An open-pit coal mine unmanned aerial vehicle surveying and mapping system

Abstract

The present application provides an open coal mine unmanned aerial vehicle surveying and mapping system, the system comprises: unmanned aerial vehicle operation unit, wireless communication unit and data processing unit; the unmanned aerial vehicle operation unit comprises unmanned aerial vehicle, ground station, and camera module and navigation module fixedly arranged on the unmanned aerial vehicle; the data communication between the camera module and the data processing unit, the unmanned aerial vehicle and the navigation module and the ground station is carried out through the wireless communication unit; the data processing unit is used for three-dimensional digital twin scene construction based on the surveying and mapping data of the open coal mine obtained by the camera module, and the safety detection of the slope angle, step height and width of the open coal mine to be detected area based on the three-dimensional digital twin scene, and the filling or excavation volume detection of the coal mining area, coal stacking area or earth stacking area. The present application solves the problems of poor accuracy and low efficiency of safety detection and production evaluation of the existing geographic surveying and mapping system for open coal mining.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of geographic mapping, and particularly relates to an open-pit coal mine unmanned aerial vehicle mapping system. BACKGROUND

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

[0003] However, traditional open-pit coal mining safety detection and production evaluation often requires personnel to enter dangerous areas for operation, which poses a high safety risk and is low in efficiency. It is limited by detection tools, terrain, climate and other natural conditions, which can lead to data loss and is not conducive to regular updating of mapping data, and cannot intuitively reflect changes in the terrain and new production and construction conditions. Therefore, an intelligent unmanned aerial vehicle mapping system is needed to accurately detect and evaluate the safety and production of open-pit coal mines, providing protection for the safe and efficient production of open-pit coal mines. SUMMARY

[0004] In view of the above analysis, the present application aims to provide an open-pit coal mine unmanned aerial vehicle mapping system to solve the problem of poor accuracy and low efficiency of geographic mapping systems in the prior art for safety detection and production evaluation of open-pit coal mining.

[0005] The main purpose of the present application is achieved through the following technical solutions:

[0006] On the one hand, the present application provides an open-pit coal mine unmanned aerial vehicle mapping system, which comprises a unmanned aerial vehicle operation unit, a wireless communication unit and a data processing unit;

[0007] The unmanned aerial vehicle operation unit comprises a unmanned aerial vehicle, a ground station, and a camera module and a navigation module fixedly arranged on the unmanned aerial vehicle;

[0008] The camera module and the data processing unit, and the unmanned aerial vehicle and the navigation module and the ground station communicate data through the wireless communication unit;

[0009] The data processing unit is configured to construct a three-dimensional digital twin scene based on surveying data of the open-pit coal mine obtained by the camera module, and perform safety detection of a slope angle, a step height and a width of a to-be-detected area of the open-pit coal mine, and detection of a volume of earthwork or excavation of a coal mining area, a coal stacking area or a soil stacking area based on the three-dimensional digital twin scene.

[0010] Further, the camera module is a five-camera module; the five-camera module is rigidly installed in an integrated manner with the navigation module and is fixedly arranged on a UAV support;

[0011] The five-camera module is arranged below a belly of the UAV; four cameras are fixedly arranged at preset tilt angles, and a fifth camera is fixedly arranged at a normal angle; the five cameras are simultaneously exposed.

[0012] Further, the ground station obtains position information of the UAV based on positioning data of the navigation module, and performs flight control, route planning and on-board service state monitoring on the UAV.

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

[0014] Based on the surveying data obtained by the camera module, a triangulation operation is performed to obtain geographic information data including a digital orthophoto map, a digital elevation model, a tilt photography model and digitalized vector data;

[0015] The digital orthophoto map in the geographic information data is processed into a map tile according to a wms standard, the digital elevation model is processed into a terrain tile, and the tilt photography model is processed into a 3dtile tile; the processed data is indexed by a surveying time to establish a three-dimensional geographic information time-series dataset of the open-pit coal mine, and is published as a web map service for visual rendering;

[0016] The digital orthophoto map, the digital elevation model, the tilt photography model and the digitalized vector data of the open-pit coal mine on a selected date are loaded into a three-dimensional scene using a Vue framework and a Cesium three-dimensional map engine to construct a web three-dimensional digital twin scene of the open-pit coal mine corresponding to the date.

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

[0018] The vertical profile is constructed by the following method: based on the three-dimensional digital twin scene, selecting a profile line starting point and an ending point of the region to be detected, performing interpolation operation between the starting point and the ending point according to distance by using an interpolation method, and obtaining three-dimensional elevation data of the starting point, the ending point and each interpolation point by using the digital elevation model or the oblique photography model, obtaining profile line data based on the three-dimensional elevation data, and constructing the vertical profile between the starting point and the ending point based on the profile line data.

[0019] Further, based on the profile line data corresponding to the slope and the step in the vertical profile, the perpendicular distance and the horizontal distance of each endpoint of the slope and the step are calculated; and the slope angle, the height and the width of the step of the region to be detected are obtained based on the perpendicular distance and the horizontal distance.

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

[0021] Based on the three-dimensional digital twin scene, a Voronoi polygon network is generated for the region to be analyzed, and the polygons in the Voronoi polygon network are segmented to obtain a triangular network; the region to be analyzed includes a coal mining area, a coal stacking area or an earth stacking area;

[0022] The height values of all endpoints on the triangular network are assigned by using a digital elevation model or an oblique photography model;

[0023] A differential calculation unit is created based on the triangular network after the height value assignment, and the volume of filling or excavation of the region to be analyzed is obtained based on the differential calculation unit.

[0024] Further, a reference height is set for each of the coal mining area, the coal stacking area or the earth stacking area; and a vertical projection is made for each triangle in the triangular network to the horizontal plane corresponding to the reference height to construct a differential calculation unit corresponding to each triangle, which is composed of a triangular prism and a quadrangular pyramid;

[0025] Among them, the differential calculation unit corresponding to the triangle higher than the corresponding reference height is a calculation unit that needs to be excavated; and the differential calculation unit corresponding to the triangle lower than the corresponding reference height is a calculation unit that needs to be filled.

[0026] Further, the volume of excavation in the region to be analyzed is obtained by the following method based on the calculation unit that needs to be excavated:

[0027] The volume of the triangular prism in the calculation unit that needs to be excavated is obtained by taking the lowest value of the height values of the three vertices of the triangle as the top surface height of the triangular prism and taking the corresponding reference height as the bottom surface height of the triangular prism;

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

[0029] Based on the volume of the triangular prism and the volume of the quadrangular pyramid, the volume of the calculation unit needing excavation is calculated, and the excavation volume in the analysis area is obtained by traversing all the calculation units needing excavation.

[0030] Further, based on the calculation unit needing filling, the filling volume in the analysis area is obtained by the following method:

[0031] The highest value of the three vertices of the triangle is taken as the bottom surface height of the triangular prism, and the corresponding reference height is taken as the top surface height of the triangular prism, and the volume of the triangular prism of the calculation unit needing filling is obtained;

[0032] The lowest two of the three vertices of the triangle and the projection points of the two vertices on the vertical projection of the triangular top surface are taken as the four vertices of the quadrangular pyramid bottom surface, the vertex with the highest height value of the triangle is taken as the vertex of the quadrangular pyramid, and the volume of the quadrangular pyramid is obtained;

[0033] Based on the volume of the triangular prism and the volume of the quadrangular pyramid, the volume of the calculation unit needing filling is calculated, and the filling volume in the analysis area is obtained by traversing all the calculation units needing filling.

[0034] The beneficial effects of the technical scheme are:

[0035] 1. The present application is based on an unmanned aerial vehicle surveying and mapping system, which uses a five-pen camera carried by an unmanned aerial vehicle to conduct regular high-precision surveying and mapping of an open-pit coal mine, provides a comprehensive and reliable data basis for open-pit coal mine safety detection and production evaluation, and obtains digital results including digital orthographic images, digital elevation models, and oblique photography models based on unmanned aerial vehicle surveying and mapping data processing to construct a scene of the open-pit coal mine; combined with digital vector data, a small scene high-precision three-dimensional pseudo-reality is realized, and the ability of a geographic information map is achieved. In the constructed high-precision three-dimensional scene, the spatial data analysis capability is used to perform spatial calculation and analysis on the research area, and the implied geographic information required for open-pit coal mine safety monitoring and production evaluation is obtained, such as providing slope angle, step height and width information, which is used for disaster risk assessment and identification of potential safety hazards; and providing filling or excavation volume data, which provides production evaluation decision basis for production decision makers and provides protection for the operation;

[0036] 2. The method of the present application realizes the rapid and accurate measurement of the slope angle, step height and width by vertical profile interpolation for the region to be detected, and provides a reliable basis for the safety detection of the open coal mine; and through the differential calculation unit division of the coal stacking area, mining area and the like, the accurate calculation and evaluation of the filling and excavation quantities and area are realized, thereby providing effective guarantee for the smooth production.

[0037] 3. The present application constructs the three-dimensional time sequence geographic information library of the region by the fixed time interval and multi-time sequence mapping of the open coal mine, thereby covering the time and space information of the region to meet the demand of the target region business demand calculation for the real-time, dynamic and accuracy of the basic geographic information.

[0038] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present application. The objects and other advantages of the present application will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. BRIEF DESCRIPTION OF DRAWINGS

[0039] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the principles of the application. In the drawings:

[0040] Figure 1 is a flow chart of the open coal mine safety detection and production evaluation method based on unmanned aerial vehicle mapping of the embodiment of the present application;

[0041] Figure 2 is a three-dimensional visualization display diagram of the mapping results of the embodiment of the present application;

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

[0043] Figure 4 is a profile line information schematic diagram of the embodiment of the present application;

[0044] Figure 5 is a triangular net calculation unit display diagram of the embodiment of the present application; Figure 5 a is an excavation calculation unit display diagram, Figure 5 b is a filling calculation unit display diagram;

[0045] Figure 6 is a differential calculation unit calculation result schematic diagram of the embodiment of the present application. DETAILED DESCRIPTION

[0046] Preferred embodiments of the present application will be described in detail below with reference to the drawings, wherein the drawings constitute a part of this application, and are used to explain the principles of the present application, and are not intended to limit the scope of the present application.

[0047] One embodiment of the present application provides an unmanned aerial vehicle surveying and mapping system for open-pit coal mines, as shown in the drawings, the system comprises an unmanned aerial vehicle operation unit, a wireless communication unit and a data processing unit. Figure 1

[0048] Specifically, the unmanned aerial vehicle operation unit comprises an unmanned aerial vehicle, a ground station, and a camera module and a navigation module fixedly arranged on the unmanned aerial vehicle.

[0049] The camera module and the data processing unit, and the unmanned aerial vehicle and the navigation module and the ground station communicate data 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 obtained by the camera module, and to detect the slope angle, step height and width of the open-pit coal mine to be detected, and to detect the filling or excavation volume of the coal mining area, the coal stacking area or the earth stacking area based on the three-dimensional digital twin scene.

[0051] Specifically, the present embodiment performs oblique photogrammetry on the target area through unmanned aerial vehicle field operation; before surveying and mapping, first calibrate the aircraft and lay out the control points; and plan the flight path through the ground station, including planning the flight route, height, speed and other parameters of the unmanned aerial vehicle according to the range, terrain, accuracy requirements and other factors of the surveying and mapping area, and sending the task instructions to the unmanned aerial vehicle through the wireless communication unit to ensure that it collects data according to the predetermined plan, and at the same time, the state of the unmanned aerial vehicle such as flight position, flight attitude, power, signal strength, etc. can be monitored in real time through the ground station during flight, and manual intervention and adjustment can be performed when necessary to ensure flight safety.

[0052] ​Further, in order to obtain the high-resolution texture information of the top surface and side view of the open-pit coal mine and the building, etc. in the rich mining area, for subsequent safety detection and production evaluation, the camera module of the embodiment adopts a high-resolution five-patch camera to synchronously collect images of the open-pit coal mine through five different viewing angles (one vertical angle and four inclined angles) to obtain high-resolution surveying and mapping data of the top surface and side view of the open-pit coal mine. Specifically, the five-patch camera is rigidly installed with the navigation module and is fixedly arranged on the unmanned aerial vehicle support; the five-patch camera is arranged below the belly of the unmanned aerial vehicle; four cameras are fixedly arranged at preset inclined angles, preferably, the four cameras are symmetrically arranged in the left front, right front, left rear and right rear directions, the inclined angles can be set to 30°-45°, and the fifth camera is fixedly arranged perpendicularly at a normal angle, and the five cameras are simultaneously exposed to realize photographing of the ground target from multiple directions, obtain more comprehensive ground information, effectively reduce the photographing dead angle, and provide more accurate data basis for three-dimensional modeling and terrain surveying and mapping.

[0053] Further, after obtaining the surveying and mapping data, the wireless communication unit sends the surveying and mapping data to the data processing 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, the angles of the target point to different position observation points are measured, and then the relative positions of the target points are determined to obtain the planar positions and elevation data of the encrypted control points. That is, through the triangulation operation of the surveying and mapping data, data including digital orthophoto, digital elevation model or oblique photography model can be obtained.

[0054] The digital orthophoto is high-precision image data of the mining area, which contains spatial form information and spatial distribution information of various geographic elements on the surface of the mining area. The digital elevation model provides the altitude of each region within the mining area range, provides three-dimensional height values for the construction of a three-dimensional scene, and also provides height latitude for subsequent profile analysis and fill-dig analysis. The oblique photography model has height and surface texture data, which can provide good visual display effect and also provide height information for profile analysis.

[0055] At the same time, in order to display the space and attribute information of various geographic elements in the mining area and the spatial distribution information of geographic elements, after obtaining the high-precision digital orthophoto of the mining area, the GIS software can be used to generate vector data of the mining area to obtain digital vector data.

[0056] In practical applications, surveying and mapping data needs to be updated regularly and timely to avoid large differences between surveying and mapping data results and actual terrain, affecting the accuracy of safety detection and production evaluation; the embodiment updates the surveying and mapping data in time by regularly surveying and mapping, and records the changes in the terrain and the production situation by establishing a geographic information dataset of the target area with the surveying and mapping time as the index after data processing of the surveying and mapping data.

[0057] After obtaining the geographic information data 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 detection and production evaluation.

[0058] Specifically, in order to realize the sharing of surveying and mapping data and directly load and display geographic information data on the Web, the embodiment processes the surveying and mapping results into a data format that can be loaded by the Web and publishes it as a map service. For example, the geographic information data can be processed by GIS software into a data format that can be used on the Web: the digital orthophoto in the geographic information data is processed into a map tile according to the wms standard, the digital elevation model is processed into a terrain tile, and the oblique photography model is processed into a 3dtile tile; and the processed data is indexed by the surveying and mapping time to establish a three-dimensional geographic information time series dataset of the open-pit coal mine, and published as a web map service for visual rendering.

[0059] The digital orthophoto, digital elevation model and oblique photography model of the open-pit coal mine on the selected date are loaded into the three-dimensional scene using the Vue framework and the Cesium three-dimensional map engine to construct the Web three-dimensional digital twin scene of the open-pit coal mine corresponding to the date; at the same time, the corresponding digital vector data can also be published to the Web, and the digital vector data of the open-pit coal mine is also loaded into the three-dimensional scene to realize the mine area one map, as shown in Figure 2 As shown, the spatial and attribute information of each step or mining area, soil area, and the spatial distribution information of each geographic feature (such as warehouse, building, etc.) can be viewed, as shown in Figure 3 With the vectorized data obtained on different dates, the geographic information of each geographic feature in the mine area changing over time can be observed.

[0060] In practical applications, the digital orthophoto map, digital elevation model or oblique photography model and digital vector data of the open-pit coal mine can be named by region + time + type, and Web service publishing can be performed using Nginx; and the digital elevation model, digital orthophoto map, digital vector data and oblique photography model of each data version can be taken as an independent basic geographic information data package by taking the shooting time as an identifier, and the geographic information data package of the target region can be loaded into a three-dimensional scene through an existing Vue framework and a Cesium three-dimensional map engine to build a Web-end three-dimensional digital twin scene of the mine site. Preferably, the three-dimensional digital twin scene can be built by using a digital elevation model combined with a digital orthophoto map in the mining operation area, and by using a digital elevation model combined with an oblique photography model in the building area, so as to achieve a better visual effect. The three-dimensional scene also supports user-defined switching of different data versions of the basic geographic information data package to achieve the effect of switching the three-dimensional scene of the mine site in different periods.

[0061] Specifically, the data processing unit performs profile detection on the to-be-detected region in the three-dimensional digital twin scene, constructs a vertical profile, and performs safety detection on the slope angle, step height and width of the to-be-detected region based on the vertical profile; and based on the three-dimensional digital twin scene, fills or excavates the coal mining area, coal stacking area or earth stacking area of the target mine area, calculates the volume, and obtains the production evaluation result.

[0062] The to-be-detected region is a region of interest selected by the user in the open-pit coal mine, i.e., a region that needs safety detection including a slope or a step, or a region that needs production evaluation including a coal mining area, a coal stacking area or an earth stacking area.

[0063] Specifically, due to safety needs, the slope of the slope, the height and width of the step need to be strictly limited in the mining operation to prevent the occurrence of safety incidents such as landslides. The data processing unit of the present embodiment provides an interactive profile safety detection function for a three-dimensional scene developed based on Cesium, which is used for safety detection of the open-pit coal mine and mainly includes safety detection of the slope angle, step height and width of the region of interest. The profile safety detection supports user's interactive selection of two points in the three-dimensional scene, performs interpolation between the two points according to the distance by using the interpolation principle, projects the longitude and latitude coordinates of each interpolation point onto the digital elevation model or oblique photography model, obtains the three-dimensional elevation corresponding to each point, and thus constructs a vertical profile line between the two points. After the vertical profile line is constructed, the perpendicular distance, horizontal distance, profile angle and other parameters of the profile line are calculated, and the slope of each point on the profile line is calculated, which provides data basis for safety detection of the slope.

[0064] Preferably, in this embodiment, the three-dimensional digital twin scene is cross-sectionally detected and a vertical cross-section is constructed using the following method:

[0065] Based on the aforementioned 3D digital twin scene, the start and end points of the profile line in the area to be detected are selected. An interpolation method is used to interpolate the distance between the start and end points, including calculating the distance between them and performing equidistant subtraction based on a preset interpolation distance to obtain multiple interpolation points. After completing the interpolation, 3D elevation data of the start, end, and each interpolation point are obtained using a digital elevation model or oblique photogrammetry model. Profile line data is then obtained based on this 3D elevation data. Figure 4 As shown, a vertical profile between the starting point and the ending point is constructed based on the profile line data. Based on the profile line data corresponding to the slope and steps in the vertical profile, the vertical and horizontal distances at each endpoint of the slope and steps are calculated. Based on these vertical and horizontal distances, the slope angle, step height, and width of the area to be detected are obtained. In practical applications, safety thresholds can be set for the slope angle, step height, and width according to the actual conditions of the open-pit coal mine, and compared with the detected slope angle, step height, and width. Warnings and other processing are then performed for safety hazards exceeding the thresholds.

[0066] Furthermore, in the process of open-pit coal mining, it is necessary to accurately calculate the earthwork volume of the coal stockpile area, soil stockpile area, and mining area for production assessment, and to conduct resource allocation and production planning based on the assessment results. A digital elevation model (DEM) or oblique photogrammetry model of a 3D scene can provide elevation references. The triangular network of faces selected using the DEM or oblique photogrammetry model can be used to calculate the earthwork volume of a selected area.

[0067] Preferably, in this embodiment, the filling or excavation of the coal mining area, coal stockpile area, or soil stockpile area of ​​the target mining area is measured and the volume is calculated using the following method:

[0068] Based on the three-dimensional digital twin scene, a Thiessen polygon network is generated for the region to be analyzed; and the polygons in the Thiessen polygon network are segmented to obtain a triangular network; the region to be analyzed includes a coal mining area, a coal stockpile area, or a soil stockpile area.

[0069] The height values ​​of all endpoints on the triangulation network are assigned using a digital elevation model and an oblique photogrammetry model.

[0070] Based on the triangular network after assigning height values, a differential calculation unit is created, and the volume of fill or excavation in the area to be analyzed is obtained based on the differential calculation unit.

[0071] Specifically, a reference height is set for the coal mining area, the coal stacking area or the earth stacking area respectively; a vertical projection is made for each triangle in the triangular network to the horizontal plane of the corresponding reference height, so that a differential calculation unit composed of a triangular prism and a square pyramid is obtained for each triangle, as shown in Figure 5 Fig. a is a diagram showing the calculation unit for excavation, Figure 5 Fig. b is a diagram showing the calculation unit for filling; Figure 5

[0072] The reference heights of the coal mining area, the coal stacking area and the earth stacking area can be set adaptively according to actual application. The reference height of the coal mining area is usually higher than the current ground level, while the reference heights of the coal stacking area and the earth stacking area are usually set as the height of the contact surface between the earth stack or the coal stack and the ground. The differential calculation unit corresponding to the triangle higher than the corresponding reference height is the calculation unit for excavation, and the differential calculation unit corresponding to the triangle lower than the corresponding reference height is the calculation unit for filling.

[0073] Based on each differential calculation unit, the area of the triangle projected to the horizontal plane is calculated by using the Heron formula, so that the filling area, the excavation area and the overall analysis area of the region to be analyzed are obtained.

[0074] Based on the calculation unit for excavation, the excavation volume in the region to be analyzed is obtained by the following method:

[0075] The height of the top surface of the triangular prism is set as the lowest height value of the three vertices of the triangle, and the height of the bottom surface of the triangular prism is set as the corresponding reference height, so that the volume of the triangular prism in the calculation unit for excavation is obtained.

[0076] The four vertices of the bottom surface of the square pyramid are set as the two vertices with the highest height among the three vertices of the triangle and the projection points of the two vertices on the vertical projection of the top surface of the triangular prism, and the vertex of the square pyramid is set as the vertex with the lowest height value of the triangle, so that the volume of the square pyramid is obtained.

[0077] Based on the volume of the triangular prism and the volume of the square pyramid, the volume of the calculation unit for excavation is calculated, and the excavation volume in the region to be analyzed is obtained by traversing all the calculation units for excavation.

[0078] Further, based on the calculation unit for filling, the filling volume in the region to be analyzed is obtained by the following method:

[0079] The height of the bottom surface of the triangular prism is set as the highest height value of the three vertices of the triangle, and the height of the top surface of the triangular prism is set as the reference height, so that the volume of the triangular prism in the calculation unit for filling is obtained.

[0080] ​The volume of the four-sided pyramid is calculated by taking the two lowest vertices of the three vertices of the triangle and the projection points of the two vertices on the vertical projection of the top surface of the triangular prism as the four vertices of the bottom surface of the four-sided pyramid, and taking the vertex of the triangle with the highest height value as the vertex of the four-sided pyramid;

[0081] Based on the volume of the triangular prism and the volume of the four-sided pyramid, the volume of the calculation unit that needs to be filled is calculated; the volume of the filled area in the analysis region is obtained by traversing the volume of all calculation units that need to be filled.

[0082] Illustratively, the analysis region can be drawn by a data processing unit using the Cesium open source map engine. After the analysis region 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 region. A Thiessen polygon is a continuous polygon composed of vertical bisectors connecting two adjacent points. The distance from any point in a Thiessen polygon to the control points of the polygon is less than the distance to other polygon control points. Since the Thiessen polygon is not a triangle, and the sizes of the polygons in the Thiessen polygon network are inconsistent, in order to solve the problem of inconsistent types and sizes of graphics used in subsequent earthwork calculation, all polygons in the Thiessen polygon network need to be cut into a set of triangles; the polygons in the Thiessen polygon network can be segmented using the polygon triangulation library earcut.js to obtain a triangular network; since the coordinates of all endpoints in the obtained triangular network do not have height attributes, it is necessary to assign height values to all endpoints in the triangular network according to the SampleHeight method of the Cesium open source geographic engine combined with the digital elevation model and oblique photography model in the three-dimensional scene. The coordinates of each point in the triangular network are vertically projected onto the digital elevation model and oblique photography model in the three-dimensional scene to obtain the height of the projection position, which is the height value of the endpoint of the triangular network. An overall heighted triangular network (TIN) covering the surface of the three-dimensional scene in the analysis region is obtained;

[0083] Further, traverse the triangular network and vertically project each triangle in the triangular network to the horizontal plane. Since the coal mining area, coal stacking area or soil stacking area of the open-pit coal mine is usually uneven, the projection will construct a combination of a triangular prism and a four-sided pyramid, which can be used as a micro calculation unit for fill and excavation calculation. The calculation units involved in fill and excavation calculation are divided into two types: one is a triangle higher than the reference height, which is a calculation unit that needs to be excavated, and the reference height is the bottom surface height of the triangular prism; the other is a triangle lower than the reference height, which is a calculation unit that needs to be filled, and the reference height is the top surface height of the triangular prism;

[0084] For each differential calculation unit, the area of the bottom triangle can be calculated using the Heron formula, and thus the area of the filling region S1, the area of the excavation region S2, and the overall analysis area S can be calculated;

[0085] For the excavation calculation unit, the lowest height value of the three vertices of the triangle is used as the height of the top surface of the triangular prism, and the reference height is used as the height of the bottom surface of the triangular prism. The volume v1 of the triangular prism in the excavation calculation unit is calculated using the volume formula of the triangular prism. The two vertices with the highest height value of the three vertices of the triangle and the projection points of the two vertices on the vertical projection of the top surface of the triangular prism are used as the four vertices of the bottom surface of the four-sided pyramid. The vertex with the lowest height value of the three vertices of the triangle is used as the vertex of the four-sided pyramid. The volume v2 of the four-sided pyramid is calculated. The volume v of the excavation calculation unit is v1+v2. The volume Vw of the excavation in the analysis region is obtained by traversing all the excavation calculation units.

[0086] For the filling calculation unit, the highest height value of the three vertices of the triangle is used as the height of the bottom surface of the triangular prism, and the reference height is used as the height of the top surface of the triangular prism. The volume v1 of the triangular prism in the excavation calculation unit is calculated using the volume formula of the triangular prism. The two vertices with the lowest height value of the three vertices of the triangle and the projection points of the two vertices on the vertical projection of the top surface of the triangular prism are used as the four vertices of the bottom surface of the four-sided pyramid. The vertex with the highest height value of the three vertices of the triangle is used as the vertex of the four-sided pyramid. The volume v2 of the four-sided pyramid is calculated. The volume v of the filling calculation unit is v1+v2. The volume Vt of the filling in the analysis region is obtained by traversing all the excavation calculation units.

[0087] For example, the present application develops an open-pit coal mine safety detection and production evaluation system based on the aforementioned safety detection and production evaluation method, which is used for surveying and mapping data management, safety detection and production evaluation. Through the system, the surveying and mapping results generated by the surveying and mapping data are processed into a data format that can be loaded by the web end, and these data are published as a map service; and the published data are indexed by the surveying and mapping time to establish a three-dimensional geographic information time series dataset of the open-pit coal mine, and the three-dimensional geographic information time series dataset of the region 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 dataset, which is used for interactive cross-section detection of the three-dimensional scene, construction of vertical sections of elements such as slopes and steps, and realization of detection functions such as slope safety detection, step height and width detection, etc.; and production evaluation based on the three-dimensional geographic information time series dataset, which is used for filling and excavation measurement of regions such as coal mining areas, coal stacking areas, and earth stacking areas of the open-pit coal mine, calculation of the volume, and assistance in coal pile management and yield measurement of the mine area; and the mine surveying and mapping result metadata, mine area geographic element data, cross-section analysis data, and filling and excavation analysis data, etc. can be exported in the form of a report to word, which assists the mine area production.

[0088] The system can perform high-precision measurement and simulation on the coal pile, generate a 3D coal pile model, and realize rapid measurement and management of the coal pile. This helps coal mining enterprises better understand the actual situation of the coal pile, prevent safety accidents in the yard, and optimize the allocation and utilization of coal resources. At the same time, through the high-precision measurement of the unmanned aerial vehicle, the coal production can be more accurately determined, and rapid data acquisition and calculation can be realized, avoiding errors and omissions in the manual operation process. The ultra-clear camera and positioning system carried by the unmanned aerial vehicle 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 slope. In addition, the unmanned aerial vehicle can also conduct inspections of surface subsidence and surface cracks, providing strong support for open-pit coal mine geological measurement and production and operation. The unmanned aerial vehicle can measure the open-pit coal mine at different heights, angles, and perspectives 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, unmanned aerial vehicle surveying and mapping not only improves measurement accuracy but also significantly improves surveying and mapping efficiency. The open-pit coal mining environment is complex and has many safety hazards. Traditional manual measurement methods require personnel to enter high-risk areas, which has high safety risks. Unmanned aerial vehicle surveying and mapping does not require personnel to enter dangerous areas to obtain the required measurement data, thereby greatly reducing the risk of work and improving the safety factor. The system can detect and analyze the long-term operation scene of the open-pit coal mine based on the long-term three-dimensional geographic time series data set of the coal mine area, providing long-term data support and analysis capability support.

[0089] For example, the present embodiment develops an open-pit coal mine safety detection and production evaluation system through a data processing unit. The system can draw the area to be calculated in the three-dimensional scene, and the calculated area is covered by a blue surface, waiting for calculation. According to the actual situation, the elevation datum and precision data for this time of fill and cut analysis calculation are set, the cut unit and fill unit in the analysis area are obtained, and the fill and cut calculation is performed. After the calculation is completed, the calculation results of the area, such as the total analysis area, the fill area (area below the elevation datum), the cut area (area above the elevation datum), the fill volume, and the cut volume, are output. The calculation results are rendered on the three-dimensional page as shown in Figure 6 Each colored prism is a single calculation unit, and 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 cut. The system also supports outputting the spatial data and attribute data of various geographic elements of the open-pit coal mine, the statistical data and alarm data of various profile lines, and the earthwork calculation amount of the mining area and the stacking area as a word format document report, providing reliable data reference for the safety detection and production evaluation of the open-pit coal mine.

[0090] In summary, the embodiment of the present application provides an open coal mine unmanned aerial vehicle surveying and mapping system, which carries a five-puzzle camera through an unmanned aerial vehicle, provides a comprehensive and reliable data basis for open coal mine safety detection and production evaluation, and obtains digital results including digital orthographic image, digital elevation model, oblique photography model, etc. based on unmanned aerial vehicle surveying and mapping data processing to construct the scene of the open coal mine, and realizes small scene high-precision three-dimensional simulation combined with digital vector data, and has the ability of geographic information one map. In the constructed high-precision three-dimensional scene, the spatial data analysis capability is used to perform spatial calculation and analysis on the research area, to obtain the implied geographic information required for open coal mine safety monitoring and production evaluation, such as providing slope angle, step height and width, etc. information, for disaster risk assessment, to identify potential safety hazards; and providing fill, excavation volume, etc. data, to provide production evaluation decision basis for production decision makers, to provide support for operation; the present application realizes rapid and accurate measurement of slope angle, step height and width for the detected area through the vertical section interpolation method, provides a reliable basis for open coal mine safety detection; and through differential calculation unit division of the coal stacking area, mining area, etc., accurate calculation and evaluation of fill, excavation volume and area are realized, to provide effective support for smooth production.

[0091] Those skilled in the art can understand that all or part of the processes of the above-mentioned embodiments can be completed by a computer program instructing related hardware, and the program can be stored in a computer readable storage medium. The computer readable storage medium includes a magnetic disk, an optical disk, a read-only memory or a random access memory, etc.

[0092] The above is only a preferred embodiment of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A UAV mapping system for open-pit coal mines, characterized in that, The system includes: a drone operation unit, a wireless communication unit, and a data processing unit; The unmanned aerial vehicle (UAV) operation unit includes a UAV, a ground station, and a camera module and a navigation module fixedly mounted on the UAV. The camera module and the data processing unit, as well as the UAV and navigation module and the ground station, all communicate with each other via the wireless communication unit. The data processing unit is used to construct a three-dimensional digital twin scene based on the surveying data of the open-pit coal mine acquired by the camera module, and to perform safety detection of the slope angle, step height and width of the area to be detected in the open-pit coal mine based on the three-dimensional digital twin scene, as well as to detect the volume of filling or excavation in the area to be analyzed. The data processing unit constructs a three-dimensional digital twin scene using the following method: Based on the surveying data acquired by the camera module, triangulation is performed to obtain geographic information data including digital orthophotos, digital elevation models, oblique photogrammetry models, and digital vector data; the digital vector data is generated by vectorizing the open-pit coal mine using GIS software. 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 photogrammetry model is processed into 3D tile. The processed data is then indexed by the surveying time to establish a three-dimensional geographic information time series dataset of the open-pit coal mine, and published as a web-based map service for visualization rendering. Using the Vue framework and Cesium 3D map engine, the digital orthophoto, digital elevation model, oblique photogrammetry model, and digital vector data of the open-pit coal mine for the selected date are loaded into the 3D scene to construct a web-based 3D digital twin scene of the open-pit coal mine corresponding to that date. The data processing unit performs fill or excavation volume detection on the area to be analyzed using the following method: Based on the three-dimensional digital twin scene, a Thiessen polygon network is generated for the region to be analyzed; and the polygons in the Thiessen polygon network are segmented to obtain a triangular network; the region to be analyzed includes a coal mining area, a coal stockpile area, or a soil stockpile area. The height values ​​of all endpoints on the triangulation network are assigned using a digital elevation model or oblique photogrammetry model. A reference height is set for the coal mining area, coal stockpile area, or soil stockpile area respectively; each triangle in the triangular network is vertically projected onto the horizontal plane of the corresponding reference height to construct a differential calculation unit composed of triangular prisms and square pyramids for each triangle; wherein, the differential calculation unit corresponding to the triangle above the corresponding reference height is the calculation unit that needs to be excavated; the differential calculation unit corresponding to the triangle below the corresponding reference height is the calculation unit that needs to be filled. Based on the calculation unit requiring excavation, the excavation volume within the area to be analyzed is obtained using the following method: The lowest value of the height of the three vertices of the triangle is taken as the height of the top surface of the triangular prism, and the corresponding reference height is taken as the height of the bottom surface of the triangular prism, so as to obtain the volume of the triangular prism in the calculation unit that needs to be excavated; The volume of the pyramid is obtained by taking the two vertices with the highest height among the three vertices of the triangle and the projection points of the two vertices onto the top surface of the triangular prism as the four vertices of the base of the pyramid, and taking the vertex with the lowest height among the three vertices of the triangle as the vertex of the pyramid. Based on the volumes of the triangular prism and the square pyramid, the volume of the calculation unit that needs to be excavated is calculated. By traversing all the calculation units that need to be excavated, the excavation volume of the area to be analyzed is obtained. Based on the calculation unit requiring fill, the fill volume within the area to be analyzed is obtained using the following method: The highest value of the height of the three vertices of the triangle is taken as the height of the base of the triangular prism, and the corresponding reference height is taken as the height of the top surface of the triangular prism, so as to obtain the volume of the triangular prism of the calculation unit that needs to be filled; The volume of the pyramid is calculated by taking the two vertices with the lowest height among the three vertices of the triangle and the projection points of the two vertices onto the top surface of the triangular prism as the four vertices of the base of the pyramid, and taking the vertex with the highest height of the triangle as the vertex of the pyramid. Based on the volume of the triangular prism and the volume of the square pyramid, the volume of the calculation unit that needs to be filled is calculated; by traversing the volumes of all calculation units that need to be filled, the filling volume within the region to be analyzed is obtained.

2. The open-pit coal mine unmanned aerial vehicle (UAV) mapping system according to claim 1, characterized in that, The camera module is a five-camera system; the five-camera system and the navigation module are rigidly integrated and fixedly mounted on the drone bracket; The five cameras are positioned under the fuselage of the drone; four cameras are fixed at a preset tilt angle, and the fifth camera is fixed at a normal angle; all five cameras are exposed simultaneously.

3. The open-pit coal mine unmanned aerial vehicle (UAV) mapping system according to claim 2, 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 onboard business status monitoring of the UAV.

4. The open-pit coal mine unmanned aerial vehicle (UAV) mapping system according to claim 1, characterized in that, 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 on the slope angle, step height, and width of the area to be detected based on the vertical profile. The vertical profile is constructed using the following method: Based on the three-dimensional digital twin scene, the start and end points of the profile line of the area to be detected are selected. An interpolation method is used to interpolate the distance between the start and end points. The three-dimensional elevation data of the start point, end point, and each interpolation point are obtained using the digital elevation model or oblique photogrammetry model. Profile line data is obtained based on the three-dimensional elevation data. The vertical profile between the start and end points is constructed based on the profile line data.

5. The open-pit coal mine unmanned aerial vehicle (UAV) mapping system according to claim 4, characterized in that, Based on the profile line data corresponding to the slope and steps in the vertical profile, the vertical distance and horizontal distance of each endpoint of the slope and steps are calculated; based on the vertical distance and horizontal distance, the slope angle, step height and width of the area to be detected are obtained.

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