Opencast coal mine safety detection and production evaluation method based on unmanned aerial vehicle surveying and mapping

Abstract

The invention provides an open pit coal mine safety detection and production evaluation method based on unmanned aerial vehicle surveying and mapping. The method comprises the steps of obtaining surveying and mapping data of a target mine field through unmanned aerial vehicle oblique photography surveying and mapping; obtaining geographic information data including a digital orthoimage, a digital elevation model, an oblique photography model and digital vector data based on the surveying and mapping data; constructing a three-dimensional digital twinborn scene of the target mine field based on the geographic information data; performing profile detection on the three-dimensional digital twinborn scene, constructing a vertical profile, and performing safety detection on the slope angle, the step height and the width based on the vertical profile; and performing filling or excavation measurement on the coal mining area, the coal piling area or the soil piling area of the target mining area, and calculating the volume to obtain a production evaluation result. The problems that in the prior art, a geographic surveying and mapping method is low in efficiency and disordered in data, and a safety detection and production evaluation method depends on detection equipment, so that safety detection and production evaluation of open pit coal mining are poor in accuracy and low in efficiency are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of three-dimensional geographic information spatial analysis, and in particular relates to an open-pit coal mine safety detection and production assessment method based on unmanned aerial vehicle mapping. Background Art

[0002] In the process of open-pit coal mining, the ore rock is usually divided into horizontal layers of a certain thickness, and mined layer by layer from top to bottom, maintaining a certain advance relationship. During the mining process, each working platform is stepped in space, each step is a platform, and there is a slope between the platforms. For safety reasons, the slope of the slope needs to be strictly limited in mining operations to prevent landslides. In addition, in the process of open-pit coal mining, it is necessary to conduct a production assessment of the mining process in advance, and accurately calculate the earthwork volume in the coal pile area, earth pile area or mining area, so as to generate a plan arrangement and resource scheduling for coal mining work, ensure the smooth progress of coal mining work, and improve the efficiency of coal mining work.

[0003] However, traditional open-pit coal mining safety inspections and production assessments often require personnel to enter dangerous areas to perform operations, which poses a high safety risk and has low work efficiency. It is also restricted by natural conditions such as terrain and climate, which can easily lead to data loss. The existing geographic surveying and mapping data used for open-pit coal mining safety inspections and production assessments have problems such as difficulty in data sharing, chaotic data structure, incomplete information, and untimely updates, which lead to large differences between the surveying and mapping data results and the actual terrain. In addition, the existing safety inspection and production assessment methods rely on the functions of the detection equipment. Traditional geographic surveying and mapping methods and detection and assessment methods greatly limit the accuracy and detection efficiency of safety inspections and production assessments for open-pit coal mining. Summary of the invention

[0004] In view of the above analysis, the present invention aims to provide an open-pit coal mine safety inspection and production assessment method based on UAV mapping, which is used to solve the problems of low efficiency and chaotic data in the prior art geographical surveying and mapping methods, and the safety inspection and production assessment methods relying on detection equipment, resulting in poor accuracy and low efficiency in safety inspection and production assessment of open-pit coal mining.

[0005] The purpose of the present invention is mainly achieved through the following technical solutions:

[0006] In one aspect, the present invention provides a method for open-pit coal mine safety detection and production assessment based on drone mapping, the method comprising: acquiring mapping data of a target mine site through drone oblique photogrammetry;

[0007] Performing aerial triangulation on the surveying and mapping data to obtain geographic information data including digital orthophotos, digital elevation models, oblique photography models and digitized vector data;

[0008] Constructing a three-dimensional digital twin scene of the target mine based on the geographic information data;

[0009] Performing profile detection on the area to be detected in the three-dimensional digital twin scene, constructing a vertical profile, and performing safety detection of the slope angle, step height and width of the area to be detected based on the vertical profile;

[0010] Based on the three-dimensional digital twin scene, the coal mining area, coal stacking area or soil stacking area of ​​the target mining area is measured for filling or excavation, and the volume is calculated to obtain a production evaluation result.

[0011] Furthermore, the performing of profile detection on the three-dimensional digital twin scene to construct a vertical profile includes:

[0012] Based on the three-dimensional digital twin scene, the starting point and end point of the profile line of the area to be detected are selected, and an interpolation operation is performed between the starting point and the end point according to the distance using an interpolation method, and the three-dimensional elevation data of the starting point, the end point and each interpolation point are obtained using the digital elevation model or the oblique photography model, and the profile line data is obtained based on the three-dimensional elevation data, and the vertical profile between the starting point and the end point is constructed based on the profile line data.

[0013] Furthermore, the interpolation method is used to interpolate between the starting point and the end point according to the distance, including: calculating the distance between the starting point and the end point, performing equidistant difference on the distance between the starting point and the end point based on a preset interpolation distance, obtaining multiple interpolation points, and completing the interpolation operation.

[0014] Furthermore, based on the profile line data corresponding to the slope and the step in the vertical section, the vertical distance and the horizontal distance of each end point of the slope and the step are calculated; based on the vertical distance and the horizontal distance, the slope angle, the height and the width of the step in the area to be detected are obtained.

[0015] Furthermore, the filling and excavation measurement is carried out on the coal mining area, coal stacking area or soil stacking area of ​​the target mining area, and the volume is calculated, including:

[0016] Based on the three-dimensional digital twin scene, a Thiessen polygon network is generated for the area to be analyzed; and polygons in the Thiessen polygon network are segmented to obtain a triangular network; the area to be analyzed includes a coal mining area, a coal stacking area or a soil stacking area;

[0017] Assigning height values ​​to all endpoints on the triangulated network using a digital elevation model and an oblique photography data model;

[0018] A differential calculation unit is created based on the triangulated network after the height value is assigned, and the volume of fill or cut in the area to be analyzed is obtained based on the differential calculation unit.

[0019] Furthermore, each triangle in the triangular network is vertically projected onto a horizontal plane at a reference height, so as to construct a differential calculation unit consisting of a triangular prism and a quadrangular pyramid corresponding to each triangle;

[0020] Among them, the differential calculation units corresponding to the triangles above the reference height are the calculation units that need to be excavated; and the triangles below the reference height are the calculation units that need to be filled.

[0021] Furthermore, based on each differential calculation unit, the Heron's formula is used to calculate the area of ​​the triangle projected onto the horizontal plane, and the fill area, cut area and overall analysis area of ​​the area to be analyzed are obtained.

[0022] Furthermore, based on the calculation unit that needs to be excavated, the excavation volume in the area to be analyzed is obtained by the following method:

[0023] The lowest value of the heights of the three vertices of the triangle is used as the top surface height of the triangular prism, and the reference height is used as the bottom surface height of the triangular prism to obtain the volume of the triangular prism in the calculation unit that needs to be excavated;

[0024] The two vertices with the highest height among the three vertices of the triangle and the projection points of the vertical projections of the two vertices on the top surface of the triangular prism are used as the four vertices of the bottom surface of the quadrangular pyramid, and the vertex with the lowest height value of the triangle is used as the vertex of the quadrangular pyramid to obtain the volume of the quadrangular pyramid;

[0025] Based on the volume of the triangular prism and the volume of the quadrangular pyramid, the volume of the calculation unit that needs to be excavated is calculated, and all the calculation units that need to be excavated are traversed to obtain the excavation volume in the area to be analyzed.

[0026] Furthermore, based on the calculation unit that needs to be filled, the filling volume in the area to be analyzed is obtained by the following method:

[0027] The highest value of the heights of the three vertices of the triangle is used as the base height of the triangular prism, and the reference height is used as the top height of the triangular prism, and the volume of the triangular prism of the calculation unit that needs to be filled is obtained;

[0028] The two lowest vertices among the three vertices of the triangle and the projection points of the vertical projections of the two vertices on the top surface of the triangular prism are taken as the four vertices of the bottom surface of the quadrangular pyramid, and the vertex with the highest triangle height is taken as the vertex of the quadrangular pyramid, and the volume of the quadrangular pyramid is calculated;

[0029] Based on the volume of the triangular prism and the volume of the quadrangular pyramid, the volume of the calculation unit that needs to be filled is calculated; the volumes of all the calculation units that need to be filled are traversed to obtain the filling volume in the area to be analyzed.

[0030] Furthermore, the three-dimensional digital twin scene is a three-dimensional digital twin scene on the Web side, which is constructed by the following method:

[0031] Process the digital orthophotos in the geographic information data into map tiles according to the WMS standard, process the digital elevation model into terrain tiles, and process the oblique photography model into 3D tiles; and use the processed data as the index of the surveying time to establish a three-dimensional geographic information time series data set of the target mine, and publish it as a web-side map service for visualization rendering;

[0032] Use the Vue framework and Cesium 3D map engine to load the digital orthophoto, digital elevation model, oblique photography data model and digitized vector data of the target mine on the selected date into the 3D scene, and construct a web-based 3D digital twin scene of the target mine corresponding to that date.

[0033] Beneficial effects of this technical solution:

[0034] 1. The present invention provides a comprehensive and reliable data foundation for open-pit coal mine safety inspection and production evaluation based on UAV oblique photography surveying and mapping data, and constructs the scene of the target mine based on the digital results including digital orthophotos, digital elevation models, oblique photography models, etc. obtained through processing of UAV mapping data, and realizes high-precision three-dimensional simulation of small scenes in combination with digital vector data, and has the ability to map geographic information in one map. In the constructed high-precision three-dimensional scene, the spatial data analysis capability is used to perform spatial calculations and analysis on the study area to obtain the implicit geographic information required for open-pit coal mine safety monitoring and production evaluation, such as providing information such as slope angles, step heights and widths for disaster risk assessment and identification of potential safety hazards; as well as providing data such as the volume of fill or excavation to provide production decision makers with a basis for production evaluation decisions and provide guarantees for the conduct of operations;

[0035] 2. The present invention uses the method of vertical profile interpolation to measure the area to be detected, which realizes the rapid and accurate measurement of the slope angle, step height and width, providing a reliable basis for the safety detection of open-pit coal mines; and by dividing the coal pile area and mining area into differential calculation units, it realizes the accurate calculation and evaluation of the volume and area of ​​filling and excavation, providing an effective guarantee for the smooth progress of production;

[0036] 3. The present invention constructs a three-dimensional time-series geographic information database of the area by mapping the target mine at fixed time intervals and multiple time series, covering the time and space information of the area to meet the requirements of the target area business demand measurement for the real-time, dynamic and accurate nature of basic geographic information.

[0037] Other features and advantages of the present invention will be described in the following description, and part of them will become obvious from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The accompanying drawings are only used for the purpose of illustrating specific embodiments and are not to be considered as limiting the present invention. In the entire drawings, the same reference symbols represent the same components;

[0039] Figure 1 It is a flow chart of an open-pit coal mine safety detection and production assessment method based on drone mapping according to an embodiment of the present invention;

[0040] Figure 2 It is a three-dimensional visualization display diagram of surveying and mapping results according to an embodiment of the present invention;

[0041] Figure 3 It is a single geographic element information display diagram of an embodiment of the present invention;

[0042] Figure 4 is a schematic diagram of section line information according to an embodiment of the present invention;

[0043] Figure 5 This is a diagram showing a triangulated network calculation unit according to an embodiment of the present invention; Figure 5 a is the excavation calculation unit display diagram, Figure 5 b is the display diagram of the filling calculation unit;

[0044] Figure 6 It is a schematic diagram of calculation results of a differential calculation unit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0045] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the implementation cases of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0046] One embodiment of the present invention provides an open-pit coal mine safety detection and production assessment method based on drone mapping, such as Figure 1 As shown, the method comprises the following steps:

[0047] Step S1: obtaining the surveying and mapping data of the target mine through oblique photogrammetry by unmanned aerial vehicle; performing aerial triangulation operation on the surveying and mapping data to obtain a digital orthophoto, a digital elevation model or an oblique photogrammetry model, and generating vectorized data based on the digital orthophoto to obtain digital vector data of the target mine; the digital orthophoto, the digital elevation model, the oblique photogrammetry model and the digital vector data constitute the geographic information data of the target mine;

[0048] Specifically, this embodiment uses UAV field operations to perform oblique photogrammetry of the target area. During the mapping process, the aircraft is first calibrated, control points are arranged, and the flight path is planned. Then, images of the target mine are synchronously collected from five different perspectives (one vertical angle and four oblique angles) to obtain high-resolution mapping data of the top and side views of the target mine.

[0049] After obtaining the surveying and mapping data, data processing is required, including data correction, aerial triangulation operation, data vectorization, etc. Through aerial triangulation operation, control points are encrypted based on a small number of control points, and the relative position of the target point is determined by measuring the angle between the target point and the observation points at different positions, so as to obtain the plane position and elevation data of the encrypted control points; that is, through the triangulation operation of the surveying and mapping data, data including digital orthophotos, digital elevation models or oblique photography models can be obtained;

[0050] Among them, the digital orthophoto is the high-precision image data of the mining area, which contains the spatial morphological information and spatial distribution information of various geographical elements on the surface of the mining area. The digital elevation model provides the altitude of each area within the mining area, provides three-dimensional height values ​​for the construction of three-dimensional scenes, and also provides altitude latitude for subsequent profile analysis and cut and fill analysis. The oblique photography model has both height and surface texture data, which can provide better visualization effects and height information, providing altitude latitude for profile analysis, etc.

[0051] At the same time, in order to display the spatial and attribute information of each geographic element in the mining area and the spatial distribution information of the geographic elements, after obtaining the high-precision digital orthophoto of the mining area, the vectorized data of the mining area can be generated through GIS software to obtain digital vector data.

[0052] In practical applications, surveying and mapping data need to be updated regularly and in a timely manner to avoid large differences between surveying and mapping data results and actual terrain, which may affect the accuracy of safety inspections and production assessments. This embodiment updates surveying and mapping data in a timely manner through regular surveying and mapping, and after data processing of the surveying and mapping data, uses the surveying and mapping time as an index to establish a geographic information data set of the target area to record terrain changes and production conditions.

[0053] Step S2: constructing a three-dimensional digital twin scene of the target mine based on the geographic information data;

[0054] Specifically, in order to share surveying and mapping data and directly load and display geographic information data on the Web, it is also necessary to process the surveying and mapping results into a data format that can be loaded on the Web and published as a map service. Exemplarily, geographic information data can be processed into a data format that can be used on the Web through GIS software: the digital orthophotos in the geographic information data are processed into map tiles according to the wms standard, the digital elevation models are processed into terrain tiles, and the oblique photography models are processed into 3dtile tiles; the processed data is indexed by the surveying time to establish a three-dimensional geographic information time series data set of the target mine, and published as a web-side map service for visualization rendering;

[0055] Use the Vue framework and Cesium 3D map engine to load the digital orthophoto, digital elevation model and oblique photography data model of the target mine on the selected date into the 3D scene, and build a Web-based 3D digital twin scene of the target mine corresponding to the date; at the same time, the corresponding digitized vector data can also be published to the Web, and the digitized vector data of the target mine can also be loaded into the 3D scene, realizing a map of the mining area, such as Figure 2 As shown in the figure, you can view the spatial and attribute information of each step or mining area, soil dumping area, and the spatial distribution information of each geographical element (such as warehouses, buildings, etc.), such as Figure 3 By combining the vectorized data obtained on different dates, we can observe the geographic information of each geographic element in the mining area changing over time.

[0056] In practical applications, the digital orthophotos, digital elevation models or oblique photography models and digitized vector data of the target mine can be named as region + time + type, and Nginx can be used for Web service publishing; and each data version of the digital elevation model, digital orthophoto, digitized vector data, and oblique photography model can be marked with the shooting time as an independent basic geographic information data package, and the geographic information data package of the target area can be loaded into the three-dimensional scene through the existing Vue framework and Cesium three-dimensional map engine to construct a three-dimensional digital twin scene of the mine on the Web. Preferably, the construction of the three-dimensional digital twin scene can be achieved in the mining operation area by combining the digital elevation model with the digital orthophoto; in the building area, it can be achieved by combining the digital elevation model with the oblique photography model, so as to achieve better visual effects. The constructed three-dimensional scene also supports users to customize the switching of basic geographic information data packages of different data versions to achieve the effect of switching the three-dimensional scenes of the mine in different periods.

[0057] Step S3: Perform profile detection on the area to be detected in the three-dimensional digital twin scene, construct a vertical profile, and perform safety detection of the slope angle, step height and width of the area to be detected based on the vertical profile; and based on the three-dimensional digital twin scene, perform filling or excavation measurement on the coal mining area, coal pile area or soil pile area of ​​the target mining area, calculate the volume, and obtain the production assessment result.

[0058] The area to be inspected is the area of ​​interest selected by the user in the target mine, that is, the area including slopes or steps that need to be safety inspected, or the area including coal mining areas, coal pile areas or soil pile areas that need to be produced.

[0059] Specifically, for safety reasons, the slope of the slope, the height and width of the steps in mining operations need to be strictly restricted to prevent the occurrence of safety incidents such as landslides. This embodiment provides a function of interactive profile safety detection of three-dimensional scenes based on Cesium, which is used to perform safety detection on open-pit coal mines, mainly including slope angles, step heights and width safety detection in areas of interest. Profile safety detection supports users to interactively select two points in a three-dimensional scene, interpolate the distance between the two points using the interpolation principle, and project the longitude and latitude coordinates of each interpolation point onto a digital elevation model or an oblique photography model to obtain the three-dimensional elevation corresponding to each point, thereby constructing a vertical profile line between the two points. After constructing the vertical profile line, the vertical distance, horizontal distance, profile angle and other parameters of the profile line are calculated, and the slope of each point on this profile line is calculated to provide a data basis for slope safety detection of the slope.

[0060] Preferably, this embodiment performs profile detection on the three-dimensional digital twin scene and constructs a vertical profile by the following method:

[0061] Based on the three-dimensional digital twin scene, the starting point and the end point of the profile line of the area to be detected are selected, and an interpolation operation is performed between the starting point and the end point according to the distance using an interpolation method, including calculating the distance between the starting point and the end point, and performing equidistant difference on the distance between the starting point and the end point based on a preset interpolation distance, that is, obtaining multiple interpolation points; after completing the interpolation operation, the three-dimensional elevation data of the starting point, the end point and each interpolation point are obtained using a digital elevation model or an oblique photography model, and the profile line data is obtained based on the three-dimensional elevation data, such as Figure 4As shown, a vertical section between the starting point and the end point is constructed based on the section line data. Based on the section line data corresponding to the slope and the step in the vertical section, the vertical distance and the horizontal distance of each end point of the slope and the step are calculated; based on the vertical distance and the horizontal distance, the slope angle, the height and the width of the step in the area to be detected are obtained; in practical applications, safety thresholds can be set for the slope angle, the height and the width of the step according to the actual situation of the target mine, and compared with the slope angle, the height and the width of the step obtained by the detection, and an alarm and other processing can be performed for the safety hazards exceeding the threshold.

[0062] Furthermore, in the process of open-pit coal mining, it is necessary to accurately calculate the earthwork volume of the coal pile area, earth pile area and mining area for production evaluation, and to carry out resource scheduling and production planning based on the production evaluation results. The digital elevation model or oblique photography model of the three-dimensional scene can provide an elevation reference. The triangular surface network screened by the digital elevation model or oblique photography model can be used to calculate the earthwork volume of the selected area.

[0063] Preferably, in this embodiment, the following method is used to measure the filling or excavation of the coal mining area, coal pile area or soil pile area of ​​the target mining area, and calculate the volume:

[0064] Based on the three-dimensional digital twin scene, a Thiessen polygon network is generated for the area to be analyzed; and polygons in the Thiessen polygon network are segmented to obtain a triangular network; the area to be analyzed includes a coal mining area, a coal stacking area or a soil stacking area;

[0065] Assigning height values ​​to all endpoints on the triangulated network using a digital elevation model and an oblique photography data model;

[0066] A differential calculation unit is created based on the triangulated network after the height value is assigned, and the volume of fill or cut in the area to be analyzed is obtained based on the differential calculation unit.

[0067] Specifically, a reference height is set for each coal mining area, coal stacking area or soil stacking area; each triangle in the triangular network is vertically projected onto a horizontal plane corresponding to the reference height, and a differential calculation unit consisting of a triangular prism and a quadrangular pyramid corresponding to each triangle is constructed, such as Figure 5 As shown, Figure 5 a is the excavation calculation unit display diagram, Figure 5 b is the display diagram of the filling calculation unit;

[0068] Among them, the benchmark heights of the coal mining area, coal stacking area and soil stacking area can be set according to the adaptability of actual applications. The benchmark height of the coal mining area is usually higher than the current surface height, while the benchmark heights of the coal stacking area and the soil stacking area are usually set to the height of the contact surface between the soil pile and the coal pile and the ground; the differential calculation units corresponding to the triangles above the corresponding benchmark heights are the calculation units that need to be excavated; the triangles below the corresponding benchmark heights are the calculation units that need to be filled.

[0069] Based on each differential calculation unit, the Heron's formula is used to calculate the area of ​​the triangle projected onto the horizontal plane, and the fill area, cut area and overall analysis area of ​​the area to be analyzed are obtained.

[0070] Based on the calculation unit that needs to be excavated, the excavation volume in the area to be analyzed is obtained by the following method:

[0071] The lowest value of the heights of the three vertices of the triangle is used as the top surface height of the triangular prism, and the corresponding reference height is used as the bottom surface height of the triangular prism to obtain the volume of the triangular prism in the calculation unit that needs to be excavated;

[0072] The two vertices with the highest height among the three vertices of the triangle and the projection points of the vertical projections of the two vertices on the top surface of the triangular prism are used as the four vertices of the bottom surface of the quadrangular pyramid, and the vertex with the lowest height value of the triangle is used as the vertex of the quadrangular pyramid to obtain the volume of the quadrangular pyramid;

[0073] Based on the volume of the triangular prism and the volume of the quadrangular pyramid, the volume of the calculation unit that needs to be excavated is calculated, and all the calculation units that need to be excavated are traversed to obtain the excavation volume in the area to be analyzed.

[0074] Furthermore, based on the calculation unit that needs to be filled, the filling volume in the area to be analyzed is obtained by the following method:

[0075] The highest value of the heights of the three vertices of the triangle is used as the base height of the triangular prism, and the reference height is used as the top height of the triangular prism, and the volume of the triangular prism of the calculation unit that needs to be filled is obtained;

[0076] The two lowest vertices among the three vertices of the triangle and the projection points of the vertical projections of the two vertices on the top surface of the triangular prism are taken as the four vertices of the bottom surface of the quadrangular pyramid, and the vertex with the highest triangle height is taken as the vertex of the quadrangular pyramid, and the volume of the quadrangular pyramid is calculated;

[0077] Based on the volume of the triangular prism and the volume of the quadrangular pyramid, the volume of the calculation unit that needs to be filled is calculated; the volumes of all the calculation units that need to be filled are traversed to obtain the filling volume in the area to be analyzed.

[0078] Exemplarily, the Cesium open source map engine can be used to draw the analysis area. After the analysis area is drawn, the drawn analysis range is combined with the open source advanced geospatial analysis library turf.js to generate the Thiessen polygon network of the area. Thiessen polygons are a set of continuous polygons composed of perpendicular bisectors connecting two adjacent point segments. The distance from any point in a Thiessen polygon to the control point that constitutes the polygon is less than the distance to the control point of other polygons. Since Thiessen polygons are not triangles, and the sizes of polygons in the Thiessen polygon network are inconsistent, in order to solve the problem of inconsistent graphics types and sizes used in subsequent earthwork calculations, all polygons in the Thiessen polygon network need to be cut into a set of triangles; the polygon triangulation library earcut.js can be used to segment the polygons in the Thiessen polygon network to obtain a triangular network; since the coordinates of all the triangle endpoints in the obtained triangular network do not have height attributes, it is necessary to assign height values ​​to all the endpoints on the triangular network according to the SampleHeight method of the Cesium open source geographic engine combined with the digital elevation model and the oblique photography model in the three-dimensional scene. Project the coordinates of each point in the triangulated network vertically onto the digital elevation model and oblique photography data model in the 3D scene to obtain the height of the projection position, which is the height value of the endpoint of the triangulated network. A triangulated network (TIN) with height that covers the surface of the 3D scene in the analysis area is obtained;

[0079] Furthermore, the triangular network is traversed, and each triangle in the triangular network is vertically projected onto the horizontal plane. Since the coal mining area, coal stacking area or soil stacking area of ​​an open-pit coal mine is usually an uneven plane, a combination of a triangular prism and a tetrahedron will be constructed after projection, which can be used as a differential calculation unit for filling and excavation calculations. There are two types of calculation units involved in filling and excavation calculations: one is that the triangle is higher than the reference height, which is a calculation unit that needs to be excavated, and the reference height is used as the bottom height of the triangular prism; the other is that the triangle is lower than the reference height, which is a calculation unit that needs to be filled, and the reference height is used as the top height of the triangular prism, such as Figure 4 As shown;

[0080] For each differential calculation unit, the Heron formula can be used to calculate the area of ​​the base triangle, thereby calculating the fill area S1, the cut area S2, and the overall analysis area S;

[0081] For the excavation calculation unit, the lowest value of the three vertices of the triangle is used as the top surface height of the triangular prism, and the reference height is used as the bottom surface height of the triangular prism. The volume v1 of the triangular prism in the excavation calculation unit is calculated using the triangular prism volume formula. The two vertices with the highest heights of the three vertices of the triangle and the projection points of the vertical projections of these two vertices on the top surface of the triangular prism are used as the four vertices of the bottom surface of the tetrahedron. The vertex with the lowest triangle height is used as the vertex of the tetrahedron to calculate the volume v2 of the tetrahedron. The volume v of the excavation calculation unit is v = v1 + v2. Traversing all the excavation calculation units can obtain the excavation volume Vw in the analysis area.

[0082] For the backfill calculation unit, use the highest value of the three vertices of the triangle as the base height of the prism, and the reference height as the top height of the prism. Use the prism volume formula to calculate the volume v1 of the prism in the cut calculation unit. Use the two vertices with the lowest heights of the three vertices of the triangle and the projection points of the vertical projections of these two vertices on the top of the prism as the four vertices of the bottom of the pyramid, and use the vertices with the highest height value of the triangle as the vertices of the pyramid to calculate the volume v2 of the pyramid. Calculate the volume v=v1+v2 of the backfill calculation unit. Traverse all the cut calculation units to obtain the backfill volume Vt in the analysis area.

[0083] Exemplarily, the present invention develops an open-pit coal mine safety detection and production assessment system based on the aforementioned safety detection and production assessment method, which is used for surveying and mapping data management, safety detection and production assessment. Through this system, the surveying and mapping results generated by the surveying and mapping data are processed into a data format that can be loaded on the web and published as a map service; the published data is indexed by the surveying and mapping time to establish a three-dimensional geographic information time series data set of the target mine, and the three-dimensional geographic information time series data set of the area is continuously supplemented and updated through regular surveying and mapping; the system also performs safety detection based on the three-dimensional geographic information time series data set, which is used to interactively perform profile detection on three-dimensional scenes, construct vertical profiles of elements such as slopes and steps, and realize detection functions such as slope safety detection, step height and width detection; and based on the three-dimensional geographic information time series data set, production evaluation is performed, and the coal mining area, coal stacking area, soil stacking area and other areas of the open-pit coal mine are measured for filling and excavation, and the volume is calculated to help the mine support coal pile management and production measurement; and the mine surveying and mapping results metadata, mining area geographic element data, profile analysis data, filling and excavation analysis data, etc. can be exported to Word in the form of reports to assist mining production.

[0084] The system can measure and simulate coal piles with high precision, generate 3D coal pile models, and realize rapid measurement and management of coal piles. This helps coal mining enterprises better understand the actual situation of coal piles, prevent safety accidents in the stockpile yard, and optimize the allocation and utilization of coal resources. At the same time, through the high-precision measurement of drones, coal production can be determined more accurately, and rapid data collection and calculation can be achieved, avoiding errors and omissions in manual operation. The ultra-clear camera and positioning system carried by drones can effectively collect surface images in a wider viewing angle, and more clearly observe geological conditions such as cracks and collapses. The profile analysis provided by the system can analyze the slope of the operating steps to avoid landslides caused by excessive slopes. In addition, drones can also conduct inspections of surface subsidence and surface cracks, providing strong guarantees for geological measurement and production and operation of open-pit coal mines. Drones can measure open-pit coal mines at different heights, angles and viewing angles to obtain high-resolution image data. These data can be converted into images of different scales to provide more comprehensive data services for open-pit coal mine surveying and mapping. Compared with traditional manual measurement methods, drone mapping not only improves measurement accuracy, but also significantly improves mapping efficiency. The open-pit coal mining environment is complex and there are many safety hazards. Traditional manual measurement methods require personnel to enter high-risk places, which poses a high safety risk. Drone mapping can obtain the required measurement data without personnel entering dangerous areas, thereby greatly reducing work risks and improving safety factors. Based on the long-term three-dimensional geographic time series data set of the coal mining area, the system can detect and analyze the long-term operation scenes of open-pit coal mines, providing long-term data support and analysis capability support.

[0085] In actual applications, the open-pit coal mine safety inspection and production evaluation system can be used to draw the area that needs volume calculation in the three-dimensional scene. After drawing, the calculation area is covered by a blue surface and waits for calculation. And according to the actual situation, the elevation benchmark and accuracy data of this filling and excavation analysis calculation are set, and the excavation unit and filling unit in the analysis area are obtained, and the filling and excavation calculation is performed. After the calculation is completed, the calculation results of the area are output, such as the total analysis area, filling area (area below the elevation benchmark), excavation area (area above the elevation benchmark), filling volume and excavation volume. And the calculation results are rendered on the three-dimensional page, such as Figure 6 As shown. Each colored prism is a single calculation unit. The smaller the calculation unit, the higher the calculation accuracy. The part not covered by the calculation unit is the part that needs to be excavated. The system also supports the output of spatial data and attribute data of various geographical elements of open-pit coal mines, statistical data and alarm data of various profile lines, and earthwork calculation data of mining areas and stacking areas into word format document reports, providing reliable data reference for safety inspection and production evaluation of open-pit coal mines.

[0086] In summary, the open-pit coal mine safety inspection and production assessment method based on UAV mapping provided by the embodiment of the present invention provides a comprehensive and reliable data basis for open-pit coal mine safety inspection and production assessment based on UAV oblique photography mapping data, and constructs the scene of the target mine based on the digital results including digital orthophotos, digital elevation models, oblique photography models, etc. obtained by processing the UAV mapping data, and realizes high-precision three-dimensional simulation of small scenes in combination with digital vector data, and has the ability of a single map of geographic information. In the constructed high-precision three-dimensional scene, spatial data analysis capabilities are used to perform spatial calculations and analyses on the study area, and the geographic information required for implicit open-pit coal mine safety monitoring and production evaluation is obtained, such as providing information such as slope angles, step heights and widths for disaster risk assessment and identification of potential safety hazards; as well as providing data such as fill and excavation volumes, to provide production decision makers with a basis for production evaluation decisions and to provide guarantees for the conduct of operations; the present invention uses a method of vertical profile interpolation to achieve rapid and accurate measurement of slope angles, step heights and widths in the area to be inspected, providing a reliable basis for safety inspections of open-pit coal mines; and by dividing the coal stacking area, mining area, etc. into differential calculation units, accurate calculation and evaluation of fill and excavation volumes and areas is achieved, providing effective guarantees for the smooth conduct of production.

[0087] Those skilled in the art will appreciate that all or part of the processes of the above-mentioned embodiments can be implemented by instructing related hardware through a computer program, and the program can be stored in a computer-readable storage medium, wherein the computer-readable storage medium is a disk, an optical disk, a read-only storage memory, or a random access memory, etc.

[0088] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for open-pit coal mine safety detection and production assessment based on drone mapping, characterized in that: include: Obtain surveying and mapping data of the target mine through UAV oblique photogrammetry; Based on the surveying and mapping data, geographic information data including digital orthophotos, digital elevation models, oblique photography models and digitized vector data are obtained; Constructing a three-dimensional digital twin scene of the target mine based on the geographic information data; Performing profile detection on the area to be detected in the three-dimensional digital twin scene, constructing a vertical profile, and performing safety detection of the slope angle, step height and width of the area to be detected based on the vertical profile; Based on the three-dimensional digital twin scene, the coal mining area, coal stacking area or soil stacking area of ​​the target mining area is measured for filling or excavation, and the volume is calculated to obtain a production assessment result.

2. The open-pit coal mine safety detection and production assessment method based on drone mapping according to claim 1 is characterized in that: The performing profile detection on the three-dimensional digital twin scene and constructing a vertical profile includes: Based on the three-dimensional digital twin scene, the starting point and end point of the profile line of the area to be detected are selected, and an interpolation operation is performed between the starting point and the end point according to the distance using an interpolation method, and the three-dimensional elevation data of the starting point, the end point and each interpolation point are obtained using the digital elevation model or the oblique photography model, and the profile line data is obtained based on the three-dimensional elevation data, and the vertical profile between the starting point and the end point is constructed based on the profile line data.

3. The open-pit coal mine safety detection and production assessment method based on drone mapping according to claim 2 is characterized in that: The interpolation method is used to interpolate the distance between the starting point and the end point, including: calculating the distance between the starting point and the end point, performing equidistant difference on the distance between the starting point and the end point based on a preset interpolation distance, obtaining multiple interpolation points, and completing the interpolation operation.

4. The open-pit coal mine safety detection and production assessment method based on drone mapping according to claim 3 is characterized in that: Based on the profile line data corresponding to the slope and the step in the vertical section, the vertical distance and the horizontal distance of each end point of the slope and the step are calculated; based on the vertical distance and the horizontal distance, the slope angle of the area to be detected and the height and width of the step are obtained.

5. The open-pit coal mine safety detection and production assessment method based on drone mapping according to claim 1 is characterized in that: Carry out filling or excavation measurement of the coal mining area, coal pile area or earth pile area of ​​the target mining area and calculate the volume, including: Based on the three-dimensional digital twin scene, a Thiessen polygon network is generated for the area to be analyzed; and polygons in the Thiessen polygon network are segmented to obtain a triangular network; the area to be analyzed includes a coal mining area, a coal stacking area or a soil stacking area; Assigning height values ​​to all endpoints on the triangulated network using a digital elevation model or an oblique photography model; A differential calculation unit is created based on the triangulated network after the height value is assigned, and the volume of fill or cut in the area to be analyzed is obtained based on the differential calculation unit.

6. The open-pit coal mine safety detection and production assessment method based on drone mapping according to claim 5 is characterized in that: The coal mining area, the coal stacking area or the soil stacking area are respectively set with reference heights; each triangle in the triangular network is vertically projected onto a horizontal plane corresponding to the reference height, and a differential calculation unit consisting of a triangular prism and a quadrangular pyramid corresponding to each triangle is constructed; Among them, the differential calculation units corresponding to the triangles above the corresponding reference height are the calculation units that need to be excavated; the differential calculation units corresponding to the triangles below the corresponding reference height are the calculation units that need to be filled.

7. The open-pit coal mine safety detection and production assessment method based on drone mapping according to claim 5 is characterized in that: Based on each differential calculation unit, the Heron's formula is used to calculate the area of ​​the triangle projected onto the horizontal plane, and the fill area, cut area and overall analysis area of ​​the area to be analyzed are obtained.

8. The open-pit coal mine safety detection and production assessment method based on drone mapping according to claim 6 is characterized in that: Based on the calculation unit that needs to be excavated, the excavation volume in the area to be analyzed is obtained by the following method: The lowest value of the heights of the three vertices of the triangle is used as the top surface height of the triangular prism, and the corresponding reference height is used as the bottom surface height of the triangular prism to obtain the volume of the triangular prism in the calculation unit that needs to be excavated; The two vertices with the highest height among the three vertices of the triangle and the projection points of the vertical projections of the two vertices on the top surface of the triangular prism are used as the four vertices of the bottom surface of the quadrangular pyramid, and the vertex with the lowest height value of the triangle is used as the vertex of the quadrangular pyramid to obtain the volume of the quadrangular pyramid; Based on the volume of the triangular prism and the volume of the quadrangular pyramid, the volume of the calculation unit that needs to be excavated is calculated, and all the calculation units that need to be excavated are traversed to obtain the excavation volume in the area to be analyzed.

9. The open-pit coal mine safety detection and production assessment method based on drone mapping according to claim 5 is characterized in that: Based on the calculation unit that needs to be filled, the filling volume in the area to be analyzed is obtained by the following method: The highest value of the height of the three vertices of the triangle is used as the base height of the triangular prism, and the corresponding reference height is used as the top height of the triangular prism to obtain the volume of the triangular prism of the calculation unit that needs to be filled; The two lowest vertices among the three vertices of the triangle and the projection points of the vertical projections of the two vertices on the top surface of the triangular prism are taken as the four vertices of the bottom surface of the quadrangular pyramid, and the vertex with the highest triangle height is taken as the vertex of the quadrangular pyramid, and the volume of the quadrangular pyramid is calculated; Based on the volume of the triangular prism and the volume of the quadrangular pyramid, the volume of the calculation unit that needs to be filled is calculated; Traverse the volumes of all calculation units that need to be filled to obtain the filling volume in the area to be analyzed.

10. The open-pit coal mine safety detection and production assessment method based on drone mapping according to claim 1 is characterized in that: The three-dimensional digital twin scene is a three-dimensional digital twin scene on the Web side, which is constructed by the following method: Process the digital orthophotos in the geographic information data into map tiles according to the WMS standard, process the digital elevation model into terrain tiles, and process the oblique photography model into 3D tiles; and use the processed data as the index of the surveying time to establish a three-dimensional geographic information time series data set of the target mine, and publish it as a web-side map service for visualization rendering; Use the Vue framework and Cesium 3D map engine to load the digital orthophotos, digital elevation models, oblique photography data models and digitized vector data of the target mine on the selected date into the 3D scene, and construct a web-based 3D digital twin scene of the target mine corresponding to that date.

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