A tree breast diameter auxiliary measurement system and method

Abstract

The application discloses a tree breast height auxiliary measurement system and method, and relates to the technical field of breast height measurement.The navigation auxiliary module loads the navigation file of the corresponding measurement area before the measurement personnel work, and then the current all trees in the to-be-measured state are selected as the target trees in sequence to perform the auxiliary navigation, so that the target loss problem caused by the dense trees in the measurement area is completely avoided, and the real-time longitude and latitude of the tree when any tree is determined as the target tree is acquired to determine whether there is a detour, a virtual auxiliary tree is selected in front of the tree according to the determination result, and when the next measurement task is performed again, a visual guide arrow is generated to navigate to the auxiliary tree first, and then navigate to the auxiliary tree, so that the navigation interference problem of the traditional navigation caused by the failure to identify the detour demand of the forest area is effectively avoided, and the safety of the auxiliary navigation is further improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of breast diameter measurement, in particular to a tree breast diameter auxiliary measurement system and method. BACKGROUND

[0002] In the fields of forestry resource investigation, ecological monitoring and timber reserve evaluation, tree breast diameter is one of the core measurement indexes, and its measurement accuracy and efficiency directly affect the overall quality and progress of forestry work. With the iteration of technology, the traditional method of carrying measurement tools by manual positioning and measurement of each tree in the forest field has problems such as high labor intensity, long measurement period, high personnel safety risk, and cannot meet the efficient and accurate needs of modern forestry management.

[0003] To solve the above-mentioned problems of manual measurement, the existing technology gradually introduces unmanned aerial vehicle technology to assist tree breast diameter measurement process. The core application logic is: through the unmanned aerial vehicle carrying a positioning module and an image acquisition device, the target forest field is scanned globally or in zones, the position information of each tree is identified and extracted based on image recognition algorithm, and then the latitude and longitude coordinates of each target tree are determined. Subsequently, the system generates navigation information according to the latitude and longitude coordinates, and generates guide arrows to guide the measurement personnel to carry the measurement tools to the target tree to complete the breast diameter measurement. This scheme realizes the rapid positioning and navigation guidance of the tree position through the unmanned aerial vehicle, to a certain extent, shortens the time of personnel searching for trees in the forest field, and improves the measurement efficiency, which has become one of the mainstream auxiliary technologies in the field of current forestry breast diameter measurement.

[0004] However, when the unmanned aerial vehicle scans the forest field to determine the latitude and longitude of the tree, its image acquisition and recognition logic mainly focuses on the tree target itself, and lacks effective recognition ability for the terrain obstacles (such as deep ditch, dense shrub belt, etc.) widely existing in the forest field. In this case, the generated guide arrow can only point to the position of the target tree, and the measurement personnel will have the risk of marching according to the navigation path, and if there are obstacles, the guide arrow will interfere with the marching of the measurement personnel. Moreover, since the terrain obstacles cannot be effectively recognized, the measurement area is not considered in the measurement personnel's marching difficulty in the area, which will lead to the imbalance of the actual operation difficulty and workload of different measurement areas:

[0005] To solve the above-mentioned problems, the present application provides a solution. SUMMARY

[0006] The purpose of the present application is to provide a tree breast diameter auxiliary measurement system and method to solve the problems in the background technology.

[0007] The present application provides a tree breast diameter auxiliary measurement system, comprising:

[0008] The overall measurement control platform is used to manage the data generated when measuring the diameter at breast height (DBH) of all trees in the target forest area. The overall measurement control platform includes a data management unit and a data analysis unit. The data management unit stores navigation files for all measurement areas in the target forest area and the identity information of the measurement personnel. The navigation files include the tree number, latitude and longitude, and measurement status of all trees in the measurement area.

[0009] The navigation assistance module is used to load the navigation file received by the surveyor, determine the target tree that the surveyor needs to measure and obtain its latitude and longitude, and provide auxiliary navigation for the surveyor in conjunction with the navigation device carried by the surveyor to guide the surveyor to the target tree for diameter at breast height measurement.

[0010] The navigation assistance module is also used to transmit the real-time latitude and longitude of the surveyor, which is obtained from the moment the target tree is identified until the moment the surveyor arrives at the target tree, as the measurement travel data of the target tree, together with the diameter at breast height measurement data and the tree number of the target tree, to the measurement control platform.

[0011] When the data analysis unit receives measurement travel data, diameter at breast height (DBH) measurement data, and tree number for a target tree, it analyzes the measurement travel data to determine whether the surveyor detours around the tree. If detours are found, the latitude and longitude of the virtual node of the tree are determined.

[0012] After receiving the latitude and longitude of a virtual node of a tree, the data management unit creates a virtual auxiliary tree for the tree in the stored navigation file containing the tree based on the latitude and longitude, uses the latitude and longitude of the virtual node as the latitude and longitude of the auxiliary tree, and generates a tree number for it.

[0013] After completing the measurement tasks for all measurement areas within the target forest farm, the data management unit conducts a rationality assessment of the division of all measurement areas within the target forest farm. Based on the assessment results, several unreasonable areas are identified. The management personnel of the target forest farm then re-divide these measurement areas based on the navigation files of all the unreasonable areas. The re-divided measurement areas and their navigation files are then updated and stored in the data management unit.

[0014] Furthermore, before any surveyor performs a measurement task, the navigation assistance module obtains the identity information entered by the surveyor and transmits the identity information to the data management unit;

[0015] The data management unit stores navigation files for all measurement areas within the target forest farm and the identity information of the measurement personnel. After receiving the identity information of the measurement personnel, the data management unit extracts the navigation files of the measurement personnel and transmits them to the navigation assistance module.

[0016] Furthermore, the target trees that the surveyors need to measure are determined as follows:

[0017] The navigation file filters out all trees whose measurement status is pending, and the tree with the smallest tree number is selected as the target tree.

[0018] Furthermore, the following are the auxiliary navigation methods provided for surveyors:

[0019] Based on the real-time latitude and longitude of the surveyor and the target tree, a visual guide arrow is generated on the navigation device's display screen. The arrow direction always dynamically points to the target tree, and the direction is adjusted in real time as the surveyor moves. The straight-line distance between the surveyor and the target tree is displayed above the arrow in the format of "XX meters".

[0020] Furthermore, the measurement data is analyzed to determine whether the surveyor detoured around the tree. If detouring is determined, the steps for determining the latitude and longitude of the virtual node of the tree are as follows:

[0021] S11: Obtain the latitude and longitude of the tree from the data management unit according to the number of the received data and perform coordinate transformation to obtain the planar coordinates A1 of the tree, and create the result variable Z1 of the tree. The initial value of the result variable Z1 is 0.

[0022] The latitude and longitude coordinates contained in the measurement data are sequentially transformed according to the order from the earliest to the latest time, to obtain the corresponding plane coordinates B1, B2, ..., Bb, where b is the total number of latitude and longitude coordinates contained in the measurement data.

[0023] S12: Establish a Cartesian coordinate system with (0, 0) as the origin. Select the horizontal rightward direction as the x-axis and extend it from the origin. Select the vertical upward direction as the y-axis and extend it from the origin.

[0024] Based on the planar coordinates A1, B1, ..., Bb, find the corresponding coordinate points in the Cartesian coordinate system, and label them as C1, C2, ..., Cb+1;

[0025] S13: Determine the deflection angle D1 of plane coordinate B1 relative to plane coordinate A1 and the straight-line distance E1 based on coordinate points C1 and C2. The formula for calculating the deflection angle is D1 = arctan(|y1-y2| / |x1-x2|), and the formula for calculating the straight-line distance E1 is... ; where x1 and y1 are the x and y coordinates of the corresponding points of plane coordinate A1 in the plane rectangular coordinate system, respectively, and x2 and y2 are the x and y coordinates of the corresponding points of plane coordinate B1 in the plane rectangular coordinate system, respectively;

[0026] S14: According to S13, determine the deflection angle D2 and straight-line distance E2 of plane coordinate B2 relative to plane coordinate A1 based on coordinate points C1 and C3;

[0027] S15: Based on coordinate points C1 and C2, determine whether the result variable Z1 should be incremented by 1, as follows:

[0028] Calculate the difference F1 between the deviation angles D1 and D2, and the difference F2 between the straight distances E1 and E2. Compare F1 with P1 and F2 with the interval [P2, P3]. If F1 > P1 and F2 ∉ [P2, P3], increment the value of the result variable Z1. At the same time, obtain the latitude and longitude of the plane coordinates corresponding to the coordinate point C2 in the Cartesian coordinate system. Use the latitude and longitude as the latitude and longitude of the result variable Z1 for this change. Otherwise, do not perform any processing. P1 is the preset standard travel angle threshold, and its value is based on the deflection angle D1, the preset standard travel speed, and the stride setting. In the interval [P2, P3], the left endpoint P2 and the right endpoint P3 are the preset minimum and maximum single movement distances, respectively.

[0029] S16: Following S13 to S15, based on coordinate points C2 and C3, C3 and C4, ..., Cb and Cb+1, determine whether the result variable Z1 should be incremented by 1, and obtain the final value D1 of the result variable Z1. Compare D1 and P4. If D1 > P4, it is determined that there is a detour between the surveyor and the tree. At this time, the latitude and longitude with the largest difference between the converted coordinate point and the deflection angle D1 is selected from the latitude and longitude of the result variable Z1 that has changed continuously multiple times as the virtual node of the tree. Otherwise, it is determined that there is no detour between the surveyor and the tree. P4 is the preset detour determination threshold.

[0030] Furthermore, during the navigation file loading process, if a tree has an auxiliary tree, a visual guide arrow is generated to guide the surveyor to the tree. The arrow direction initially points dynamically to the auxiliary tree, and when the surveyor reaches the auxiliary tree, the visual guide arrow direction dynamically points to the tree.

[0031] Furthermore, the rationality assessment for any given measurement area includes the following:

[0032] Obtain the number of virtual nodes of trees in the measurement area, G1, and compare G1 with P5. If G1 ≥ P5, it is determined that detours in the measurement area have a significant impact on the measurement task of the measurement area, and the measurement area is marked as an unreasonable area. Otherwise, it is determined that detours in the measurement area have no impact on the measurement task of the measurement area or can be ignored.

[0033] A method for auxiliary measurement of tree diameter at breast height (DBH) includes the following steps:

[0034] Step 1: Before performing a measurement task, any surveyor must first enter their identity information, which will be acquired by the navigation assistance module and transmitted to the data management unit.

[0035] Step 2: After receiving the transmitted identity information, the data management unit extracts the navigation file of the surveyor and transmits it to the navigation assistance module;

[0036] Step 3: The navigation assistance module loads the received navigation file, determines the target tree that the surveyor needs to measure, and obtains its latitude and longitude. Combined with the navigation device carried by the surveyor, the module provides navigation assistance to guide the surveyor to the target tree for diameter at breast height measurement.

[0037] Step 4: After the surveyor completes the diameter at breast height (DBH) measurement of the target tree, the navigation assistance module obtains the DBH measurement data of the target tree. It uses the real-time latitude and longitude of the surveyor, which is obtained from the moment the target tree is identified until the moment the surveyor arrives at the target tree, as the measurement movement data of the target tree. This data, along with the DBH measurement data and the tree number of the target tree, is transmitted to the measurement control platform.

[0038] Step 5: When the data analysis unit receives measurement travel data, diameter at breast height (DBH) measurement data, and tree number for a target tree, it analyzes the measurement travel data to determine whether the surveyor detours around the tree. If detours are found, the latitude and longitude of the virtual node of the tree are determined and transmitted to the data management unit.

[0039] Step Six: After receiving the latitude and longitude of a virtual node of a tree, the data management unit creates a virtual auxiliary tree for the tree in the stored navigation file containing the tree based on the latitude and longitude, uses the latitude and longitude of the virtual node as the latitude and longitude of the auxiliary tree, and generates a tree number for it.

[0040] Step 7: After all the measurement tasks in all measurement areas within the target forest farm have been completed, the data management unit will conduct a rationality assessment of the division of all measurement areas in the target forest farm. Based on the assessment results, several unreasonable areas will be identified. The management personnel of the target forest farm will then re-divide the several measurement areas of the target forest farm based on the navigation files of all the unreasonable areas. The re-divided measurement areas and their navigation files will be updated and stored in the data management unit.

[0041] Compared with existing technologies, it has the following advantages:

[0042] This invention utilizes a navigation assistance module to acquire and load a navigation file representing the measurement area within a target forest before the surveyor begins their measurement task. During loading, all trees currently awaiting measurement are sequentially selected as target trees based on their tree numbers. The system provides navigation assistance as the surveyor reaches each target tree in sequence. After measuring the diameter at breast height (DBH) of a target tree, the measurement status of that tree is updated. This approach completely avoids the problem of surveyors getting lost due to dense tree cover within the measurement area, eliminating missed measurements at the source. Furthermore, through explicit tree-by-tree navigation, it significantly reduces ineffective walking time and substantially improves the overall efficiency of the measurement task.

[0043] This invention uses a navigation device carried by the surveyor to obtain the latitude and longitude from when any tree is identified as a target tree until the surveyor reaches the tree. It then determines whether the surveyor needs to detour between reaching the tree and the target tree. Based on the determination result, a virtual auxiliary tree is added in the navigation file before the target tree. When the next survey task is executed and navigation to the target tree is required, a visual guide arrow is generated to first navigate to the auxiliary tree to remind the surveyor that a detour is needed. Once the surveyor reaches the auxiliary tree, the navigation then proceeds to the auxiliary tree. This method effectively avoids the navigation interference problem caused by the visual arrow being misleading due to the inability of traditional navigation to recognize detour requirements in forest areas, and further improves the safety of assisted navigation.

[0044] This invention assesses the rationality of all measurement areas within the target forest farm after all surveyors have completed their measurement tasks, based on the number of measurement areas that need to be detoured. Unreasonable areas are then identified and redefined by the forest farm management personnel to ensure that the actual operational difficulty and workload of each measurement area remain balanced. Attached Figure Description

[0045] Figure 1 This is a system block diagram of the present invention;

[0046] Figure 2 This is a flowchart of the method of the present invention. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] Please see Figure 1 , Figure 2 This application provides a tree diameter at breast height (DBH) auxiliary measurement system and method, including a navigation auxiliary module and a measurement control platform;

[0049] The navigation assistance module is used to assist surveyors in navigating to the target tree to complete the diameter at breast height (DBH) measurement in real time. Before performing a measurement task, any surveyor first enters their identity information, which is then acquired by the navigation assistance module and transmitted to the overall measurement control platform. The identity information includes, but is not limited to, name, ID number, and personnel-tree number. The personnel-tree number is a unique identifier assigned to each surveyor, consisting of a letter prefix and a combination of numbers, such as RY-001, which is used to associate the surveyor with the corresponding measurement area and navigation file.

[0050] It should be noted that for any given measurement area, the entrance that the surveyor enters when performing a measurement task in the measurement area is fixed, that is, the location where the surveyor obtains the navigation file for the measurement area is the same.

[0051] After receiving the transmitted identity information, the measurement control platform transmits it to the data management unit. The data management unit extracts the navigation file of the surveyor based on the received identity information and transmits it to the navigation assistance module. The navigation file includes the tree number, latitude and longitude, measurement status, and items to be measured for all trees in the measurement area. The measurement status is divided into two types: to be measured and measured. The format of the navigation file can be either JSON or CSV.

[0052] It should be noted that, by default, all trees in the navigation files transmitted from the measurement control platform are in the measurement status as pending measurement. In this application, the item to be measured is diameter at breast height (DBH).

[0053] In this application, the tree number consists of two parts: area identifier and tree identifier. For example, the tree numbers in measurement area 1 are T1-001, T1-002, ..., where T1 is the area identifier of measurement area 1 and 001 is the tree identifier of the first tree in measurement area 1 that needs to be measured for diameter at breast height.

[0054] In this application, the smaller the value of the tree identifier in the tree number, the higher the priority of the tree's diameter at breast height measurement.

[0055] After receiving the transmitted navigation file, the navigation assistance module first parses its format and loads its data. After loading, it determines the target trees that the surveyor needs to measure based on the navigation file. The determined content is as follows:

[0056] Filter out all trees in the navigation file whose measurement status is to be measured, and select the tree with the smallest tree number as the target tree, and obtain the latitude and longitude of the target tree;

[0057] The surveyor's latitude and longitude are obtained in real time using a navigation device carried by the surveyor. This latitude and longitude are then combined with those of the target tree to provide auxiliary navigation, guiding the surveyor to the target tree. The auxiliary navigation content is as follows:

[0058] Based on the real-time latitude and longitude of the surveyor and the target tree, a visual guide arrow is generated on the display screen of the navigation device. The arrow direction always dynamically points to the target tree and adjusts its direction in real time as the surveyor moves. The straight-line distance between the surveyor and the target tree is displayed above the arrow in the format of "XX meters".

[0059] Once the surveyor reaches the target tree, the diameter at breast height (DBH) of the target tree is measured using a measuring device to obtain the DBH measurement data. The real-time latitude and longitude of the surveyor, obtained from the moment the target tree is identified until the moment the surveyor arrives at the target tree, is used as the measurement movement data for the target tree. This data, along with the DBH measurement data and the tree number of the target tree, is transmitted to the measurement control platform. The measurement data also includes the acquisition time corresponding to the latitude and longitude. In this application, the measuring device is a DBH measuring tape.

[0060] Synchronously, the navigation assistance module updates the navigation file within it, changing the "to be measured" status of the target trees in the navigation file to "measured". After the modification is completed, the navigation assistance module continues to determine the next target tree according to the updated navigation file, until all target trees in the measurement area are determined as target trees and the diameter at breast height measurement is completed.

[0061] The overall measurement control platform is used to manage the data generated when measuring the diameter at breast height (DBH) of all trees in the target forest area. The overall measurement control platform includes a data management unit and a data analysis unit.

[0062] The data management unit stores navigation files for all measurement areas within the target forest area, along with the identity information of the surveyors. The process for generating the initial navigation file for any measurement area is as follows:

[0063] The drone flies within the measurement area according to the pre-input flight trajectory to complete the scanning of the measurement area. During the scanning process, the drone will carry out data collection work simultaneously with multiple sensor devices, including but not limited to acquiring forest-related data through LiDAR and high-resolution optical cameras, and recording the coordinates of sampling points in combination with GNSS positioning module to ensure that core data such as tree number, latitude and longitude can be accurately generated in subsequent navigation files.

[0064] After the scanning task is completed, the collected multi-source data is processed by the backend to form a navigation file of the measurement area containing all tree numbers, latitude and longitude, measurement status and items to be measured. The file is then packaged in a standard format and stored in the data management unit.

[0065] It should be noted that the initial division of the target forest area was done by the management personnel, who divided the target forest area into several measurement areas according to the size of the target forest area, the number of trees to be measured, and the topographical boundaries within the target forest area, and assigned measurement personnel to each measurement area.

[0066] When the measurement control platform receives measurement movement data, diameter at breast height (DBH) measurement data, and tree number for a target tree, it transmits them to the data analysis unit. Upon receiving the same data, the data analysis unit first stores the DBH measurement data and then analyzes the movement data to determine if the surveyor has detoured between the trees. If detouring is found, the latitude and longitude of the virtual node of the tree are determined. The analysis steps are as follows:

[0067] S11: Obtain the latitude and longitude of the tree from the data management unit according to the tree number received in the data and perform coordinate transformation to obtain the planar coordinates A1 of the tree, and create the result variable Z1 of the tree. The initial value of the result variable Z1 is 0.

[0068] The latitude and longitude coordinates contained in the measurement data are sequentially transformed according to the order from the earliest to the latest time, to obtain the corresponding plane coordinates B1, B2, ..., Bb, where b is the total number of latitude and longitude coordinates contained in the measurement data.

[0069] S12: Establish a Cartesian coordinate system with (0, 0) as the origin. Select the horizontal rightward direction as the x-axis and extend it from the origin. Select the vertical upward direction as the y-axis and extend it from the origin.

[0070] Based on the planar coordinates A1, B1, ..., Bb, find the corresponding coordinate points in the Cartesian coordinate system, and label them as C1, C2, ..., Cb+1;

[0071] S13: Determine the deflection angle D1 of plane coordinate B1 relative to plane coordinate A1 and the straight-line distance E1 based on coordinate points C1 and C2. The formula for calculating the deflection angle is D1 = arctan(|y1-y2| / |x1-x2|), and the formula for calculating the straight-line distance E1 is... ; where x1 and y1 are the x and y coordinates of the corresponding points of plane coordinate A1 in the plane rectangular coordinate system, respectively, and x2 and y2 are the x and y coordinates of the corresponding points of plane coordinate B1 in the plane rectangular coordinate system, respectively;

[0072] S14: According to S13, determine the deflection angle D2 and straight-line distance E2 of plane coordinate B2 relative to plane coordinate A1 based on coordinate points C1 and C3;

[0073] S15: Based on coordinate points C1 and C2, determine whether the result variable Z1 should be incremented by 1, as follows:

[0074] Calculate the difference F1 between the deviation angles D1 and D2, and the difference F2 between the straight distances E1 and E2. Compare F1 with P1 and F2 with P2. If F1 > P1 and F2 ∉ [P2, P3], increment the value of the result variable Z1. At the same time, obtain the latitude and longitude of the plane coordinates corresponding to the coordinate point C2 in the Cartesian coordinate system. Use the latitude and longitude as the latitude and longitude of the result variable Z1 for this change. Otherwise, do not perform any processing. P1 is the preset standard travel angle threshold. Its value is based on the deflection angle D1, the preset standard travel speed, and the stride setting. In the interval [P2, P3], the left and right endpoints are the preset minimum and maximum single movement distances, respectively. The speed and stride settings are based on the preset standards.

[0075] S16: Following S13 to S15, based on coordinate points C2 and C3, C3 and C4, ..., Cb and Cb+1, determine whether the result variable Z1 should be incremented by 1, and obtain the final value D1 of the result variable Z1. Compare D1 and P4. If D1 > P4, it is determined that there is a detour between the surveyor and the tree. In this case, select the latitude and longitude with the largest difference between the converted coordinate point and the deflection angle D1 from the latitude and longitude of the continuously changing result variable Z1 as the virtual node of the tree. It should be noted that if there are several continuously changing result variables Z1, the latitude and longitude with the largest difference is selected as the latitude and longitude of the virtual node of the tree. Otherwise, it is determined that there is no detour between the surveyor and the tree. P4 is a preset detour determination threshold.

[0076] The data analysis unit determines the latitude and longitude of a virtual node for each tree and transmits it to the data management unit. The data management unit creates a virtual auxiliary tree for the tree in the navigation file containing the tree based on the latitude and longitude. The latitude and longitude of the virtual node are used as the latitude and longitude of the auxiliary tree. Based on the tree number, the tree number is decremented by 1 and used as the tree number of the auxiliary tree. The tree number of the remaining trees is incremented by 1 in sequence.

[0077] It should be noted that the auxiliary trees in the navigation file only have tree numbers and latitude and longitude, and do not have measurement status or items to be measured; the system can use this to distinguish between trees and auxiliary trees.

[0078] It should be noted that during the navigation file loading process, if there are auxiliary trees for a tree, the generated visual guidance arrow will first dynamically point to the auxiliary tree while guiding the surveyor to the tree. When the surveyor reaches the auxiliary tree, the visual guidance arrow will then dynamically point to the tree to help the surveyor automatically avoid obstacles, improve the practicality of the assisted navigation, and avoid navigation interference caused by the assisted navigation failing to recognize obstacles.

[0079] After all measurement tasks within the target forest area have been completed, the data management unit will conduct a rationality assessment of the division of all measurement areas within the target forest area. The rationality assessment for any given measurement area includes the following:

[0080] Obtain the number of virtual nodes of trees in the measurement area, G1, and compare G1 with P5. If G1 ≥ P5, it is determined that detours in the measurement area have a significant impact on the measurement task of the measurement area, and the measurement area is marked as an unreasonable area. Otherwise, it is determined that detours in the measurement area have no impact on the measurement task of the measurement area or can be ignored. P5 is a preset standard impact quantification value.

[0081] All areas marked as unreasonable and their navigation files are displayed to the management personnel of the target forest farm. The management personnel then re-divide the measurement area of ​​the target forest farm based on all the virtual auxiliary trees in these unreasonable areas. The re-divided measurement areas and their navigation files are updated and stored in the data management unit. It should be noted that the management personnel only divide the measurement area according to the number and type of trees in the measurement area. Therefore, the auxiliary trees still exist when measuring individual trees, and can still help the surveyors automatically avoid obstacles when the next measurement task is started.

[0082] Some of the data in the above formulas are numerical calculations with dimensions removed, and the contents not described in detail in this specification are all prior art known to those skilled in the art.

[0083] The above embodiments are only used to illustrate the technical methods of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical methods of the present invention without departing from the spirit and scope of the technical methods of the present invention.

Claims

1. A tree diameter at breast height (DBH) auxiliary measurement system, characterized in that, include: The overall measurement control platform is used to manage the data generated when measuring the diameter at breast height (DBH) of all trees in the target forest area. The overall measurement control platform includes a data management unit and a data analysis unit. The data management unit stores navigation files for all measurement areas in the target forest area and the identity information of the measurement personnel. The navigation files include the tree number, latitude and longitude, and measurement status of all trees in the measurement area. The navigation assistance module is used to load the navigation file received by the surveyor, determine the target tree that the surveyor needs to measure and obtain its latitude and longitude, and provide auxiliary navigation for the surveyor in conjunction with the navigation device carried by the surveyor to guide the surveyor to the target tree for diameter at breast height measurement. The navigation assistance module is also used to transmit the real-time latitude and longitude of the surveyor, which is obtained from the moment the target tree is identified until the moment the surveyor arrives at the target tree, as the measurement travel data of the target tree, together with the diameter at breast height measurement data and the tree number of the target tree, to the measurement control platform. When the data analysis unit receives measurement travel data, diameter at breast height (DBH) measurement data, and tree number for a target tree, it analyzes the measurement travel data to determine whether the surveyor detours around the tree. If detours are found, the latitude and longitude of the virtual node of the tree are determined. After receiving the latitude and longitude of a virtual node of a tree, the data management unit creates a virtual auxiliary tree for the tree in the stored navigation file containing the tree based on the latitude and longitude, uses the latitude and longitude of the virtual node as the latitude and longitude of the auxiliary tree, and generates a tree number for it. After completing the measurement tasks for all measurement areas within the target forest farm, the data management unit conducts a rationality assessment of the division of all measurement areas within the target forest farm. Based on the assessment results, several unreasonable areas are identified. The management personnel of the target forest farm then re-divide these measurement areas based on the navigation files of all the unreasonable areas. The re-divided measurement areas and their navigation files are then updated and stored in the data management unit.

2. The tree diameter at breast height (DBH) auxiliary measurement system according to claim 1, characterized in that, The target trees that the surveyors need to measure are determined as follows: The navigation file filters out all trees whose measurement status is pending, and the tree with the smallest tree number is selected as the target tree.

3. The tree diameter at breast height (DBH) auxiliary measurement system according to claim 1, characterized in that, The following are the contents of the auxiliary navigation for surveyors: Based on the real-time latitude and longitude of the surveyor and the target tree, a visual guide arrow is generated on the navigation device's display screen. The arrow direction always dynamically points to the target tree, and the direction is adjusted in real time as the surveyor moves. The straight-line distance between the surveyor and the target tree is displayed above the arrow in the format of "XX meters".

4. The tree diameter at breast height (DBH) auxiliary measurement system according to claim 1, characterized in that, Analyzing the measured travel data to determine whether the surveyor detoured around the tree, and if so, determining the latitude and longitude of the virtual node of the tree, the steps are as follows: S11: Obtain the latitude and longitude of the tree from the data management unit according to the number of the received data and perform coordinate transformation to obtain the planar coordinates A1 of the tree, and create the result variable Z1 of the tree. The initial value of the result variable Z1 is 0. The latitude and longitude coordinates contained in the measurement data are sequentially transformed according to the order from the earliest to the latest time, to obtain the corresponding plane coordinates B1, B2, ..., Bb, where b is the total number of latitude and longitude coordinates contained in the measurement data. S12: Establish a Cartesian coordinate system with (0, 0) as the origin. Select the horizontal rightward direction as the x-axis and extend it from the origin. Select the vertical upward direction as the y-axis and extend it from the origin. Based on the planar coordinates A1, B1, ..., Bb, find the corresponding coordinate points in the Cartesian coordinate system, and label them as C1, C2, ..., Cb+1; S13: Determine the deflection angle D1 of plane coordinate B1 relative to plane coordinate A1 and the straight-line distance E1 based on coordinate points C1 and C2. The formula for calculating the deflection angle is D1 = arctan(|y1-y2| / |x1-x2|), and the formula for calculating the straight-line distance E1 is... ; where x1 and y1 are the x and y coordinates of the corresponding points of plane coordinate A1 in the plane rectangular coordinate system, respectively, and x2 and y2 are the x and y coordinates of the corresponding points of plane coordinate B1 in the plane rectangular coordinate system, respectively; S14: According to S13, determine the deflection angle D2 and straight-line distance E2 of plane coordinate B2 relative to plane coordinate A1 based on coordinate points C1 and C3; S15: Based on coordinate points C1 and C2, determine whether the result variable Z1 should be incremented by 1, as follows: Calculate the difference F1 between the deviation angles D1 and D2, and the difference F2 between the straight distances E1 and E2. Compare F1 with P1 and F2 with the interval [P2, P3]. If F1 > P1 and F2 ∉ [P2, P3], increment the value of the result variable Z1. At the same time, obtain the latitude and longitude of the plane coordinates corresponding to the coordinate point C2 in the Cartesian coordinate system. Use the latitude and longitude as the latitude and longitude of the result variable Z1 for this change. Otherwise, do not perform any processing. P1 is the preset standard travel angle threshold, and its value is based on the deflection angle D1, the preset standard travel speed, and the stride setting. In the interval [P2, P3], the left endpoint P2 and the right endpoint P3 are the preset minimum and maximum single movement distances, respectively. S16: Following S13 to S15, based on coordinate points C2 and C3, C3 and C4, ..., Cb and Cb+1, determine whether the result variable Z1 should be incremented by 1, and obtain the final value D1 of the result variable Z1. Compare D1 and P4. If D1 > P4, it is determined that there is a detour between the surveyor and the tree. At this time, the latitude and longitude with the largest difference between the converted coordinate point and the deflection angle D1 is selected from the latitude and longitude of the result variable Z1 that has changed continuously multiple times as the virtual node of the tree. Otherwise, it is determined that there is no detour between the surveyor and the tree. P4 is the preset detour determination threshold.

5. The tree diameter at breast height (DBH) auxiliary measurement system according to claim 1, characterized in that, During the navigation file loading process, if a tree has an auxiliary tree, a visual guide arrow is generated to guide the surveyor to the tree. The arrow direction initially points dynamically to the auxiliary tree, and when the surveyor reaches the auxiliary tree, the visual guide arrow direction dynamically points to the tree.

6. The tree diameter at breast height (DBH) auxiliary measurement system according to claim 1, characterized in that, The rationale assessment for any given measurement area includes the following: Obtain the number of virtual nodes of trees in the measurement area, G1, and compare G1 with P5. If G1 ≥ P5, it is determined that detours in the measurement area have a significant impact on the measurement task of the measurement area, and the measurement area is marked as an unreasonable area. Otherwise, it is determined that detours in the measurement area have no impact on the measurement task of the measurement area or can be ignored. P5 is a preset standard impact quantification value.

7. A method for auxiliary measurement of tree diameter at breast height (DBH), using a tree DBH auxiliary measurement system as described in any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Before performing a measurement task, any surveyor must first enter their identity information, which will be acquired by the navigation assistance module and transmitted to the data management unit. Step 2: After receiving the transmitted identity information, the data management unit extracts the navigation file of the surveyor and transmits it to the navigation assistance module; Step 3: The navigation assistance module loads the received navigation file, determines the target tree that the surveyor needs to measure, and obtains its latitude and longitude. Combined with the navigation device carried by the surveyor, the module provides navigation assistance to guide the surveyor to the target tree for diameter at breast height measurement. Step 4: After the surveyor completes the diameter at breast height (DBH) measurement of the target tree, the navigation assistance module obtains the DBH measurement data of the target tree. It uses the real-time latitude and longitude of the surveyor, which is obtained from the moment the target tree is identified until the moment the surveyor arrives at the target tree, as the measurement movement data of the target tree. This data, along with the DBH measurement data and the tree number of the target tree, is transmitted to the measurement control platform. Step 5: When the data analysis unit receives measurement travel data, diameter at breast height (DBH) measurement data, and tree number for a target tree, it analyzes the measurement travel data to determine whether the surveyor detours around the tree. If detours are found, the latitude and longitude of the virtual node of the tree are determined and transmitted to the data management unit. Step Six: After receiving the latitude and longitude of a virtual node of a tree, the data management unit creates a virtual auxiliary tree for the tree in the stored navigation file containing the tree based on the latitude and longitude, uses the latitude and longitude of the virtual node as the latitude and longitude of the auxiliary tree, and generates a tree number for it. Step 7: After all the measurement tasks in all measurement areas within the target forest farm have been completed, the data management unit will conduct a rationality assessment of the division of all measurement areas in the target forest farm. Based on the assessment results, several unreasonable areas will be identified. The management personnel of the target forest farm will then re-divide the several measurement areas of the target forest farm based on the navigation files of all the unreasonable areas. The re-divided measurement areas and their navigation files will be updated and stored in the data management unit.

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