Forest measurement path generation device and forest measurement path generation method

Abstract

This makes it possible to more comprehensively measure the trunk surfaces of trees within the measurement range while generating travel routes that minimize travel time. [Solution] The system includes a tree position acquisition unit 102 that acquires tree position information of trees within a designated area, a grouping unit 104 that groups trees based on the tree position information acquired by the tree position acquisition unit 102, a virtual wall setting unit 106 that sets a virtual wall connecting the trees grouped by the grouping unit 104, and a path generation unit 107 that generates a movement path for measuring the state of the trees from the side using a measuring instrument. The path generation unit 107 generates a movement path that follows both sides of the virtual wall set by the virtual wall setting unit 106.

Description

Technical Field

[0001] The present disclosure relates to a forest measurement route generation device and a forest measurement route generation method.

Background Art

[0002] Techniques for collecting information about forests for forest management are known. For example, Patent Document 1 discloses that an unmanned aerial vehicle flying over a forest generates point clouds at a plurality of different positions within the forest by a light detection and ranging system. In the technique disclosed in Patent Document 1, as a route for generating information about the forest, a route is dynamically generated so as to head to a new position where forest-related information is generated with a desired level of quality even if there are clouds.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to more precisely grasp the growth and value of the trees in a forest, it is preferable to measure the trunk surfaces of the trees. On the other hand, in the technique disclosed in Patent Document 1, since a movement route flying over the forest is generated, it is difficult to comprehensively measure the trunk surfaces of the trees within the section to be measured. Further, when generating a movement route for measurement, from the viewpoints of the time and cost required for measurement, it is required to generate a movement route so that the movement time is shortened.

[0005] One object of this disclosure is to provide a forest measurement route generation device and a forest measurement route generation method that can generate a movement route with a shorter movement time while more comprehensively measuring the trunk surfaces of the trees within the section to be measured. [Means for solving the problem]

[0006] The above objectives are achieved by a combination of features described in the independent claims, and the subordinate claims provide further advantageous specific examples of the disclosure. The reference numerals in parentheses in the claims indicate correspondences with specific means described in the embodiments described later as one aspect, and do not limit the technical scope of this disclosure.

[0007] To achieve the above objective, the forest measurement path generation device of this disclosure comprises a path generation unit (107) that generates a movement path for measuring the condition of trees within a designated section of a forest using measuring instruments (21, 21a) that perform measurements within a predetermined measurement range, wherein the path generation unit generates a movement path for measuring the condition of trees from the side of the trees using measuring instruments, and comprises a tree position acquisition unit (102, 102a) that acquires tree position information, which is information about the location of trees within the section, a grouping unit (104, 104a) that groups trees based on the tree position information acquired by the tree position acquisition unit, and a virtual wall setting unit (106, 106a) that sets a virtual wall connecting the trees grouped by the grouping unit, wherein the path generation unit generates a movement path along both sides of the virtual wall set by the virtual wall setting unit.

[0008] To achieve the above objective, the forest measurement path generation method of this disclosure includes a path generation step that generates a movement path for measuring the condition of trees in a designated section of a forest using measuring instruments (21, 21a) that perform measurements within a predetermined measurement range, which are executed by at least one of a processor and a circuit, wherein the path generation step generates a movement path for measuring the condition of trees from the side of the trees using measuring instruments, and includes a tree position acquisition step that acquires tree position information, which is information about the location of trees in the section, a grouping step that groups the trees based on the tree position information acquired in the tree position acquisition step, and a virtual wall setting step that sets a virtual wall connecting the trees grouped in the grouping step, wherein the path generation step generates a movement path along both sides of the virtual wall set in the virtual wall setting step.

[0009] With the above configuration, the movement path used by the measuring instrument to measure the condition of the trees is generated to follow both sides of a virtual wall connecting the grouped trees. Therefore, compared to generating a movement path that goes around the entire circumference of each individual tree, it is possible to generate a movement path that allows measurement of each tree while keeping the movement path shorter. In addition, since the movement path is generated by the measuring instrument to measure the condition of the trees from the side, it becomes possible to measure the trunk surface of the trees within the measurement area more comprehensively. As a result, it is possible to generate a movement path that measures the trunk surface of the trees within the measurement area more comprehensively while keeping the movement time shorter. [Brief explanation of the drawing]

[0010] [Figure 1] This figure shows an example of a schematic configuration of a forest measurement system in Embodiment 1. [Figure 2] This figure shows an example of a schematic configuration of the route generation device in Embodiment 1. [Figure 3] This is a diagram illustrating one example of a selection rule. [Figure 4] This flowchart shows an example of the grouping-related processing flow. [Figure 5] This diagram illustrates an example of grouping that results in a shape without branching. [Figure 6] This diagram illustrates an example of grouping trees that are less than a set distance apart by treating them as a single tree. [Figure 7] This diagram illustrates an example of setting necessary waypoints. [Figure 8] This figure illustrates the generation of a travel path using the configuration of Embodiment 1. [Figure 9] This figure illustrates the generation of a travel path when the configuration of Embodiment 1 is not used. [Figure 10] This figure illustrates the generation of a travel path when the configuration of Embodiment 1 is not used. [Figure 11] This flowchart shows an example of the process flow related to measurement within a known range. [Figure 12] This is a schematic diagram illustrating the flow of processing related to measurement within a known range. [Figure 13] This figure shows an example of a schematic configuration of a forest measurement system in Embodiment 2. [Figure 14] This figure shows an example of a schematic configuration of the route generation device in Embodiment 2. [Figure 15] This flowchart shows an example of the flow of measurement-related processing. [Figure 16] This flowchart shows an example of the flow of known range measurement-related processing in Embodiment 2. [Figure 17] This flowchart shows an example of the flow of additional related processing. [Figure 18] This is a schematic diagram illustrating the flow of measurement-related processing. [Figure 19] This figure shows an example of a schematic configuration of a forest measurement system in Embodiment 3. [Figure 20] This figure shows an example of a schematic configuration of the forest measurement system in Embodiment 4. [Figure 21]It is a diagram showing an example of the schematic configuration of the route generation device in Embodiment 4. [Figure 22] It is a diagram showing an example of a cylinder model. [Figure 23] It is a diagram for explaining an example of setting waypoints and movement routes along a cylinder model. [Figure 24] It is a flowchart showing an example of the flow of tree measurement related processing in Embodiment 4. [Figure 25] It is a diagram showing an example of the schematic configuration of the forest measurement system in Embodiment 5. [Figure 26] It is a diagram showing an example of the schematic configuration of the route generation device in Embodiment 5. [Figure 27] It is a flowchart showing an example of the flow of tree measurement related processing in Embodiment 5.

Modes for Carrying Out the Invention

[0011] A plurality of embodiments for disclosure will be described while referring to the drawings. For convenience of explanation, among the plurality of embodiments, parts having the same functions as the parts shown in the drawings used in the previous explanations may be denoted by the same reference numerals, and the explanations thereof may be omitted. For parts denoted by the same reference numerals, the explanations in other embodiments can be referred to.

[0012] (Embodiment 1) <Schematic Configuration of Forest Measurement System 1> Hereinafter, Embodiment 1 of the present disclosure will be described with reference to the drawings. As an example, as shown in FIG. 1, the forest measurement system 1 includes a route generation device 10 and an autonomous mobile robot 20.

[0013] The autonomous mobile robot 20 is a robot that moves autonomously. The autonomous mobile robot 20 automatically moves along the movement path generated by the path generation device 10. As the autonomous mobile robot 20, a vehicle-type robot, walking robot, UAV (Unmanned Aerial Vehicle), etc., can be used. A vehicle-type robot is a robot that travels on the ground on wheels. A walking robot is a robot that moves on the ground on its feet. A walking robot may be a bipedal robot or a multi-legged robot that moves using four or more legs. A UAV is an unmanned aerial vehicle. As a UAV, a drone can be used, for example.

[0014] The autonomous mobile robot 20 automatically moves along a travel path by controlling its drive so that its position aligns with the travel path. The autonomous mobile robot 20 can determine its own position using a locator installed on the robot. The locator may, for example, be equipped with a GNSS (Global Navigation Satellite System) receiver and an inertial sensor. The GNSS receiver receives positioning signals from multiple positioning satellites. The inertial sensor may, for example, be equipped with a gyroscope and an accelerometer. The locator sequentially determines the position of the autonomous mobile robot 20 (hereinafter referred to as the "device position") by combining the positioning signals received by the GNSS receiver with the measurement results from the inertial sensor. The device position may be expressed as a three-dimensional coordinate system of latitude, longitude, and altitude.

[0015] The autonomous mobile robot 20 is equipped with a measuring instrument 21. The measuring instrument 21 is a device that performs measurements within a predetermined measurement range. The measuring instrument 21 is used to measure trees in a forest. This measurement can also be described as observation. Examples of the measuring instrument 21 include an imaging device and a depth sensor. The imaging device images a predetermined range starting from itself. The imaging device may be a monocular camera or a depth-sensing camera. A depth-sensing camera can also be described as a depth camera. The depth sensor transmits depth waves within a predetermined range starting from itself. The depth sensor obtains sensing information based on the scanned result obtained when it receives a reflected wave that has been reflected by an object. The depth sensor observes the distance, direction, and shape of an object by transmitting and receiving depth waves. Examples of depth sensors include Lidar (Light Detection and Ranging / Laser Imaging Detection and Ranging). The depth sensor may also be a millimeter-wave radar, sonar, etc. The measuring instrument 21 may be an imaging device or a probe wave sensor.

[0016] The measuring instrument 21 moves through the forest in conjunction with the autonomous mobile robot 20, measuring the trees. The measuring instrument 21 measures the condition of the trees. The condition of the trees measured by the measuring instrument 21 includes the thickness of the trunk and the pattern on the surface of the trunk. The thickness of the trunk can be referred to as the diameter at breast height. The diameter at breast height is the diameter of the tree trunk at a height of 1.2m or 1.3m above the ground. The condition of the trees can also be described as the characteristics of the trees. The measuring instrument 21 collects measurement results for a pre-designated section of the forest (hereinafter referred to as the designated section). The measuring instrument 21 collects measurement results for the designated section as the autonomous mobile robot 20 moves through the designated section.

[0017] The route generation device 10 is mainly composed of a computer equipped with, for example, a processor, volatile memory, non-volatile memory, I / O, and a bus connecting these. The route generation device 10 performs processing related to the generation of a movement path (hereinafter referred to as the measurement movement path) for measuring the condition of trees within a designated area of ​​the forest using the measuring instrument 21. In other words, it performs processing related to the generation of a movement path for the autonomous mobile robot 20 equipped with the measuring instrument 21. Note that at least a part of the functions performed by the processor in the route generation device 10 may be performed by a circuit. The circuit referred to here is a hardware circuit. The route generation device 10 may also be configured to be installed in a server or the like. In this embodiment, the explanation will be given using as an example a configuration in which the route generation device 10 is installed separately from the autonomous mobile robot 20, but it is not necessarily limited to this. The route generation device 10 may also be configured to be installed in the autonomous mobile robot 20. The route generation device 10 corresponds to a route generation device for forest measurement. Details of the route generation device 10 will be described below.

[0018] <Outline configuration of the route generation device 10> As shown in Figure 2, the route generation device 10 includes a tree location database (hereinafter referred to as DB) 101, a tree location acquisition unit 102, a measurement list DB 103, a grouping unit 104, a waypoint setting unit 105, a virtual wall setting unit 106, and a route generation unit 107 as functional blocks. Furthermore, the execution of processing by each functional block of the route generation device 10 by a computer corresponds to the execution of the forest measurement route generation method. Note that some or all of the functions performed by the route generation device 10 may be configured hardware-wise by one or more circuits. Alternatively, some or all of the functional blocks provided by the route generation device 10 may be realized by a combination of software execution by a processor and hardware circuits.

[0019] The tree location database 101 pre-stores information on the locations of trees in a forest that are known (hereinafter referred to as "known location information"), obtained from aerial photographs, forest maps, user input information, etc. Non-volatile memory may be used for the tree location database 101. The known location information should represent the tree locations using coordinates on a geographic coordinate system. The known location information may be entered by the user via the operation input unit, or it may be obtained from a server or the like via a network. The tree location database 101 may also be configured to be located on a server or the like outside the route generation device 10.

[0020] The tree position acquisition unit 102 acquires tree position information, which is information about the locations of trees within a designated area. The processing performed by this tree position acquisition unit 102 corresponds to the tree position acquisition process. The designated area can be set by the user, for example, via the operation input unit. The tree position acquisition unit 102 acquires known position information that corresponds to the designated area from among the known position information stored in the tree position DB 101 as tree position information. The tree position acquisition unit 102 stores the acquired known position information of trees within the designated area in the measurement list DB 103. The known position information of trees within the designated area stored in the measurement list DB 103 will be referred to as the measurement list below.

[0021] The grouping unit 104 groups trees based on the tree position information acquired by the tree position acquisition unit 102. The processing in this grouping unit 104 corresponds to the grouping process. In this embodiment, the grouping unit 104 groups trees based on the known position information of trees within a designated area stored in the measurement list DB 103. Grouping is performed according to predetermined rules (hereinafter referred to as selection rules). The selection rules may differ depending on the type of tree to be measured in the designated area. The selection rules may be set in advance by the user via the operation input unit. The parameters used in the selection rules may be set according to the autonomous mobile robot 20, measuring instrument 21, and measurement environment used for measuring trees.

[0022] For example, the grouping unit 104 can group trees whose distance from each other is less than or equal to a predetermined value. This grouping can be done by adding adjacent trees whose distance from each other is less than or equal to a predetermined value to a group, starting with a designated tree, and then repeating the same process for the added trees. The starting tree can be specified by the user via the operation input unit, or the tree closest to the autonomous mobile robot 20 can be specified. The predetermined value can be set to any arbitrary value. The distance between trees corresponds to the parameter of the selection rule.

[0023] Furthermore, when sequentially adding trees to a group, the condition for adding a tree to the group is that the angle between the line connecting the previous tree and the line connecting the next candidate tree to the group must be less than or equal to a specified value. This is because the closer the lines connecting the grouped trees are to a straight line, the faster the movement path that can be measured in the movement path generation described later can be generated. This specified angle can also be set to an arbitrary value. Note that the angle of the lines connecting the grouped trees is also a parameter of the selection rule.

[0024] Furthermore, when sequentially adding trees to a group, the condition for adding a tree to the group is that the elevation difference between it and the previous tree is less than or equal to a specified value. This is to enable the generation of travel routes that avoid crossing difficult-to-navigate areas such as cliffs or steps. This specified elevation difference can also be set to an arbitrary value. Note that the elevation difference of the trees to be grouped is also a parameter of the selection rule.

[0025] Additionally, when adding trees to a group sequentially, the trees may be added to the group on the condition that the total length of the lines connecting the grouped trees is less than or equal to a predetermined value. This predetermined total length can also be set to an arbitrary value. The total length of the lines connecting the grouped trees is also a parameter of the selection rule. Furthermore, when adding trees to a group sequentially, the trees may be added to the group on the condition that the number of trees in the grouped group is less than or equal to a predetermined value. This predetermined number can also be set to an arbitrary value. The number of trees to be grouped is also a parameter of the selection rule. Furthermore, when adding trees to a group sequentially, the trees may be added to the group on the condition that the distance from trees in another already created group is not less than or equal to a minimum distance. Here, the minimum distance can also be set to an arbitrary value. This minimum distance is also a parameter of the selection rule.

[0026] Furthermore, when sequentially adding trees to a group, as shown in Figure 3, the trees may be added to the group on the condition that they do not intersect with another group that has already been created. The condition that the trees do not intersect with another group that has already been created is the selection rule. Figure 3 is a diagram illustrating one example of a selection rule. TR in Figure 3 indicates the position of the trees. Figure 3 schematically shows the arrangement of trees as viewed from above. GRcom in Figure 3 indicates an already created group, and GRpro indicates a group that is being created. As shown in Figure 3, if we try to add the tree indicated by the dotted arrow to group GRpro, it will intersect with the already created group GRcom. Therefore, the grouping unit 104 does not add the tree indicated by the dotted arrow to group GRpro.

[0027] The virtual wall setting unit 106 sets a virtual wall, which is a virtual wall connecting the trees grouped by the grouping unit 104. The processing in this virtual wall setting unit 106 corresponds to the virtual wall setting process. The virtual wall setting unit 106 only needs to set a virtual wall of a predetermined height on the line segment connecting the position coordinates of the trees. The predetermined height should be a value that fits within the height of the trees and can be set arbitrarily. The position coordinates of the trees can be, for example, the coordinates of the centroid position in the horizontal cross-section of the trunk at a certain height of the tree.

[0028] The virtual wall setting unit 106 may be configured to set a virtual wall each time trees are sequentially added to a group by the grouping unit 104. In other words, it may be configured to extend the virtual wall each time trees are sequentially added to a group by the grouping unit 104. Alternatively, the virtual wall setting unit 106 may be configured to set a virtual wall each time a group is completed by the grouping unit 104. In the following explanation, the virtual wall setting unit 106 will be described as setting a virtual wall each time trees are sequentially added to a group by the grouping unit 104.

[0029] Here, using the flowchart in Figure 4, we will explain an example of the flow of grouping-related processing (hereinafter referred to as grouping-related processing) in the route generation device 10. The flowchart in Figure 4 can be configured to start, for example, when an input is received instructing the route generation device 10 to start generating a travel route.

[0030] First, in step S1, the grouping unit 104 selects a starting tree for grouping from trees whose measurement list contains known position information. For example, suppose an autonomous mobile robot 20 has been brought into the designated area, and the tree closest to the equipment location of the autonomous mobile robot 20 is selected as the starting tree. The equipment location can be obtained by the path generation device 10 from the locator of the autonomous mobile robot 20 and used by the path generation device 10. If grouping has progressed and there are groups that have been grouped, the following should be done: The tree closest to the location of the last tree added to the group that was grouped previously should be selected as the starting tree for the new grouping.

[0031] In step S2, the grouping unit 104 adds trees that meet the aforementioned selection rules to a group. The virtual wall setting unit 106 also sets virtual walls for the trees added to the group. As the flow progresses, if virtual walls have already been set, new virtual walls are added to the existing virtual walls and set, extending the virtual walls.

[0032] In step S3, if it is possible to add more trees that meet the selection rules to the group (YES in S3), the process is repeated by returning to S2. On the other hand, if it is not possible to add more trees that meet the selection rules to the group (NO in S3), the process moves to step S4. It is not possible to add more trees that meet the selection rules to the group if there are no trees remaining in the measurement list that meet the selection rules.

[0033] In step S4, the grouping unit 104 completes the grouping of the groups that were being grouped. The virtual wall setting unit 106 also completes the setting of virtual walls for the groups that have been grouped. In step S5, the grouping unit 104 removes the known location information of the trees that have been grouped from the measurement list.

[0034] In step S6, if there are any known location data points that have not been grouped remaining in the measurement list (YES in S6), the process returns to S1 and is repeated. That is, a start tree is selected for a new group, and a new grouping is started. On the other hand, if there are no known location data points that have not been grouped remaining in the measurement list (NO in S6), the grouping-related processing is terminated.

[0035] The grouping unit 104 preferably groups the trees such that the shape of the virtual wall connecting the grouped trees extends in a shape without branching. This makes it possible to make the movement path generated by the path generation unit 107 (described later) along both sides of the virtual wall a movement path with a smaller maximum curvature. The smaller the maximum curvature of the movement path, the faster the autonomous mobile robot 20 can move along the movement path. Therefore, with the above configuration, it is possible to generate a movement path that shortens the travel time.

[0036] Here, using Figure 5, we will explain an example of grouping that results in a shape without branching. Figure 5 schematically shows the arrangement of trees TR as seen from above. WB in Figure 5 is an example of grouping that results in a shape with branching. On the other hand, NB in ​​Figure 5 is an example of grouping that results in a shape without branching. The arrangement of trees is the same in WB and NB. GR in Figure 5 indicates a group. The grouping unit 104 does not group trees that produce branches as shown in WB, and performs grouping to result in a shape without branching as shown in NB.

[0037] The grouping unit 104 preferably groups trees where the distance between adjacent trees is less than a set distance by assuming that they are a single tree. The set distance is the distance that the entity performing the measurement using the measuring instrument 21 can enter. In this embodiment, this entity is the autonomous mobile robot 20. With the above configuration, it is not necessary to set up a virtual wall connecting trees where the distance between them is less than the set distance, and it is not necessary to generate a travel path that passes through trees where the distance is less than the set distance using the path generation unit 107 described later. Therefore, it becomes difficult to generate a travel path that hinders the movement of the entity performing the measurement using the measuring instrument 21. From this point of view, it is also possible to generate a travel path that reduces travel time. When multiple trees are assumed to be a single tree, the assumed single tree (hereinafter referred to as the assumed tree) can be treated as occupying the range that includes those multiple trees.

[0038] Here, using Figure 6, we will explain an example of grouping trees that are less than a set distance apart by assuming they are a single tree. Figure 6 schematically shows the arrangement of trees TR as seen from above. NI in Figure 6 is an example where trees less than a set distance apart are not assumed to be a single tree. On the other hand, IN in Figure 6 is an example where trees less than a set distance apart are assumed to be a single tree. The arrangement of trees is the same in both NI and IN. VW in Figure 6 represents the virtual wall. MR in Figure 6 represents the movement path generated based on the virtual wall. DA in Figure 6 represents the region where the distance between adjacent trees is less than the set distance. TT in Figure 6 represents the assumed tree. In the case shown in NI, a dead end occurs in the movement path, such as the region shown in DA, where the autonomous mobile robot 20 can get stuck. In contrast, in the case shown in IN, such dead ends can be avoided in the movement path.

[0039] The waypoint setting unit 105 sets waypoints when generating a travel path. The waypoint setting unit 105 sets waypoints according to the positions of the trees grouped by the grouping unit 104 and the virtual walls set by the virtual wall setting unit 106. For example, this can be done as follows: The waypoint setting unit 105 provisionally sets waypoints at regular angular intervals around each of the grouped trees. The waypoint setting unit 105 can provisionally set waypoints at, for example, 90-degree intervals with respect to the position coordinates of one tree. The reference direction for provisionally setting waypoints at regular angular intervals may be a specific direction such as north. Alternatively, if the target tree is at the end of the group, the direction in which the virtual wall extends from that tree may be used as the reference direction. If the target tree is not at the end of the group, the direction in which the bisectors of the extension directions of the virtual wall extending in two directions from that tree extend may be used as the reference direction. The waypoint setting unit 105 deletes the waypoints that interfere with the virtual walls set by the virtual wall setting unit 106 from among the provisionally set waypoints. Then, it sets the remaining waypoints (hereinafter referred to as necessary waypoints) as waypoints. Interference with a virtual wall means that the distance to the virtual wall is less than a threshold. The threshold here can be set to any arbitrary value.

[0040] Here, we will explain an example of setting necessary waypoints using Figure 7. Figure 7 schematically shows the arrangement of trees TR as seen from above. BD in Figure 7 is an example before the deletion of necessary waypoints. On the other hand, AD in Figure 7 is an example after the deletion of necessary waypoints. The arrangement of trees is assumed to be the same in BD and AD. VP in Figure 7 indicates the waypoints. Before the deletion of necessary waypoints, as shown in BD, four waypoints are provisionally set at 90-degree intervals around the position of each tree TR. In contrast, as shown in AD, the waypoints that interfere with the virtual wall surface VW among the provisionally set waypoints are deleted, and the remaining necessary waypoints are set as waypoints.

[0041] The path generation unit 107 generates a movement path for measuring the condition of trees within a designated area of ​​the forest using the measuring instrument 21. This processing in the path generation unit 107 corresponds to the path generation process. The path generation unit 107 generates a movement path for measuring the condition of trees from the side using the measuring instrument 21. The path generation unit 107 generates a movement path that follows both sides of the virtual wall set by the virtual wall setting unit 106. By generating a movement path that follows both sides of the virtual wall, a movement path is generated that allows the measuring instrument 21 to measure the condition of trees from the side.

[0042] According to the configuration of this embodiment, it is possible to generate a travel path that more comprehensively measures the trunk surface of trees within the area to be measured while minimizing travel time. This effect will be explained using Figures 8 to 10. Figure 8 is a diagram illustrating the generation of a travel path when using the configuration of this embodiment. Figures 9 and 10 are diagrams illustrating the generation of a travel path when not using the configuration of this embodiment. Figures 8 to 10 schematically show the arrangement of tree TRs as seen from above.

[0043] According to the configuration of this embodiment, as shown in Figure 8, the movement path MR for measuring the condition of the trees is generated to follow both sides of the virtual wall surface VW connecting the grouped trees. This makes it possible to shorten the movement path compared to generating a movement path MR that goes around the entire circumference of each individual tree, as shown in Figure 9. Furthermore, as shown in Figure 10, it is difficult to comprehensively measure the trunk surface of the trees with a movement path that only passes through pre-fixed coordinates FC. This is because no measures have been taken to reduce the areas where measurement is not performed, as shown in the MEA of Figure 10. In contrast, according to the configuration of this embodiment, as shown in Figure 8, the movement path MR is generated to follow both sides of the virtual wall surface VW connecting the grouped trees. Therefore, areas where measurement is not performed, as shown in the MEA of Figure 10, are less likely to occur. As a result, it is possible to generate a movement path that more comprehensively measures the trunk surface of the trees within the area to be measured while keeping the movement time shorter. Furthermore, according to the configuration of this embodiment, the measuring instrument 21 generates a movement path for measuring the condition of the trees from the side, which also makes it possible to more comprehensively measure the trunk surface of the trees within the area to be measured.

[0044] The path generation unit 107 only needs to generate a travel path that passes through all the necessary waypoints set by the waypoint setting unit 105. The path generation unit 107 only needs to generate a travel path that passes through all the necessary waypoints based on an optimization method such as a greedy algorithm. Alternatively, the path generation device 10 may not have a waypoint setting unit 105 and may be configured to generate a travel path based on a virtual wall without using waypoints. For example, the path generation unit 107 may generate a travel path that traces both sides of the virtual wall while maintaining a certain distance from the virtual wall. The following explanation will continue with an example of generating a travel path using waypoints.

[0045] Here, using the flowchart in Figure 11, we will explain an example of the flow of processing related to the generation of movement paths in the forest measurement system 1 and measurement by the measuring instrument 21 (hereinafter referred to as known range measurement-related processing) after the completion of grouping-related processing. Figure 12 is a schematic diagram illustrating the flow of known range measurement-related processing. Figure 12 schematically shows the arrangement of trees TR as viewed from above. RL in Figure 12 indicates the position of the autonomous mobile robot 20. The flowchart in Figure 11 can be configured to start, for example, when the grouping-related processing is completed.

[0046] First, in step S21, the waypoint setting unit 105 determines the measurement order of the multiple groups grouped in the grouping-related processing. The measurement order of the groups may also be determined by the path generation unit 107. The measurement order of the groups can be determined by assigning small numbers to the groups based on the representative coordinates of each group, in order of proximity to the equipment position of the autonomous mobile robot 20. Alternatively, the measurement order may be such that the path connecting the representative coordinates of each group, with this equipment position as the starting point, is the shortest. The representative coordinates of a group can be the coordinates of the centroid position of each tree cross-section within the group. Alternatively, the representative coordinates of a group may be the position coordinates of the central tree within the group, the position coordinates of the trees at the ends of the group, etc. The equipment position can be obtained by the path generation device 10 from the locator of the autonomous mobile robot 20 and used by the path generation device 10.

[0047] In the example in Figure 12, the order is determined such that the path connecting the representative coordinates of each group is shortest, with the position of the autonomous mobile robot 20 as the starting position. In the example in Figure 12, the order of the four groups is determined as 1st, 2nd, 3rd, and 4th. In Figure 12, the 1st is represented as 1st, the 2nd as 2nd, the 3rd as 3rd, and the 4th as 4th.

[0048] In step S22, the waypoint setting unit 105 sets waypoints for the target group. The target group is the group that has not yet been measured and whose measurement order is earliest as determined in S1. If the group with the first measurement order has not yet been measured, the group with the first measurement order becomes the target group. If the group with the first measurement order has already been measured, and the group with the second measurement order has not yet been measured, the group with the second measurement order becomes the target group. The waypoint setting unit 105 sets the necessary waypoints for the target group as described above. As shown in Figure 12, if the group with the first measurement order has not yet been measured, waypoint VP is set for the first group. On the other hand, if the group with the first measurement order has already been measured, and the second group has not yet been measured, waypoint VP is set for the second group.

[0049] In step S23, the route generation unit 107 generates a travel route that passes through all the necessary waypoints set in S22. As shown in Figure 12, if the first group in the measurement order has not been measured, the travel route MR is set for the first group. On the other hand, if the first group in the measurement order has been measured but the second group has not been measured, the travel route MR is set for the second group.

[0050] In step S24, the autonomous mobile robot 20 is controlled to move along the travel path set in S23. While moving along the travel path, the autonomous mobile robot 20 takes measurements sequentially using the measuring instrument 21. Measurements by the measuring instrument 21 may be taken periodically, for example, every 100 msec. In a configuration where the autonomous mobile robot 20 and the path generation device 10 are provided separately, the autonomous mobile robot 20 can acquire the travel path generated by the path generation unit 107 via wireless communication. As shown in Figure 12, if the first group in the measurement order has not yet been measured, the autonomous mobile robot 20 takes measurements of the travel path MR for the first group while moving using the measuring instrument 21. On the other hand, if the first group in the measurement order has already been measured but the second group has not yet been measured, the autonomous mobile robot 20 takes measurements of the travel path MR for the second group while moving using the measuring instrument 21.

[0051] In step S25, if the autonomous mobile robot 20 has passed all the necessary waypoints for the target group set in S22 (YES in S25), the process proceeds to step S26. On the other hand, if the autonomous mobile robot 20 has not yet passed all of the necessary waypoints (NO in S25), the process returns to S24 and is repeated. The autonomous mobile robot 20 can determine whether it has passed the necessary waypoints by checking whether the device position, which is sequentially measured by the locator, has passed the necessary waypoints. The autonomous mobile robot 20 can obtain and use the information of the necessary waypoints set in the waypoint setting unit 105 from the route generation device 10.

[0052] In step S26, if there are still groups that the autonomous mobile robot 20 has not measured (YES in S26), the process returns to S22 and is repeated. On the other hand, if there are no groups that the autonomous mobile robot 20 has not measured (NO in S26), the known range measurement-related processing is terminated. The autonomous mobile robot 20 can determine whether there are no groups that the autonomous mobile robot 20 has not measured. The autonomous mobile robot 20 can determine this, for example, by checking if a movement path is not output from the path generation device 10 for a certain period of time or longer.

[0053] (Embodiment 2) Embodiment 1 shows a configuration that generates a movement path using only known location information as information about the location of trees in a forest, but it is not necessarily limited to this. For example, a configuration that generates a movement path using not only known location information but also unknown information as information about the location of trees in a forest (hereinafter referred to as Embodiment 2) may be used. Below, an example of the configuration of Embodiment 2 will be explained with reference to a figure.

[0054] <Outline configuration of forest measurement system 1a> As shown in Figure 13, the forest measurement system 1a of Embodiment 2 includes a path generation device 10a and an autonomous mobile robot 20a. The autonomous mobile robot 20a is equipped with a measuring instrument 21a. The autonomous mobile robot 20a is the same as the autonomous mobile robot 20 of Embodiment 1, except that it is equipped with a measuring instrument 21a instead of a measuring instrument 21. The autonomous mobile robot 20a also corresponds to the main body that performs measurements.

[0055] The measuring instrument 21a is the same as the measuring instrument 21 of Embodiment 1, except for a few differences. These differences will be explained below. The measuring instrument 21a will also measure the positions of trees. The measuring instrument 21a can measure the position of trees from the distance from the measuring instrument 21a to the trees and the orientation of the trees relative to the measuring instrument 21a. The measuring instrument 21a can measure the position coordinates of the trees on the geographic coordinate system using the equipment position of the autonomous mobile robot 20a. The measuring instrument 21a can obtain the equipment position of the autonomous mobile robot 20a from the locator of the autonomous mobile robot 20a.

[0056] <Outline configuration of route generation device 10a> As shown in Figure 14, the route generation device 10a includes a tree position DB 101, a tree position acquisition unit 102a, a measurement list DB 103a, a grouping unit 104a, a waypoint setting unit 105a, a virtual wall setting unit 106a, a route generation unit 107, and a correction judgment unit 108 as functional blocks. The route generation device 10a is the same as the route generation device 10 of Embodiment 1, except that some processing differs. The route generation device 10a also corresponds to a route generation device for forest measurement. Furthermore, the execution of processing for each functional block of the route generation device 10a by a computer corresponds to the execution of a route generation method for forest measurement. The following describes the differences between the route generation device 10a and the route generation device 10 of Embodiment 1.

[0057] The tree position acquisition unit 102a is the same as the tree position acquisition unit 102 of Embodiment 1, except that some processing differs. The differences will be explained below. The tree position acquisition unit 102a also acquires tree position information, which is sequentially measured by the measuring instrument 21a (hereinafter referred to as sequential measurement position information). In other words, in addition to the known tree position information stored in the tree position DB, it also acquires tree position information newly obtained from measurements by the measuring instrument 21a. The processing in the tree position acquisition unit 102a also corresponds to the tree position acquisition process. The tree position acquisition unit 102a also stores the acquired sequential measurement position information in the measurement list DB 103a. As a result, the tree position acquisition unit 102a adds or updates tree position information to the measurement list stored in the measurement list DB 103a.

[0058] For example, the tree position acquisition unit 102a can choose between adding and updating depending on whether the error in the position coordinates with the known position information included in the measurement list is greater than or equal to a threshold. Specifically, sequentially measured position information with an error greater than or equal to the threshold can be added to the measurement list as tree position information for an unknown tree. On the other hand, sequentially measured position information with an error less than the threshold can be updated in the measurement list as tree position information that updates the known tree position information that had an error with the actual position. The threshold here is a value that distinguishes whether or not the position error is for the same tree, and can be set to any arbitrary value. The measurement list DB 103a is the same as the measurement list DB 103 of Embodiment 1, except that it also stores sequentially measured position information.

[0059] The correction determination unit 108 determines whether or not the group already grouped by the grouping unit 104a needs to be corrected (hereinafter referred to as "group correction necessity"). The correction determination unit 108 determines that a group correction is necessary if the acquisition of sequential measurement position information causes a change greater than a specified amount in the position of the trees used to set the virtual wall surface. The scope of the change greater than a specified amount can be set arbitrarily. For example, the correction determination unit 108 may determine that a group correction is necessary if an addition or update is made to the measurement list by acquiring sequential measurement position information.

[0060] The grouping unit 104a is the same as the grouping unit 104 of Embodiment 1, except that some processing differs. These differences will be explained below. The grouping unit 104a regroups the trees when the correction judgment unit 108 determines that a group correction is necessary. The grouping unit 104a simply regroups the trees based on the tree position information of the measurement list that has been added or updated. The processing in the grouping unit 104a is equivalent to the grouping process.

[0061] The virtual wall setting unit 106a modifies the virtual wall if the correction judgment unit 108 determines that a group needs to be corrected after the virtual wall has been set, based on the sequential measurement position information newly acquired by the tree position acquisition unit 102a after the virtual wall was set. Specifically, the virtual wall connecting the trees that have been regrouped by the grouping unit 104a based on the tree position information of the measurement list that has been added or updated can be reset. For groups that have not been corrected by the grouping unit 104a, it is not necessary to reset the virtual wall. The processing in the virtual wall setting unit 106a is equivalent to the virtual wall setting process.

[0062] The waypoint setting unit 105a is the same as the waypoint setting unit 105 of Embodiment 1, except that some processing differs. The differences will be explained below. The waypoint setting unit 105a resets the necessary waypoints for the groups that have been modified by the grouping unit 104a. For virtual walls that have been reset by the virtual wall setting unit 106a, the waypoint setting unit 105a uses these virtual walls to reset the necessary waypoints. Then, the route generation unit 107 generates a route that passes through all the necessary waypoints set by the waypoint setting unit 105a as a travel route.

[0063] Here, using the flowcharts in Figures 15 to 17, we will explain an example of the flow of processing related to the generation of movement paths in the forest measurement system 1a and measurement in the measuring instrument 21a (hereinafter referred to as measurement-related processing). Figure 18 is a schematic diagram illustrating the flow of measurement-related processing. Figure 18 schematically shows the arrangement of trees TR as seen from above. In Figure 18, UA indicates an area within the designated area where tree position information is unknown (hereinafter referred to as the unknown area). The flowchart in Figure 15 should be configured to start when the grouping-related processing described in Embodiment 1 is completed. In other words, it should be configured to start when the grouping-related processing using known position information is completed. When the grouping-related processing using known position information is completed, grouping is completed for trees in the area within the designated area excluding the unknown area.

[0064] First, in step S41, known range measurement-related processing is performed, and then the process moves to step S42. The known range measurement-related processing is the same as the known range measurement-related processing described in Embodiment 1, except that some processing differs. Here, an example of the flow of known range measurement-related processing in Embodiment 2 will be explained using Figure 16. Here, it is assumed that after the autonomous mobile robot 20a starts moving along the movement path, sequential measurement position information is sequentially acquired by the tree position acquisition unit 102a. Then, for known position information that needs to be updated, the position coordinates are updated using the sequential measurement position information. In addition, as the autonomous mobile robot 20a moves, sequential measurement position information for trees in the unknown area is also sequentially added to the measurement list.

[0065] Steps S411 to S415 perform the same processing as S21 to S25. Step S416 performs the same processing as S26. In S416, if there are still groups remaining that have not been measured by the autonomous mobile robot 20a (YES in S416), proceed to step S417. On the other hand, if there are no remaining groups that have not been measured by the autonomous mobile robot 20a (NO in S416), proceed to step S42.

[0066] In step S417, if the correction determination unit 108 determines that correction is necessary for the group already grouped by the grouping unit 104a (YES in S417), the process moves to step S418. This situation occurs when the tree position information of the trees included in the grouped group is updated sequentially with the measured position information. On the other hand, if the correction determination unit 108 determines that correction is not necessary for the group already grouped by the grouping unit 104a (NO in S417), the process returns to S412 and is repeated. In other words, processing for the next group in the measurement sequence that has not yet been measured begins.

[0067] In step S418, the grouping unit 104a regroups the trees based on the updated tree position information in the measurement list and modifies the groups. Also in S418, the virtual wall setting unit 106a sets virtual walls connecting the regrouped trees, thereby resetting the virtual walls. Then, returning to S411, if a change in the measurement order is necessary due to the group modification, the measurement order is changed and the process is repeated.

[0068] Returning to Figure 15, in step S42, additional association processing is performed, and then the process moves to step S43. Here, using Figure 17, an example of the flow of additional association processing will be explained. First, in step S421, if ungrouped sequential measurement position information remains in the measurement list (YES in S421), the process moves to step S422. The situation where ungrouped sequential measurement position information remains in the measurement list occurs when sequential measurement position information for an unknown area is obtained through measurement. On the other hand, if ungrouped sequential measurement position information does not remain in the measurement list (NO in S421), the process moves to step S43.

[0069] In step S422, the same grouping-related processing as described in Embodiment 1 is performed on the sequentially measured position information that has not been grouped, and the process moves to step S43. As the autonomous mobile robot 20a moves, sequentially measured position information for previously unknown areas becomes newly available through measurement. In response to this, the additional related processing, as shown in Figure 18, sets up new groups and virtual wall surfaces VW for those groups using the newly obtained sequentially measured position information. As a result, the tree TR used to set up the new groups and virtual wall surfaces VW undergoes known range measurement-related processing, and a movement path MR is generated for those groups.

[0070] Returning to Figure 15, in step S43, if there are still groups that the autonomous mobile robot 20a has not measured (YES in S43), the process returns to S41 and is repeated. The situation where there are still groups that the autonomous mobile robot 20a has not measured occurs when a new group is added and set by the additional related process. On the other hand, if there are no groups that the autonomous mobile robot 20a has not measured (NO in S43), the measurement related process is terminated. Whether or not there are still groups that the autonomous mobile robot 20a has not measured can be determined in the same way as in S26.

[0071] According to the configuration of Embodiment 2, even if the positions of the trees in the designated area are unknown before measurement begins with the measuring instrument 21, it is possible to generate a travel path that more comprehensively measures the trunk surfaces of the trees in the area to be measured while minimizing travel time. Furthermore, according to the configuration of Embodiment 2, even if the positions of the trees in the designated area are known but there is a large error between that and their actual positions, it is possible to generate a travel path that more comprehensively measures the trunk surfaces of the trees in the area to be measured while minimizing travel time.

[0072] Embodiment 2 shows a configuration for generating a movement path using known location information and sequentially measured location information, but it is not necessarily limited to this. For example, a configuration may be used to generate a movement path without using known location information. In this case, the movement path can be generated using sequentially measured location information. In this case, the direction of movement at the start of measurement may be specified by the user, or it may be determined autonomously by the autonomous mobile robot 20a. If the autonomous mobile robot 20a determines the direction of movement autonomously, the direction in which a tree exists that can be measured by the measuring instrument 21a should be used as the initial direction of movement. Then, the subsequent movement path can be generated from the sequentially measured location information measured by the measuring instrument 21a while approaching that tree.

[0073] (Embodiment 3) In the above-described embodiment, the entity performing the measurement using the measuring instruments 21, 21a is shown to be an autonomous mobile robot 20, 20a, but the configuration is not necessarily limited to this. For example, the configuration of Embodiment 3 below may also be used.

[0074] <Outline configuration of forest measurement system 1b> Embodiment 3 will be described below with reference to the drawings. As an example, the forest measurement system 1b includes a path generation device 10 and an auxiliary device 30, as shown in Figure 19. The forest measurement system 1b may also be configured to include a path generation device 10a instead of the path generation device 10.

[0075] The auxiliary device 30 is equipped with a measuring instrument 21. The auxiliary device 30 is held by a person and automatically takes measurements using the measuring instrument 21 as the person moves. In Embodiment 3, the measuring instrument 21 collects measurement results for a designated area as the person holding the auxiliary device 30 moves within the designated area. The auxiliary device 30 provides guidance to guide the person along the movement path generated by the path generation device 10. The guidance may be provided by display and audio output, or at least one of the latter. The auxiliary device 30 is enabled to move along the movement path by causing the person to move according to the guidance. If the forest measurement system 1b includes a path generation device 10a, the auxiliary device 30 may be configured to include a measuring instrument 21a.

[0076] In the configuration of Embodiment 3, measurements are also taken by measuring instruments 21, 21a along the travel path generated by the path generation devices 10, 10a. Therefore, similar to Embodiments 1 and 2 described above, it is possible to generate a travel path that more comprehensively measures the trunk surfaces of trees within the area to be measured while keeping travel time shorter.

[0077] (Embodiment 4) The embodiment described above is not the only possible configuration in which a movement path for each individual tree is generated as follows (hereinafter referred to as Embodiment 4).

[0078] <Outline configuration of forest measurement system 1c> Embodiment 4 will be described below with reference to the drawings. As an example, the forest measurement system 1c includes a path generation device 10c and an autonomous mobile robot 20c, as shown in Figure 20.

[0079] The autonomous mobile robot 20c is similar to the autonomous mobile robot 20 of Embodiment 1, except for a few differences. These differences will be explained below. It is preferable that the autonomous mobile robot 20c is capable of easily moving in the vertical direction relative to trees. For example, a drone or the like may be used as the autonomous mobile robot 20c.

[0080] The path generation device 10c is mainly composed of a computer equipped with, for example, a processor, volatile memory, non-volatile memory, I / O, and a bus connecting these. The path generation device 10c performs processing related to the generation of movement paths by measuring the condition of trees within a designated area of ​​the forest using the measuring instrument 21. In other words, it performs processing related to the generation of movement paths for the autonomous mobile robot 20c equipped with the measuring instrument 21. As part of the process for generating movement paths, the path generation device 10c performs processing related to the generation of movement paths for each individual tree. Note that at least a part of the functions performed by the processor may be performed by a circuit in the path generation device 10c. The circuit referred to here is a hardware circuit. The path generation device 10c may also be configured to be installed in a server or the like. In this embodiment, the explanation will be given using as an example a configuration in which the path generation device 10c is installed separately from the autonomous mobile robot 20c, but it is not necessarily limited to this. The path generation device 10c may also be configured to be installed in the autonomous mobile robot 20c. Details of the path generation device 10c will be described below.

[0081] <Outline configuration of route generation device 10c> As shown in Figure 21, the route generation device 10c includes a tree condition DB 111, a cylinder model generation unit 112, a waypoint setting unit 113, and a route generation unit 114 as functional blocks. Furthermore, the execution of processing by each functional block of the route generation device 10c by a computer corresponds to the execution of the forest measurement route generation method described later. Note that some or all of the functions performed by the route generation device 10c may be configured hardware-wise by one or more circuits. Alternatively, some or all of the functional blocks provided by the route generation device 10c may be realized by a combination of software execution by a processor and hardware circuits.

[0082] The tree condition DB111 stores information about tree characteristics in advance. Non-volatile memory can be used for the tree condition DB111. Tree characteristics are geometric conditions that are presumed to be satisfied by any tree. Examples of such geometric conditions include: the condition that branches become thinner as they approach the tip; the condition that the diameter of the branches is in the range of 0.2 to 2 m; and the condition that the angle between the branches and the trunk is always acute. The tree condition DB111 may also store tree characteristics for each type of tree. The tree condition DB111 may be configured to be stored on a server or the like, outside of the path generation device 10c.

[0083] The cylinder model generation unit 112 generates a cylinder model representing the tree shape based on the tree features stored in the tree condition DB 111. In other words, the cylinder model generation unit 112 generates a cylinder model that satisfies geometric conditions that are presumed to be satisfied by any tree. Based on the tree features, the cylinder model generation unit 112 generates a cylinder model that approximates the tree shape with a combination of multiple cylinders, as shown in Figure 22. Figure 22 is a diagram showing an example of a cylinder model. Co in Figure 22 indicates the cylinders that are combined in the cylinder model. The cylinder model may be represented by parameters that have the coordinates and radius of the endpoints of the cylinders, corresponding to the number of cylinders that make up the trunk or branches. The cylinder model may be represented by three-dimensional coordinates.

[0084] The cylindrical model generation unit 112 may be configured to generate a cylindrical model corresponding to the type of tree to be measured in a designated area. The trees to be measured in the designated area shall be of a single type. The cylindrical model generation unit 112 should generate a cylindrical model corresponding to the type of tree by using tree features corresponding to the type of tree to be measured, among the tree features stored in the tree condition DB 111. The cylindrical model generation unit 112 may receive information on the type of tree to be measured from the user, for example, via an operation input unit.

[0085] The waypoint setting unit 113 sets waypoints at regular intervals along the surface of the cylindrical model generated by the cylindrical model generation unit 112. As shown in Figure 23, the waypoint setting unit 113 sets waypoints at regular intervals along the surface of the cylindrical model in a spiral shape in the height direction. In other words, the waypoint setting unit 113 sets waypoints at regular intervals in both the axial and radial directions of the cylindrical model. Figure 23 is a diagram illustrating an example of setting waypoints and movement paths along a cylindrical model. CM in Figure 23 represents the cylindrical model. VP in Figure 23 represents the waypoints. MR in Figure 23 represents the movement path generated by the path generation device 10c. The setting interval of the waypoints can be set to an arbitrarily configurable value. The waypoints are set so that the distance from the surface of the cylindrical model is greater than or equal to a predetermined value so that the autonomous mobile robot 20c does not interfere with the trees. This predetermined value can be, for example, a value corresponding to the size of the autonomous mobile robot 20c.

[0086] The path generation unit 114 generates a movement path for measuring the condition of trees within a designated area of ​​the forest using the measuring instrument 21. This processing in the path generation unit 114 corresponds to the path generation process described later. The path generation unit 114 generates a movement path for measuring the condition of trees from the side using the measuring instrument 21. For this movement path for a single tree, the path generation unit 114 generates a movement path that spirals along the surface of the cylindrical model set by the cylindrical model generation unit 112 in the height direction. By generating a movement path that spirals along the surface of the cylindrical model in the height direction, a movement path is generated that allows the measuring instrument 21 to measure the condition of the actual trees from the side.

[0087] As shown in Figure 23, the path generation unit 114 only needs to generate a travel path that passes through all the waypoints set by the waypoint setting unit 113. The path generation unit 114 only needs to generate a travel path that passes through all the waypoints based on an optimization method such as a greedy algorithm. Note that the path generation device 10c may not have a waypoint setting unit 113 and may be configured to generate a travel path without using waypoints. For example, the path generation unit 114 may generate a travel path that follows a spiral in the height direction along the surface of the cylindrical model while maintaining a constant distance from the cylindrical model. The following explanation will continue with an example of generating a travel path using waypoints.

[0088] Here, using the flowchart in Figure 24, an example of the flow of processing related to the generation of a movement path for each tree in the forest measurement system 1c and measurement by the measuring instrument 21 (hereinafter referred to as "tree measurement-related processing") will be explained. The flowchart in Figure 24 may be configured to start each time the system approaches a tree to be measured, for example, when the start of measurement of trees in a designated area is instructed. Alternatively, it may be configured to start when the system approaches a designated tree to be measured. The trees to be measured may be designated as trees that have not been measured sufficiently, for example, by input from the user via the operation input unit. Approach to a tree to be measured may be determined from the position of the autonomous mobile robot 20c at a point set for each tree in the movement path for measuring multiple trees as described in Embodiments 1 and 2. Approach to a tree to be measured may also be determined from the detection of the presence of the tree by the measuring instrument 21.

[0089] First, in step S61, the cylinder model generation unit 112 generates a cylinder model corresponding to the type of tree to be measured. As mentioned above, the cylinder model generation unit 112 should generate a cylinder model corresponding to the type of tree based on the tree characteristics corresponding to the type of tree stored in the tree condition DB 111.

[0090] In step S62, the waypoint setting unit 113 sets waypoints at regular intervals so as to follow the surface of the cylindrical model generated in S61 in a spiral shape in the height direction. In step S63, the path generation unit 114 generates a path that passes through all the waypoints set in S62 as the travel path.

[0091] In step S64, the autonomous mobile robot 20c is controlled to move along the movement path set in S63. While moving along the movement path, the autonomous mobile robot 20c takes measurements sequentially using the measuring instrument 21. The measurements by the measuring instrument 21 may be taken periodically, for example, every 100 msec, as described in Embodiment 1. In a configuration in which the autonomous mobile robot 20c and the path generation device 10c are provided separately, the autonomous mobile robot 20c may acquire the movement path generated by the path generation unit 114 via wireless communication.

[0092] In step S65, if the autonomous mobile robot 20c has passed through all the waypoints set in S62 (YES in S65), the process proceeds to step S66. On the other hand, if the autonomous mobile robot 20c has not yet passed through all of the waypoints (NO in S65), the process returns to S64 and is repeated. The autonomous mobile robot 20c can determine whether it has passed a waypoint by checking whether the position of the equipment, which is sequentially measured by the locator, has passed a waypoint. The autonomous mobile robot 20c can obtain and use the information of the waypoints set in the waypoint setting unit 113 from the route generation device 10c.

[0093] In step S66, if there are still trees that the autonomous mobile robot 20c has not yet measured (YES in S66), the process returns to S61 and is repeated. On the other hand, if there are no trees that the autonomous mobile robot 20c has not yet measured (NO in S66), the tree measurement-related processing is terminated. Whether or not there are still trees that the autonomous mobile robot 20c has not yet measured can be determined by whether or not it has completed movement along a movement path that measures multiple trees.

[0094] Furthermore, the tree measurement-related processing may be configured not to generate a cylindrical model for each tree. For example, a common cylindrical model and movement path may be generated for each tree, and measurements may be performed by the autonomous mobile robot 20c using a common movement path for each tree.

[0095] The technology disclosed in Patent Document 1 generates a travel path that flies over a forest, making it difficult to comprehensively measure the trunk surfaces of trees within the area to be measured. Furthermore, even when generating a travel path along both sides of a virtual wall surface as shown in Embodiments 1 to 3, if a tree has many branches, it may be difficult to comprehensively measure the trunk surfaces of the trees even after circling the tree multiple times. In addition, when generating a travel path for measurement, it is required to generate a travel path that minimizes travel time from the viewpoint of measurement time and cost.

[0096] In contrast, the configuration of Embodiment 4 includes either Feature A or Feature B as described below. According to the configuration of Feature A or Feature B below, a movement path is generated that follows a spiral in the height direction along the surface of a cylindrical model that approximates the tree shape with a combination of multiple cylinders. Therefore, even for trees with many branches, it becomes easier to comprehensively measure the surface of the tree trunks. Furthermore, by simplifying the process using a cylindrical model that approximates the tree shape, faster calculations are possible compared to when the tree shape itself is the target. As a result, it becomes possible to generate a movement path that more comprehensively measures the surface of the tree trunks within the measurement target area while keeping the movement time shorter.

[0097] [Feature A] A forest measurement path generation device comprising a path generation unit (114) that generates a travel path for measuring the condition of trees within a designated section of a forest using measuring instruments (21, 21d) that perform measurements within a predetermined measurement range, The path generation unit generates a movement path for measuring the condition of the trees from the side using the measuring instrument. The system includes a cylinder model generation unit (112,112d) that generates a cylinder model approximating the tree shape of a tree using a combination of multiple cylinders, based on geometric conditions that are presumed to be satisfied by trees. The path generation unit is a forest measurement path generation device that generates the movement path for a single tree such that it follows the surface of the cylindrical model set by the cylindrical model generation unit in a spiral shape in the height direction.

[0098] [Feature B] Executed by at least one of a processor and a circuit, A forest measurement path generation method, which includes a path generation step that generates a travel path for measuring the condition of trees within a designated section of a forest using measuring instruments (21, 21d) that perform measurements within a predetermined measurement range, In the aforementioned path generation step, a movement path is generated in which the measuring instrument measures the condition of the trees from the side of the trees. The process includes a cylinder model generation step, which generates a cylinder model that approximates the tree shape of a tree using a combination of multiple cylinders, based on geometric conditions that are presumed to be satisfied by trees. A forest measurement path generation method in which, as the path generation step, the path is generated so as the path to move along a single tree, the path is generated such that it follows the surface of the cylindrical model set in the cylindrical model generation step in a spiral shape in the height direction.

[0099] Furthermore, the configurations of Embodiments 1 to 3 and Embodiment 4 may be combined. For example, the following can be done: Using the configurations of Embodiments 1 to 3, a movement path is set along both sides of the virtual wall surface, and measurements are taken along that movement path. Subsequently, if trees whose measurements were insufficient due to manual measurement or other reasons are identified, a movement path for each tree can be generated using the configuration of Embodiment 4.

[0100] (Embodiment 5) The configuration is not limited to Embodiment 4; the configuration of Embodiment 5 described below may also be used. Below, an example of the configuration of Embodiment 5 will be explained with reference to a diagram.

[0101] <Outline configuration of forest measurement system 1d> Embodiment 5 will be described below with reference to the drawings. As an example, the forest measurement system 1d includes a path generation device 10d and an autonomous mobile robot 20d, as shown in Figure 25.

[0102] The autonomous mobile robot 20d is equipped with a measuring instrument 21d. The autonomous mobile robot 20d is the same as the autonomous mobile robot 20c of Embodiment 4, except that it is equipped with a measuring instrument 21d instead of a measuring instrument 21. The measuring instrument 21d is the same as the measuring instrument 21 of Embodiment 1, except that there are some differences. These differences will be explained below. It is preferable that the measuring instrument 21d performs measurements by capturing images. In other words, it is preferable to use an imaging device as the measuring instrument 21d.

[0103] <Outline configuration of route generation device 10d> As shown in Figure 26, the path generation device 10d includes a tree condition DB 111, a cylinder model generation unit 112d, a waypoint setting unit 113, a path generation unit 114, an image acquisition unit 115, and a contour extraction unit 116 as functional blocks. The path generation device 10d includes a cylinder model generation unit 112d instead of a cylinder model generation unit 112. The path generation device 10d includes an image acquisition unit 115 and a contour extraction unit 116. Except for these points, the path generation device 10d is the same as the path generation device 10c of Embodiment 4. This path generation device 10d also corresponds to a path generation device for forest measurement. Furthermore, the execution of processing for each functional block of the path generation device 10d by a computer corresponds to the execution of the path generation method for forest measurement described in Feature B.

[0104] The image acquisition unit 115 acquires captured images of trees taken from multiple directions. The image acquisition unit 115 only needs to acquire captured images taken by the measuring instrument 21d while the autonomous mobile robot 20d is moving. The captured images taken by the measuring instrument 21d should be configured to have the coordinates of the imaging position or the position coordinates of the trees that were the target of imaging linked to them. These coordinates can be used to associate the position on the geographic coordinate system with the position on the 3D model described later. Alternatively, the system may be configured to acquire captured images taken by the imaging device during a preliminary survey of a designated area of ​​the forest. The captured images taken by the imaging device during the preliminary survey can be stored, for example, on a server, linked to the position coordinates of the trees. In this case, the image acquisition unit 115 only needs to acquire captured images of trees taken from multiple directions and the position coordinates of those trees from this server. The position coordinates of the trees can be used to distinguish individual trees.

[0105] The contour extraction unit 116 extracts the contour of a tree based on the captured images obtained by the image acquisition unit 115 from multiple directions. The contour extraction unit 116 can extract the contour of the tree by performing binarization, edge detection, etc., on the captured images.

[0106] The cylindrical model generation unit 112d is the same as the cylindrical model generation unit 112 of Embodiment 4, except that some processing differs. The differences will be explained below. For trees whose contours have been extracted by the contour extraction unit 116, the extracted contours are also used to generate a cylindrical model. This makes it possible to generate a cylindrical model that more closely approximates the tree shape of the tree to be measured. Therefore, it becomes easier to measure the trunk surface of trees more comprehensively.

[0107] The cylinder model generation unit 112d should generate a cylinder model such that the width of the cylinder used for the cylinder model matches the contour of the tree in the 2D captured image extracted by the contour extraction unit 116. The cylinder model generation unit 112d should calculate the 3D position and radius of a cylinder that satisfies the contour extracted by the contour extraction unit 116 and the constraint conditions based on the tree features stored in the tree condition DB 111. Then, a cylinder model should be generated as a combination of these cylinders. The cylinder model generation unit 112d should generate a cylinder model by finding parameters using a gradient method or the like that maximize the degree of agreement between the contour of the cylinder model as viewed from the direction of the captured image and the contour extracted from the captured image by the contour extraction unit 116, and that also satisfy the tree features. With the above configuration, a 3D model approximating a tree can be generated at a faster speed compared to 3D model generation technologies such as Visual SLAM (Simultaneous Localization and Mapping) and SfM (Structure from Motion). For example, a cylindrical model can be generated in a short time of about one second from just a few images of a tree. This makes it easy to replan the movement path while measuring the tree.

[0108] Here, using the flowchart in Figure 27, we will explain an example of the flow of tree measurement-related processing in the forest measurement system 1d. The flowchart in Figure 27 should be configured to start in the same way as the flowchart in Figure 24.

[0109] First, in step S81, the image acquisition unit 115 acquires captured images of the tree from multiple directions. In step S82, the contour extraction unit 116 extracts the contour of the tree based on the captured images acquired in S81.

[0110] In step S83, the cylinder model generation unit 112d calculates the three-dimensional position and radius of a cylinder that satisfies the contour extracted in S82 and the constraint conditions based on the tree features stored in the tree condition DB 111. Then, it generates a cylinder model such that the width of the cylinder used for the cylinder model matches the contour of the tree in the two-dimensional captured image. The processing in steps S84 to S88 is the same as the processing in S61 to S66.

[0111] The configuration of Embodiment 5 includes the following feature A-1. According to the configuration of feature A-1, even when the tree shapes are unknown, it becomes possible to generate movement paths based on images of trees. Furthermore, it speeds up the generation of cylindrical models and makes it easier to replan movement paths during tree measurement.

[0112] [Feature A-1] A forest measurement path generation device as described in Feature A, An image acquisition unit (115) acquires images of trees taken from multiple directions, For trees that can acquire captured images from multiple directions using the aforementioned image acquisition unit, the system includes a contour extraction unit (116) that extracts the outline of the tree based on the captured images. The cylindrical model generation unit (112d) is a forest measurement path generation device that generates the cylindrical model using the extracted contours of trees whose contours have been extracted by the contour extraction unit.

[0113] (Disclosed technical ideas) This specification discloses several technical concepts, as set forth in the following paragraphs. Some paragraphs may be written in a multiple dependent form, where subsequent paragraphs alternately refer to preceding paragraphs. Furthermore, some paragraphs may be written in a multiple dependent form, referring to other multiple dependent forms. These paragraphs written in multiple dependent forms define several technical concepts.

[0114] (Technical thought 1) A forest measurement path generation device comprising a path generation unit (107) that generates a travel path for measuring the condition of trees within a designated section of a forest using measuring instruments (21, 21a) that perform measurements within a predetermined measurement range, The path generation unit generates a movement path for measuring the condition of the trees from the side using the measuring instrument. A tree position acquisition unit (102, 102a) acquires tree position information, which is information about the location of trees within the aforementioned section. Based on the tree position information acquired by the aforementioned tree position acquisition unit, a grouping unit (104, 104a) groups the trees, The grouping unit includes a virtual wall setting unit (106, 106a) for setting virtual walls that are virtual walls connecting the trees grouped together, The path generation unit is a forest measurement path generation device that generates the movement path along both sides of the virtual wall set by the virtual wall setting unit.

[0115] (Technical thought 2) A forest measurement path generation device as described in Technical Concept 1, The measuring instrument (21a) is also capable of measuring the positions of the trees, The tree position acquisition unit (102a) also acquires sequentially measured position information, which is information about the positions of the trees that are sequentially measured by the measuring instrument, as tree position information. The virtual wall setting unit (106a) is a forest measurement path generation device that modifies the virtual wall based on the sequential measurement position information newly acquired by the tree position acquisition unit after the virtual wall has been set, if the positions of the trees used to set the virtual wall change by more than a specified amount.

[0116] (Technical Thought 3) A forest measurement path generation device as described in Technical Idea 1 or 2, The grouping section is a forest measurement path generation device that groups trees such that the shape of the virtual wall connecting the grouped trees extends in a shape without branching.

[0117] (Technical Thought 4) A forest measurement path generation device described in any one of the technical concepts 1 to 3, The grouping unit is a forest measurement path generation device that groups trees where the distance between adjacent trees is less than a set distance, which is set as the distance that the entity (20, 20a, 30) performing the measurement using the measuring instrument can enter, by treating them as a single tree.

[0118] In this disclosure or claims, the term "processor" refers to one or more hardware processors configured to execute processing defined by computer program code (i.e., one or more instructions of a computer program) contained in a computer program by reading the code each time. In other words, a "processor" is a hardware device that executes one or more programmed processes. Therefore, computer program code can also be considered software that can define the processing of the processor according to its content. For example, a "processor" may be a general-purpose or specific-purpose processor, and may be, but is not limited to, a CPU, microprocessor, GPU, and DFP (Data Flow Processor).

[0119] In this disclosure or claims, the term “memory” means one or more hardware memories that are non-transitional tangible recording media configured to record computer program code and / or data in a manner accessible from a processor. “Memory” can be implemented by memory technologies such as SRAM, SDRAM, non-volatile / flash type memory, or other types of memory. The computer program code that constitutes the program is recorded in memory and executed by a processor, thereby enabling the processor to perform the various functions described above.

[0120] In this disclosure or claims, the term “circuit” refers to one or more logic circuits as hardware, configured to perform specific processing defined by a pre-designed circuit configuration. In other words (and, in contrast to “processor”), “circuit” in this disclosure or claims refers to a hardware device that performs specific processing based on a circuit configuration, rather than processing defined by software such as the computer program code described above. For example, “circuit” may include custom ICs such as ASICs (Application Specific Integrated Circuits) and FPGAs (Field Programmable Gate Arrays) designed with Hardware Description Language (HDL). That is, “circuit” in this disclosure or claims includes all hardware circuits except for the processor described above, which performs processing by reading computer program code.

[0121] In this disclosure or claims, the expression "at least one of a processor and a circuit" should be interpreted as a disjunctive (logical OR) and not as at least one processor and at least one circuit. Therefore, in this disclosure or claims, "at least one of a processor and a circuit" includes cases where the circuit alone performs all functions. Also, in this disclosure or claims, "at least one of a processor and a circuit" includes cases where the processor alone performs all functions. In this disclosure or claims, "at least one of a processor and a circuit" includes cases where the circuit performs some functions and the processor performs the remaining functions. [Explanation of symbols]

[0122] 1,1a,1b Forest measurement system, 10,10a,10b Path generation device, 20,20a Autonomous mobile robot (main unit for measurement), 21,21a Measuring instrument, 30 Auxiliary device (main unit for measurement), 102,102a Tree position acquisition unit, 105,105a Grouping unit, 106,106a Virtual wall setting unit, 107 Path generation unit

Claims

1. A forest measurement path generation device comprising a path generation unit (107) that generates a travel path for measuring the condition of trees within a designated section of a forest using measuring instruments (21, 21a) that perform measurements within a predetermined measurement range, The path generation unit generates a movement path for measuring the condition of the trees from the side using the measuring instrument. A tree position acquisition unit (102, 102a) acquires tree position information, which is information about the location of trees within the aforementioned section. Based on the tree position information acquired by the tree position acquisition unit, a grouping unit (104, 104a) groups the trees, The grouping unit includes a virtual wall setting unit (106, 106a) for setting virtual walls that are virtual walls connecting the trees grouped together, The path generation unit is a forest measurement path generation device that generates the movement path along both sides of the virtual wall set by the virtual wall setting unit.

2. A forest measurement route generation device according to claim 1, The measuring instrument (21a) is also capable of measuring the positions of the trees, The tree position acquisition unit (102a) also acquires sequentially measured position information, which is information about the positions of the trees that are sequentially measured by the measuring instrument, as tree position information. The virtual wall setting unit (106a) is a forest measurement path generation device that modifies the virtual wall based on the sequential measurement position information newly acquired by the tree position acquisition unit after the virtual wall has been set, if the positions of the trees used to set the virtual wall change by more than a specified amount.

3. A forest measurement route generation device according to claim 1, The grouping section is a forest measurement path generation device that groups trees such that the shape of the virtual wall connecting the grouped trees extends in a shape without branching.

4. A forest measurement route generation device according to any one of claims 1 to 3, The grouping unit is a forest measurement path generation device that groups trees where the distance between adjacent trees is less than a set distance, which is set as the distance that the entity (20, 20a, 30) performing the measurement using the measuring instrument can enter, by treating them as a single tree.

5. Executed by at least one of a processor and a circuit, A forest measurement path generation method, which includes a path generation step that generates a travel path for measuring the condition of trees within a designated section of a forest using measuring instruments (21, 21a) that perform measurements within a predetermined measurement range, In the aforementioned path generation step, a movement path is generated in which the measuring instrument measures the condition of the trees from the side of the trees. A tree location acquisition step is to acquire tree location information, which is information about the location of trees within the aforementioned section. Based on the tree location information obtained in the aforementioned tree location acquisition step, a grouping step is performed to group the trees, The process includes a virtual wall setting step, which sets a virtual wall that connects the trees grouped in the grouping step, A forest measurement path generation method, wherein the path generation step generates the movement path along both sides of the virtual wall set in the virtual wall setting step.

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