Unmanned aerial vehicle route planning method for vertical dam close photography
By calculating the optimal distance and waypoint coordinates between the route plane and the vertical embankment, and generating a standard KML route file, the problems of cumbersome UAV route planning process and insufficient image resolution were solved, and efficient and accurate vertical embankment monitoring was achieved.
Patent Information
- Application Number
- CN202510798529.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-16
- Publication Date
- 2025-09-16
AI Technical Summary
Existing drone route planning methods are cumbersome and time-consuming for close-up photography of vertical embankments, and fail to balance safety and image resolution, resulting in data redundancy and waste of drone energy.
By calculating the optimal distance between the route plane and the vertical embankment, planning the number and coordinates of waypoints, and combining camera parameters and safe flight altitude, a standard KML route file is generated to ensure image resolution and safety.
It achieves efficient and accurate acquisition of vertical dam position information, improves the three-dimensional reconstruction effect, and reduces drone energy consumption and route planning time.
Smart Images
Figure CN120653011A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of unmanned aerial vehicle (UAV) navigation, and in particular relates to a UAV route planning method for close-up photography of vertical dams. Background Art
[0002] In water conservancy projects, dams serve as critical flood control and water storage facilities. Their structural stability directly impacts public safety and the lifespan of the project, necessitating regular monitoring. Drone monitoring addresses the inefficiency, high cost, and inaccessibility of high-risk areas associated with traditional manual monitoring. The images captured by drones at close range provide accurate and reliable data for deformation analysis and 3D model reconstruction.
[0003] Currently, close-up drone photography is mostly performed using Agisoft Metashape software. The process involves: capturing the entire area → building a rough model → dividing the area → setting the route → importing the route → close-up photography. This process is cumbersome, time-consuming, and inefficient. Furthermore, the number of waypoints is manually assigned, without considering the area captured for each photo. This leads to data redundancy and wasteful drone energy consumption. Furthermore, for close-up photography of vertical levees, existing drone route planning is affected by the water surface, making it difficult to balance safety and image resolution. Summary of the Invention
[0004] In view of the shortcomings of the existing technology, the technical problem to be solved by the present invention is to provide a UAV route planning method for close-up photography of vertical embankments.
[0005] The present invention solves the technical problem by adopting the following technical solutions:
[0006] A method for planning a drone route for close-up photography of a vertical embankment, comprising the following steps:
[0007] Step 1: Calculate the optimal distance between the flight path plane and the vertical embankment;
[0008]
[0009] Where H d represents the optimal distance between the flight path plane and the vertical embankment, H s Indicates safe flight altitude, θ h Indicates the camera's vertical viewing angle;
[0010] Step 2: Determine the flight path plane based on the optimal distance between the flight path plane and the vertical embankment, obtain the coordinates of the flight path plane control points in the geodetic coordinate system, and obtain the coordinates of the flight path plane control points in the spatial rectangular coordinate system through coordinate conversion;
[0011] Step 3: Plan the number of waypoints and calculate the coordinates of each waypoint;
[0012] Horizontal shooting width of a single photo:
[0013]
[0014] Vertical width of a single photo:
[0015]
[0016] Area for a single photo:
[0017]
[0018] Where θ v Indicates the camera's horizontal viewing angle;
[0019] Horizontal width of flight plane:
[0020]
[0021] Vertical height of flight plane:
[0022]
[0023] Where (x1, y1, z1), (x2, y2, z2), and (x3, y3, z3) represent the coordinates of the bottom, upper left, and lower right control points of the route plane in the spatial rectangular coordinate system respectively;
[0024] Camera horizontal movement distance:
[0025] Y v =(1-D o )W v (10)
[0026] Camera vertical movement distance:
[0027] Y h =(1-D o )W h (11)
[0028] Number of horizontal waypoints in the route plane:
[0029]
[0030] Number of waypoints in the vertical direction of the route plane:
[0031] Where, Indicates rounding up, D o Indicates the degree of overlap with the photographic photo;
[0032] Total number of waypoints:
[0033] n=n v ·n h (14)
[0034] The coordinates of each waypoint in the spatial rectangular coordinate system are calculated using formula (15):
[0035]
[0036] Where s i =(i-1)Y v +0.5W v , t j =(j-1)Y h +0.5W h ,(x i,j ,y i,j ,z i,j ) represents the coordinates of the waypoint (i, j) in the spatial rectangular coordinate system;
[0037] Through iterative solution, the coordinates of each waypoint in the spatial rectangular coordinate system are converted to the geodetic coordinate system to obtain the coordinates of each waypoint in the geodetic coordinate system;
[0038] Step 4: Calculate the pitch angle and heading angle of the drone at each waypoint;
[0039] Calculate two vectors on the flight plane and Calculate the normal vector of the flight plane and the unit normal vector of the flight plane Calculate the pitch angle of the drone and heading angle in, is the unit vector in the Z-axis direction, Represents the normal vector of the flight plane Projection in the Y and X axis directions;
[0040] Step 5: Generate a standard KML route file based on the coordinates of each waypoint in the geodetic coordinate system and the pitch angle and heading angle of the drone at each waypoint. The drone traverses each waypoint in sequence according to the standard KML route file to achieve close-up photography of the vertical embankment.
[0041] Compared with the prior art, the present invention has the following beneficial effects:
[0042] The optimal distance between the flight plane and the vertical embankment is calculated based on camera parameters and a safe flight altitude to ensure image resolution. This prevents excessive distance between the drone and the vertical embankment, which can lead to poor image resolution and, in turn, poor 3D reconstruction of the vertical embankment. The safe flight altitude is combined with the photographic baseline to determine the flight plane for close-up photography. The minimum number of waypoints is determined based on factors such as the flight plane size, overlap between close-up photos, the area captured in a single photo, and the camera's travel distance. The coordinates of each waypoint are then calculated to achieve route planning. This allows for efficient and accurate acquisition of vertical embankment location information. By constructing a standard KML flight path file, the goal of automatic close-up photography is achieved. BRIEF DESCRIPTION OF THE DRAWINGS
[0043] Figure 1 It is the overall flow chart of the present invention;
[0044] Figure 2 is a schematic diagram of the route plane in the present invention;
[0045] Figure 3 Schematic diagram of the relationship between the geodetic coordinate system and the spatial rectangular coordinate system in the present invention;
[0046] Figure 4 Schematic diagram of each waypoint in the present invention;
[0047] Figure 5 Schematic diagram of the three-dimensional model of the vertical dam in the present invention. DETAILED DESCRIPTION
[0048] Specific embodiments are given below in conjunction with the accompanying drawings. The specific embodiments are only used to introduce the technical solutions of the present invention in detail and are not intended to limit the scope of protection of the present application.
[0049] The present invention provides a method for planning a UAV route for close-up photography of a vertical dam, comprising the following steps:
[0050] Step 1: Obtain camera sensor parameters and safe flight altitude to calculate the optimal distance between the flight path plane and the vertical embankment;
[0051] The camera sensing parameters include focal length f, width w and height h; the safe flight altitude H is determined based on factors such as wave height, obstacles, and water surface height. s , it is recommended to be ≥5m; calculate the optimal distance H between the flight plane and the vertical embankment d , the calculation formula is:
[0052]
[0053] Where θ h Indicates the vertical viewing angle of the camera.
[0054] Step 2: Determine the flight plane, obtain the coordinates of the flight plane control points in the geodetic coordinate system, and obtain the coordinates of the flight plane control points in the spatial rectangular coordinate system through coordinate conversion;
[0055] Use a drone equipped with an RTK module to fly to the vertical embankment in front of H d The spatial quadrilateral plane completely covered by the UAV's perspective and parallel to the vertical embankment is used as the flight path plane. The UAV flies to the upper left and upper right control points of the flight path plane to collect images, and the coordinates of the upper left and upper right control points of the flight path plane in the geodetic coordinate system are recorded. The coordinates of the lower and lower right control points of the flight path plane in the geodetic coordinate system are determined in combination with the height of the vertical embankment.
[0056] Alternatively, combining the water surface and the optimal distance between the route plane and the vertical embankment, a spatial quadrilateral plane can be fitted using map software with coordinate information. The spatial quadrilateral plane that can completely cover the vertical embankment can be determined as the route plane, and the coordinates of the four control points of the route plane in the geodetic coordinate system can be directly obtained.
[0057] For a schematic diagram of the flight path, see Figure 2 The plane size of the route is 1.1 to 1.2 times the vertical embankment area.
[0058] The coordinates of the control points of the flight path plane in the geodetic coordinate system are converted to the spatial rectangular coordinate system to obtain the coordinates of the control points of the flight path plane in the spatial rectangular coordinate system. The conversion formula is:
[0059]
[0060] In the formula, (x k ,y k ,z k ) represents the coordinate of the control point k of the route plane in the spatial rectangular coordinate system, and k is 1, 2, 3, and 4, representing the lower left, lower right, upper left, and upper right control points of the route plane respectively; (B k ,L k ,H k ) represents the coordinates of the route plane control point k in the geodetic coordinate system, B k , L k 、H k are the longitude, latitude, and altitude of the route plane control point k, N is the radius of the earth's circumference, and e 2 is the first eccentricity of the Earth.
[0061] Figure 3It is a schematic diagram of the relationship between the geodetic coordinate system and the spatial rectangular coordinate system. For a point P in three-dimensional space, the geodetic coordinate system describes the spatial position of point P with longitude B, latitude L, and altitude H. The spatial rectangular coordinate system describes the spatial position of point P with X, Y, and Z coordinates. The reference ellipsoid represents the earth.
[0062] Step 3: Plan the number of waypoints and calculate the coordinates of each waypoint;
[0063] According to the size of the flight plane and the overlap degree of the close-up photographs D o (generally required to be greater than 70%), the shooting area of a single photo, the camera movement distance, etc., calculate the number of waypoints;
[0064] Horizontal shooting width of a single photo:
[0065]
[0066] Vertical width of a single photo:
[0067]
[0068] Area for a single photo:
[0069]
[0070] The horizontal viewing angle of the camera:
[0071]
[0072] Horizontal width of flight plane:
[0073]
[0074] Vertical height of flight plane:
[0075]
[0076] Camera horizontal movement distance:
[0077] Y v =(1-D o )W v (10)
[0078] Camera vertical movement distance:
[0079] Y h =(1-D o )W h (11)
[0080] Number of horizontal waypoints in the route plane:
[0081]
[0082] Number of waypoints in the vertical direction of the route plane:
[0083] Where, Indicates rounding up;
[0084] Total number of waypoints:
[0085] n=n v ·n h (14)
[0086] The coordinates of each waypoint in the spatial rectangular coordinate system are calculated using formula (15):
[0087]
[0088] Where s i =(i-1)Y v +0.5W v , t j =(j-1)Y h +0.5W h ,(x i,j ,y i,j ,z i,j ) represents the coordinates of the waypoint (i, j) in the spatial rectangular coordinate system;
[0089] Starting from the lower left of the route plane and in an S-shaped direction, number each waypoint sequentially from 1 to n, and then convert the waypoint distribution form from a two-dimensional matrix to a one-dimensional array, then we have:
[0090]
[0091] P(index(i,j))=(x i,j ,y i,j ,z i,j ) (17)
[0092] Where index(i,j) is the one-dimensional number corresponding to the waypoint (i,j), and P(index(i,j)) represents the coordinates of the waypoint numbered index(i,j) in the spatial rectangular coordinate system;
[0093] Through iterative solution, the coordinates of each waypoint in the spatial rectangular coordinate system are converted to the geodetic coordinate system to obtain the coordinates of each waypoint in the geodetic coordinate system; the conversion formula is:
[0094]
[0095] Where, (L index(i,j) ,B index(i,j ),H index(i,j)) represents the coordinates of the waypoint numbered index(i,j) in the geodetic coordinate system;
[0096] In this embodiment, the focal length of the camera lens is 12.29 mm, the width and height are 17.4 mm and 13 mm respectively, the overlap of close-up photos is 70%, the safe flight altitude is 5 m, and the optimal distance between the flight path plane and the vertical embankment is calculated to be 10 m. The total number of waypoints is 32. The position diagram of each waypoint on the flight path plane can be seen in Figure 4 .
[0097] Step 4: Calculate the pitch angle and heading angle of the UAV at each waypoint to characterize the UAV's flight attitude;
[0098] Arbitrarily select three control points on the route plane, whose coordinates in the spatial rectangular coordinate system are P1 = (x1, y1, z1), P2 = (x2, y2, z2) and P3 = (x3, y3, z3); calculate the two vectors on the route plane and According to the vector and Calculate the normal vector of the flight plane Further calculate the unit normal vector of the flight plane Calculate the pitch angle of the drone and heading angle in, is the unit vector in the Z-axis direction, that is, (0,0,1); Represents the normal vector of the flight plane Projection in the Y and X axis directions.
[0099] Step 5: Generate a standard KML route file based on the coordinates of each waypoint in the geodetic coordinate system and the pitch angle and heading angle of the drone at each waypoint; import the standard KML route file into the drone, so that the drone traverses each waypoint in sequence and takes real-life photos of the vertical embankment at each waypoint to achieve close-up photography of the vertical embankment.
[0100] The real-life photos of the vertical embankment taken at each waypoint were imported into the model reconstruction software Agisoft Metashape to reconstruct a 3D model of the vertical embankment for 3D visual monitoring of the vertical embankment. The overall schematic diagram of the 3D model of the vertical embankment is shown in Figure 5 .
[0101] Any matters not described in the present invention are applicable to the prior art.
Claims
1. A method for planning a drone route for close-up photography of vertical embankments, characterized in that: The steps include: Step 1: Calculate the optimal distance between the flight path plane and the vertical embankment; Where H d represents the optimal distance between the flight path plane and the vertical embankment, H s Indicates safe flight altitude, θ h Indicates the camera's vertical viewing angle; Step 2: Determine the flight path plane based on the optimal distance between the flight path plane and the vertical embankment, obtain the coordinates of the flight path plane control points in the geodetic coordinate system, and obtain the coordinates of the flight path plane control points in the spatial rectangular coordinate system through coordinate conversion; Step 3: Plan the number of waypoints and calculate the coordinates of each waypoint; Horizontal shooting width of a single photo: Vertical width of a single photo: Area for a single photo: Where θ v Indicates the camera's horizontal viewing angle; Horizontal width of flight plane: Vertical height of flight plane: Where (x1, y1, z1), (x2, y2, z2), and (x3, y3, z3) represent the coordinates of the bottom, upper left, and lower right control points of the route plane in the spatial rectangular coordinate system respectively; Camera horizontal movement distance: Y v =(1-D o )W v (10) Camera vertical movement distance: Y h =(1-D o )W h (11) Number of horizontal waypoints in the route plane: Number of waypoints in the vertical direction of the route plane: Where, Indicates rounding up, D o Indicates the degree of overlap with the photographic photo; Total number of waypoints: n=n v ·n h (14) The coordinates of each waypoint in the spatial rectangular coordinate system are calculated using formula (15): Where s i =(i-1)Y v +0.5W v , t j =(j-1)Y h +0.5W h ,(x i,j ,y i,j ,z i,j ) represents the coordinates of the waypoint (i, j) in the spatial rectangular coordinate system; Through iterative solution, the coordinates of each waypoint in the spatial rectangular coordinate system are converted to the geodetic coordinate system to obtain the coordinates of each waypoint in the geodetic coordinate system; Step 4: Calculate the pitch angle and heading angle of the drone at each waypoint; Calculate two vectors on the flight plane and Calculate the normal vector of the flight plane and the unit normal vector of the flight plane Calculate the pitch angle of the drone and heading angle in, is the unit vector in the Z-axis direction, Represents the normal vector of the flight plane Projection in the Y and X axis directions; Step 5: Generate a standard KML route file based on the coordinates of each waypoint in the geodetic coordinate system and the pitch angle and heading angle of the drone at each waypoint. The drone traverses each waypoint in sequence according to the standard KML route file to achieve close-up photography of the vertical embankment.
2. The method for planning a UAV route for close-up photography of a vertical dam according to claim 1, characterized in that: The determination of the flight path plane includes: the UAV flies to the vertical embankment front H d At the location, a quadrilateral plane completely covered by the UAV and parallel to the vertical embankment is used as the flight path plane; alternatively, the flight path plane is determined by fitting based on the optimal distance between the water surface and the flight path plane and the vertical embankment; the size of the flight path plane is 1.1 to 1.2 times the area of the vertical embankment.
3. The method for planning a UAV route for close-up photography of a vertical dam according to claim 1 or 2, characterized in that: In the third step, starting from the lower left of the route plane, the waypoints are numbered sequentially in an S-shaped direction, and the waypoint distribution is converted into a one-dimensional array, which is: P(index(i,j))=(x i,j ,y i,j ,z i,j )(17) Where index(i,j) is the one-dimensional number corresponding to the waypoint (i,j), and P(index(i,j)) represents the coordinates of the waypoint numbered index(i,j) in the spatial rectangular coordinate system; The conversion formula for the waypoint coordinates in the spatial rectangular coordinate system to the geodetic coordinate system is: Where, (L index (i,j),B index (i,j),H index ( i,j )) represents the coordinates of the waypoint numbered index(i,j) in the geodetic coordinate system, N is the radius of the earth's circumference, e 2 is the first eccentricity of the Earth.