Building measurement method based on remote sensing of unmanned aerial vehicle

Abstract

The invention discloses a building measurement method based on unmanned aerial vehicle remote sensing, and relates to the technical field of building measurement, and the method comprises the steps: obtaining the initial position information of an unmanned aerial vehicle through a GPS, measuring the surrounding building information, constructing an initial three-dimensional building model, recording the movement track of the unmanned aerial vehicle, randomly extracting track points in the movement track, and carrying out the measurement of the unmanned aerial vehicle. The method has the advantages that by extracting the track points and calculating the distance between the track points and the adjacent tracks, the coverage integrity of the current layer can be verified, repeated measurement or missed measurement is avoided, data are extracted according to a preset period, redundant sampling is avoided, and the method is high in practicability and easy to popularize. Coverage of key point locations is guaranteed while the data size is reduced, the overall measurement time is shortened, measurement modes of a laser radar, a millimeter wave radar and an ultrasonic radar are divided into a measurement unit, a verification unit and an auxiliary measurement mode, and abnormal data are recognized and removed through data comparison of different combinations.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of building surveying, and particularly relates to a building surveying method based on unmanned aerial vehicle remote sensing. BACKGROUND

[0002] As a basic link of engineering construction, city planning and building informatization, the technical requirement of building surveying is continuously upgraded with the development of the building industry, and traditional building surveying mainly relies on manual ground surveying equipment such as total station and level, and gradually builds the building contour through single-point surveying, meanwhile, the rise of building informatization, digital twin city and other technologies puts forward new requirements of 'high precision, high efficiency and full elements' for building surveying. When the common building surveying method is used, the prior art mainly adopts a single time interval or a single space interval, does not dynamically adjust in combination with the unmanned aerial vehicle speed and the building structure complexity, and is inconvenient to verify the coverage degree through the track point distance calculation, so that holes are generated on the model surface for measuring the building, and the edge curvature is not dynamically adjusted, so that partial area is prone to be missed, therefore, the application provides a building surveying method based on unmanned aerial vehicle remote sensing. SUMMARY

[0003] The application aims to provide a building surveying method based on unmanned aerial vehicle remote sensing.

[0004] To achieve the above object, the application provides the following technical scheme: a building surveying method based on unmanned aerial vehicle remote sensing, the building surveying method comprises the following steps: S100, obtaining initial position information of the unmanned aerial vehicle by using GPS, measuring surrounding building information, and obtaining initial building information; S200, constructing an initial three-dimensional building model by using the initial building information, and setting a period time and a space distance , sequentially using the period time and the space distance to extract building information measured by the unmanned aerial vehicle, and simultaneously constructing a multi-layer framework, setting an adjacent distance threshold value for the multi-layer framework , wherein the adjacent distance threshold value is 50 cm; S300, setting a measurement unit and a verification unit, respectively extracting a measurement mode of the initial building information for the measurement unit and the verification unit, and taking the remaining one measurement mode as an auxiliary measurement mode used in the measurement unit; S400, formulating a weight for the measurement mode in the measurement unit and the auxiliary measurement mode, and then perfecting the size of the building in the initial three-dimensional building model by using the building information and data obtained by the measurement unit and the verification unit, and obtaining an output building model.

[0005] ​As a further scheme of the present application: in the S200, when recording the moving track of the unmanned aerial vehicle in the multi-layer framework, a track point is extracted from the moving track randomly, and the straight line distance between the track point and the adjacent moving track is less than the adjacent distance threshold value At this time, the building information measurement of a single level in the multi-layer framework is completed, and then the building information measurement of the remaining levels is performed until the building information measurement of all levels in the multi-layer framework is completed, so as to obtain multi-angle building measurement data. As a further scheme of the present application: in the S200, the use permission of the cycle time is higher than that of the spatial distance, and when extracting the building information measured by the unmanned aerial vehicle, the building information obtained at the first time is regarded as the original point building information, and then the moving speed of the unmanned aerial vehicle is set, and when the unmanned aerial vehicle moves at the set moving speed for a time After that, the building information measured at the current position of the unmanned aerial vehicle is obtained. After the measurement of the building information is completed, the unmanned aerial vehicle is controlled to move again, and at this time, when the spatial distance After that, the building information is measured by the unmanned aerial vehicle again, and then when the building information is measured by the unmanned aerial vehicle next time, the cycle time is used as a standard to determine the position of the next measurement. In the S200, the user has the permission to edit the number of layers of the multi-layer framework and the adjacent distance threshold value. When recording the moving track of the unmanned aerial vehicle, the range size value of the measured building is obtained, and a solid measurement model is constructed in the multi-layer framework by using the range size value of the measured building, and the edge line of the solid measurement model is divided to form a closed solid measurement model, so as to obtain a closed model. When the unmanned aerial vehicle moves to the edge line of the closed model, the moving direction of the unmanned aerial vehicle is actively adjusted, so that the unmanned aerial vehicle translates along the edge line, and the moving track of the unmanned aerial vehicle is extracted, and the extraction distance is set. The extraction distance is a track segment threshold value set by the user, and the default value is 2m. According to the extraction distance, the moving track of the unmanned aerial vehicle is divided into X track segments, the edge line is regarded as a fixed track, and then the fixed track is regarded as the moving track of the unmanned aerial vehicle.

[0006] As a further scheme of the present application: in the S200, after the track segments are obtained, the starting point and the ending point of different track segments are taken as track points, the track points are mapped to the adjacent moving track, at this time, the line segment of the track point reaching the adjacent moving track is a mapping line, and the mapping line has a perpendicular relationship with the adjacent moving track, the distance values of different track points and the adjacent moving track are calculated, the distance values are sorted in descending order, the first distance value and the corresponding track point are extracted, and a target point is obtained.

[0007] As a further scheme of the present application: in the S200, after the target point is obtained, the middle point of the mapping line is intercepted, and the middle point is extended to the edge line of the closed model, so as to obtain an extension line of the middle point, and the extension line and the adjacent moving track are in parallel, and the intersection point of the extension line and the edge line is taken as an extension intersection point, and the unmanned aerial vehicle is controlled to move to the extension intersection point, and the unmanned aerial vehicle moves along the extension line of the middle point.

[0008] As a further scheme of the present application: in the S200, the distance value of the different track points and the adjacent moving track The calculation formula is as follows: ; Wherein is the three-dimensional space position of the track point, is the intersection point of the mapping line and the adjacent moving track, and the intersection point coordinates are calculated by the foot formula: assuming that the adjacent track is a vector , the track point , and the intersection point .

[0009] As a further scheme of the present application: in the S300, the user has the right to edit the number of building measurement methods, and the number of auxiliary measurement methods is , wherein is the total number of building measurement methods, and the building measurement methods include laser radar, millimeter wave radar and ultrasonic wave radar, and the total number .

[0010] As a further scheme of the present application: in the S400, after the weight is determined, the influence of the building information measured by the auxiliary measurement method on the building information in the measurement unit is determined according to the weight of the auxiliary measurement method, and the building values measured in the measurement unit and the building values measured by the auxiliary measurement method are extracted synchronously, so as to calculate the building values finally output by the measurement unit , and the calculation formula is as follows: ; Wherein is the weight of the auxiliary measurement method, is the weight of the measurement unit, is the building value measured in the measurement unit, is the building value measured by the auxiliary measurement method.

[0011] By adopting the above technical scheme, compared with the prior art, the present application has the beneficial effects that: 1、The present application can verify the coverage integrity of the current layer by extracting trajectory points and calculating the distance from adjacent trajectories, avoid repeated measurement or missed measurement, and extract data at a preset period to avoid redundant sampling, reduce the amount of data while ensuring the coverage of key points, complete each layer measurement from bottom to top, simultaneously build the basic framework of the three-dimensional model, measure and model at the same time, shorten the overall measurement time, split the measurement methods of laser radar, millimeter wave radar and ultrasonic radar into measurement units, verification units and auxiliary measurement methods, identify and eliminate abnormal data through comparison of different combinations of data; 2、The present application ensures the timeliness of data in dynamic scenes and guarantees the sampling density in static scenes, and constructs a closed model based on the size of the building range, so that the UAV measurement range is clear, the probability of flying out of the building area or missing the edge structure is reduced, the edge line of the closed model is used as a trajectory constraint, so that the UAV flies along the building contour, improves the geometric consistency of the model surface and the actual building, improves the measurement integrity, and accurately quantifies the trajectory distance through the perpendicular relationship between the mapping line and the adjacent trajectory, avoiding the subjective error of traditional manual judgment; 3、The present application makes the UAV move along the extension line of the edge line, so that the trajectory and the building surface keep equidistant, avoiding edge missing caused by deviation of turning angle, and the unified distance calculation method facilitates comparison of measurement data of different projects and different equipment, improves the reusability of data, makes the scheme more scalable, and the auxiliary measurement method can make up for the shortcomings of the main sensor and improve the data reliability. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 The method flowchart in the embodiments of the present application is shown. DETAILED DESCRIPTION

[0013] The specific embodiments of the present application will be further described below with reference to the accompanying drawings, and it should be noted that the description of these embodiments is used to help understand the present application, but does not constitute a limitation on the present application.

[0014] In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0015] Embodiment one: The present invention discloses a building measurement method based on drone remote sensing. In the conservation work of ancient buildings such as the Yingxian Wooden Pagoda in Shanxi Province, the building structures have undergone thousands of years of erosion, with hidden dangers such as deformation of brackets and cracking of beams and columns. Traditional measurement methods require manual climbing of scaffolding for contact measurement, which may cause secondary damage to the fragile wooden structure and make it difficult to capture three-dimensional data of complex components such as cornices and caissons. In this case, the building measurement method based on drone remote sensing uses multi-sensor fusion technology to perform non-contact scanning of the building, which can quickly obtain millimeter-level precision point cloud data and construct a complete three-dimensional model. Therefore, in order to effectively solve the above problems, this application proposes a building measurement method based on drone remote sensing, as shown in the accompanying drawings of the specification. Figure 1 As shown, the building measurement method includes the following steps: S100, using GPS to obtain initial location information of the drone, measuring surrounding building information, and obtaining initial building information; S200: Build an initial 3D building model using initial building information and set a cycle time and spatial distance , sequentially use the cycle time and spatial distance to extract the building information measured by the drone, and simultaneously build a multi-layer framework and set the adjacent distance threshold for the multi-layer framework , where the adjacent distance threshold 50cm; In S200, when recording the movement trajectory of the drone in the multi-layer framework, a trajectory point is randomly extracted from the movement trajectory, and the straight-line distance between the trajectory point and the adjacent movement trajectory is , then the building information measurement of a single layer in the multi-layer framework is completed, and then the building information measurement of the remaining layers is carried out until the building information measurement of all layers in the multi-layer framework is completed, thereby obtaining multi-angle building measurement data; S300, setting a measurement unit and a verification unit, extracting measurement methods of initial building information from the measurement unit and the verification unit respectively, and using the remaining measurement method as an auxiliary measurement method in the measurement unit; S400, weighting the measurement methods and auxiliary measurement methods in the measurement unit, and then improving the dimensions of the building in the initial three-dimensional building model using the building information and data obtained by the measurement unit and the verification unit to obtain an output building model; 3D architectural model building software such as SketchUp, Autodesk Revit and Autodesk 3ds Max.

[0016] Specifically, obtain the initial position information of the drone, measure the surrounding building information, use the initial building information to build the initial 3D building model, and set the cycle time and spatial distance , sequentially use the cycle time and spatial distance to extract the building information measured by the drone, and at the same time build a multi-layer framework, record the movement trajectory of the drone in the multi-layer framework, randomly extract the trajectory point in the movement trajectory, and the straight-line distance between the trajectory point and the adjacent movement trajectory At this time, the building information measurement of a single layer in the multi-layer framework is completed, and then the building information measurement of the remaining layers is carried out until the building information measurement of all layers in the multi-layer framework is completed. The measurement method of the initial building information is extracted for the measurement unit and the verification unit respectively, and the remaining measurement method is used as an auxiliary measurement method in the measurement unit. Weights are set for the measurement methods and auxiliary measurement methods in the measurement unit, and then the initial building model is improved through the building information obtained from the measurement unit and the verification unit to obtain the output building model.

[0017] Example 2: In S200, the permission to use the cycle time is higher than the permission to use the spatial distance, and when extracting the building information measured by the drone, the building information obtained at the first time is regarded as the origin building information, and then the moving speed of the drone is set. When the drone moves at the set moving speed, the time Then obtain the building information measured at the current position of the drone; After completing the measurement of the building information, control the drone to move again. At this time, when the drone moves the spatial distance After that, the drone is used to measure the building information again, and then the next time the drone is used to measure the building information, the cycle time is used. Determine the location for the next measurement for the standard; S200, the user has the authority to edit the number of layers and the adjacent distance threshold of the multi-layer framework; When the drone's movement trajectory is recorded, the range dimension values ​​of the measured building are obtained, and a stereo measurement model is constructed in a multi-layer framework based on the range dimension values ​​of the measured building. At the same time, the edge lines of the stereo measurement model are divided to form a closed stereo measurement model, thereby obtaining a closed model. S200, after the closed model is formed, transmits the closed model data to the UAV; When the drone moves to the edge of the closed model, the drone's movement direction is actively adjusted so that the drone moves along the edge. At the same time, the drone's movement trajectory is extracted and the extraction distance is set. The extraction distance is the trajectory segmentation threshold set by the user, with a default value of 2m. The drone's moving trajectory is divided into X segments based on the extraction distance, and the edge lines are regarded as fixed trajectories, and then the fixed trajectories are regarded as the drone's moving trajectory; In S200, after the trajectory segments are obtained, the starting points and ending points of different trajectory segments are taken as trajectory points, the trajectory points are mapped to adjacent moving trajectories, at this time, the line segment of the trajectory point reaching the adjacent moving trajectory is a mapping line, and the mapping line and the adjacent moving trajectory are in a perpendicular relationship, the distance values of different trajectory points and the adjacent moving trajectories are calculated, the distance values are sorted in descending order, the first distance value and the corresponding trajectory point are extracted, and a target point is obtained; where X is an unknown number; Specifically, when extracting building information measured by the unmanned aerial vehicle, the building information obtained at the first time is regarded as the original point building information, then the moving speed of the unmanned aerial vehicle is set, the building information measured at the current position of the unmanned aerial vehicle is obtained, after the measurement of the building information is completed, the unmanned aerial vehicle is controlled to move again to measure the building information, when the moving trajectory of the unmanned aerial vehicle is recorded, the range size value of the measured building is obtained, and a solid measurement model is constructed in a multi-layer framework according to the range size value of the measured building, and the edge line of the solid measurement model is divided to form a closed solid measurement model, the closed model data is transmitted to the unmanned aerial vehicle, when the unmanned aerial vehicle moves to the edge line of the closed model, the moving direction of the unmanned aerial vehicle is actively adjusted, the unmanned aerial vehicle is translated along the edge line, the moving trajectory of the unmanned aerial vehicle is extracted, the extraction distance is set, the moving trajectory of the unmanned aerial vehicle is divided into X trajectory segments according to the extraction distance, the edge line is regarded as a fixed trajectory, the fixed trajectory is included in the judgment of adjacent moving trajectories, after the trajectory segments are obtained, the starting points and ending points of different trajectory segments are taken as trajectory points, the trajectory points are mapped to adjacent moving trajectories, at this time, the line segment of the trajectory point reaching the adjacent moving trajectory is a mapping line, and the mapping line and the adjacent moving trajectory are in a perpendicular relationship, the first distance value and the corresponding trajectory point are extracted.

[0018] Example three: In S200, after the target point is obtained, the middle point of the mapping line is intercepted, the middle point is extended to the edge line of the closed model to obtain an extension line of the middle point, and the extension line and the adjacent moving trajectory are in a parallel state, at this time, the intersection point of the extension line and the edge line is taken as an extension intersection point, the unmanned aerial vehicle is controlled to move to the extension intersection point, and the unmanned aerial vehicle is moved along the extension line of the middle point; In S200, the distance values of different trajectory points and adjacent moving trajectories The calculation formula is as follows: ; where is the three-dimensional space position of the trajectory point, is the intersection point of the mapping line and the adjacent moving trajectory, and the intersection point coordinates are calculated by the foot formula: assuming that the adjacent trajectory is a vector , the trajectory point , and the intersection point ; In S300, the user has the right to edit the number of building measurement methods, and the number of auxiliary measurement methods is , wherein is the total number of building measurement methods, including laser radar, millimeter wave radar, ultrasonic radar, and the total number ; In S400, after the weight is determined, the influence of the building information measured by the auxiliary measurement method on the building information in the measurement unit is determined according to the weight of the auxiliary measurement method, and the building values measured in the measurement unit and the building values measured by the auxiliary measurement method are extracted synchronously, so as to calculate the final output building values of the measurement unit , and the calculation formula is as follows: ; , wherein is the weight of the auxiliary measurement method, is the weight of the measurement unit, is the building value measured in the measurement unit, is the building value measured by the auxiliary measurement method; Specifically, the middle point of the mapping line is intercepted, and the middle point is extended to the edge line of the closed model to obtain an extension line of the middle point, and the extension line and the adjacent moving track are in parallel state, and the intersection point of the extension line and the edge line is taken as the extension intersection point, at this time, the unmanned aerial vehicle is controlled to move to the extension intersection point, and the unmanned aerial vehicle moves along the extension line of the middle point, and the distance values of different track points and adjacent moving tracks are calculated , according to the weight of the auxiliary measurement method, the influence of the building information measured by the auxiliary measurement method on the building information in the measurement unit is determined, and the building values measured in the measurement unit and the building values measured by the auxiliary measurement method are extracted synchronously, so as to calculate the final output building values of the measurement unit .

[0019] Although the present application is disclosed in the preferred embodiments as above, it is not intended to limit the present application, and any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present application. Therefore, any modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, without departing from the technical solutions of the present application, fall within the protection scope defined by the claims of the present application.

Claims

1. A building measurement method based on drone remote sensing, characterized in that: The building measurement method comprises the following steps: S100, using GPS to obtain initial location information of the drone, measuring surrounding building information, and obtaining initial building information; S200: Build an initial 3D building model using initial building information and set a cycle time and spatial distance , sequentially use the cycle time and spatial distance to extract the building information measured by the drone, and simultaneously build a multi-layer framework and set the adjacent distance threshold for the multi-layer framework , where the adjacent distance threshold 50cm; S300, setting a measurement unit and a verification unit, extracting measurement methods of initial building information from the measurement unit and the verification unit respectively, and using the remaining measurement method as an auxiliary measurement method in the measurement unit; S400: weighting the measurement methods and auxiliary measurement methods in the measurement unit, and then improving the dimensions of the building in the initial three-dimensional building model using the building information and data obtained from the measurement unit and the verification unit to obtain an output building model.

2. The method for building measurement based on drone remote sensing according to claim 1, characterized in that: In the S200, when recording the movement trajectory of the drone in the multi-layer framework, a trajectory point is randomly extracted from the movement trajectory, and the straight-line distance between the trajectory point and the adjacent movement trajectory is calculated. At this time, the building information measurement of a single layer in the multi-layer framework is completed, and then the building information measurement of the remaining layers is carried out until the building information measurement of all layers in the multi-layer framework is completed, thereby obtaining multi-angle building measurement data.

3. The method for building measurement based on drone remote sensing according to claim 2, characterized in that: In the above S200, the permission to use the cycle time is higher than the permission to use the spatial distance, and when extracting the building information measured by the drone, the building information obtained at the first time is regarded as the origin building information, and then the moving speed of the drone is set. When the drone moves at the set moving speed, the time Then obtain the building information measured at the current position of the drone; After completing the measurement of the building information, control the drone to move again. At this time, when the drone moves the spatial distance After that, the drone is used to measure the building information again, and then the next time the drone is used to measure the building information, the cycle time is used. Determine the location for the next measurement for the standard; In the above S200, the user has the authority to edit the number of layers and the adjacent distance threshold of the multi-layer framework; When the drone's moving trajectory is recorded, the range dimension values ​​of the measured building are obtained, and a three-dimensional measurement model is constructed in a multi-layer framework based on the range dimension values ​​of the measured building. At the same time, the edge lines of the three-dimensional measurement model are divided to form a closed three-dimensional measurement model, thereby obtaining a closed model.

4. The method for building measurement based on drone remote sensing according to claim 3, characterized in that: After the closed model is formed, the closed model data is transmitted to the UAV in S200; When the drone moves to the edge of the closed model, the drone's movement direction is actively adjusted so that the drone moves along the edge. At the same time, the drone's movement trajectory is extracted and the extraction distance is set. The extraction distance is the trajectory segmentation threshold set by the user, with a default value of 2m. The drone's moving trajectory is divided into X segments based on the extraction distance, and the edge line is regarded as a fixed trajectory, which is then regarded as the drone's moving trajectory.

5. The method for building measurement based on drone remote sensing according to claim 4, characterized in that: In S200, after the trajectory segments are obtained, the starting points and end points of different trajectory segments are included as trajectory points, and the trajectory points are mapped to adjacent moving trajectories. At this time, the line segment where the trajectory point reaches the adjacent moving trajectory is the mapping line, and the mapping line and the adjacent moving trajectory are in a perpendicular relationship. The distance values ​​between different trajectory points and adjacent moving trajectories are calculated, and the distance values ​​are sorted in descending order. The first distance value and the corresponding trajectory point are extracted to obtain the target point.

6. The method for building measurement based on drone remote sensing according to claim 5, characterized in that: In S200, after the target point is obtained, the middle point of the mapping line is intercepted, and the extension is performed with the middle point as the starting point, so that the middle point is extended to the edge line of the closed model, and the extension line of the middle point is obtained, and the extension line is parallel to the adjacent moving trajectory. At this time, the intersection of the extension line and the edge line is used as the extension intersection. At this time, the drone is controlled to move to the extension intersection and move along the extension line of the middle point.

7. The method for building measurement based on drone remote sensing according to claim 5, characterized in that: In the above S200, the distance values ​​between different trajectory points and adjacent moving trajectories The calculation formula is as follows: ； in is the three-dimensional spatial position of the trajectory point, The intersection of the mapping line and the adjacent moving trajectory is calculated by the perpendicular foot formula: let the adjacent trajectory be the vector , trajectory point , then the intersection .

8. The method for building measurement based on drone remote sensing according to claim 1, characterized in that: In S300, the user has the authority to edit the number of building measurement methods, and the number of auxiliary measurement methods is ,in is the total number of building measurement methods, including lidar, millimeter wave radar, and ultrasonic radar. .

9. The method for building measurement based on drone remote sensing according to claim 1, characterized in that: In S400, after the weights are determined, the influence of the building information measured by the auxiliary measurement method on the building information in the measurement unit is determined according to the weights of the auxiliary measurement method, and the building values ​​measured in the measurement unit and the building values ​​measured by the auxiliary measurement method are simultaneously extracted, thereby calculating the building values ​​finally output by the measurement unit. , which is calculated as follows: ； in is the weight of the auxiliary measurement method, is the weight of the measurement unit, is the building value measured in the measurement unit, The building values ​​measured by auxiliary measurement methods.

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