Aerial photography system and device for modeling steep slopes and complex buildings

Abstract

The present disclosure relates to the technical field of aerial photography surveying of flight platforms, in particular to an aerial photography system and device for steep slope and complex building modeling; the device comprises a flight platform and a tilt three-camera aerial photography module, the flight platform is used for flying in a three-dimensional route in the shape of a cross; the tilt three-camera aerial photography module is arranged at the lower end of the flight platform, the tilt three-camera aerial photography module has a first camera and two second cameras, the two second cameras are symmetrically distributed on the two sides of the first camera, the included angle between the optical axis of the second camera and the optical axis of the first camera is 40-50 degrees, the focal length of the lens of the first camera is 30-40 mm, and the focal length of the lens of the second camera is 40-50 mm. The device can realize multi-angle unobstructed shooting, effectively solve the obstruction problem, and realize high-precision three-dimensional modeling without control points.

Description

Technical Field

[0001] This disclosure relates to the field of oblique photogrammetry technology for flight platforms, and more specifically, to an aerial photography system and apparatus for modeling steep slopes and complex buildings. Background Technology

[0002] In related technologies, "five-lens" or "three-lens" cameras with the same settings parameters are used to perform aerial photogrammetry along a single flight path.

[0003] However, when performing high-precision 3D modeling for scenes such as steep slopes (e.g., mountain slopes, mine slopes), steep cliff facades, and independent complex buildings (e.g., ancient pagodas, irregularly shaped factory buildings), the following problems exist: (1) When a fixed tilt camera flies in a single direction, it is difficult to completely avoid occlusion caused by the terrain or buildings themselves, resulting in local texture loss or geometric deformation of the model; (2) In order to obtain sufficient detail and coverage, it is often necessary to increase the number of flights or manually re-fly, which is inefficient and costly; (3) Relying on ground control points for precise positioning and model correction, it is difficult and dangerous to set up control points in dangerous or hard-to-reach areas (e.g., slopes, steep cliffs), which increases the difficulty and risk of operation; (4) The existing system does not provide sufficient automated support for complex 3D flight paths.

[0004] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this disclosure is to overcome the shortcomings of the prior art and provide an aerial photography system and device for modeling steep slopes and complex buildings, which can realize multi-angle unobstructed shooting, effectively solve the occlusion problem, and achieve high-precision, control-point-free 3D modeling.

[0006] According to one aspect of this disclosure, an aerial photography apparatus for modeling steep slopes and complex buildings is provided, comprising:

[0007] Flight platform for flying in a grid-like three-dimensional flight path;

[0008] A tilted three-camera aerial photography module is installed at the lower end of the flight platform. The tilted three-camera aerial photography module has a first camera and two second cameras. The two second cameras are symmetrically distributed on both sides of the first camera. The angle between the optical axis of the second camera and the optical axis of the first camera is 40°-50°. The focal length of the lens of the first camera is 30-40mm, and the focal length of the lens of the second camera is 40-50mm.

[0009] In one embodiment of this disclosure, the angle between the optical axis of the second camera and the optical axis of the first camera is 45°.

[0010] In one embodiment of this disclosure, the focal length of the lens of the first camera is 35mm; the focal length of the lens of the second camera is 50mm.

[0011] In one embodiment of this disclosure, the aerial photography device further includes a humidity sensor, which is disposed on the tilted three-camera aerial photography module and configured to detect ambient humidity.

[0012] In one embodiment of this disclosure, the aerial photography device further includes a lens sweeping structure;

[0013] The lens blowing structure includes:

[0014] An air intake shell is provided on the flight platform. The air intake shell has an air intake channel with a connected inlet section and an outlet section. The inlet section is funnel-shaped, and the diameter of the outlet section is not greater than the diameter of the smaller diameter section of the inlet section.

[0015] The first connecting pipe is connected to the intake housing and communicates with the outlet section;

[0016] A diversion valve is located on the side of the first connecting pipe away from the outlet section; the diversion valve has three diversion outlets.

[0017] A purge pipe is connected to each of the aforementioned diversion outlets. The purge pipe has a diaphragm valve and a purge nozzle at its end.

[0018] A drive assembly is disposed on the flight platform and connected to the purge nozzle; the drive assembly is configured to drive the purge nozzle to move so that the purge nozzle purges the lens.

[0019] In one embodiment of this disclosure, the first connecting pipe is a venturi tube.

[0020] In one embodiment of this disclosure, the purging pipe is a retractable corrugated pipe.

[0021] In one embodiment of this disclosure, the three purge nozzles are respectively arranged one-to-one with the first camera and the second camera, and the angle between the purge nozzle located at the edge and the purge nozzle located in the middle is equal to the angle between the first camera and the second camera.

[0022] In one embodiment of this disclosure, the aerial photography device further includes a Hall sensor disposed on the tilted three-camera aerial photography module, the Hall sensor being used to detect whether one of the second cameras is in a designated position.

[0023] According to another aspect of this disclosure, an aerial photography system for modeling steep slopes and complex buildings is provided, comprising a ground control system and the aforementioned aerial photography device for modeling steep slopes and complex buildings;

[0024] The ground control is used to generate a grid-shaped three-dimensional flight path and to control the aerial photography device to fly along the grid-shaped three-dimensional flight path.

[0025] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0026] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0027] Figure 1 This is a schematic diagram of the first-view structure of a tilted three-camera aerial photography module in one embodiment of the present disclosure.

[0028] Figure 2 This is a schematic diagram of the second-view structure of a tilted three-camera aerial photography module in one embodiment of the present disclosure.

[0029] Figure 3 This is a schematic diagram of the third-view structure of a tilted three-camera aerial photography module in one embodiment of the present disclosure.

[0030] Figure 4 This is a schematic diagram of the flight path of the aerial photography device in one embodiment of the present disclosure.

[0031] Figure 5 This is a schematic diagram of the control principle of the aerial photography device in one embodiment of the present disclosure.

[0032] Figure 6 This is a schematic diagram of the lens sweeping structure in one embodiment of the present disclosure. Detailed Implementation

[0033] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore detailed descriptions of them will be omitted. Furthermore, the drawings are merely illustrative of this disclosure and are not necessarily drawn to scale.

[0034] Although relative terms such as "up" and "down" are used in this specification to describe the relative relationship of one component of an icon to another, these terms are used only for convenience, such as according to the orientation of the examples shown in the accompanying drawings. It is understood that if the device of the icon is flipped upside down, the component described as "up" will become the component described as "down." When a structure is "up" of another structure, it may mean that the structure is integrally formed on the other structure, or that the structure is "directly" mounted on the other structure, or that the structure is "indirectly" mounted on the other structure through another structure.

[0035] The terms “a,” “one,” “the,” and “the” are used to indicate the existence of one or more elements / components / etc.; the terms “including” and “having” are used to indicate an open-ended meaning of inclusion and that there may be other elements / components / etc. in addition to the listed elements / components / etc.

[0036] In this application, unless otherwise expressly specified and limited, the term "connection" shall be interpreted broadly. For example, "connection" may be a fixed connection, a detachable connection, or an integral part; it may be a direct connection or an indirect connection through an intermediate medium.

[0037] In related technologies, "five-lens" or "three-lens" cameras with the same settings parameters are used to perform aerial photogrammetry along a single flight path.

[0038] However, when performing high-precision 3D modeling for scenes such as steep slopes (e.g., mountain slopes, mine slopes), steep cliff facades, and independent complex buildings (e.g., ancient pagodas, irregularly shaped factory buildings), the following problems exist: (1) When a fixed tilt camera flies in a single direction, it is difficult to completely avoid occlusion caused by the terrain or buildings themselves, resulting in local texture loss or geometric deformation of the model; (2) In order to obtain sufficient detail and coverage, it is often necessary to increase the number of flights or manually re-fly, which is inefficient and costly; (3) Relying on ground control points for precise positioning and model correction, it is difficult and dangerous to set up control points in dangerous or hard-to-reach areas (e.g., slopes, steep cliffs), which increases the difficulty and risk of operation; (4) The existing system does not provide sufficient automated support for complex 3D flight paths.

[0039] To address at least one of the aforementioned problems, this disclosure provides an aerial photography system for modeling steep slopes and complex buildings, comprising a ground control system and an aerial photography device for modeling steep slopes and complex buildings.

[0040] Among them, see Figures 1-4 The aerial photography device used for modeling steep slopes and complex buildings includes a flight platform 1, an airborne RTK module (not shown in the figure), and a tilting three-camera aerial photography module 2.

[0041] Among them, flight platform 1 is used to carry the tilted three-camera aerial photography module 2 and the airborne RTK module, see [link / reference] Figure 4 The tilted three-camera aerial photography module 2 is used to collect image cloud data of the survey area.

[0042] In one embodiment of this disclosure, the flight platform 1 is a multi-rotor flight platform such as a quadcopter, hexacopter, or octagon.

[0043] In this example, flight platform 1 is connected to an airborne RTK module (not shown in the diagram), a tilting three-camera aerial photography module 2, an autopilot module, a communication module, and a power supply module. See also... Figure 5 The tilted three-camera aerial photography module 2, the airborne RTK module, the autopilot module, and the communication module are all electrically connected to the power module. The autopilot module is also electrically connected to the airborne RTK module, the communication module, and the tilted three-camera aerial photography module 2.

[0044] Among them, the airborne RTK module is used for positioning. This disclosure can obtain high-precision positioning results through the airborne RTK module. In subsequent modeling, a high-precision real-scene 3D model can be generated without the need for ground control points, which significantly reduces the difficulty and risk of working in dangerous or hard-to-reach areas (such as steep slopes and cliffs).

[0045] The autopilot module is responsible for controlling the flight of the entire flight platform 1 and acquiring image cloud data from the tilting three-camera aerial photography module 2. The communication module is used to receive external commands, and the power module is responsible for supplying power to the flight platform 1 and its various electronic modules.

[0046] In one embodiment of this disclosure, the airborne RTK module includes at least an airborne multimode high-frequency GNSS receiver, a GNSS receiving antenna, a history data storage, an RTK communication link radio, and electronic coupling accessories. In one example, the airborne GNSS differential and RTK module consists of an airborne multimode high-frequency GNSS receiver, a GNSS receiving antenna, a history data storage, an RTK communication link radio, and electronic coupling accessories.

[0047] The system comprises an airborne multi-mode high-frequency GNSS receiver electrically connected to the GNSS receiving antenna, a history data storage device electrically connected to the airborne multi-mode high-frequency GNSS receiver, an RTK communication link radio electrically connected to the airborne multi-mode high-frequency GNSS receiver, and an electronic coupling connector connected at one end to the airborne multi-mode high-frequency GNSS receiver and at the other end to the autopilot module. The airborne multi-mode high-frequency GNSS receiver can receive broadcast signals from four commonly used satellite navigation systems: GPS, GLONASS, GALILEO, and BDS. The history data storage device has a collection frequency of no less than 20Hz, thereby acquiring and storing accurate position information. This enables the multi-rotor flight platform 1 to perform image-controlled-free measurements and provides precise observation data for the 3D image reconstruction of flight platform 1.

[0048] Optionally, the autopilot module in this disclosure adopts the existing autopilot equipment of the flight platform 1 for automatic flight control and transmission and control of aerial photography pulse signals. In actual use, it enables the flight platform 1 to fly autonomously along a preset route, while simultaneously driving the tilting three-camera aerial photography module 2 and the airborne multi-mode GNSS receiver to record and collect data.

[0049] Optionally, the communication module in this disclosure adopts the existing GNSS-RTK field base station and rover signal transmission module, which is used for real-time positioning information communication between the tilted three-camera aerial photography module 2 and the ground base station, realizing stable and efficient transmission of data transmission signals and positioning coordinate signals between the flight platform 1 and the ground control system in real time.

[0050] In this disclosure, the airborne RTK module can accurately acquire the spatial information of the flight platform 1 during aerial photography, and achieve image control-free measurement in complex terrain where it is difficult to set up image control points.

[0051] In one embodiment of this disclosure, the tilted three-camera aerial photography module 2 is disposed at the lower end of the flight platform 1. See also... Figures 1-3 The tilted three-camera aerial photography module 2 has three cameras: a first camera 21 and two second cameras 22. The two second cameras 22 are symmetrically arranged on both sides of the first camera 21, and the three cameras are arranged sequentially along a first direction. In this structure, the first camera 21 is a front-facing camera, and the two second cameras 22 are tilted cameras.

[0052] In one embodiment of this disclosure, the first direction can be the same as the flight direction of the flight platform. When the relative position of the second camera 22 to the first camera 21 changes under the drive of the rotation device of the tilting three-camera aerial photography module 2, the first direction also changes accordingly. In other words, the direction in which the three cameras are arranged in sequence is the first direction.

[0053] In one embodiment of this disclosure, the first camera 21 is vertically downward, i.e., with a tilt angle of 0° (the vertical downward refers to the vertical downward when the flight platform 1 is in flight state), and the lenses of the two second cameras 22 are set close to the first camera 21.

[0054] In one embodiment of this disclosure, the angle between the optical axis of the second camera 22 and the optical axis of the first camera 21 is 40°-50° (this angle only indicates the magnitude of the angle and does not consider the quadrants in the coordinate system. It can be understood that if the quadrants are considered, the angle between the optical axis of one second camera 22 and the optical axis of the first camera 21 is (+40°)-(+50°); the angle between the optical axis of the other second camera 22 and the optical axis of the first camera 21 is (-40°)-(-50°)). The focal length of the lens of the first camera 21 is 30-40mm, and the focal length of the lens of the second camera 22 is 40-50mm.

[0055] In one embodiment of this disclosure, see [link to relevant documentation]. Figure 4 The ground control system, in conjunction with the aerial photography equipment, can generate a grid-like three-dimensional flight path based on the Digital Surface Model (DSM) of the survey area. Flight platform 1 uses this grid-like three-dimensional flight path to achieve multi-angle, unobstructed photography. The grid-like three-dimensional flight path includes: in the first horizontal direction, multiple parallel flight paths are laid out according to the designed side image overlap; in the second horizontal direction perpendicular to it, multiple parallel flight paths are also laid out according to the designed side image overlap. The flight altitude of flight platform 1 is calculated and determined based on the required ground resolution. In this embodiment, automatic flight based on the planned route can be achieved, avoiding tedious manual operation and re-flying, thus improving operational efficiency and safety.

[0056] The system proposed in this invention, through a specific combination of three cameras at different angles and lens focal lengths, combined with the "grid" shaped three-dimensional flight path of the flight platform, has been shown in experiments to achieve multi-angle unobstructed shooting, effectively solving the occlusion problem and realizing high-precision, control-point-free 3D modeling. It is particularly suitable for 3D modeling of slopes, steep cliffs, and independent complex buildings, effectively solving the modeling loopholes caused by occlusion on steep slopes, cliffs, and complex buildings, significantly improving the integrity and accuracy of the model, and reducing the risk of operation in high-risk areas.

[0057] In one embodiment of this disclosure, the angle between the optical axis of the second camera 22 and the optical axis of the first camera 21 is 45° (this angle only indicates the magnitude of the angle and does not consider the quadrants in the coordinate system. It can be understood that if the quadrants are considered, the angle between the optical axis of one second camera 22 and the optical axis of the first camera 21 is +45°; the angle between the optical axis of the other second camera 22 and the optical axis of the first camera 21 is -45°). The focal length of the lens of the first camera 21 is 35mm; the focal length of the lens of the second camera 22 is 50mm.

[0058] The aerial photography device in this invention adopts a specific design, consisting of a third camera combination: a second camera 22 (optical axis tilted to the left +45°), a first camera 21 (vertically downward), and another second camera 22 (optical axis tilted to the right -45°). Combined with a "grid" shaped three-dimensional flight path, it can image steep slopes, cliff facades, and the sides and tops of complex buildings from multiple angles, greatly reducing photographic gaps and modeling deficiencies caused by terrain or building occlusion.

[0059] In addition, in this disclosure, the first camera has a focal length of 35mm, which can ensure sufficient coverage and efficiency, while the second camera has a focal length of 50mm, which can provide images with higher ground resolution, especially beneficial for capturing the texture details of steep slopes and cliff facades, thereby improving the overall precision and integrity of 3D modeling, while effectively reducing the frequency of rework in aerial photography and indoor modeling for 3D modeling.

[0060] In one embodiment of this disclosure, see [link to relevant documentation]. Figure 2 The aerial photography device also has a humidity sensor 3, which is installed on the tilted three-camera aerial photography module 2 and is configured to detect the ambient humidity of the environment where the tilted three-camera aerial photography module 2 is located.

[0061] In this disclosure, a humidity sensor 3 is provided to detect the ambient humidity of the tilted three-camera aerial photography module 2. In this way, during flight operations, the humidity detected by the humidity sensor 3 can be used to determine changes in the external environment. When the humidity is high, it can be preliminarily determined whether it is conducive to the tilted three-camera aerial photography module 2 to continue collecting image cloud data (when the humidity is high, a water film may form on the lens, which will reduce the image pixel count and is not conducive to 3D modeling).

[0062] Of course, in other embodiments of this disclosure, the humidity sensor 3 may also be mounted on the flight platform 1.

[0063] In one embodiment of this disclosure, see [link to relevant documentation]. Figure 6 ( Figure 6 To simplify the diagram and illustrate its working principle and general structure, the aerial photography device also has a lens sweeping structure; in one example, the lens sweeping structure includes an air intake housing 5, a first connecting pipe 6, a diverter valve 7, a sweeping pipe 8, and a drive assembly.

[0064] Optionally, the air intake shell 5 is mounted on the flight platform 1. The air intake shell 5 has an air intake channel 4, which has a connected inlet section and an outlet section. The inlet section is funnel-shaped (facing the flight direction to facilitate airflow formation), and the diameter of the outlet section is no larger than the diameter of the smaller diameter section of the inlet section. A first connecting pipe 6 is connected to the air intake shell 5 and communicates with the outlet section. A diverter valve 7 is located on the side of the first connecting pipe 6 away from the outlet section. The diverter valve 7 has three diverter outlets. Each diverter outlet is connected to a purge pipe 8, which has a diaphragm valve 9 and a purge nozzle 10 at its end. A drive assembly is mounted on the flight platform 1, connected to the purge nozzle 10, and configured to drive the purge nozzle 10 to move so that the purge nozzle 10 purges the lens.

[0065] When humidity is high and there is a water film on the lens, the lens blowing structure provided in this disclosure can be used to blow away the water film on the lens. In this way, flight operations can still be carried out when humidity is high, with less interference from the environment. This makes the aerial photography device of this disclosure more widely applicable and can be used in harsh environments.

[0066] In addition, no additional air storage container is set in this disclosure. Instead, the atmosphere is used to set up an air intake channel 4 with a unique structure. By using Bernoulli's principle, the air velocity is increased. After passing through the diversion valve 7 on the first connecting pipe 6, the air is divided into three air paths. After reaching a certain pressure, the diaphragm valve 9 opens to blow the lens. In this way, the weight of the entire lens blowing structure can be reduced.

[0067] In one embodiment of this disclosure, the first connecting pipe 6 is a Venturi tube. The Venturi tube can further increase the airflow velocity and dynamic pressure, and at high flow rates, it can further improve the efficiency of lens cleaning and achieve better cleaning results.

[0068] In one embodiment of this disclosure, the purge pipe 8 is a retractable corrugated pipe. In this disclosure, the air intake shell 5, the first connecting pipe 6, the diverter valve 7, and the drive assembly can be fixed on the flight platform. The drive assembly is used to drive the purge nozzle 10 to move and perform purge, which reduces the vibration caused by the lens purge structure during flight and helps to ensure the stability of the flight platform 1.

[0069] In this embodiment, the specific positions of each structure can be arranged based on the perspective of maintaining the stability of the entire aerial photography device. Other transition structures can also be connected between the air intake shell 5 and the first connecting pipe 6, and between the first connecting pipe 6 and the diversion valve 7.

[0070] In one embodiment of this disclosure, the drive assembly includes a drive member (not shown in the figure) and a clamping member 11. The drive member is mounted on the flight platform 1, and the clamping member 11 can be a clamping plate located at the power output end of the drive member and clamping the blow-blowing nozzle 10 to drive the blow-blowing nozzle 10 to move. Depending on the specific mounting position, the drive member can be a dual-axis gimbal (with telescopic and forward / backward movement functions, enabling the blow-blowing nozzle 10 to be aligned with the lens for blowing) or a three-axis gimbal, as long as the blow-blowing nozzle 10 can be aligned with the lens after being driven to move. Of course, the drive member can also use two cylinders stacked sequentially for movement.

[0071] In use, the drive unit moves the blow nozzle 10 downward (away from the flight platform 1) until the distance to the flight platform 1 is greater than the distance between the first camera 21 and the flight platform 1. The three blow nozzles 10 correspond to the first camera 21 and the second camera 22 respectively. Then, by using the forward and backward movement function (the forward and backward direction is perpendicular to the first direction), the blow nozzle 10 blows the lens.

[0072] In one embodiment of this disclosure, three purge nozzles 10 are respectively arranged corresponding to the first camera 21 and the second camera 22. The angle between the purge nozzle 10 located at the edge and the purge nozzle 10 located in the middle is equal to the angle between the first camera 21 and the second camera 22. In this way, the purge nozzles 10 can perform targeted purge on the first camera 21 and the second camera 22, thereby speeding up the purge efficiency.

[0073] In one embodiment of this disclosure, the aerial photography device further includes a Hall sensor (not shown in the figure). The Hall sensor is disposed on the fixed housing of the tilting three-camera aerial photography module 2. The Hall sensor is used to detect whether one of the second cameras 22 is in a designated position. When the Hall sensor detects the second camera 22, it indicates that the second camera 22 is in the designated position, which is a pre-calibrated position where the blower nozzle 10 blows the lens. After the second camera 22 is in the designated position, the drive unit controls the blower nozzle 10 to move and blow the lens.

[0074] In one embodiment of this disclosure, the humidity sensor 3, the Hall sensor, and the driving component can be electrically connected to the autopilot module, and the autopilot module can control the humidity sensor 3, the Hall sensor, and the driving component and collect information.

[0075] In one embodiment of this disclosure, the lens blowing structure can be selected based on the weight requirements of the flight platform 1, including the selection of materials, etc.

[0076] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the appended claims.

Claims

1. An aerial photography device for modeling steep slopes and complex buildings, characterized in that, include: Flight platform (1) for flying in a grid-like three-dimensional flight path; A tilted three-camera aerial photography module (2) is installed at the lower end of the flight platform (1). The tilted three-camera aerial photography module (2) has a first camera (21) and two second cameras (22). The two second cameras (22) are symmetrically distributed on both sides of the first camera (21). The angle between the optical axis of the second camera (22) and the optical axis of the first camera (21) is 40°-50°. The focal length of the lens of the first camera (21) is 30-40mm, and the focal length of the lens of the second camera (22) is 40-50mm.

2. The aerial photography device for modeling steep slopes and complex buildings according to claim 1, characterized in that, The angle between the optical axis of the second camera (22) and the optical axis of the first camera (21) is 45°.

3. The aerial photography device for modeling steep slopes and complex buildings according to claim 2, characterized in that, The first camera (21) has a lens focal length of 35mm; the second camera (22) has a lens focal length of 50mm.

4. The aerial photography device for modeling steep slopes and complex buildings according to any one of claims 1-3, characterized in that, The aerial photography device also has a humidity sensor (3), which is mounted on the tilted three-camera aerial photography module (2) and is configured to detect ambient humidity.

5. The aerial photography device for modeling steep slopes and complex buildings according to claim 4, characterized in that, The aerial photography device also has a lens sweeping structure; The lens blowing structure includes: An air intake shell (5) is provided on the flight platform (1). The air intake shell (5) has an air intake channel (4). The air intake channel (4) has a connected inlet section and an outlet section. The inlet section is trumpet-shaped, and the diameter of the outlet section is not greater than the diameter of the smaller diameter section of the inlet section. The first connecting pipe (6) is connected to the air intake shell (5) and communicates with the outlet section; A diversion valve (7) is disposed on the side of the first connecting pipe (6) away from the outlet section; the diversion valve (7) has three diversion outlets; A purge pipe (8) is connected to each of the aforementioned diversion outlets. The purge pipe (8) has a diaphragm valve (9) and a purge nozzle (10) at the end of the purge pipe (8). A drive assembly is disposed on the flight platform (1) and connected to the purge nozzle (10); the drive assembly is configured to drive the purge nozzle (10) to move so that the purge nozzle (10) purges the lens.

6. The aerial photography device for modeling steep slopes and complex buildings according to claim 5, characterized in that, The first connecting pipe (6) is a venturi pipe.

7. The aerial photography device for modeling steep slopes and complex buildings according to claim 6, characterized in that, The purging pipe (8) is a retractable corrugated pipe.

8. The aerial photography device for modeling steep slopes and complex buildings according to claim 5, characterized in that, The three purge nozzles (10) are respectively set to correspond one-to-one with the first camera (21) and the second camera (22). The angle between the purge nozzle (10) located at the edge and the purge nozzle (10) located in the middle is equal to the angle between the first camera (21) and the second camera (22).

9. The aerial photography device for modeling steep slopes and complex buildings according to claim 5, characterized in that, The aerial photography device also includes a Hall sensor, which is disposed on the tilted three-camera aerial photography module (2) and is used to detect whether one of the second cameras (22) is in a designated position.

10. An aerial photography system for modeling steep slopes and complex buildings, characterized in that, It has a ground control system and an aerial photography device for modeling steep slopes and complex buildings as described in any one of claims 1-9; The ground control is used to generate a grid-shaped three-dimensional flight path and to control the aerial photography device to fly along the grid-shaped three-dimensional flight path.

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