Unmanned aerial vehicle surveying and mapping system for opencast coal mine

Abstract

The invention provides an unmanned aerial vehicle surveying and mapping system for an open pit coal mine. The system comprises an unmanned aerial vehicle operation unit, a wireless communication unit and a data processing unit, the unmanned aerial vehicle operation unit comprises an unmanned aerial vehicle, a ground station, and a camera module and a navigation module which are fixedly arranged on the unmanned aerial vehicle; data communication is performed between the camera module and the data processing unit, and between the unmanned aerial vehicle and the navigation module and the ground station through the wireless communication unit; and the data processing unit is used for constructing a three-dimensional digital twin scene based on the surveying and mapping data of the open pit coal mine acquired by the camera module, and carrying out safety detection on the slope angle, the step height and the width of a to-be-detected area of the open pit coal mine based on the three-dimensional digital twin scene, and carrying out fill or excavation quantity detection on a coal mining area, a coal piling area or a soil piling area. According to the invention, the problems of poor accuracy and low efficiency of safety detection and production evaluation of open pit coal mining by a geographic surveying and mapping system in the prior art are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of geographic surveying and mapping, and in particular relates to an open-pit coal mine unmanned aerial vehicle surveying and mapping system. Background Art

[0002] As an emerging technology in the field of geographic information surveying and mapping, drone oblique photography technology plays an increasingly important role in the actual operation of surveying and mapping projects; the high-precision sensors and positioning systems carried by drones can ensure the accuracy of surveying and mapping data. Through professional data processing software, the accuracy of surveying and mapping results can be further improved to meet the needs of various application scenarios. Drone surveying and mapping can obtain image data of the target area in real time and perform rapid processing and analysis. This provides timely and accurate information support for disaster warning, environmental monitoring and other fields, helping decision makers make correct decisions in a timely manner.

[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 limited by natural conditions such as detection tools, terrain, and climate, which can easily lead to data loss and is not conducive to the regular updating of surveying and mapping data. It cannot intuitively reflect changes in terrain and new production and construction conditions. Therefore, an intelligent UAV surveying and mapping system is needed to achieve accurate safety inspections and production assessments of open-pit coal mines, and to provide guarantees for the safe and efficient production of open-pit coal mines. Summary of the invention

[0004] In view of the above analysis, the present invention aims to provide an open-pit coal mine UAV mapping system to solve the problems of poor accuracy and low efficiency of the existing geographic mapping system in safety inspection and production evaluation 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 an open-pit coal mine UAV mapping system, the system comprising: a UAV operation unit, a wireless communication unit and a data processing unit;

[0007] The UAV operation unit includes a UAV, a ground station, and a camera module and a navigation module fixedly arranged on the UAV;

[0008] Data communication is performed between the camera module and the data processing unit, and between the drone and the navigation module and the ground station through the wireless communication unit;

[0009] The data processing unit is used to construct a three-dimensional digital twin scene based on the surveying and mapping data of the open-pit coal mine acquired by the camera module, and to perform safety detection of slope angles, step heights and widths of the area to be inspected in the open-pit coal mine based on the three-dimensional digital twin scene, as well as fill or excavation volume detection in the coal mining area, coal stacking area or soil stacking area.

[0010] Furthermore, the camera module is a five-piece camera; the five-piece camera is rigidly installed integrally with the navigation module and is fixedly arranged on the drone bracket;

[0011] The five cameras are arranged under the belly of the drone; four of the cameras are fixedly arranged at preset tilt angles, and the fifth camera is fixedly arranged at an orthographic angle; the five cameras are exposed simultaneously.

[0012] Furthermore, the ground station obtains the location information of the UAV based on the positioning data of the navigation module, and performs flight control, route planning and onboard service status monitoring on the UAV.

[0013] Furthermore, the data processing unit constructs a three-dimensional digital twin scene by the following method:

[0014] Perform triangulation operation based on the surveying and mapping data acquired by the camera module to obtain geographic information data including digital orthophotos, digital elevation models, oblique photography models and digitized vector data;

[0015] The digital orthophotos in the geographic information data are processed into map tiles according to the WMS standard, the digital elevation model is processed into terrain tiles, and the oblique photography model is processed into 3D tiles; the processed data is indexed by the surveying time to establish a three-dimensional geographic information time series data set of the open-pit coal mine, and it is published as a web-side map service for visualization rendering;

[0016] The Vue framework and Cesium three-dimensional map engine are used to load the digital orthophoto, digital elevation model, oblique photography model and digitized vector data of the open-pit coal mine on the selected date into the three-dimensional scene, and a web-based three-dimensional digital twin scene of the open-pit coal mine corresponding to the date is constructed.

[0017] Furthermore, the data processing unit constructs a vertical section by performing a profile detection on the area to be detected in the three-dimensional digital twin scene, and performs a safety detection of the slope angle, step height and width of the area to be detected based on the vertical section;

[0018] Among them, the vertical section is constructed by the following method: based on the three-dimensional digital twin scene, the starting point and end point of the section line of the area to be detected are selected, and the interpolation operation is performed according to the distance between the starting point and the end point using the 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 section line data is obtained based on the three-dimensional elevation data, and the vertical section between the starting point and the end point is constructed based on the section line data.

[0019] 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.

[0020] Furthermore, the data processing unit detects the volume of filling or excavation in the coal mining area, coal stacking area or soil stacking area by the following method:

[0021] 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;

[0022] Assigning height values ​​to all endpoints on the triangulated network using a digital elevation model or an oblique photography model;

[0023] A differential calculation unit is created based on the triangulated network after the height value is assigned, and the volume of fill or cut of the area to be analyzed is obtained based on the differential calculation unit.

[0024] Furthermore, a reference height is set for each of the 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;

[0025] 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.

[0026] 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:

[0027] 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;

[0028] 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;

[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 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.

[0030] 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:

[0031] 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;

[0032] 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;

[0033] 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.

[0034] Beneficial effects of this technical solution:

[0035] 1. The present invention is based on an unmanned aerial vehicle mapping system. It uses an unmanned aerial vehicle carrying a five-camera to conduct regular high-precision mapping of open-pit coal mines, providing a comprehensive and reliable data basis for open-pit coal mine safety inspections and production assessments, and constructing open-pit coal mine scenes based on digital results such as digital orthophotos, digital elevation models, and oblique photography models obtained through processing of unmanned aerial vehicle mapping data; combined with digital vector data, it realizes high-precision three-dimensional simulation of small scenes, and has the ability to map geographic information. In the constructed high-precision three-dimensional scene, the spatial data analysis capability is utilized to perform spatial calculations and analysis on the study area, and obtain the implicit geographic information required for open-pit coal mine safety monitoring and production assessment, such as providing information such as slope angles, step heights and widths, which are used for disaster risk assessments 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 assessment decisions and provide guarantees for the conduct of operations;

[0036] 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;

[0037] 3. The present invention constructs a three-dimensional time-series geographic information database of the open-pit coal mine by mapping the open-pit coal 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.

[0038] 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

[0039] 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;

[0040] 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;

[0041] Figure 2 It is a three-dimensional visualization display diagram of the surveying and mapping results of an embodiment of the present invention;

[0042] Figure 3 It is a single geographic element information display diagram of an embodiment of the present invention;

[0043] Figure 4 is a schematic diagram of section line information according to an embodiment of the present invention;

[0044] 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;

[0045] 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

[0046] 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.

[0047] One embodiment of the present invention provides an open-pit coal mine UAV mapping system, such as Figure 1 As shown, the system includes: a drone operation unit, a wireless communication unit and a data processing unit;

[0048] Specifically, the UAV operation unit includes a UAV, a ground station, and a camera module and a navigation module fixedly arranged on the UAV;

[0049] Data communication is performed between the camera module and the data processing unit, and between the drone and the navigation module and the ground station through the wireless communication unit;

[0050] The data processing unit is used to construct a three-dimensional digital twin scene based on the surveying and mapping data of the open-pit coal mine acquired by the camera module, and to perform safety detection of slope angles, step heights and widths of the area to be inspected in the open-pit coal mine based on the three-dimensional digital twin scene, as well as fill or excavation volume detection in the coal mining area, coal stacking area or soil stacking area.

[0051] Specifically, this embodiment uses UAV field operations to perform oblique photogrammetry of the target area; before mapping, the aircraft is first calibrated and control points are arranged; and flight path planning is performed through a ground station, including planning the flight route, altitude, speed and other parameters of the UAV according to factors such as the scope, terrain, and accuracy requirements of the mapping area, and sending mission instructions to the UAV through a wireless communication unit to ensure that it collects data according to a predetermined plan. At the same time, during the flight, the status of the UAV can be monitored in real time through the ground station, such as flight position, flight attitude, power, signal strength, etc., and manual intervention and adjustment can be performed when necessary to ensure flight safety.

[0052] Furthermore, in order to obtain high-resolution texture information of the top and side views of rich mining areas and buildings in open-pit coal mines, so as to carry out subsequent safety inspections and production assessments, the camera module of this embodiment adopts a high-resolution five-piece camera, which synchronously collects images of the open-pit coal mine through five different viewing angles (one vertical angle and four inclined angles), and obtains high-resolution mapping data of the top and side views of the open-pit coal mine. Specifically, the five-piece camera is rigidly installed with the navigation module and fixedly mounted on the drone bracket; the five-piece camera is arranged under the belly of the drone; four of the cameras are fixedly arranged according to a preset inclination angle, preferably, the four cameras can be symmetrically arranged in the left front, right front, left rear and right rear directions, and the inclination angle can be set between 30° and 45°, and the fifth camera is fixedly arranged vertically according to the orthographic angle, and the five cameras are exposed at the same time, so as to realize the shooting of ground targets from multiple directions, obtain more comprehensive ground object information, effectively reduce shooting blind spots, and provide a more accurate data basis for three-dimensional modeling and terrain mapping.

[0053] Furthermore, after the surveying and mapping data is acquired, it is sent to the data processing unit through the wireless communication unit for data processing, including data correction, aerial triangulation operation, data vectorization, etc.; through the aerial triangulation operation, based on a small number of control points, the control points are encrypted, and the relative position of the target point is determined by measuring the angle from the target point to 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;

[0054] 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.

[0055] 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.

[0056] 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.

[0057] After the geographic information data is obtained through data processing, a three-dimensional digital twin scene of the open-pit coal mine needs to be constructed based on the geographic information data for subsequent safety testing and production evaluation;

[0058] Specifically, in order to realize the sharing of surveying and mapping data and to directly load and display geographic information data on the Web, this embodiment processes the surveying and mapping results into a data format that can be loaded on the Web and publishes it as a map service. Exemplarily, the 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 open-pit coal mine, and it is published as a web-side map service for visual rendering;

[0059] The Vue framework and Cesium 3D map engine are used to load the digital orthophoto, digital elevation model and oblique photography model of the open-pit coal mine on the selected date into the 3D scene, and a Web-based 3D digital twin scene of the open-pit coal mine corresponding to the date is constructed; at the same time, the corresponding digitized vector data can also be published to the Web side, and the digitized vector data of the open-pit coal 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.

[0060] In practical applications, the digital orthophoto, digital elevation model or oblique photography model and digitized vector data of the open-pit coal 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 identified by the shooting time as an independent basic geographic information data packet, and the geographic information data packet 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, the digital elevation model can be combined with the oblique photography model to achieve better visual effects. The constructed three-dimensional scene also supports users to customize the switching of basic geographic information data packets of different data versions to achieve the effect of switching the three-dimensional scenes of the mine in different periods.

[0061] Specifically, the data processing unit performs profile detection on the area to be detected in the three-dimensional digital twin scene, constructs a vertical profile, and performs 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, performs filling or excavation measurement on the coal mining area, coal stacking area or soil stacking area of ​​the target mining area, calculates the volume, and obtains the production evaluation result.

[0062] The area to be inspected is an area of ​​interest selected by the user in the open-pit coal mine, that is, an area including slopes or steps that require safety inspection, or an area including coal mining areas, coal stacking areas or soil stacking areas that require production evaluation.

[0063] Specifically, for safety reasons, the slope of the slope, the height and width of the steps in the mining operation need to be strictly restricted to prevent the occurrence of safety incidents such as landslides. The data processing unit of this embodiment provides a function of interactive profile safety detection of three-dimensional scenes based on Cesium development, which is used to perform safety detection on open-pit coal mines, mainly including slope angle, step height and width safety detection of the area of ​​interest. Profile safety detection supports users to interactively select two points in the 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 data basis for slope safety detection of the slope.

[0064] Preferably, this embodiment performs profile detection on the three-dimensional digital twin scene and constructs a vertical profile by the following method:

[0065] 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 4 As 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 open-pit coal mine, and compared with the slope angle, the height and the width of the step obtained by detection, and an alarm and other processing can be performed for safety hazards exceeding the threshold.

[0066] 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.

[0067] 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:

[0068] 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;

[0069] Assigning height values ​​to all endpoints on the triangulated network using a digital elevation model and an oblique photography model;

[0070] 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.

[0071] 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;

[0072] 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.

[0073] 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.

[0074] 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:

[0075] 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;

[0076] 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;

[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 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.

[0078] 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:

[0079] 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;

[0080] 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;

[0081] 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.

[0082] Exemplarily, the data processing unit can use the Cesium open source map engine 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 constituting 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 model in the 3D scene to obtain the height of the projection position, which is the height value of the triangulated network endpoint. A triangulated network (TIN) with height that covers the surface of the 3D scene in the analysis area is obtained;

[0083] 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 quadrangular pyramid 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;

[0084] 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;

[0085] 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.

[0086] 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.

[0087] 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. The system processes the surveying and mapping results generated by the surveying and mapping data into a data format that can be loaded on the web side and publishes these data as a map service; and uses the surveying and mapping time as an index for the published data to establish a three-dimensional geographic information time series data set of the open-pit coal mine, and continuously supplements and updates the three-dimensional geographic information time series data set of the area 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 performs production evaluation based on the three-dimensional geographic information time series data set, performs filling and excavation measurement on the coal mining area, coal stacking area, soil stacking area and other areas of the open-pit coal mine, calculates the volume, and helps the mining area to support coal pile management and production measurement; and can export the mine surveying and mapping results metadata, mining area geographic element data, profile analysis data, filling and excavation analysis data, etc. in the form of reports to Word to assist mining area production.

[0088] 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.

[0089] Illustratively, this embodiment develops an open-pit coal mine safety detection and production evaluation system through a data processing unit, which can draw the area that requires volume calculation in a 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 reference 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 calculations are performed. After the calculation is completed, the calculation results of the area are output, such as the total analysis area, the filling area (the area below the elevation reference), the excavation area (the area above the elevation reference), the filling volume and the excavation volume. And the calculation results are rendered on the three-dimensional page 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.

[0090] In summary, an open-pit coal mine drone mapping system provided by an embodiment of the present invention provides a comprehensive and reliable data basis for open-pit coal mine safety inspection and production evaluation through a drone carrying a five-camera, and constructs the scene of the open-pit coal mine based on digital results such as digital orthophotos, digital elevation models, and oblique photography models obtained through drone mapping data processing, and realizes high-precision three-dimensional simulation of small scenes in combination with digital vector data, and has the ability to provide 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.

[0091] 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.

[0092] 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. An open-pit coal mine UAV mapping system, characterized in that: The system comprises: a drone operation unit, a wireless communication unit and a data processing unit; The UAV operation unit includes a UAV, a ground station, and a camera module and a navigation module fixedly arranged on the UAV; Data communication is performed between the camera module and the data processing unit, and between the drone and the navigation module and the ground station through the wireless communication unit; The data processing unit is used to construct a three-dimensional digital twin scene based on the surveying and mapping data of the open-pit coal mine acquired by the camera module, and to perform safety detection of slope angles, step heights and widths of the area to be inspected in the open-pit coal mine based on the three-dimensional digital twin scene, as well as fill or excavation volume detection in the coal mining area, coal stacking area or soil stacking area.

2. The open-pit coal mine UAV mapping system according to claim 1 is characterized in that: The camera module is a five-piece camera; the five-piece camera is rigidly installed integrally with the navigation module and is fixedly arranged on the drone bracket; The five cameras are arranged under the belly of the drone; four of the cameras are fixedly arranged at preset tilt angles, and the fifth camera is fixedly arranged at an orthographic angle; the five cameras are exposed simultaneously.

3. The open-pit coal mine UAV mapping system according to claim 2 is characterized in that: The ground station obtains the location information of the UAV based on the positioning data of the navigation module, and performs flight control, route planning and airborne service status monitoring on the UAV.

4. The open-pit coal mine UAV mapping system according to claim 1 is characterized in that: The data processing unit constructs a three-dimensional digital twin scene by the following method: Perform triangulation operation based on the surveying and mapping data acquired by the camera module to obtain geographic information data including digital orthophotos, digital elevation models, oblique photography models and digitized vector data; The digital orthophotos in the geographic information data are processed into map tiles according to the WMS standard, the digital elevation model is processed into terrain tiles, and the oblique photography model is processed into 3D tiles; the processed data is indexed by the surveying time to establish a three-dimensional geographic information time series data set of the open-pit coal mine, and it is published as a web-side map service for visualization rendering; The Vue framework and Cesium three-dimensional map engine are used to load the digital orthophoto, digital elevation model, oblique photography model and digitized vector data of the open-pit coal mine on the selected date into the three-dimensional scene, and a web-based three-dimensional digital twin scene of the open-pit coal mine corresponding to the date is constructed.

5. The open-pit coal mine UAV mapping system according to claim 4 is characterized in that: The data processing unit constructs a vertical section by performing a profile detection on the area to be detected in the three-dimensional digital twin scene, and performs a safety detection of the slope angle, step height and width of the area to be detected based on the vertical section; Among them, the vertical section is constructed by the following method: based on the three-dimensional digital twin scene, the starting point and end point of the section line of the area to be detected are selected, and the interpolation operation is performed according to the distance between the starting point and the end point using the 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 section line data is obtained based on the three-dimensional elevation data, and the vertical section between the starting point and the end point is constructed based on the section line data.

6. The open-pit coal mine UAV mapping system according to claim 5, 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.

7. The open-pit coal mine UAV mapping system according to claim 1, characterized in that: The data processing unit detects the volume of filling or excavation in the coal mining area, coal stacking area or soil stacking area by the following method: 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 of the area to be analyzed is obtained based on the differential calculation unit.

8. The open-pit coal mine UAV mapping system according to claim 7, 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.

9. The open-pit coal mine UAV mapping system according to claim 8, 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.

10. The open-pit coal mine UAV mapping system according to claim 8, 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.

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