D-InSAR mining area settlement monitoring method and system based on optical flow method

Abstract

The invention provides a D-InSAR mining area settlement monitoring method and system based on an optical flow method.While a D-InSAR technology is utilized to obtain a mining area settlement result, the optical flow method is adopted to calculate an offset result of an intensity image before and after deformation of a mining area for a low-coherence and non-coherence area, and after geocoding, the offset result is indirectly converted into the settlement amount of an actual geographic position, so that the settlement amount of the mining area is calculated. Therefore, the defect of monitoring of a D-InSAR technology in a related area is overcome, and an accurate and complete mining area settlement monitoring result is obtained. Therefore, under the condition of a single radar data source, large-range monitoring data can be obtained through the InSAR technology, an accurate optical flow monitoring result can be obtained in an area where monitoring of the InSAR technology is insufficient, the capacity of rapidly obtaining the monitoring result is achieved, and meanwhile high-precision monitoring of mining area settlement in the whole range is achieved.

Description

Technical Field

[0001] The invention belongs to the field of mining area monitoring, and in particular relates to a D-InSAR mining area subsidence monitoring method and system based on an optical flow method. Background Art

[0002] The surface subsidence caused by mining has always attracted wide attention, and the monitoring of mining area subsidence is particularly important. Traditional monitoring methods are mainly based on ground leveling, which has a small monitoring range and monitors the subsidence at discrete points, and cannot meet the needs of large-scale and surface subsidence monitoring.

[0003] In recent years, with the development of InSAR (Interferometric Synthetic Aperture Radar) technology, it has achieved good results in monitoring terrain or deformation, with monitoring accuracy reaching millimeter level, and has achieved good application results in monitoring earthquakes, landslides, mining settlement and many other fields. D-InSAR technology (Differential Interferometric Synthetic Rader) is also called differential interferometric measurement technology, which uses the phase difference between two or more radar images to obtain surface deformation information. Compared with traditional ground leveling, D-InSAR technology has obvious advantages. It can cover a large area of ​​ground monitoring, especially suitable for mining areas with complex terrain and large areas, and can provide high-precision surface settlement information, making up for the shortcomings of traditional methods that can only measure discrete points. It can also work under severe weather and lighting conditions, and is not affected by time and climate, greatly improving the timeliness and reliability of monitoring. However, the current shortcomings of InSAR technology monitoring are that mining areas are covered with a lot of vegetation and subsidence areas are often covered with water, which has a great impact on the interference results. The images are also affected by factors such as spatial incoherence, temporal incoherence, and atmospheric noise during the interference process. Therefore, the monitoring accuracy in incoherence and large deformation areas is low. It is difficult to meet the monitoring needs in the complex environment of mining areas using only a single InSAR monitoring technology.

[0004] The optical flow method was originally applied to video data, mainly to monitor the changes in images between adjacent frames in a time series, and represented by vectors. The optical flow vector can be used to describe the displacement change of pixels in a very short time interval F = (u, v), so it can also characterize the instantaneous speed of the object's movement. When the optical flow vectors formed by all the pixels in a certain area converge together, an optical flow field is formed. The calculation algorithm of optical flow has been continuously improved and developed, and it plays an increasingly important role in the field of computer vision. It is widely used in moving target detection, target tracking, visual navigation, etc. in image sequences. Introducing the optical flow method into the calculation of the offset of mining area images is more suitable for optical flow estimation in areas with large deformations. It can obtain the horizontal offset of the mining area surface and provide monitoring data for mining area settlement.

[0005] In summary, the previous InSAR monitoring technology still has certain shortcomings in monitoring the incoherence and large deformation areas in mining areas. Recalculating the settlement in these areas based on the optical flow method can make up for the shortcomings of a single technology and obtain more complete monitoring data for mining areas.

[0006] Existing technologies for monitoring incoherent and large deformation areas in mining areas mostly use multi-source data such as ground leveling, GNSS measurement, and UAV photogrammetry to supplement. However, ground leveling requires a lot of manpower and material resources. GNSS measurement obtains point-based settlement rather than surface settlement information. The cost of obtaining multi-source data such as UAV photogrammetry is relatively high, which cannot meet the requirements of long-term monitoring of mining areas and large data volumes.

[0007] Prior art document 1 (CN 114114256A, application publication date 2022.03.01) discloses a large-area mining subsidence monitoring method based on D-InSAR-GIS overlay analysis technology. It includes: SAR image data processing, after phase transformation and geocoding, the absolute calibration and unwrapped phase is combined with the synthetic phase to convert it into deformation data. Then, the deformation data in the slant range projection coordinate system of SAR is converted to the mapping coordinate system through geocoding to obtain the deformation information in the LOS (radar line of sight) direction and the vertical direction.

[0008] Prior art document 2 (CN 111595293 A, application publication date 2020.08.28) provides a surface deformation monitoring method and system based on multi-source monitoring data fusion. The present invention adopts a collective Kalman filter assimilation method with high-precision leveling settlement data as the main body to realize the fusion of radar image differential surface element settlement results in the mining subsidence area and discrete measured leveling data, thereby realizing high-precision monitoring of the mining area.

[0009] Prior art document 1 monitors the settlement of the working face in the mining area based on the D-InSAR GIS overlay analysis technology. Its essence is still to obtain monitoring data using the D-InSAR technology, but the settlement results are overlaid with the vector data of the working face in the mining area for analysis during the analysis process. Therefore, there is still the problem of insufficient monitoring by a single D-InSAR technology. Prior art document 2 improves the monitoring accuracy by means of multi-source data fusion, but this method requires leveling data of the mining area, and the leveling data requires manual field measurement, and cannot be updated synchronously with the remote sensing image data, so its applicability is limited. The present invention adopts the method of combining D-InSAR technology with the optical flow method to obtain monitoring data. A single radar image data source can be used, and the acquisition is relatively convenient. At the same time, the optical flow method can make up for the shortcomings of D-InSAR technology in monitoring decoherence or large-scale deformation areas, thereby obtaining more comprehensive and rich deformation monitoring information. Summary of the invention

[0010] In order to solve the deficiencies in the prior art, the present invention provides a D-InSAR monitoring method for mining area subsidence based on the optical flow method. On the basis of obtaining the mining area deformation by D-InSAR technology, the optical flow method is used to recalculate the settlement of the area for the decoherence and large deformation areas, thereby making up for the insufficient deformation monitoring accuracy of the single D-InSAR technology in these areas.

[0011] The present invention adopts the following technical solution.

[0012] A D-InSAR mining area subsidence monitoring method based on optical flow method, characterized by comprising:

[0013] Two radar images S1 and S2 of the mining area before and after the set time period are obtained, and the D-InSAR technology is used to process them to obtain the settlement map of the mining area within the set time period, and the boundaries of the incoherent areas in the settlement map are preliminarily extracted. The settlement results of the incoherent areas are supplemented by the optical flow method to obtain the horizontal offset of the surface of the mining area within the set time period; the horizontal offset is geocoded and converted into actual vertical settlement data, the incoherent areas are further extracted from the actual vertical settlement data, and the settlement data obtained by the D-InSAR technology and the supplemented optical flow settlement data are image mosaicked and fused.

[0014] Preferably, the process of processing the image using D-InSAR technology includes registration, interference, filtering, unwrapping, phase transformation and geocoding.

[0015] Preferably, the set time period is 10-20 days.

[0016] Preferably, the acquired mining area settlement map is a settlement map in the radar line of sight within a set time period.

[0017] Preferably, the optical flow method is used to calculate the offset of the radar intensity image and convert it into the surface settlement. The intensity data of radar images S1 and S2 are extracted and projected to the geographic coordinate system. The optical flow vector of each pixel point is calculated to obtain the horizontal offset of the surface of the mining area within the set time period.

[0018] Preferably, the horizontal offset is geocoded, and the image offset without coordinate information after the optical flow method is calculated is converted to the actual geographical location to obtain the horizontal offset at the actual geographical location.

[0019] Preferably, the horizontal offset after geocoding is converted into actual vertical settlement data, where m is the horizontal offset calculated by the optical flow method, h is the actual vertical settlement, θ is the radar incident angle, and β is the angle between the horizontal offset direction and the range direction.

[0020] The present invention also provides a D-InSAR mining area subsidence monitoring system based on the optical flow method, the system is a system used by the aforementioned D-InSAR mining area subsidence monitoring method based on the optical flow method, comprising:

[0021] The collection module is used to obtain radar images of the mining area before and after the mining area;

[0022] The analysis module is used to perform preliminary analysis on radar images using D-InSAR technology and extract the boundaries of the decoherent regions in the subsidence map;

[0023] The calculation module is used to supplement the settlement results of the decoherent area using the optical flow method.

[0024] The present invention also provides a terminal, including a processor and a storage medium; the characteristics are:

[0025] The storage medium is used to store instructions;

[0026] The processor is configured to operate according to the instructions to execute the steps according to the aforementioned method.

[0027] The present invention also provides a computer-readable storage medium on which a computer program is stored, characterized in that the program implements the steps of the above method when executed by a processor.

[0028] The beneficial effect of the present invention is that, compared with the prior art, the method adopted by the present invention does not need to fuse multi-source data, and a single radar data source can make up for the shortcomings of D-InSAR technology in monitoring decoherence and large deformation areas, and it is faster and more efficient to obtain mining area settlement monitoring data. It is difficult to obtain multi-source data, such as leveling data, GNSS measurement, UAV photogrammetry, etc., which consumes more manpower and material resources. In addition, the update time of these multi-source data is relatively lagging, and it cannot be updated synchronously with remote sensing image data, and it is difficult to obtain the monitoring results of the mining area in the most recent time period, and its scope of application is relatively small. When using D-InSAR technology to process radar data to obtain deformation information, the traditional D-InSAR technology has large monitoring errors and cannot achieve effective monitoring when processing decoherence and large deformation areas. Therefore, this paper uses optical flow method to process radar image data for these monitoring errors that are large and cannot achieve effective monitoring areas, and indirectly extracts settlement results to supplement the measurement content of this part. In this way, the mining area settlement monitoring results of the most recent time can be quickly obtained, and the shortcomings of traditional D-InSAR technology in monitoring can be made up.

[0029] The present invention proposes a D-InSAR mining area settlement monitoring method and system based on the optical flow method. While using the D-InSAR technology to obtain the mining area settlement results, the optical flow method is used to calculate the offset results of the intensity image before and after the mining area deformation for low coherence and incoherence areas. After geocoding, it is indirectly converted into the settlement amount of the actual geographical location, thereby making up for the shortcomings of D-InSAR technology in monitoring related areas and obtaining accurate and complete mining area settlement monitoring results. In this way, under the condition of a single radar data source, it is possible to obtain a large range of monitoring data through the InSAR technology, and to obtain accurate optical flow monitoring results in areas where the InSAR technology is insufficiently monitored. While having the ability to quickly obtain monitoring results, high-precision monitoring of the entire range of mining area settlement is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a technical flow chart of the method of the present invention;

[0031] Figure 2 Schematic diagram of converting the horizontal monitoring quantity of the optical flow method into the actual vertical monitoring quantity. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The embodiments described in this application are only part of the embodiments of the present invention, not all of them. Based on the spirit of the present invention, other embodiments obtained by ordinary technicians in this field without creative work are all within the scope of protection of the present invention.

[0033] The purpose of the present invention is to address the above problems and provide a D-InSAR monitoring method for mining area subsidence based on the optical flow method. On the basis of obtaining the mining area deformation using the D-InSAR technology, the optical flow method is used to recalculate the settlement of the area for the decoherent and large deformation areas, thereby making up for the lack of deformation monitoring accuracy of the single D-InSAR technology in these areas.

[0034] Embodiment 1 of the present invention provides a D-InSAR monitoring method for mining area subsidence based on an optical flow method, comprising:

[0035] Step 1: Obtain two radar images S1 and S2 before and after the mining area under study;

[0036] Step 2: Use D-InSAR technology to process the synthetic aperture radar (SAR) images of the mining area. By registering, interfering, filtering, unwrapping, phase transformation and geocoding the images, the settlement map of the mining area in the LOS direction (radar line of sight) during the time period is obtained and converted into the actual settlement result map.

[0037] Step 3, extract the incoherent area from the settlement map obtained by D-InSAR technology. Mining areas are usually covered with more vegetation, and there are certain waterlogging areas or areas with large deformation gradients. In these areas, the reflected signals of radar waves are weak or unstable, causing the incoherence of the interference image. In the settlement result map, the incoherent area is masked as a null value during the interference process. The masking process refers to shielding the area in the image whose coherence value is lower than the preset threshold, effectively eliminating the interference of the low coherence area on the subsequent image analysis and processing, making the processing results more accurate and reliable.

[0038] Select the approximate range of the incoherence area in the settlement result map, and use the shp vector to draw the boundary of the incoherence area on the ArcGis platform.

[0039] Step 4, supplement the settlement results of the decoherent area. The D-InSAR technology is used to process radar images. Its essence is to extract deformation information from the phase information of the radar image. Its basic principle is to perform differential interference processing on the two images, that is, phase subtraction, and obtain the differential interference phase. Then, by removing the terrain phase, atmospheric phase, noise phase, etc., the deformation phase is further extracted to obtain the deformation information. In this way, in the low coherence and decoherent areas, the deformation monitoring results obtained have large errors and cannot reflect the actual settlement situation. Therefore, for these areas, the deformation amount cannot be extracted from the phase information. The intensity information in the radar image can also reflect the basic information characteristics of the object, and can be indirectly converted into the actual settlement amount by calculating the horizontal offset of the intensity image. Therefore, the present invention chooses to complete the monitoring of the low coherence and decoherent areas based on the optical flow method to supplement the shortcomings of the D-InSAR technology monitoring.

[0040] However, the intensity information in radar images may not necessarily reflect the information characteristics of ground objects. The offset of radar intensity images calculated using the optical flow method can be indirectly converted into the amount of surface settlement.

[0041] Radar intensity images are used to indicate the strength of the backscattering energy of radar waves from ground objects, and can reflect the information characteristics of ground objects. Therefore, in order to calculate the displacement of the mining area surface in the image, the intensity data of the two-view SAR images of the mining area are extracted and projected into the geographic coordinate system, and then the two-view intensity images before and after the deformation of the mining area are processed using the optical flow method. The "Classic+NL" algorithm is used to calculate the optical flow vector of each pixel point of the two-view images of the mining area, that is, to obtain the horizontal displacement of the mining area surface during this time period.

[0042] Step 5: Geocode the horizontal offset, convert the image offset without coordinate information calculated by the optical flow method to the actual geographical location, and obtain the horizontal offset at the actual geographical location. The optical flow method calculates the offset of the radar intensity image, and geocoding is required to convert it to the actual geographical coordinate position.

[0043] Step 6: Figure 2 As shown in the figure, the horizontal offset of the radar intensity image calculated by the optical flow method after geocoding is converted into the actual vertical settlement data, where m is the horizontal offset calculated by the optical flow method, h is the actual vertical settlement, θ is the known radar incident angle, and β is the angle between the horizontal offset direction and the range direction. In the result of the calculation using "Classic+NL", m = (u, v), u is the offset component in the range direction, and v is the offset component in the azimuth direction, then

[0044] Step 7: Extract the data of the decoherent area from the converted settlement data. According to the decoherent area boundary that has been drawn, select the approximate range of the area that needs additional monitoring. Then, in the ArcGis platform, extract the corresponding area from the image results calculated by the optical flow method according to the drawn vector range.

[0045] Step 8: Perform image mosaic fusion on the settlement amount obtained by D-InSAR technology and the settlement monitoring amount supplemented by the optical flow method. The settlement amount obtained by D-InSAR technology is null in the decoherence area or large deformation area, while the settlement monitoring amount of the optical flow method can be appropriately supplemented in these null areas. The combination of the two can obtain more complete mining area settlement monitoring data.

[0046] Embodiment 2 of the present invention provides a D-InSAR mining area subsidence monitoring system based on the optical flow method, and the system is a system used in the D-InSAR mining area subsidence monitoring method based on the optical flow method described in any one of claims 1 to 7, comprising:

[0047] The collection module is used to obtain radar images of the mining area before and after the mining area;

[0048] The analysis module is used to perform preliminary analysis on radar images using D-InSAR technology and extract the boundaries of the decoherent regions in the subsidence map;

[0049] The calculation module is used to supplement the settlement results of the decoherent area using the optical flow method.

[0050] Preferably, the system also includes a monitoring module and a feedback module. The monitoring module is used to monitor the entire mining area settlement monitoring process. When it is detected that any link does not meet the set standards, the corresponding error information is sent to the feedback module, and the feedback module makes corresponding adjustments to the system structure based on the error information.

[0051] Example 3

[0052] A. Obtain radar images of the study mining area before and after the scene.

[0053] At present, the radar data obtained in the mining area is mainly the Sentinel-1 satellite data that can be downloaded for free from the official website of the European Space Agency. It has a revisit period of 12 days, an image resolution of 10m, a wide coverage area, and relatively easy data acquisition.

[0054] B. Use D-InSAR technology to process SAR images of mining areas.

[0055] The D-InSAR technology is used to process the two SAR image data before and after the deformation of the mining area. The open source GMTSAR software is used to perform interference processing on the two SAR images. After interference, filtering, unwrapping, phase transformation, geocoding and other steps, the settlement monitoring results are obtained. The deformation result of the radar LOS direction is recorded as h', and the radar incident angle is θ. The actual vertical settlement amount is The vertical settlement map can be obtained through raster calculation tools on the ArcGIS platform.

[0056] C. Extraction of incoherence areas from the sedimentation map obtained using InSAR technology.

[0057] According to the settlement map obtained by D-InSAR technology, the areas with more serious incoherence are extracted. The coherence value is generally 0-1. The closer the value is to 0, the lower the coherence and the less accurate the result. The closer the value is to 1, the higher the coherence and the more accurate the result. Such areas are usually unable to obtain more accurate measurements due to vegetation coverage, waterlogging or large deformation gradients, and additional monitoring is required. In the settlement map of the mining area obtained, these areas are displayed as null values ​​due to the setting of the coherence threshold mask in the early interference processing process. The coherence threshold is also 0-1. After setting the threshold, the area with coherence below this threshold is shielded. The monitoring results of this area are generally set to null values, showing a local blank area in the image. After determining the approximate range of the incoherence area, the boundary of the incoherence area can be drawn with vectors on the ArcGIS platform.

[0058] D. Obtain the horizontal offset result of the incoherent area based on the optical flow method.

[0059] During the interferometric processing, the intensity image after SAR image registration can be extracted. The horizontal offset result of the mining area surface can be obtained by calculating the two radar intensity images according to the classic "Classic+NL" algorithm program in the open source optical flow method.

[0060] The dense optical flow method HS is one of the most classic optical flow algorithms. Most of the algorithms developed later are based on its improvements. Among them, the "Classic+NL" algorithm shows good computing performance. This algorithm can also handle optical flows with large displacements to a certain extent. According to the dense optical flow algorithm HS, the velocity vector of each pixel point in the image can be calculated. The amount of calculation will be relatively large, but it can obtain rich motion field details information of the image.

[0061] The optical flow method detects the displacement changes of each pixel point for images in different phases, and expresses the pixel offset in the form of a vector. Optical flow characterizes the displacement changes of pixel points in the previous and next phases, including both size and direction. The optical flows of all pixel points converge to form an optical flow field. The optical flow method can detect the movement changes of pixels, which are expressed in the form of displacement vectors and can be applied to pixel change detection. It has many applications in computer vision and other fields. The calculated optical flow result can be expressed as (u, v), where u and v are the offset results in the distance and azimuth directions respectively.

[0062] Applying the concepts and methods of optical flow method to the field of mining area subsidence remote sensing image processing can play its role in detecting surface displacement changes. It can be used to monitor surface displacement changes in mining areas and provide important reference value for geological disaster prevention and scientific decision-making in mining areas.

[0063] E. Geocoding the optical flow results

[0064] The optical flow result is represented by (u, v). After the actual required u vector is extracted and saved as a tiff format image, it can be geocoded in the GMTSAR software. According to the conversion relationship between the radar coordinate system and the geographic coordinate system of the original intensity image, the u image can be projected to the corresponding geographical location.

[0065] F. Conversion of the optical flow calculation results after geocoding into actual settlement

[0066] The optical flow method only calculates the displacement result of the surface level of the mining area, but not the actual settlement result of the mining area, which needs to be converted to a certain extent. Figure 2 , the horizontal offset of any point on the surface of the mining area is m, the angle between it and the radar range direction is β, the actual vertical settlement is h, and the incident angle of the radar is θ, then it can be calculated If m=(u,v), then Among them, the radar incident angle θ can be directly found out based on the radar image data. According to this formula, the horizontal offset result calculated by the optical flow method can be converted into the actual vertical settlement.

[0067] G. Extract the data of the decoherence area from the converted sedimentation data.

[0068] After obtaining the vector boundary of the decoherence area, the vector boundary of the research area of ​​actual interest is selected from it and used as the approximate range of the supplementary settlement monitoring area. Based on the vector data, the settlement monitoring results of the corresponding area are extracted again from the settlement map obtained by the optical flow method on the ArcGIS platform.

[0069] Monitoring results.

[0070] H. Fusion of the subsidence results obtained by D-InSAR technology with supplementary subsidence monitoring results.

[0071] The highly correlated mining area subsidence result map obtained by D-InSAR technology is mosaicked and fused with the incoherent area subsidence result map calculated by optical flow method. The mosaicking and fusion function of the two images can be realized in ArcGIS platform, so as to obtain the subsidence monitoring results in the complete range of mining area.

[0072] Calculating the horizontal offset of the mining area according to the optical flow method can supplement the shortcomings of single D-InSAR technology monitoring. This article only lists the method of using radar intensity images for optical flow calculation. The optical flow method can also be calculated using the high-precision optical images of the mining area, which can also achieve the purpose of the present invention.

[0073] The beneficial effect of the present invention is that, compared with the prior art, the method adopted by the present invention does not need to fuse multi-source data, and a single radar data source can make up for the shortcomings of D-InSAR technology in monitoring decoherence and large deformation areas, and it is faster and more efficient to obtain mining area settlement monitoring data. It is difficult to obtain multi-source data, such as leveling data, GNSS measurement, UAV photogrammetry, etc., which consumes more manpower and material resources. In addition, the update time of these multi-source data is relatively lagging, and it is impossible to update synchronously with remote sensing image data, and it is difficult to obtain the monitoring results of the mining area in the most recent time period, and its scope of application is relatively small. When using D-InSAR technology to process radar data to obtain deformation information, traditional D-InSAR technology has problems such as large monitoring errors and inability to achieve effective monitoring when processing decoherence and large deformation areas. Therefore, this paper uses optical flow method to process radar image data for these monitoring errors and inability to achieve effective monitoring areas, and indirectly extracts settlement results to supplement the measurement content of this part. In this way, we can not only quickly obtain the most recent mining area subsidence monitoring results, but also make up for the shortcomings of traditional D-InSAR technology in monitoring.

[0074] The present invention proposes a D-InSAR mining area settlement monitoring method and system based on the optical flow method. While using the D-InSAR technology to obtain the mining area settlement results, the optical flow method is used to calculate the offset results of the intensity image before and after the mining area deformation for low coherence and incoherence areas. After geocoding, it is indirectly converted into the settlement amount of the actual geographical location, thereby making up for the shortcomings of D-InSAR technology in monitoring related areas and obtaining accurate and complete mining area settlement monitoring results. In this way, under the condition of a single radar data source, it is possible to obtain a large range of monitoring data through the InSAR technology, and to obtain accurate optical flow monitoring results in areas where the InSAR technology is insufficiently monitored. While having the ability to quickly obtain monitoring results, high-precision monitoring of the entire range of mining area settlement is achieved.

[0075] The present disclosure may be a system, a method and / or a computer program product. The computer program product may include a computer-readable storage medium carrying computer-readable program instructions for causing a processor to implement various aspects of the present disclosure.

[0076] A computer-readable storage medium may be a tangible device that can hold and store instructions used by an instruction execution device. A computer-readable storage medium may be, for example, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. More specific examples of computer-readable storage media (a non-exhaustive list) include: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disk read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanical encoding device, such as a punch card or a raised structure in a groove on which instructions are stored, and any suitable combination of the foregoing. As used herein, a computer-readable storage medium is not to be interpreted as a transient signal per se, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission medium (e.g., a light pulse through a fiber optic cable), or an electrical signal transmitted through a wire.

[0077] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to each computing / processing device, or downloaded to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network can include copper transmission cables, optical fiber transmissions, wireless transmissions, routers, firewalls, switches, gateway computers, and / or edge servers. The network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in the computer-readable storage medium in each computing / processing device.

[0078] The computer program instructions for performing the operation of the present disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-related instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages, such as Smalltalk, C++, etc., and conventional procedural programming languages, such as "C" language or similar programming languages. Computer-readable program instructions may be executed completely on a user's computer, partially on a user's computer, as an independent software package, partially on a user's computer, partially on a remote computer, or completely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., using an Internet service provider to connect via the Internet). In some embodiments, an electronic circuit, such as a programmable logic circuit, a field programmable gate array (FPGA), or a programmable logic array (PLA), may be customized by utilizing the state information of the computer-readable program instructions, and the electronic circuit may execute the computer-readable program instructions, thereby realizing various aspects of the present disclosure.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A D-InSAR mining area subsidence monitoring method based on optical flow method, characterized in that: include: Two radar images S1 and S2 of the mining area before and after the set time period are obtained, and the D-InSAR technology is used to process them to obtain the settlement map of the mining area within the set time period, and the boundaries of the incoherent areas in the settlement map are preliminarily extracted. The settlement results of the incoherent areas are supplemented by the optical flow method to obtain the horizontal offset of the surface of the mining area within the set time period; the horizontal offset is geocoded and converted into actual vertical settlement data, the incoherent areas are further extracted from the actual vertical settlement data, and the settlement data obtained by the D-InSAR technology and the supplemented optical flow settlement data are image mosaicked and fused.

2. The D-InSAR mining area subsidence monitoring method based on optical flow method according to claim 1 is characterized in that: The process of processing the image using the D-InSAR technology includes registration, interference, filtering, unwrapping, phase transformation and geocoding.

3. The D-InSAR mining area subsidence monitoring method based on optical flow method according to claim 2 is characterized in that: The set time period is 10-20 days.

4. The D-InSAR mining area subsidence monitoring method based on optical flow method according to claim 3 is characterized in that: The obtained mining area subsidence map is a subsidence map in the radar line of sight within a set time period.

5. The D-InSAR mining area subsidence monitoring method based on optical flow method according to claim 4 is characterized in that: The optical flow method is used to calculate the offset of the radar intensity image and convert it into the surface settlement. The intensity data of radar images S1 and S2 are extracted and projected into the geographic coordinate system. The optical flow vector of each pixel point is calculated to obtain the horizontal offset of the surface of the mining area within the set time period.

6. The D-InSAR mining area subsidence monitoring method based on optical flow method according to claim 5 is characterized in that: The horizontal offset is geocoded, and the image offset without coordinate information after optical flow calculation is converted to the actual geographical location to obtain the horizontal offset at the actual geographical location.

7. The D-InSAR mining area subsidence monitoring method based on optical flow method according to claim 6 is characterized in that: The horizontal offset after geocoding is converted into the actual vertical settlement data, where m is the horizontal offset calculated by the optical flow method, h is the actual vertical settlement, θ is the radar incident angle, and β is the angle between the horizontal offset direction and the range direction.

8. A D-InSAR mining area subsidence monitoring system based on optical flow method, the system being the system used in the D-InSAR mining area subsidence monitoring method based on optical flow method as claimed in any one of claims 1 to 7, comprising: The collection module is used to obtain radar images of the mining area before and after the mining area; The analysis module is used to perform preliminary analysis on radar images using D-InSAR technology and extract the boundaries of the decoherent regions in the subsidence map; The calculation module is used to supplement the settlement results of the decoherent area using the optical flow method.

9. A terminal comprising a processor and a storage medium; characterized in that: The storage medium is used to store instructions; The processor is configured to operate according to the instructions to execute the steps of the method according to any one of claims 1-8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

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