Forest canopy fine structure measurement system and method based on combination of foundation and airborne laser radar

Abstract

The invention discloses a forest canopy fine structure measurement system and method based on the combination of a foundation and an airborne laser radar in the technical field of forest ecological research, and the system comprises an airborne collection unit, a foundation collection unit and a processing unit, and the airborne collection unit comprises an unmanned plane and a second laser radar disposed on the unmanned plane. The foundation acquisition unit comprises a mounting seat and a first laser radar arranged on the mounting seat, and the processing unit comprises processing equipment; the measuring system further comprises a mobile vehicle body, the unmanned aerial vehicle, the mounting base and the processing equipment are all arranged on the mobile vehicle body, and a leveling assembly is arranged at the bottom of the mobile vehicle body. And a forest canopy fine structure is obtained by adopting a multi-modal data fusion technology, so that accurate data is provided for researching how the plant individuals in the forest obtain and utilize light resources.

Description

Technical Field

[0001] The present invention relates to the technical field of forest ecological research, and particularly to a forest canopy fine structure measurement system and method based on the combination of ground-based and airborne lidar. Background Technique

[0002] As one of the most important ecosystems on the earth, the fine measurement of the canopy structure of forests is of extremely important significance for understanding forest ecological functions, evaluating forest health conditions, predicting forest biomass, and formulating reasonable management and protection strategies; traditional forestry surveys usually use manual methods (visual inspection) to estimate parameters such as the base of the crown width, the height under the branches, and the crown depth, or solely use radar (such as ground-based radar or airborne radar) to obtain data, which will affect the accuracy of data acquisition and the accuracy of measuring the fine structure of the forest canopy. Moreover, due to the unevenness of the forest ground, the measuring equipment is greatly restricted when placed on the ground, resulting in inconvenient selection of the placement area of the measuring equipment and affecting the measurement efficiency. Summary of the Invention

[0003] The purpose of the present invention is to provide a forest canopy fine structure measurement system and method based on the combination of ground-based and airborne lidar, so as to solve the problem that traditional forestry surveys usually use manual methods to estimate parameters such as the base of the crown width, the height under the branches, and the crown depth, or solely use radar to obtain data, which will affect the accuracy of data acquisition as mentioned in the above background technique.

[0004] To achieve the above purpose, the present invention provides the following technical solution: A forest canopy fine structure measurement system based on the combination of ground-based and airborne lidar, including: an airborne acquisition unit, a ground-based acquisition unit and a processing unit;

[0005] The airborne acquisition unit includes a drone and a second lidar installed on the drone;

[0006] The ground-based acquisition unit includes a mounting base and a first lidar installed on the mounting base;

[0007] The processing unit includes a processing device; both the first lidar and the second lidar are used to obtain the LiDAR three-dimensional structure point cloud data of vegetation, and the processing device is used to process the obtained LiDAR three-dimensional structure point cloud data and obtain the fine structure of the forest canopy through multi-modal data fusion;

[0008] Among them, the measurement system further includes a mobile vehicle body, the drone, the mounting base and the processing device are all installed on the mobile vehicle body, and a leveling component is provided at the bottom of the mobile vehicle body, and the leveling component is used to keep the mobile vehicle body horizontal in an inclined area.

[0009] Preferably, the leveling assembly includes support plates provided around the bottom of the mobile vehicle body and driving members for driving the support plates to move up and down. An installation groove is provided in the support plate. A fixed insertion block for extending outside the installation groove and an elastic reset member connected to the fixed insertion block are slidably provided in the installation groove. An airbag for communicating with the installation groove is provided at the bottom of the support plate.

[0010] Preferably, a support rod is provided on the support plate. A sleeve for sleeving on the outer wall of the support rod is provided on the moving end of the driving member. A limiting pressing block for restricting the rotation of the sleeve and an elastic member connected to the limiting pressing block are slidably provided on the support plate. A placement groove for communicating with the installation groove is provided on the support plate. A connecting rod for connecting with the limiting pressing block is slidably provided in the placement groove.

[0011] Preferably, an air storage tank is provided on the support plate. A pressing plate and an elastic element connected to the pressing plate are slidably provided in the air storage tank. A push rod for extending into the airbag is provided on the pressing plate. A vent hole for communicating the air storage tank with the installation groove is provided on the air storage tank.

[0012] Preferably, a push plate is provided at the end of the push rod away from the pressing plate. A partition block is provided on the side of the push plate facing the push rod.

[0013] Preferably, a method for measuring the fine structure of a forest canopy based on the combination of ground-based and airborne lidars uses the above-mentioned system for measuring the fine structure of a forest canopy based on the combination of ground-based and airborne lidars, and includes the following steps:

[0014] S1: After the mobile vehicle body moves the airborne acquisition unit, the ground-based acquisition unit and the processing unit to the detection area, the leveling assembly works to make the top of the mobile vehicle body in a horizontal state;

[0015] S2: The first lidar obtains the LiDAR three-dimensional structure point cloud data of the vegetation on the ground, the unmanned aerial vehicle carries the second lidar to obtain the LiDAR three-dimensional structure point cloud data of the vegetation in the air, and the processing device processes the LiDAR three-dimensional structure point cloud data obtained by the first lidar and the second lidar, extracts the canopy parameters and uses the multi-modal data fusion technology to obtain the fine structure of the forest canopy.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] 1. Through the collaborative operation of the ground-based acquisition unit and the airborne acquisition unit, the forest laser point cloud is collected, the canopy parameters are extracted, and the multi-modal data fusion technology is used to obtain the fine structure of the forest canopy, providing accurate data for studying how plant individuals in the forest obtain and utilize light resources, and providing a scientific basis and technical support for improving forest management and carbon sequestration capabilities;

[0018] 2. The mobile vehicle is used to transport the mounting seat, the first lidar, the drone, the second lidar and the processing device, which facilitates moving the measurement equipment to the measurement area. Moreover, when the mobile vehicle is placed on an uneven area through the leveling component, its top can still be in a horizontal state, enabling the measurement equipment to be conveniently placed in the detection area without being restricted by the terrain, thus improving the detection efficiency. Description of the Drawings

[0019] Figure 1 It is a schematic structural diagram of the fine structure measurement system for forest canopy of the present invention;

[0020] Figure 2 It is a schematic structural diagram of the connection between the mobile vehicle and the processing device of the present invention;

[0021] Figure 3 It is a schematic structural diagram of the connection between the mobile vehicle and the leveling component of the present invention;

[0022] Figure 4 It is a schematic cross-sectional view of the connection between the driving part and the support plate of the present invention;

[0023] Figure 5 For the present invention Figure 4 The enlarged schematic diagram of the structure at A in;

[0024] Figure 6 For the present invention Figure 4 The enlarged schematic diagram of the structure at B in.

[0025] In the figure: 1. Mobile vehicle; 2. Mounting seat; 3. First lidar; 4. Drone; 5. Second lidar; 6. Processing device; 7. Leveling component; 71. Driving part; 72. Support plate; 73. Fixed plug; 74. Airbag; 75. Installation groove; 76. Elastic reset part; 77. Gas storage tank; 78. Kit; 79. Support rod; 710. Limit pressing block; 711. Elastic part; 712. Placement groove; 713. Connecting rod; 714. Pressing plate; 715. Elastic element; 716. Vent hole; 717. Push rod; 718. Push plate; 719. Partition block. Detailed Embodiments

[0026] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0027] Embodiment 1

[0028] Please refer to Figure 1, a forest canopy fine structure measurement system based on the combination of ground-based and airborne lidar, comprising: an airborne acquisition unit, a ground-based acquisition unit and a processing unit;

[0029] Among them, please refer to Figure 2 , the airborne acquisition unit includes a drone 4 and a second lidar 5, and the second lidar 5 is installed on the drone 4; the ground-based acquisition unit includes a mounting base 2 and a first lidar 3, and the first lidar 3 is installed on the top wall of the mounting base 2. The processing unit includes a processing device 6 (such as a computer).

[0030] It should be noted that an electric telescopic rod is installed on the mounting base 2, and the electric telescopic rod is used to change the height of the first lidar 3.

[0031] Please refer to Figure 2 , the measurement system further includes a mobile vehicle body 1, and the drone 4, the mounting base 2 and the processing device 6 are all arranged on the top wall of the mobile vehicle body 1; a leveling assembly 7 is arranged at the bottom of the mobile vehicle body 1;

[0032] Among them, please refer to Figure 2 and Figure 3 , the leveling assembly 7 includes a driving member 71 (electric telescopic rod) and a support plate 72. There are four driving members 71 and four support plates 72. The four driving members 71 are respectively installed around the bottom of the mobile vehicle body 1, and the support plate 72 is installed on the mobile end of the driving member 71.

[0033] It should be noted that the drone 4 is fixed to the top wall of the mobile vehicle body 1 by straps or other fixing parts, and the drone 4 can be detached from the top wall of the mobile vehicle body 1.

[0034] A method for measuring the fine structure of a forest canopy based on the combination of ground-based and airborne lidar is as follows:

[0035] First, after the mobile vehicle body 1 moves the airborne acquisition unit, the ground-based acquisition unit and the processing unit to the detection area, according to the flatness of the area where the mobile vehicle body 1 is located, the driving member 71 of the leveling assembly 7 works to drive the support plate 72 to move down and contact the ground to support the mobile vehicle body 1 and make the top of the mobile vehicle body 1 in a horizontal state;

[0036] Second, the first lidar 3 obtains the LiDAR three-dimensional structure point cloud data of the vegetation on the ground, the drone 4 with the second lidar 5 obtains the LiDAR three-dimensional structure point cloud data of the vegetation in the air, and the processing device 6 processes the LiDAR three-dimensional structure point cloud data obtained by the first lidar 3 and the second lidar 5, and extracts the canopy parameters and then uses multi-modal data fusion technology to obtain the fine structure of the forest canopy.

[0037] It should be noted that the technology of fusing the data of ground-based lidar and airborne lidar of drones belongs to the existing technical solutions, and will not be described in detail here.

[0038] In this embodiment, as a further optimized solution, please refer to Figure 2 , Figure 3 and Figure 4 , an installation groove 75 is provided inside the support plate 72, air is stored inside the installation groove 75, an installation hole is provided on the bottom wall of the support plate 72, the installation hole communicates with the installation groove 75, and a fixed plug 73 is slidably inserted into the inner cavity of the installation hole (the fixed plug 73 can move up and down, and a sealing treatment is performed between the fixed plug 73 and the installation hole to prevent the air inside the installation groove 75 from leaking out), and an elastic reset member 76 (spring) is installed between the installation groove 75 and the fixed plug 73; a gasbag 74 is provided at the bottom of the support plate 72, air is filled inside the gasbag 74, and air holes are provided in the connection area between the support plate 72 and the gasbag 74, and the installation groove 75 is communicated with the gasbag 74 through the air holes; when the driving member 71 drives the support plate 72 to contact the ground, the gasbag 74 will be squeezed, and the gas inside the gasbag 74 will be introduced into the inner cavity of the installation groove 75, increasing the air pressure inside the installation groove 75, so that the fixed plug 73 moves outward to the outside of the installation hole and is inserted into the soil, increasing the stability of the support plate 72 placed on the ground, preventing it from accidentally translating, and ensuring stability during measurement.

[0039] In this embodiment, as a further optimized solution, please refer to Figure 4 and Figure 5 , a support rod 79 is provided on the support plate 72, a sleeve 78 (pipe fitting) is provided on the moving end of the driving member 71, the sleeve 78 is sleeved on the outer wall of the support rod 79 (the sleeve 78 can rotate on the outer wall of the support rod 79), a limiting pressure block 710 is slidably provided on the support plate 72, an elastic member 711 (such as a spring) is installed between the support plate 72 and the limiting pressure block 710, a placement groove 712 is provided on the support plate 72, the placement groove 712 communicates with the installation groove 75, a connecting rod 713 is slidably provided in the inner cavity of the placement groove 712, one end of the connecting rod 713 is connected to the limiting pressure block 710, and the connecting rod 713 blocks the placement groove 712, so that the air inside the installation groove 75 will not leak out through the placement groove 712; by rotating the sleeve 78 on the outer wall of the support rod 79, the support plate 72 can rotate on the moving end of the driving member 71 to change its own angle, ensuring that the support plate 72 can rotate to an angle matching the ground, so that the support plate 72 is in full contact with the ground; when the gasbag 74 is squeezed and the air inside the gasbag 74 enters the inside of the installation groove 75, increasing the air pressure inside the installation groove 75, it is used to push the connecting rod 713 to move, so that the limiting pressure block 710 contacts the end of the sleeve 78, used to limit the rotation of the sleeve 78 on the outer wall of the support rod 79, thereby restricting the rotation of the support plate 72 and fixing it.

[0040] In this embodiment, as a further optimized solution, please refer to Figure 4 and Figure 6 , an air storage tank 77 is provided on the support plate 72. A pressing plate 714 is slidably provided in the inner cavity of the air storage tank 77. An elastic element 715 (spring) is installed between the air storage tank 77 and the pressing plate 714. A push rod 717 is provided on the side of the pressing plate 714 away from the air storage tank 77. One end of the push rod 717 away from the pressing plate 714 extends into the inner cavity of the airbag 74. An air vent hole 716 is formed in the air storage tank 77, and the air storage tank 77 is communicated with the installation groove 75 through the air vent hole 716; when the support plate 72 contacts the ground and the airbag 74 is squeezed, the push rod 717 will be pushed to move, so that the pressing plate 714 moves into the inner cavity of the air storage tank 77, so that the air inside the air storage tank 77 enters the inner cavity of the installation groove 75 through the air vent hole 716, to increase the air inside the installation groove 75 and ensure that the fixed insert block 73 will be pushed to move to fix the kit 78.

[0041] It should be noted that a push plate 718 is provided at one end of the push rod 717 away from the pressing plate 714, and a spacer block 719 is provided on the side of the push plate 718 facing the push rod 717; when the airbag 74 is squeezed, the push plate 718 will be pushed to move and contact the support plate 72, and there is a gap between the push plate 718 and the support plate 72 through the spacer block 719, ensuring that the push plate 718 will not separate the communication area between the airbag 74 and the installation groove 75.

[0042] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A forest canopy fine structure measurement system based on the combination of ground-based and airborne lidar, characterized in that: Including: An airborne acquisition unit, a ground-based acquisition unit and a processing unit; The airborne acquisition unit includes a drone (4) and a second lidar (5) provided on the drone (4); The ground-based acquisition unit includes a mounting base (2) and a first lidar (3) provided on the mounting base (2); The processing unit includes a processing device (6); both the first lidar (3) and the second lidar (5) are used to obtain LiDAR three-dimensional structural point cloud data of vegetation, and the processing device (6) is used to process the obtained LiDAR three-dimensional structural point cloud data and obtain the fine structure of the forest canopy through multi-modal data fusion; Among them, the measurement system further includes a mobile vehicle body (1), the drone (4), the mounting base (2) and the processing device (6) are all provided on the mobile vehicle body (1), and a leveling assembly (7) is provided at the bottom of the mobile vehicle body (1), and the leveling assembly (7) is used to keep the mobile vehicle body (1) horizontal in an inclined area.

2. The forest canopy fine structure measurement system based on the combination of ground-based and airborne lidar according to claim 1, characterized in that: The leveling assembly (7) includes support plates (72) provided around the bottom of the mobile vehicle body (1) and a driving member (71) for driving the support plates (72) to lift. An installation groove (75) is provided in the support plate (72), and a fixed plug (73) for extending outside the installation groove (75) and an elastic reset member (76) connected to the fixed plug (73) are slidably provided in the installation groove (75). An airbag (74) for communicating with the installation groove (75) is provided at the bottom of the support plate (72).

3. The forest canopy fine structure measurement system based on the combination of ground-based and airborne lidar according to claim 2, characterized in that: A support rod (79) is provided on the support plate (72), and a sleeve (78) for sleeving on the outer wall of the support rod (79) is provided on the moving end of the driving member (71). A limit pressing block (710) for restricting the rotation of the sleeve (78) and an elastic member (711) connected to the limit pressing block (710) are slidably provided on the support plate (72). A placement groove (712) for communicating with the installation groove (75) is provided on the support plate (72), and a connecting rod (713) for connecting with the limit pressing block (710) is slidably provided in the placement groove (712).

4. A fine structure measurement system for forest canopy based on the combination of ground-based and airborne lidar according to claim 2, characterized in that: An air storage tank (77) is provided on the support plate (72). A pressing plate (714) and an elastic element (715) connected to the pressing plate (714) are slidably provided in the air storage tank (77). A push rod (717) for extending into the airbag (74) is provided on the pressing plate (714), and a ventilation hole (716) for communicating the air storage tank (77) with the installation groove (75) is provided on the air storage tank (77).

5. The forest canopy fine structure measurement system based on the combination of ground-based and airborne lidar according to claim 4, characterized in that: A push plate (718) is provided at one end of the push rod (717) away from the pressing plate (714), and a partition block (719) is provided on the side of the push plate (718) facing the push rod (717).

6. A method for measuring the fine structure of forest canopy by combining ground-based and airborne lidar, using a system for measuring the fine structure of forest canopy by combining ground-based and airborne lidar according to any one of claims 1-5, characterized in that: Including the following steps: S1: After the mobile vehicle body (1) moves the airborne acquisition unit, the ground-based acquisition unit and the processing unit to the detection area, the leveling assembly (7) works to make the top of the mobile vehicle body (1) in a horizontal state; S2: The first lidar (3) obtains the LiDAR three-dimensional structural point cloud data of vegetation on the ground, the drone (4) carries the second lidar (5) to obtain the LiDAR three-dimensional structural point cloud data of vegetation in the air, and the processing device (6) processes the LiDAR three-dimensional structural point cloud data obtained by the first lidar (3) and the second lidar (5), extracts canopy parameters and uses multi-modal data fusion technology to obtain the fine structure of the forest canopy.

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