A method and system for three-dimensional mapping of unmanned aerial vehicles based on airborne multi-viewing angles

Abstract

The present invention discloses a method and system for three-dimensional mapping of unmanned aerial vehicles based on airborne multi-viewing angles, the method comprising: starting from the initial area of ​​the target object, determining the mapping starting point according to the top contour line of the target object, detecting the distance data sequence from the unmanned aerial vehicle to each point on the intersection line segment S of the side of the target object, and calculating the critical distance corresponding to the tilted viewing angle and making a size judgment, determining whether the unmanned aerial vehicle descends for mapping according to the judgment result, thereby entering the subsequent cyclic mapping step, merging and processing all mapping data to obtain the final target object unmanned aerial vehicle three-dimensional mapping data. Through the above scheme, the method of the present invention controls the unmanned aerial vehicle to perform three-dimensional mapping according to the photographic data corresponding to the changing airborne photography tilted viewing angle, solves the top occlusion problem in the three-dimensional mapping of unmanned aerial vehicles, and significantly improves the accuracy of the three-dimensional mapping results and the user experience.

Description

Technical Field

[0001] The present application belongs to the field of UAV mapping technology, and in particular relates to a UAV three-dimensional mapping method and system based on airborne multi-viewing angles. Background Art

[0002] UAV photography technology collects images from different angles such as vertical, horizontal, and tilt by equipping the UAV platform with multiple sensors, such as infrared distance sensors, high spatial resolution array digital cameras, and GPS / Beidou positioning systems, so as to obtain more complete and accurate information about ground objects. The image data is processed through data cleaning, image processing, data registration, data fusion and splicing, and three-dimensional processing, and finally a three-dimensional model is generated through mapping. This technology has the advantages of high efficiency, low hardware cost, and flexibility in executing tasks. Its characteristics are that it can truly reflect the situation of ground objects and effectively obtain image information such as ground object texture, and is widely used in the market.

[0003] At present, the three-dimensional mapping of drones on the market is mainly suitable for a wide range of wide-area vision environments. In this environment, the three-dimensional model mapping of specific targets still has many shortcomings. The first is the lack of detail accuracy. The accuracy of drone mapping is mainly related to the accuracy of the camera system and the workspace. Drone mapping is usually based on three-dimensional mapping of remote vision. Under this condition, the modeling accuracy of small textures of target objects (such as the external window structure of a building and the texture of top tiles) is insufficient; secondly, the blind spots of the mapping vision have a great impact on the mapping results. For example, buildings with eaves structures, single-eaved pavilions or multi-eaved pavilions, hollow buildings, special structural buildings, tree-shaped vegetation, bridges and tunnels, etc., these ground objects have many blind spots in vision. Whether it is vertical photography or oblique photography technology, the mapping data generated will inevitably have data gaps or losses due to blind spots in vision, affecting the final modeling results. In order to solve the above problems, the existing technology adopts a variety of different types of technologies including data blanking, texture filling, and limiting model angles, but inevitably there is a problem of large-scale model distortion.

[0004] The information disclosed in the background technology section of the present invention is only intended to deepen the understanding of the general background technology of the present invention, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art already known to those skilled in the art. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a three-dimensional mapping method and system for unmanned aerial vehicle based on airborne multi-perspective.

[0006] Specifically, the present application claims an airborne multi-perspective UAV three-dimensional mapping method, the method comprising the steps of:

[0007] S110, determining an initial area of ​​the target object to be three-dimensionally mapped and a top contour line of a vertical projection of the initial area onto the ground;

[0008] S120, take any point T on the top contour line, take its projection point on the ground as T', and obtain the intersection line of the side surface of the target object with the normal line passing through point T and perpendicular to the horizontal plane, obtain the current hovering position of the drone, the hovering position is the normal direction of the point T, the horizontal distance from point T is X, and the vertical distance is Y, let the line segment of the intersection line with point T as the starting point and close to the side of the drone be the side intersection line segment S, obtain the drone oblique photography data, based on the oblique viewing angle The change of the distance data sequence from the drone to each point on the side intersection line S of the target object is detected. And calculate the tilt angle The corresponding critical distance ;

[0009] S130, obtain the current tilt angle for , execute the mapping algorithm:

[0010] i. Adjust the tilt angle according to the step length that meets the surveying accuracy Get smaller if you tilt your viewing angle If the corresponding target object has reached the bottom of the object, then go to step iii;

[0011] ii. Determine the current tilt angle Corresponding distance data Critical distance Size: If , then the drone is controlled to save the 3D mapping data of the current initial area of ​​the target object and use it at an oblique angle. The corresponding target object area is the new initial area of ​​the target object, and the process re-enters step S110; if , then the drone is controlled to save the 3D mapping data of the current initial area of ​​the target object and the drone is made to descend in altitude , , indicating the current tilt viewing angle The corresponding hollow height of the target object is taken as the target object initial area with the same height as the current drone, and step S110 is re-entered;

[0012] iii. Clean and fuse the saved 3D mapping data of all areas of the target object to obtain the final UAV 3D mapping data of the target object.

[0013] Further, in the step iii, if , after controlling the drone to save the 3D mapping data of the current initial area of ​​the target object and before the drone is ordered to descend, a model library matching is first performed. The model library stores conventional object measurement models. When the matching is successful, the 3D mapping data of the corresponding area is obtained based on the successfully matched mapping model, and the tilt angle is adjusted. , the target object area corresponding to it is taken as the new initial area of ​​the target object, and the process goes back to step S110; if the matching is unsuccessful, the subsequent steps are continued.

[0014] Furthermore, before step S110, drone photography data is acquired, the target object to be mapped is identified, and the top area of ​​the target object is used as the initial area of ​​the target object.

[0015] Furthermore, after the target object to be mapped is identified, the initial three-dimensional model of the target object is displayed on the console; the initial three-dimensional model of the target object does not have a hollow feature; when the drone is controlled to save the three-dimensional mapping data of the current initial area of ​​the target object, the initial three-dimensional model of the target object is updated based on the three-dimensional mapping data and displayed synchronously on the console.

[0016] Furthermore, after the target object to be mapped is identified, the initial three-dimensional model of the target object is displayed on the console; control points are manually marked in the initial three-dimensional model of the target object through the console operation interface; and the flight trajectory of the drone when performing the three-dimensional mapping task is determined based on the control points.

[0017] A multi-view UAV 3D mapping system is also provided, including

[0018] A top area determination module, used to determine an initial area of ​​a target object to be three-dimensionally mapped and a top contour line of a vertical projection of the initial area onto the ground;

[0019] The critical distance determination module takes an arbitrary point T on the top contour line, takes its projection point on the ground as T', and obtains the intersection line of the side surface of the target object with the normal line passing through point T and perpendicular to the horizontal plane, obtains the current hovering position of the drone, the hovering position is the normal direction of the point T, the horizontal distance from point T is X, and the vertical distance is Y, and the line segment with point T as the starting point and close to the side of the drone in the intersection line is the side intersection line segment S, obtains the drone oblique photography data, and based on the oblique viewing angle The change of the distance data sequence from the drone to each point on the side intersection line S of the target object is detected. And calculate the tilt angle The corresponding critical distance = ;

[0020] Mapping algorithm execution module, used to obtain the current tilt angle for , execute the mapping algorithm:

[0021] i. Adjust the tilt angle according to the step length that meets the surveying accuracy Get smaller if you tilt your viewing angle If the corresponding target object has reached the bottom of the object, then go to step iii;

[0022] ii. Determine the current tilt angle Corresponding distance data Critical distance Size: If , then the drone is controlled to save the 3D mapping data of the current initial area of ​​the target object and use it at an oblique angle. The corresponding target object area is the new initial area of ​​the target object, and the top area determination module is called again; if , then the drone is controlled to save the 3D mapping data of the current initial area of ​​the target object and the drone is made to descend in altitude , , indicating the current tilt viewing angle The corresponding hollow height of the target object is taken as the initial area of ​​the target object, and the top area determination module is called again;

[0023] iii. Clean and fuse the saved 3D mapping data of all areas of the target object to obtain the final UAV 3D mapping data of the target object.

[0024] Further, in the mapping algorithm execution module, in the step iii, if , after controlling the drone to save the 3D mapping data of the current initial area of ​​the target object and before the drone is ordered to descend, a model library matching is first performed. The model library stores conventional object measurement models. When the matching is successful, the 3D mapping data of the corresponding area is obtained based on the successfully matched mapping model, and the tilt angle is adjusted. , the target object area it corresponds to is taken as the new initial area of ​​the target object, and the top area determination module is called again; if the matching is unsuccessful, the subsequent steps are continued.

[0025] Furthermore, before calling the top area determination module, the drone photography data is obtained, the target object to be mapped is identified, and the top area of ​​the target object is used as the initial area of ​​the target object.

[0026] Furthermore, after the target object to be mapped is identified, the initial three-dimensional model of the target object is displayed on the console; the initial three-dimensional model of the target object does not have a hollow feature; when the drone is controlled to save the three-dimensional mapping data of the current initial area of ​​the target object, the initial three-dimensional model of the target object is updated based on the three-dimensional mapping data and displayed synchronously on the console.

[0027] Furthermore, after the target object to be mapped is identified, the initial three-dimensional model of the target object is displayed on the console; control points are manually marked in the initial three-dimensional model of the target object through the console operation interface; and the flight trajectory of the drone when performing the three-dimensional mapping task is determined based on the control points.

[0028] The present invention provides an airborne multi-view UAV three-dimensional mapping method and system. The method starts with the initial area of ​​the target object, determines the mapping starting point according to the top contour line of the target object, and detects the distance data sequence of each point on the intersection line segment S between the UAV and the side of the target object. And calculate the tilt angle The corresponding critical distance The size is judged and the UAV is determined to descend for mapping according to the judgment result, so as to enter the subsequent cycle mapping step, merge and process all mapping data to obtain the final target object UAV three-dimensional mapping data. The corresponding photographic data is used to control the drone to perform three-dimensional mapping, which solves the problem of top occlusion in drone three-dimensional mapping. In particular, it can handle the distortion of mapping data caused by multi-layer occlusion, significantly improve the accuracy of three-dimensional mapping results, and enhance user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art description. Obviously, the drawings described below are only used to illustrate some embodiments of the present application. For ordinary technicians in this field, without paying creative work, they can also obtain other technical features, connection relationships and even method steps not mentioned in the drawings based on these drawings.

[0030] Figure 1 This is a flow chart of an airborne multi-view UAV three-dimensional mapping method provided by an embodiment of the present invention;

[0031] Figure 2 This is a structural diagram of an airborne multi-view UAV three-dimensional mapping system provided by an embodiment of the present invention;

[0032] Figure 3 is a hardware structure diagram of an electronic device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0034] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example. In addition, the terms "including" and "corresponding to" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0035] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0036] Embodiment 1: Figure 1 As shown, the present invention provides an airborne multi-perspective UAV three-dimensional mapping method, the method comprising the steps of:

[0037] S110, determining an initial area of ​​the target object to be three-dimensionally mapped and a top contour line of a vertical projection of the initial area onto the ground;

[0038] The drone photography data contains a variety of object data. Usually, certain specific types of target objects will cause distortion of the surveying and mapping data due to the existence of blind spots in the field of vision. Therefore, before executing step S110 of the core algorithm, the above-mentioned specific types of target objects should be located and identified first. The drone photography data can be obtained to identify the target objects to be surveyed, such as buildings with eaves structures (such as single-eave pavilions or multi-eave pavilions), hollow buildings, special structure buildings, tree-shaped vegetation, bridges and tunnels, etc. In one embodiment, the top surface image data of conventional target objects is obtained based on the orthographic method, and a conventional type target object library is set based on the acquired top surface image data set, and the target object is identified based on the similarity matching method of the target object library. Target recognition is performed only based on the orthographic top surface image, which reduces the amount of data processing. In another embodiment, the target object is manually identified in the image data obtained by drone photography.

[0039] After the target object is determined, the target object area that is first subjected to 3D scanning is used as the initial area. When the algorithm starts, the initial area is usually the top area of ​​the target object. When the algorithm loop is entered, the initial area gradually moves down in the target object. The specific movement method will be described in more detail in the subsequent embodiments. The top contour line of the vertical projection of the initial area onto the ground is obtained through the orthographic data.

[0040] S120, take any point T on the top contour line, take its projection point on the ground as T', and obtain the intersection line of the side surface of the target object with the normal line passing through point T and perpendicular to the horizontal plane, obtain the current hovering position of the drone, the hovering position is the normal direction of the point T, the horizontal distance from point T is X, and the vertical distance is Y, let the line segment of the intersection line with point T as the starting point and close to the side of the drone be the side intersection line segment S, obtain the drone oblique photography data, based on the oblique viewing angle The change of detection UAV to each point on the intersection line segment S of the target object side distance data sequence , and oblique viewing angles The corresponding critical distance = ;

[0041] The drone is located on the side of any point T on the top contour line of the target object, with the horizontal distance from point T being X and the vertical distance being Y. The drone's pan-tilt inhibition device controls the pan-tilt angle, and the maximum pitch angle of the tilt camera device scanning the target object should be able to meet Therefore, the specific parameter values ​​of X and Y are determined by the performance of the drone gimbal device and the requirements for accuracy. After determining the spatial position of the drone, the distance data sequence of each point on the intersection line segment S between the drone and the side of the target object can be detected from the drone's oblique photography data. In one embodiment, the spatial positions of a series of points on the side intersection line segment S can be located first, and then the spatial distance data sequence from the drone to the target point can be determined by distance detection or oblique photography data. .

[0042] S130, obtain the current tilt angle for , execute the mapping algorithm:

[0043] i. Adjust the tilt angle according to the step length that meets the surveying accuracy Get smaller if you tilt your viewing angle If the corresponding target object has reached the bottom of the object, then go to step iii;

[0044] ii. Determine the current tilt angle Corresponding distance data Critical distance The size of the drone is determined based on the judgment result.

[0045] Since the projection area of ​​the top structure of the target object is larger than the projection area of ​​other parts, when the drone faces the target object in the tilted photography space, the top structure blocks other parts, that is, the blind area of ​​vision. The size of the blind area of ​​vision is affected by the photography space position of the drone. Corresponding distance data Critical distance The size of the visual field is used to determine whether there is a blind spot. When , it means that the distance from other parts of the object to the drone is smaller than the distance from the corresponding part on the top vertical line to the drone, and there is no obstruction at this time; on the contrary, when When , it means that the distance from the other parts of the object to the drone is greater than the distance from the corresponding part on the top vertical line to the drone, and the other parts of the object are concave relative to the top structure, and there is occlusion at this time. Moreover, there must be no occlusion in the initial area of ​​the target object, and drone 3D mapping can be directly realized.

[0046] like , then save the 3D mapping data of the current initial area of ​​the target object and use it as an oblique perspective The corresponding target object area is the new initial area of ​​the target object, and step S110 is re-entered. In this case, there is no occlusion. After entering step S110, the drone continues the mapping algorithm based on the current position and the re-determined initial area, and the three-dimensional mapping can be completed without moving the drone, saving drone battery energy, saving workload, and improving image processing efficiency.

[0047] like , then the drone is controlled to save the 3D mapping data of the current initial area of ​​the target object and the drone is made to descend in altitude , , indicating the current tilt viewing angle The corresponding hollow height of the target object is obtained, and the target object area with the same height as the current drone is obtained as the initial area of ​​the target object, and step S110 is re-entered. In this case, there is occlusion, and the drone can accurately map by bypassing the top occlusion by descending the altitude. After descending the altitude, the target object area with the same height as the current drone is taken as the initial area of ​​the target object, and step S110 is re-entered. The descent operation is performed only when there is occlusion, and mapping can be achieved directly at the original spatial position when there is no occlusion. As a significant effect, the above algorithm can solve the blind spot problem of multi-layer occlusion. Specifically, if the target object is a double-eaved pavilion structure or other special-shaped structure, there are 2 or more blind spots of the target object for the mapping drone. The above algorithm sets the tilt angle The steps become smaller to determine whether there is a blind spot layer by layer. If there is a blind spot, the drone will be lowered and the tilt angle will be reset. The mapping algorithm is repeatedly executed, thereby efficiently solving the problem of multiple blind spots caused by multiple layers of occlusion in a single target object. In a preferred embodiment, after the drone descends, the three-dimensional mapping data of the target object area at the same height as the current drone is saved by horizontal photography; the horizontal photography is controlled by the pan-tilt device; or, after the drone descends, the drone is controlled to approach the target object by a preset distance according to the actual hollowing of the target object, and the three-dimensional mapping data is continued to be obtained by conventional methods.

[0048] iii. Perform data cleaning, data registration and data fusion on the saved 3D mapping data of all areas of the target object to obtain the final UAV 3D mapping data of the target object.

[0049] Each execution of the mapping algorithm will save the current 3D mapping data of the target object. When the mapping algorithm terminates, all the saved 3D mapping data constitute the complete 3D mapping data of the target object. After cleaning all the above 3D mapping data, and then undergoing mapping data processing such as data registration and data fusion, the final 3D mapping data of the target object can be obtained.

[0050] In a preferred embodiment, in step iii, if , after controlling the drone to save the 3D mapping data of the current initial area of ​​the target object and before the drone is ordered to descend, a model library matching is first performed. The model library stores conventional object measurement models. When the matching is successful, the 3D mapping data of the corresponding area is obtained based on the successfully matched mapping model, and the tilt angle is adjusted. , the target object area corresponding to it is the new initial area of ​​the target object, and step S110 is re-entered; if the match is unsuccessful, the subsequent steps are continued. In one embodiment, the target object that has been scanned can be added to the model library based on experience, so that subsequent surveying and mapping of target objects of the same type can be matched based on the model library. In one embodiment, the surveying and mapping data of the top model of the target object can be obtained based on the orthographic data, and the type of the target object can be identified based on the surveying and mapping data of the top model, which reduces the data processing amount of target identification and improves the matching efficiency of the model library.

[0051] In one embodiment, considering that not all occlusions need to be processed, the data loss caused by small occlusions can be ignored under the oblique photography technology, and whether it needs to be processed is also related to the actual needs of the user. Therefore, a preset comparison threshold parameter m is set in the mapping algorithm, and the distance data is Critical distance Perform the assignment operation before the comparison, so , so that the distance data Slightly smaller than (related to the size of m) In this case, there is still no need to lower the drone to bypass the obstruction, and target mapping can be completed at the original camera position. The comparison threshold m can be set to 1 meter or 0.5 meter according to the accuracy and performance requirements.

[0052] In a preferred embodiment, after the target object to be mapped is identified, the initial 3D model of the target object is displayed on the console; control points are manually marked in the initial 3D model of the target object through the console operation interface; and the flight trajectory of the drone when performing the 3D mapping task is determined based on the control points. In one embodiment, multiple arbitrary points are taken on the top contour line of the initial area to form a set , traverse the set elements, and repeat the above mapping algorithm according to each traversed element to obtain accurate three-dimensional mapping data of the target object in all directions. Preferably, for the hollow target object of the through structure type, the set elements can be set to 2, respectively located at the two ends of the top contour line; for the hollow target object of the eaves structure type, the set elements can be set to 4, respectively located at the four vertices of the top contour line; for the hollow target object of the special-shaped type, the set elements can be set according to the actual situation; for the hollow target object of the symmetrical type, the number of set elements can be halved according to the symmetry based on the above setting method.

[0053] In a preferred embodiment, after the target object to be mapped is identified, the initial 3D model of the target object is displayed on the console; the initial 3D model of the target object has not been updated with mapping data, so it does not have hollow features; when the drone is controlled to save the 3D mapping data of the current initial area of ​​the target object, the initial 3D model of the target object is updated based on the 3D mapping data and displayed on the console synchronously. Specifically, the model details of the target object in the current direction are updated according to the scanning situation of the drone in the current direction, and the model details of the target object in the current direction are updated according to the scanning situation of the drone in the collection. Points in Scan the position of the target object and update the corresponding points The initial 3D model of the target object is updated synchronously, and the detailed surveying and mapping data of the target object is gradually displayed on the console, which significantly improves the user experience of surveying and mapping work.

[0054] Embodiment 2: Figure 2 As shown, the present invention provides an airborne multi-view UAV three-dimensional mapping system, comprising:

[0055] A top area determination module, used to determine an initial area of ​​a target object to be three-dimensionally mapped and a top contour line of a vertical projection of the initial area onto the ground;

[0056] The critical distance determination module takes an arbitrary point T on the top contour line, takes its projection point on the ground as T', and obtains the intersection line of the side surface of the target object with the normal line passing through point T and perpendicular to the horizontal plane, obtains the current hovering position of the drone, the hovering position is the normal direction of the point T, the horizontal distance from point T is X, and the vertical distance is Y, and the line segment with point T as the starting point and close to the side of the drone in the intersection line is the side intersection line segment S, obtains the drone oblique photography data, and based on the oblique viewing angle The change of the distance data sequence from the drone to each point on the side intersection line S of the target object is detected. And calculate the tilt angle The corresponding critical distance = ;

[0057] Mapping algorithm execution module, used to obtain the current tilt angle for , execute the mapping algorithm:

[0058] i. Adjust the tilt angle according to the step length that meets the surveying accuracy Get smaller if you tilt your viewing angle If the corresponding target object has reached the bottom of the object, then go to step iii;

[0059] ii. Determine the current tilt angle Corresponding distance data Critical distance Size: If , then the drone is controlled to save the 3D mapping data of the current initial area of ​​the target object and use it at an oblique angle. The corresponding target object area is the new initial area of ​​the target object, and the top area determination module is called again; if , then the drone is controlled to save the 3D mapping data of the current initial area of ​​the target object and the drone is made to descend in altitude , , indicating the current tilt viewing angle The corresponding hollow height of the target object is taken as the initial area of ​​the target object, and the top area determination module is called again;

[0060] iii. Clean and fuse the saved 3D mapping data of all areas of the target object to obtain the final UAV 3D mapping data of the target object.

[0061] In a preferred embodiment, in the mapping algorithm execution module, in step iii, if , after controlling the drone to save the 3D mapping data of the current initial area of ​​the target object and before the drone is ordered to descend, a model library matching is first performed. The model library stores conventional object measurement models. When the matching is successful, the 3D mapping data of the corresponding area is obtained based on the successfully matched mapping model, and the tilt angle is adjusted. , the target object area it corresponds to is taken as the new initial area of ​​the target object, and the top area determination module is called again; if the matching is unsuccessful, the subsequent steps are continued.

[0062] In a preferred embodiment, before calling the top area determination module, drone photography data is acquired, the target object to be mapped is identified, and the top area of ​​the target object is used as the initial area of ​​the target object.

[0063] In a preferred embodiment, after the target object to be mapped is identified, the initial three-dimensional model of the target object is displayed on the console; the initial three-dimensional model of the target object does not have a hollow feature; when the drone is controlled to save the three-dimensional mapping data of the current initial area of ​​the target object, the initial three-dimensional model of the target object is updated based on the three-dimensional mapping data and displayed synchronously on the console.

[0064] In a preferred embodiment, after the target object to be mapped is identified, the initial three-dimensional model of the target object is displayed on the console; control points are manually marked in the initial three-dimensional model of the target object through the console operation interface; and the flight trajectory of the drone when performing the three-dimensional mapping task is determined based on the control points.

[0065] The present invention provides an airborne multi-view UAV three-dimensional mapping method and system. The method starts with the initial area of ​​the target object, determines the mapping starting point according to the top contour line of the target object, and detects the distance data sequence of each point on the intersection line segment S between the UAV and the side of the target object. And calculate the tilt angle The corresponding critical distance The size is judged and the UAV is determined to descend for mapping according to the judgment result, so as to enter the subsequent cycle mapping step, merge and process all mapping data to obtain the final target object UAV three-dimensional mapping data. The corresponding photographic data is used to control the drone to perform three-dimensional mapping, which solves the problem of top occlusion in drone three-dimensional mapping. In particular, it can handle the distortion of mapping data caused by multi-layer occlusion, significantly improve the accuracy of three-dimensional mapping results, and enhance user experience.

[0066] like Figure 3 As shown, according to one embodiment, a program product such as a machine-readable medium is provided. The machine-readable medium may have instructions (i.e., the above-mentioned elements implemented in the form of software), which, when executed by a machine, causes the machine to execute the above-mentioned combination of various embodiments of this specification. Figure 1 Specifically, a system or device equipped with a readable storage medium may be provided, on which a software program code implementing the functions of any of the above-mentioned embodiments is stored, and a computer or processor of the system or device reads and executes the instructions stored in the readable storage medium.

[0067] In this case, the program code itself read from the machine-readable medium can realize the function of any one of the above embodiments, and thus the machine-readable code and the machine-readable storage medium storing the machine-readable code constitute part of this specification.

[0068] Examples of readable storage media include floppy disks, hard disks, magneto-optical disks, optical disks (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD-RW), magnetic tapes, non-volatile memory cards, and ROMs. Optionally, the program code may be downloaded from a server computer or a cloud via a communication network.

[0069] Those skilled in the art should understand that the various embodiments disclosed above can be modified and altered in various ways without departing from the essence of the invention. Therefore, the protection scope of this specification should be defined by the appended claims.

[0070] It should be noted that not all steps and units in the above-mentioned processes and system structure diagrams are necessary, and some steps or units can be ignored according to actual needs. The execution order of each step is not fixed and can be determined as needed. The device structure described in the above-mentioned embodiments can be a physical structure or a logical structure, that is, some units may be implemented by the same physical client, or some units may be implemented by multiple physical clients, or some components in multiple independent devices may be implemented together.

[0071] In the above embodiments, the hardware unit or module can be implemented mechanically or electrically. For example, a hardware unit, module or processor can include permanent dedicated circuits or logic (such as special processors, FPGA or ASIC) to complete the corresponding operation. The hardware unit or processor can also include programmable logic or circuits (such as general-purpose processors or other programmable processors), which can be temporarily set by software to complete the corresponding operation. The specific implementation method (mechanical method, or dedicated permanent circuit, or temporarily set circuit) can be determined based on cost and time considerations.

[0072] The specific embodiments described above in conjunction with the accompanying drawings describe exemplary embodiments, but do not represent all embodiments that can be implemented or fall within the scope of protection of the claims. The term "exemplary" used throughout this specification means "used as an example, instance or illustration" and does not mean "preferred" or "having advantages" over other embodiments. For the purpose of providing an understanding of the described technology, the specific embodiments include specific details. However, these technologies can be implemented without these specific details. In some instances, in order to avoid making the concepts of the described embodiments difficult to understand, well-known structures and devices are shown in block diagram form.

[0073] The above description of the present disclosure is provided to enable any person of ordinary skill in the art to implement or use the present disclosure. Various modifications to the present disclosure will be apparent to those of ordinary skill in the art, and the general principles corresponding to the present disclosure may be applied to other variations without departing from the scope of protection of the present disclosure. Therefore, the present disclosure is not limited to the examples and designs described herein, but is consistent with the widest range of principles and novel features disclosed herein.

Claims

1. A method for three-dimensional mapping of an airborne multi-view UAV, the method comprising the steps of: S110, determining an initial area of ​​the target object to be three-dimensionally mapped and a top contour line of a vertical projection of the initial area onto the ground; S120, take any point T on the top contour line, take its projection point on the ground as T', and obtain the intersection line of the side surface of the target object with the normal line passing through point T and perpendicular to the horizontal plane, obtain the current hovering position of the drone, the hovering position is the normal direction of the point T, the horizontal distance from point T is X, and the vertical distance is Y, let the line segment of the intersection line with point T as the starting point and close to the side of the drone be the side intersection line segment S, obtain the drone oblique photography data, based on the oblique viewing angle The change of the distance data sequence from the drone to each point on the side intersection line S of the target object is detected. And calculate the tilt angle The corresponding critical distance = ; S130, obtain the current tilt angle for , execute the mapping algorithm: i. Adjust the tilt angle according to the step length that meets the surveying accuracy Get smaller if you tilt your viewing angle If the corresponding target object has reached the bottom of the object, then go to step iii; ii. Determine the current tilt angle Corresponding distance data Critical distance Size: If , then the drone is controlled to save the 3D mapping data of the current initial area of ​​the target object and use it at an oblique angle. The corresponding target object area is the new initial area of ​​the target object, and the process re-enters step S110; if , then the drone is controlled to save the 3D mapping data of the current initial area of ​​the target object and the drone is made to descend in altitude , , indicating the current tilt viewing angle The corresponding hollow height of the target object is taken as the target object initial area with the same height as the current drone, and step S110 is re-entered; iii. Clean and fuse the saved 3D mapping data of all areas of the target object to obtain the final UAV 3D mapping data of the target object.

2. The method for three-dimensional mapping of an unmanned aerial vehicle with multiple viewing angles as claimed in claim 1, characterized in that: In the step iii, if , after controlling the drone to save the 3D mapping data of the current initial area of ​​the target object and before the drone is ordered to descend, a model library matching is first performed. The model library stores conventional object measurement models. When the matching is successful, the 3D mapping data of the corresponding area is obtained based on the successfully matched mapping model, and the tilt angle is adjusted. , the target object area corresponding to it is taken as the new initial area of ​​the target object, and the process goes back to step S110; if the matching is unsuccessful, the subsequent steps are continued.

3. The method for three-dimensional mapping of an unmanned aerial vehicle with multiple viewing angles as claimed in claim 1, characterized in that: Before step S110, drone photography data is acquired, the target object to be mapped is identified, and the top area of ​​the target object is used as the initial area of ​​the target object.

4. The method for three-dimensional mapping of an airborne multi-view drone as claimed in claim 3, characterized in that: After identifying the target object to be mapped, the initial three-dimensional model of the target object is displayed on the console; The initial three-dimensional model of the target object does not have a hollow feature; When the drone is controlled to save the three-dimensional mapping data of the current initial area of ​​the target object, the initial three-dimensional model of the target object is updated based on the three-dimensional mapping data and displayed on the console synchronously.

5. The method for three-dimensional mapping of an airborne multi-view drone as claimed in claim 3, characterized in that: After identifying the target object to be mapped, the initial three-dimensional model of the target object is displayed on the console; control points are manually marked in the initial three-dimensional model of the target object through the console operation interface; and the flight trajectory of the drone when performing the three-dimensional mapping task is determined based on the control points.

6. An airborne multi-view UAV three-dimensional mapping system, comprising: A top area determination module, used to determine an initial area of ​​a target object to be three-dimensionally mapped and a top contour line of a vertical projection of the initial area onto the ground; The critical distance determination module takes an arbitrary point T on the top contour line, takes its projection point on the ground as T', and obtains the intersection line of the side surface of the target object with the normal line passing through point T and perpendicular to the horizontal plane, obtains the current hovering position of the drone, the hovering position is the normal direction of the point T, the horizontal distance from point T is X, and the vertical distance is Y, and the line segment with point T as the starting point and close to the side of the drone in the intersection line is the side intersection line segment S, obtains the drone oblique photography data, and based on the oblique viewing angle The change of the distance data sequence from the drone to each point on the side intersection line S of the target object is detected. And calculate the tilt angle The corresponding critical distance = ; Mapping algorithm execution module, used to obtain the current tilt angle for , execute the mapping algorithm: i. Adjust the tilt angle according to the step length that meets the surveying accuracy Get smaller if you tilt your viewing angle If the corresponding target object has reached the bottom of the object, then go to step iii; ii. Determine the current tilt angle Corresponding distance data Critical distance Size: If , then the drone is controlled to save the 3D mapping data of the current initial area of ​​the target object and use it at an oblique angle. The corresponding target object area is the new initial area of ​​the target object, and the top area determination module is called again; if , then the drone is controlled to save the 3D mapping data of the current initial area of ​​the target object and the drone is made to descend in altitude , , indicating the current tilt viewing angle The corresponding target object hollowing height, taking the target object area with the same height as the current drone as the target object initial area, and re-calling the top area determination module; iii. Clean and fuse the saved 3D mapping data of all areas of the target object to obtain the final UAV 3D mapping data of the target object.

7. The airborne multi-view UAV 3D mapping system as claimed in claim 6, characterized in that: In the step iii, if , after controlling the drone to save the 3D mapping data of the current initial area of ​​the target object and before the drone is ordered to descend, a model library matching is first performed. The model library stores conventional object measurement models. When the matching is successful, the 3D mapping data of the corresponding area is obtained based on the successfully matched mapping model, and the tilt angle is adjusted. , the target object area it corresponds to is taken as the new initial area of ​​the target object, and the top area determination module is called again; If the match is unsuccessful, continue with the subsequent steps.

8. The airborne multi-view UAV 3D mapping system as claimed in claim 6, characterized in that: Before calling the top area determination module, the drone photography data is obtained to identify the target object to be mapped, and the top area of ​​the target object is used as the initial area of ​​the target object.

9. The airborne multi-view UAV 3D mapping system as claimed in claim 8, characterized in that: After the target object to be mapped is identified, an initial three-dimensional model of the target object is displayed on the console; the initial three-dimensional model of the target object does not have a hollow feature; When the drone is controlled to save the three-dimensional mapping data of the current initial area of ​​the target object, the initial three-dimensional model of the target object is updated based on the three-dimensional mapping data and displayed on the console synchronously.

10. The airborne multi-view UAV 3D mapping system as claimed in claim 8, characterized in that: After identifying the target object to be mapped, the initial three-dimensional model of the target object is displayed on the console; control points are manually marked in the initial three-dimensional model of the target object through the console operation interface; and the flight trajectory of the drone when performing the three-dimensional mapping task is determined based on the control points.

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