A method for measuring the diameter and angle of branches

Abstract

The present invention discloses a method for measuring the diameter and angle of branches, which relates to the technical field of forestry research. It includes a support rod, one end of the support rod is sleeved with one end of a movable rod, and one end of a fixed rod is also connected to the support rod. The distance between the fixed rod and the movable rod is adjustable to clamp the branch. RFID cards are provided at the ends of the fixed rod and the movable rod connected to the support rod. The fixed rod and the movable rod are hinged by two connecting rods, and the two connecting rods are also hinged. RFID cards are also provided at the connection of the two connecting rods; a tripod, with a reader provided at each end point. The reader is used to read and measure the position signals of the RFID cards, so as to determine the coordinates of the RFID cards through the coordinates of the reader and calculate the diameter and center of the branch, and obtain the included angle between the branch and the main branch through the center of the branch and the center of the main branch; through the communication connection between the RFID card and the reader, according to the coordinates of the corresponding points, the diameter of the branch and the included angle between the branch and the main branch can be calculated. The measurement method is simple and easy to operate, and the cost is low.

Description

Technical Field

[0001] The present invention relates to the technical field of forestry research, and in particular to a method for measuring branch diameter and angle. Background Art

[0002] In forestry research, branch diameter and angle are crucial measurement indicators. The diameter and angle of branches are the basic data for constructing a three-dimensional tree model. The diameter and angle of branches have a certain randomness in actual tree growth and there is no fixed pattern. Coupled with the influence of the external environment, the diameter and angle of branches are prone to change.

[0003] For the above reasons, it is necessary to accurately measure the diameter and angle of branches. Currently, the measurement of branch diameter and angle is based on a laser scanner. Using laser scanning, the diameter and angle of branches can be obtained very accurately. However, the laser scanner is relatively expensive and has a limited standby time, which is not suitable for long-term outdoor measurement; and the measured point cloud data requires a large storage space and a long indoor analysis, and it is also not suitable for collecting data on branch diameter and angle over a large area. Summary of the Invention

[0004] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a method for measuring branch diameter and angle, which uses a fixed rod and a movable rod to clamp the branch, and obtains the position information of the RFID card according to the reader on the tripod, and then the branch diameter and branch center can be calculated. According to the branch center and the connection length, the center coordinates can be obtained, and finally the angle of the branch relative to the main branch can be obtained.

[0005] To achieve the above purpose, the present invention is implemented through the following technical solutions:

[0006] A method for measuring branch diameter and angle, characterized in that it includes a device for measuring branch diameter and angle, and the device for measuring branch diameter and angle includes:

[0007] A support rod, one end of the support rod is sleeved with one end of the movable rod, and one end of the fixed rod is also connected to the support rod. The distance between the fixed rod and the movable rod is adjustable to clamp the branch. RFID cards are provided at the ends where the fixed rod and the movable rod are connected to the support rod. The fixed rod and the movable rod are hinged by two connecting rods, and the two connecting rods are also hinged. An RFID card is also provided at the connection of the two connecting rods;

[0008] A tripod, with a reader provided at each end point. The reader is used to read and measure the position signal of the RFID card, so as to determine the RFID card coordinates through the reader coordinates and calculate the branch diameter and the center, and obtain the included angle between the branch and the main branch through the branch center and the main branch center;

[0009] Adjust the position of the movable rod relative to the support rod, and clamp and fix the branch through the fixed rod and the movable rod;

[0010] Take the RFID card at the end of the fixed rod as point A, the RFID card at the end of the movable rod as point B, and the RFID card at the connection of the connecting rod as point C;

[0011] Place the tripod on the ground and level it. The three endpoint readers are point D, point E, and point F respectively;

[0012] According to the reader coordinates of point D, point E, and point F, measure the coordinates of different RFID cards, and then calculate the branch diameter;

[0013] According to the length L of the connecting rod and the radius R from the connection of the connecting rod to the branch center O, calculate the coordinates of the center O;

[0014] Continue to measure and finally obtain the coordinates of two branch centers and the coordinates of two main branch centers, and then use the inverse cosine function to calculate the angles between the main branches and the branches.

[0015] As a further implementation method, a groove is provided on the support rod, and the connecting rod is arranged through the groove.

[0016] As a further implementation method, a level is provided on the tripod.

[0017] As a further implementation method, a compass is provided on one side of the tripod.

[0018] As a further implementation method, a card seat is arranged at each endpoint of the tripod, and the card seat is used to install the reader.

[0019] As a further implementation method, a measurement switch is provided on the support rod, and the measurement switch is connected to the RFID card.

[0020] As a further implementation method, an RFID coil is provided in the reader for receiving RFID card signals.

[0021] As a further implementation method, the fixed rod and the support rod are perpendicularly arranged.

[0022] As a further implementation method, the movable rod and the fixed rod are parallelly arranged.

[0023] The beneficial effects of the present invention are as follows:

[0024] 1. The present invention utilizes a fixed rod and a movable rod to clamp a branch. According to the reader on the tripod, the coordinate position information of the RFID card can be obtained. Furthermore, based on the distance between the reading card and the RFID card, the branch diameter and the branch center can be calculated. According to the branch center and the length of the connecting rod, the center coordinates can be obtained. Finally, through the main branch center and the branch center, the angle of the branch relative to the main branch can be obtained using the inverse cosine function. Without using a laser scanner, the operation is simple and the cost is low.

[0025] 2. A level is provided on the tripod of the present invention to facilitate leveling the tripod when measuring the branch diameter and angle, so that the three readers are located on the same horizontal plane, and it is convenient to determine the coordinate axes based on the compass. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings forming a part of this specification are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0027] Figure 1 It is a schematic structural diagram of the device for measuring the branch diameter and angle in the embodiment of the present invention.

[0028] Figure 2 It is a schematic diagram for determining the position of the RFID card in the embodiment of the present invention.

[0029] Figure 3 It is a schematic diagram of the method for obtaining the branch diameter in the embodiment of the present invention.

[0030] Figure 4 It is a schematic diagram of the method for obtaining the branch angle in the embodiment of the present invention.

[0031] In the figure: The distances or sizes between each part are exaggerated for showing the positions of each part, and the schematic diagram is only for illustration.

[0032] Among them: 1. Fixed rod, 2. Movable rod, 3. Measurement switch, 4. Rotating shaft, 5. Support rod, 6. Tripod. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0034] Embodiment 1

[0035] In a typical implementation manner of the present invention, with reference to Figures 1-4As shown in the figure, a method for measuring the diameter and angle of branches includes a device for measuring the diameter and angle of branches. The device for measuring the diameter and angle of branches includes a support rod 5 and a tripod 6. The support rod 5 is used to be vertically arranged and closely attached to the branch or main branch. One end of a fixed rod 1 is connected to the support rod 5. One end of a movable rod 2 is sleeved on the support rod 5. The support rod 5 is perpendicularly connected to the fixed rod 1 and the movable rod 2. The movable rod 2 and the fixed rod 1 are arranged in parallel. By sliding the movable rod 2 on the support rod 5, the relative distance between the fixed rod 1 and the movable rod 2 can be adjusted, so as to clamp the branch or main branch.

[0036] The fixed rod 1 and the movable rod 2 are hinged by two equal-length connecting rods, and the two connecting rods are also hinged. The hinged part is a rotating shaft 4, which is convenient for rotation.

[0037] It can be understood that a slot is opened on the support rod 5. The slot is a through slot, which is arranged along the length direction of the support rod 5, and the connecting rod passes through the slot, ensuring that the connecting rod, the fixed rod and the movable rod can be located in the same plane. RFID cards are provided at the ends of the fixed rod 1 and the movable rod 2 connected to the support rod 5, and RFID cards are also provided at the connection of the two connecting rods. A measurement switch 3 is provided on the support rod 5. The measurement switch 3 is connected to the RFID card, which is convenient for controlling the opening and closing of the RFID card through the measurement switch 3.

[0038] A card seat is provided at each end point of the tripod 6. The card seat is used to install a reader. Therefore, three readers are provided. A level is provided on the tripod 6. When in use, the tripod 6 is used to be set on the ground, and the bubble in the level can ensure that the tripod 6 is horizontal. A compass is provided on one side of the tripod 6. When in use, it is convenient to determine the X-axis, Y-axis and Z-axis with the help of the compass.

[0039] An RFID coil is provided in the reader, which is used to receive the RFID card signal, so that the reader is signal-connected to the RFID card, so as to determine the coordinates of the RFID card and calculate the branch diameter and the center of the circle through the reader coordinates, and obtain the included angle between the branch and the main branch through the center of the branch circle and the center of the main branch circle.

[0040] As Figure 1 shown, taking the RFID card at the end of the fixed rod 1 as point A, the RFID card at the end of the movable rod 2 as point B, and the RFID card at the connection of the connecting rods as point C.

[0041] As Figure 2 shown, taking the end points D, E, F of the tripod 3, a reader is provided at each end point. Taking point G to represent one of points A, B, C, the coordinates of the RFID card (point G) can be calculated according to the coordinates of points D, E, F, and then the branch diameter can be calculated.

[0042] During measurement, slide the movable rod 2, clamp the branches with the movable rod 2 and the fixed rod 1, and fix the relative positions of the two rods with a rope. The support 5 is closely attached to the branches.

[0043] After leveling the tripod 6 on the ground, the distance from the reader to the RFID card can be measured through the RFID coil, and based on the measured distance, the coordinates of the RFID cards at points A, B, and C can be determined. The reader in this embodiment is loaded with a data processing module, which can record the diameter of the branches and the distance information for measuring each RFID card.

[0044] The method for determining the position coordinates of the RFID cards by the three readers at points D, E, and F refers to Figure 2 . The coordinate axes are shown in Figure 2 . Level the tripod 6 through a level to ensure that the three readers are on the same horizontal plane. A compass is provided on the DE side to ensure that the direction of the tripod 6 is fixed. In this embodiment, the Y-axis points to the due north direction.

[0045] In Figure 2 , the tripod 6 has an isosceles triangle structure, and the coordinates of the three readers at points D, E, and F are in a known state. Let F(50, 0, 0), D(0, 50, 0), E(0, -50, 0), where 50 units are centimeters.

[0046] Let point G represent one of points A, B, and C. The lengths of FG, EG, and DG can be obtained through measurement (the distance from the reader to the RFID card can be measured through the RFID coil). Let the coordinates of point G with the RFID card be (x, y, z), where z is a positive number. The calculation formula is as follows:

[0047]

[0048] The position coordinates of point G that can be obtained are:

[0049]

[0050] Based on the measurement, the position coordinates of the RFID cards at points H, I, and J can be calculated. On this basis, the position coordinates of the center O can be calculated, as shown in Figure 3 :

[0051] Let the coordinates of H be (X H , Y H , Z H ), the coordinates of I be (X I , Y I , Z I ), and the coordinates of J be (X J , Y J , Z J ). The calculated diameter d of the branches is:

[0052]

[0053] Since the lengths of HJ and IJ are equal and known, the line segment of OJ is perpendicular to and bisects HI. The lengths of HJ and IJ are both L, the branch cross-section is approximately circular, and the radius from the connection of the connecting rod to the center O of the branch is R.

[0054] The center O of the circle is calculated from the position coordinates:

[0055]

[0056] According to the position of the center O of the branch, the branch angle can be determined, as Figure 4 shown.

[0057] Repeat the above method of measuring the center of the circle to obtain two different centers of the branch and the coordinates of the two main branch centers.

[0058] As Figure 4 , K, L, M, and N are all centers of the circle. Among them, K and L are on the main branch, and N and M are on the branch. The coordinates of the four points K, L, M, and N are measured.

[0059] The vector of KL is The vector of NM is α is the branch angle, and the calculation formula is as follows:

[0060]

[0061] Through the inverse cosine function, α is obtained, which is the angle between the main branch and the branch.

[0062] In this embodiment, through the communication connection between the RFID card and the reader, according to the coordinates of the corresponding points, the diameter of the branch and the included angle between the branch and the main branch can be calculated. The measurement method is simple and easy to operate, and the cost is low.

[0063] The method for measuring the diameter and angle of the branch uses a device for measuring the diameter and angle of the branch, including the following steps:

[0064] Adjust the position of the movable rod relative to the support rod, and clamp and fix the branch through the fixed rod and the movable rod;

[0065] Take the RFID card at the end of the fixed rod as point A, the RFID card at the end of the movable rod as point B, and the RFID card at the connection of the connecting rod as point C;

[0066] Place the tripod on the ground and level it. The three-end readers are points D, E, and F respectively;

[0067] According to the coordinates of points D, E, and F, the coordinates of the RFID card can be calculated, and then the diameter of the branch can be calculated;

[0068] Specifically, let the coordinates of point G represent the position of the RFID card. The lengths of FG, EG, and DG can be measured (the distance from the reader to the RFID card can be measured through the RFID coil). Let the coordinates of point G where the RFID card is installed be (x, y, z), where z is a positive number, and the calculation formula is as follows:

[0069]

[0070] The position coordinates of point G that can be obtained are:

[0071]

[0072] According to the measurement, the position coordinates of points H, I, and J, which are the positions of the RFID card, can be calculated. Based on this, the position coordinates of the center O of the circle can be calculated, as Figure 3 shown:

[0073] Let the coordinates of H be (X H , Y H , Z H ), the coordinates of I be (X I , Y I , Z I ), and the coordinates of J be (X J , Y J , Z J ). The calculated diameter d of the branch is:

[0074]

[0075] Since the lengths of HJ and IJ are equal and known, the line segment OJ is perpendicular to and bisects HI. The lengths of HJ and IJ are both L, the cross-section of the branch is approximately circular, and the radius from the connection of the connecting rod to the center O of the branch is R.

[0076] The center O of the circle is calculated from the position coordinates:

[0077]

[0078] According to the position of the center O of the branch, the branch angle can be determined, as Figure 4 shown.

[0079] Repeat the above method of measuring the center of the circle to obtain the coordinates of the centers of two different branches and the centers of two main branches.

[0080] As Figure 4 , K, L, M, and N are all centers of the circle. Among them, K and L are on the main branch, and N and M are on the branch. The coordinates of the four points K, L, M, and N are measured.

[0081] The vector of KL is The vector of NM is α is the branching angle, and the calculation formula is as follows:

[0082]

[0083] Through the arccosine function, α is obtained, which is the angle between the main branch and the branch.

[0084] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for measuring the diameter and angle of branches, characterized in that, A device for measuring the diameter and angle of branches, the device for measuring the diameter and angle of branches comprising: A support rod, one end of the support rod is sleeved with one end of a movable rod, and one end of a fixed rod is also connected to the support rod. The distance between the fixed rod and the movable rod is adjustable to clamp a branch. RFID cards are provided at the ends of the fixed rod and the movable rod connected to the support rod. The fixed rod and the movable rod are hinged by two connecting rods, and the two connecting rods are also hinged. An RFID card is also provided at the connection of the two connecting rods; A tripod, with a reader provided at each end point. The reader is used to read and measure the position signal of the RFID card, so as to determine the coordinates of the RFID card through the coordinates of the reader and calculate the diameter and the center of the branch. The included angle between the branch and the main branch is obtained through the center of the branch and the center of the main branch; Adjust the position of the movable rod relative to the support rod, and clamp and fix the branch through the fixed rod and the movable rod; Taking the RFID card at the end of the fixed rod as point A, the RFID card at the end of the movable rod as point B, and the RFID card at the connection of the connecting rods as point C; Place the tripod on the ground and level it. The readers at the three end points are point D, point E, and point F respectively; According to the reader coordinates of point D, point E, and point F, measure the coordinates of different RFID cards, and then calculate the diameter of the branch; According to the length L of the connecting rod and the radius R from the connection of the connecting rods to the center O of the branch, calculate the coordinates of the center O; Continue to measure and finally obtain the coordinates of the centers of two branches and the coordinates of the centers of two main branches, and then use the inverse cosine function to calculate the angle between the main branch and the branch.

2. The method for measuring the branch diameter and angle according to claim 1, characterized in that, A slot is provided on the support rod, and the connecting rod passes through the slot.

3. A method for measuring the diameter and angle of branches according to claim 1, characterized in that A level is provided on the tripod.

4. A method for measuring the diameter and angle of branches according to claim 3, characterized in that A compass is provided on one side of the tripod.

5. A method for measuring the diameter and angle of branches according to claim 4, characterized in that, A card seat is provided at each end point of the tripod, and the card seat is used to install the reader.

6. A method for measuring the diameter and angle of a branch according to claim 1, characterized in that, A measurement switch is provided on the support rod, and the measurement switch is connected to the RFID card.

7. A method for measuring the diameter and angle of a branch according to claim 1, characterized in that, An RFID coil is provided in the reader for receiving the RFID card signal.

8. A method for measuring the diameter and angle of branches according to claim 1, characterized in that, The fixed rod is perpendicular to the support rod.

9. A method for measuring the diameter and angle of branches according to claim 8, characterized in that, The movable rod is parallel to the fixed rod.

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