountain was established based on DEM data;

[0006] Using InSAR, at least three interferograms are formed by acquiring at least three pairs of SAR images of the target mountain from different line-of-sight directions. The coordinate information of each pixel in the difference result corresponding to each interferogram is read to obtain three displacement vector matrices in their respective directions.

[0007] Each value in the displacement vector matrix is ​​calculated individually to obtain the deformation components of each pixel in the spatial rectangular coordinate system;

[0008] A new three-dimensional model of the target mountain is established based on the deformation components of each pixel in the spatial rectangular coordinate system.

[0009] The volume change of the target mountain is obtained by subtracting the initial three-dimensional model of the target mountain from the new three-dimensional model of the target mountain.

[0010] Optionally, the transformation matrix L between the three interferogram coordinate systems and the spatial rectangular coordinate system can be obtained based on the angular relationship between the three pairs of SAR images;

[0011] The transformation matrix L is used to transform the displacement vector matrix of each pixel in the three interferogram coordinate systems to the spatial rectangular coordinate system:

[0012] D = L -1 R,

[0013] D is the coordinate system in a spatial rectangular coordinate system, and R is the displacement vector matrix.

[0014] Optionally, select a point that corresponds one-to-one with each pixel of dem, and calculate the deformation component of each point in the spatial rectangular coordinate system.

[0015] Optionally, the transformation matrix is:

[0016]

[0017] Where, θ i (i = 1, 2, 3) correspond to the local incident angle of each pair of SAR images in the three pairs of SAR images, α i (i = 1, 2, 3) are the satellite headings projected onto a horizontal plane measured clockwise from the north.

[0018] This invention also proposes an explosion equivalent analysis method, which calculates the change in the volume of the target mountain before and after the explosion based on the above-mentioned method for calculating the change in mountain volume, and calculates the explosion equivalent based on the change in volume.

[0019] The beneficial effects of this invention are:

[0020] This invention combines DEM data and InSAR methods to analyze the volume changes of a target mountain by establishing an initial 3D model and a new 3D model of the target mountain and calculating the volume difference between the two 3D models. It can understand the detailed geographical information changes of a region without physically visiting it. At the same time, it overcomes the problems of InSAR methods, such as the mismatch between the results and the coordinate system commonly used by engineering departments, the difficulty in quantifying volume changes, and the inability to clearly distinguish the boundaries of the blast range.

[0021] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0022] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0023] Figure 1 This is a flowchart illustrating the present invention;

[0024] Figures 2 to 4The images are three pairs of ALOS-2 images from the same location, generating land subsidence maps in different directions (one pair is a descending trajectory, which needs to be reversed).

[0025] Figure 5 This is a schematic diagram of the initial three-dimensional model of the target mountain before the explosion;

[0026] Figure 6 It is a 3D model of the target mountain after the explosion;

[0027] Figure 7 It is a visual diagram showing the volume change of the target mountain after the explosion. Detailed Implementation

[0028] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0029] In the description of this invention, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two components. They can be direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0030] Example 1

[0031] like Figure 1 As shown in the figure, this embodiment provides a method for calculating the volume change of a mountain after an explosion, specifically including the following steps:

[0032] Since the DEM data available for the deformed portion of the target mountain area in this embodiment consists of only 40,000 to 50,000 pixels, 40,000 points of 200×200 pixels are extracted from the explosion area according to the average pattern as representative of the deformation of the deformation area.

[0033] First, using DEM data as a foundation, an initial three-dimensional model of the target mountain is established using the DEM data of the target mountain before the explosion, such as... Figure 5 As shown, the position and elevation information represented by each pixel in the initial 3D model is read.

[0034] Then, using InSAR, at least three interferograms are formed by at least three pairs of SAR images of the target mountain from different line-of-sight directions, such as... Figures 2 to 4As shown. The coordinate information of each pixel in the difference result corresponding to each interferogram is read to obtain at least three displacement vector matrices in their respective directions. Since each number in the displacement vector matrix represents the displacement of a single pixel in the line-of-sight direction, and the position represented by the number corresponds to the latitude and longitude of that pixel, the coordinate information of each pixel is its latitude and longitude position. The latitude and longitude grid forms the x-axis and y-axis of a spatial rectangular coordinate system. The pixel, as the smallest calculable unit in a high-resolution image, yields the z-axis change value in the spatial rectangular coordinate system through calculation of its displacement vector value. Therefore, the deformation component of each pixel in the spatial rectangular coordinate system is calculated for each displacement vector matrix. The specific calculation steps are as follows:

[0035] Taking three displacement vector matrices as an example, the displacement vectors of the three interferograms obtained from three pairs of SAR images can be represented as a matrix, which is a matrix with one column and three rows, denoted by R, R = [r1, r2, r3]. T r1, r2, and r3 are pixel values, representing displacements in directions specific to the interferogram. This matrix does not include coordinates, i.e., it does not include latitude and longitude. The matrix contains only three numbers. For example, in this embodiment, there are 40,000 pixels, so there are 40,000 matrices. These 40,000 matrices need to be calculated separately.

[0036] Based on the angular relationship between the three pairs of SAR images, the transformation matrix L between the three interferogram coordinate systems and the spatial rectangular coordinate system is obtained.

[0037]

[0038] Where, θ i (i = 1, 2, 3) correspond to the local incident angle of each pair of SAR images in the three pairs of SAR images, α i (i = 1, 2, 3) are the satellite headings projected onto a horizontal plane measured clockwise from the north.

[0039] The transformation matrix L is used to transform the displacement vector matrix of each pixel in the three interferogram coordinate systems to the spatial rectangular coordinate system:

[0040] D = L -1 R,

[0041] D is the coordinate [xyz] in a spatial rectangular coordinate system. T R is the displacement vector matrix.

[0042] In this embodiment,

[0043] For the dataset in this embodiment, L is calculated from the spatial positional relationships of the three interferograms: the ascending pair acquired on July 27, 2017 and September 7, 2017; the rising pair acquired on August 29, 2017 and September 12, 2017; and the descending pair acquired on August 31, 2017 and September 28, 2017. In this case, the specific formula for calculating the deformation of a single pixel in the x, y, and z directions in the spatial rectangular coordinate system is as follows:

[0044]

[0045] After performing InSAR processing on three SAR image pairs from different directions, the ArgGIS tool is used to select points that correspond one-to-one with each pixel of the DEM, i.e., pixels with the same latitude and longitude, and the deformation components of each corresponding pixel in the spatial rectangular coordinate system are calculated.

[0046] A new 3D model of the target mountain is established based on the deformation components of each pixel in the Cartesian coordinate system, such as... Figure 6 As shown.

[0047] The volume change of the target mountain is obtained by subtracting the initial 3D model from the new 3D model of the target mountain. Figure 7 As shown, the volume change of the area before and after the explosion was calculated to be 0.058 cubic kilometers.

[0048] Example 2

[0049] This embodiment provides a method for calculating explosive yield, which calculates the change in the volume of the target mountain before and after the explosion based on the method for calculating the change in mountain volume described in Embodiment 1, and calculates the explosive yield based on the calculated volume change.

[0050] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0051] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A method of calculating a volume change of a mountain, characterized by, The method comprises the following steps: An initial three-dimensional model of the target mountain is established based on DEM data; At least three interferograms are obtained by using InSAR to obtain at least three pairs of SAR images of the target mountain in different line-of-sight directions, and coordinate information of each pixel point in a differential result corresponding to each interferogram is read to obtain three displacement vector matrices in respective directions; Each value in the displacement vector matrix is calculated to obtain a deformation component of each pixel point in a space rectangular coordinate system; A new three-dimensional model of the target mountain is established according to the deformation component of each pixel point in the space rectangular coordinate system; The initial three-dimensional model of the target mountain and the new three-dimensional model of the target mountain are subtracted to obtain a volume change of the target mountain.

2. The method according to claim 1, wherein a conversion matrix L between the three interferogram coordinate systems and the space rectangular coordinate system is obtained according to an angle relationship between the three pairs of SAR images; the displacement vector matrix of each pixel point in the three interferogram coordinate systems is converted to the space rectangular coordinate system by using the conversion matrix L: D is a coordinate in the space rectangular coordinate system, and R is the displacement vector matrix. D = L -1 R, A point corresponding to each pixel of the DEM is selected, and a deformation component of each point in the space rectangular coordinate system is calculated.

3. The mountain volume change calculation method according to claim 2, characterized by, The conversion matrix is:

4. The mountain volume change calculation method according to claim 2, characterized by, The volume change of the target mountain before and after the explosion is calculated by using the method according to any one of claims 1-4, and the equivalent of the explosion is calculated according to the volume change. where θ i (i = 1, 2, 3) corresponds to the local incidence angle of each pair of SAR images, and α i (i = 1, 2, 3) are the satellite headings projected on the horizontal plane measured clockwise from North, respectively.

5. A method of calculating an explosion equivalent, characterized by, ​

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