JP7680340B2 - Work area management method, work area management system, and work area management program - Google Patents

Description

The present invention relates to a work area management method, a work area management system, and a work area management program, which can be suitably used, for example, to manage work areas in farm fields where agricultural work is carried out.

Patent Document 1 (JP Patent Publication 2019-162053 A) discloses an invention for a farm field registration device. This farm field registration device periodically measures the position information of positioning points that a work vehicle passes through while moving through a farm field and performing agricultural work, and estimates the shape of the work area in which the work vehicle performed work as a polygon shape obtained by calculating the convex hull of these positioning points.

JP 2019-162053 A

The invention of Patent Document 1 is advantageous in that it can identify the shape of the work area by simply measuring the position information of the positioning points during farm work, without the need for special work such as measuring the work area after the work. However, if the shape of the work area is relatively complex, such as a concave polygon, the area outside the work area may be calculated as part of the work area only by processing the convex hull.

In view of the above circumstances, one of the objectives of the present disclosure is to provide a work area management method, a work area management system, and a work area management program for efficiently and accurately estimating a work area. Other issues and novel features will become apparent from the description of this specification and the accompanying drawings.

Below, the means for solving the problem are explained using the numbers used in (Mode for carrying out the invention). These numbers are added to clarify the correspondence between the description in (Claims) and (Mode for carrying out the invention). However, these numbers should not be used to interpret the technical scope of the invention described in (Claims).

According to one embodiment, the work area management method includes acquiring (S11) a plurality of pieces of position information measured at a plurality of positioning points (91) passed by a work vehicle (2) moving in a predetermined area to perform farm work. The work area management method further includes calculating (S13) first reference polygon information representing a first reference polygon (88C) as a set of small areas included in the work area in which the work vehicle (2) performed farm work, among a plurality of small areas obtained by dividing the area into a mesh shape in a predetermined first direction and a second direction different from the first direction. The work area management method further includes calculating (S14) a plurality of concave hulls (89) corresponding to each of the plurality of concave hull calculation parameters (α) using a concave hull calculation parameter (α) that determines the shape of the concave hull (89) calculated from the plurality of positioning points (91). The work area management method further includes selecting (S16) a concave hull (89) whose relationship with the first reference polygon (88C) satisfies a predetermined condition as the estimated shape of the work area. The work area management method further includes outputting information representing the estimated shape of the work area to the outside (S18).

According to one embodiment, the work area management system (1) includes an acquisition unit (421), a reference polygon calculation unit (423), a concave hull calculation unit (424), a selection unit (426), and an output unit (427). The acquisition unit (421) acquires a plurality of pieces of position information measured at a plurality of positioning points (91) passed by a work vehicle (2) performing farm work while moving in a predetermined area. The reference polygon calculation unit (423) calculates first reference polygon information representing a first reference polygon (88C) as a set of small areas included in the work area in which the work vehicle (2) performed farm work, among a plurality of small areas obtained by dividing the area into a mesh shape in a predetermined first direction and a second direction different from the first direction. The concave hull calculation unit (424) calculates a plurality of concave hulls (89) corresponding to each of the plurality of concave hull calculation parameters (α) using a concave hull calculation parameter (α) that determines the shape of the concave hull calculated from the plurality of positioning points (91). The selection unit (426) selects, from among the multiple concave hulls (89), a concave hull (89) whose relationship with the first reference polygon (88C) satisfies a predetermined condition as the estimated shape of the work area. The output unit (427) outputs information representing the estimated shape of the work area to the outside.

According to one embodiment, the work area management program is a program for implementing a predetermined process by executing it. This process includes acquiring (S11) a plurality of pieces of position information measured at a plurality of positioning points (91) passed by a work vehicle (2) performing farm work while moving in a predetermined area. This process further includes calculating (S13) first reference polygon information representing a first reference polygon (88C) as a set of small areas included in the work area in which the work vehicle (2) performed farm work, among a plurality of small areas obtained by dividing the area into a mesh shape in a predetermined first direction and a second direction different from the first direction. This process further includes calculating (S14) a plurality of concave hulls (89) corresponding to each of a plurality of concave hull calculation parameters (α) using a concave hull calculation parameter (α) that determines the shape of the concave hull (89) calculated from the plurality of positioning points (91). This process further includes selecting (S16) a concave hull (89) whose relationship with the first reference polygon (88C) satisfies a predetermined condition as the estimated shape of the work area from among the plurality of concave hulls (89). This process further includes outputting information representing the estimated shape of the work area to the outside (S18).

According to one embodiment, the working area can be estimated efficiently and accurately.

FIG. 1 is a diagram showing an example of a configuration of a work area management system according to an embodiment. FIG. 2 is a block circuit diagram showing an example of the configuration of a working area management device according to an embodiment. FIG. 3 is a flow chart showing an example of a configuration of a working area management method according to an embodiment. FIG. 4A is a diagram showing an example of a work area estimated by calculating the convex hull of a set of measured position points of a work vehicle. FIG. 4B is a diagram showing an example of a working area estimated by calculating the concave hull of the same set of positioning points as in FIG. 4A. FIG. 4C is a diagram showing an example of a working area estimated by calculating another concave hull of the same set of positioning points as in FIGS. 4A and 4B. FIG. 5A is a diagram showing an example of a convex hull of a set of points. FIG. 5B is a diagram showing an example of the concave hull of the same set of points as FIG. 5A. FIG. 5C shows another example of a concave hull for the same set of points as FIGS. 5A and 5B. FIG. 6A is a diagram illustrating an example of a set of positioning points and a set of movement trajectories according to one embodiment. FIG. 6B is a diagram illustrating an example of a reference region according to one embodiment. FIG. 6C is a diagram illustrating an example of a reference polygon according to one embodiment. FIG. 7A is a diagram showing an example of a concave hull calculated from the same set of positioning points as in FIG. 6A. FIG. 7B is a diagram showing an example of a concave hull calculated from the same set of positioning points as in FIG. 6A. FIG. 7C is a diagram showing an example of a concave hull calculated from the same set of positioning points as in FIG. 6A. FIG. 7D is a diagram showing an example of a concave hull calculated from the same set of positioning points as in FIG. 6A. FIG. 7E is a diagram showing an example of a concave hull calculated from the same set of positioning points as in FIG. 6A. FIG. 8A is a diagram for explaining a specific example of a technique for calculating the degree of similarity between two graphics according to one embodiment. FIG. 8B is a diagram for explaining a specific example of a method for calculating the degree of similarity between two graphics according to one embodiment. FIG. 8C is a diagram for explaining a specific example of a method for calculating the degree of similarity between two graphics according to one embodiment. FIG. 8D is a diagram for explaining a specific example of a method for calculating the degree of similarity between two graphics according to one embodiment. FIG. 9 is a flow chart showing an example of a configuration of a working area management method according to an embodiment. FIG. 10A is a diagram showing an example of positioning points and a topographical contour of a farm field in one embodiment. FIG. 10B is a diagram showing an example of a convex hull of the positioning points in FIG. 10A. FIG. 10C is a diagram showing an example of a convex hull of some of the positioning points in FIG. 10A. FIG. 10D is a diagram showing an example of a convex hull of another part of the positioning points of FIG. 10A. FIG. 11A is a diagram for explaining a modified example of the method for calculating the degree of coincidence between two graphics in one embodiment. FIG. 11B is a diagram for explaining a modified example of the method for calculating the degree of coincidence between two figures in one embodiment.

The following describes, with reference to the attached drawings, the embodiments for implementing the work area management method, work area management system, and work area management program disclosed herein.

(First embodiment)
As shown in Fig. 1, a work area management system 1 according to one embodiment includes a work area management device 4. The work area management system 1 may further include an external terminal 5. The work area management device 4, the external terminal 5, and an on-board terminal 20 mounted on the work vehicle 2 may be communicatively connected via a network 3. The work vehicle 2 performs work such as agricultural work while moving within the fields 9A, 9B. The work vehicle 2 may further move between the fields 9A, 9B. Hereinafter, when the fields 9A, 9B are not distinguished from each other, they will be collectively referred to as the field 9.

As shown in FIG. 2, the working area management device 4 according to one embodiment may be configured as a so-called computer. That is, the working area management device 4 includes a bus 41, a computing device 42, a storage device 43, a communication device 44, and an input/output device 45. The bus 41 is configured to connect the computing device 42, the storage device 43, the communication device 44, and the input/output device 45 so that they can communicate with each other.

The calculation device 42 includes an acquisition unit 421, an extraction unit 422, a reference polygon calculation unit 423, a concave hull calculation unit 424, a matching calculation unit 425, a selection unit 426, and an output unit 427. The storage device 43 includes a working area management program storage unit 431. The working area management program storage unit 431 stores the working area management program.

The calculation device 42 executes the working area management program to realize the processing of the acquisition unit 421, extraction unit 422, reference polygon calculation unit 423, concave hull calculation unit 424, coincidence calculation unit 425, selection unit 426, and output unit 427. In other words, the acquisition unit 421, extraction unit 422, reference polygon calculation unit 423, concave hull calculation unit 424, coincidence calculation unit 425, selection unit 426, and output unit 427 are virtual functional blocks that perform processing realized by the calculation device 42 and the working area management program working together. The processing of these functional blocks will be described later.

The work area management program may be read from an external recording medium 430 and stored in the work area management program storage unit 431. The recording medium 430 may be a non-transitory and tangible medium.

The communication device 44 communicates with external devices including the in-vehicle terminal 20 and/or the external terminal 5 by wireless communication and/or wired communication via the network 3, for example under the control of the acquisition unit 421 or the output unit 427. The work area management program may be received from the outside via the network 3 by the communication device 44 and stored in the work area management program storage unit 431.

The input/output device 45 outputs information to the user and accepts operations input by the user. As an example, the input/output device 45 includes a display device that outputs images, a speaker that outputs sound, buttons that accept press operations, a microphone that accepts sound input, a touch panel that accepts touch operations and outputs images, etc.

The vehicle-mounted terminal 20 includes a positioning device and a communication device, and is configured to transmit position information indicating a position measured by the positioning device using, for example, the Global Navigation Satellite System (GNSS) to the working area management device 4 via the network 3. The vehicle-mounted terminal 20 may be configured as a computer in which a calculation device executes a program to realize processing.

The external terminal 5 includes a communication device and a display device, and is configured to output information received from the work area management device 4 via the network 3 on the display device. The external terminal 5 may be configured as a computer in which a calculation device executes a program to realize processing.

With reference to the flowchart in FIG. 3, an example of the configuration of a work area management method according to one embodiment will be described. In other words, with reference to the flowchart in FIG. 3, an example of the operation of a work area management system 1 according to one embodiment will be described. In other words, the flowchart in FIG. 3 shows an example of the configuration of a work area management program executed by a work area management device 4 according to one embodiment.

An overview of a work area management method according to one embodiment will be described. First, multiple pieces of position information measured at multiple positioning points passed by a work vehicle 2 performing work while moving within a specified area are obtained. An operating trajectory or movement trajectory connecting any two of these positioning points that are consecutive in the measurement order is approximated by a straight line (strictly speaking, a line segment) connecting these two positioning points. Note that an operating trajectory is a trajectory that the work vehicle 2 moves while performing work in a field 9. Also, a movement trajectory is a trajectory that the work vehicle 2 moves without performing work, for example, outside the field 9.

Next, from the set of positioning points, multiple concave hulls are calculated as alpha shapes when multiple values are set for a predetermined concave hull calculation parameter. The alpha shape is a generalized shape of the concave hull and convex hull calculated from multiple points, and is defined, for example, as follows using a predetermined parameter α (alpha). When the predetermined parameter α is greater than zero, any two points among the multiple points are connected by a line of the alpha shape only if these two points are on the boundary of a disk whose radius is the inverse of the parameter α, and there exists a disk with no other points inside the disk. When the parameter α is equal to zero, the definition is valid with the disk in the definition when the parameter α is greater than zero replaced with a closed half plane. Note that the alpha shape calculated from multiple points when the parameter α is equal to zero is a convex hull calculated from the same multiple points. Also, the alpha shape calculated from multiple points when the parameter α is greater than zero is a concave hull calculated from the same multiple points. In the following, for ease of reading, the convex hull may be described as a type of concave hull.

Figure 4A is a diagram showing an example of a working area 8A estimated by calculating the convex hull of a set of positioning points 91 of a work vehicle 2. As described above, the convex hull is a concave hull calculated when the parameter α is zero. Figure 4B is a diagram showing an example of a working area 8B estimated by calculating the concave hull of the same set of positioning points 91 as in Figure 4A. The concave hull in Figure 4B is calculated using a relatively large parameter α. Figure 4C is a diagram showing an example of a working area 8C estimated by calculating another concave hull of the same set of positioning points 91 as in Figures 4A and 4B. The concave hull in Figure 4C is calculated using an intermediate parameter α.

From among these multiple concave hulls, the concave hull with the highest degree of agreement with the reference polygon is selected, and the selected concave hull is regarded as the result of inferring the position and shape of the work area where the work vehicle 2 performed work. Of the convex hull 81 in FIG. 4A, the concave hull 82 in FIG. 4B, and the concave hull 83 in FIG. 4C, the concave hull that best matches the contour of the set of operating trajectories 93 is the concave hull 83 in FIG. 4C. On the other hand, the convex hull 81 in FIG. 4A includes an area 84A outside the work area, and has a lower accuracy of inferring the work area than the concave hull 83 in FIG. 4C. Conversely, the concave hull 82 in FIG. 4B excludes an area 84B included in the work area, and has a lower accuracy of inferring the work area than the concave hull 83 in FIG. 4C.

The shape of the concave hull of the same set of points differs depending on the parameter α. FIG. 5A is a diagram showing an example of a convex hull 72A of a set of points 71. In the example of FIG. 5A, the convex hull 72A passes through the outer points 71 among the points 71, but does not pass through the inner points 71A. FIG. 5B is a diagram showing an example of a concave hull 72B of the same set of points 71 as FIG. 5A. In the example of FIG. 5B, the concave hull 72B is calculated with a relatively large parameter α, and passes through all the points 71. FIG. 5C is a diagram showing an example of another concave hull 72C of the same set of points 71 as FIG. 5A and FIG. 5B. In the example of FIG. 5C, the concave hull 72C is calculated with an intermediate parameter α, and passes through almost all the points 71, but does not pass through some of the points 71C. The convex hull 72A shown in FIG. 5A is also the concave hull calculated when the parameter α is zero, so the concave hull in FIG. 5C, where the parameter α is intermediate, can be said to have an intermediate shape between the convex hull 72A in FIG. 5A, where the parameter α is zero, and the concave hull 72B in FIG. 5B, where the parameter α is relatively large. In this way, the shape of the concave hull of the same point 71 differs depending on the parameter α.

In one embodiment, in order to estimate the work area efficiently and accurately, an operation trajectory 93 other than the movement trajectory 92 is extracted from the trajectory of the work vehicle 2, a figure called a reference polygon is calculated based on the set of areas enclosed by the operation trajectories 93, and the shape of the concave hull that most closely matches the reference polygon is selected as the estimated shape of the work area. Also, in one embodiment, when the work vehicle 2 moves between multiple work areas and performs work in these work areas, the shape of each work area is estimated individually.

Before the processing of the flowchart in FIG. 3 starts, the positioning device of the on-board terminal 20 of the work vehicle 2 measures its position and acquires position information. The point at which the on-board terminal 20 acquires position information is called a positioning point. The positioning point is included in the working trajectory that the work vehicle 2 passed while performing farm work in the field 9 or the movement trajectory that the work vehicle 2 moved without performing farm work. The on-board terminal 20 acquires position information at each of a plurality of times and stores the position information in the storage device in association with positioning time information that indicates the positioning time at which the position information was acquired. The on-board terminal 20 may perform positioning at a predetermined cycle. Strictly speaking, the position information indicates the position of the positioning device at the corresponding positioning time, but if the positioning device is fixed to the work vehicle 2, it actually indicates the position of the work vehicle 2 at that positioning time. The on-board terminal 20 starts acquiring position information when the work vehicle 2 starts operating by key-on operation. In addition, when the work vehicle 2 ends its operation by turning off the key, the in-vehicle terminal 20 stops acquiring the position information and transmits the position information stored in the storage device to the work area management device 4 via the network 3. When the work area management device 4 receives the position information, it starts the process of the flowchart in FIG. 3.

When the processing of the flowchart in FIG. 3 starts, step S11 is executed. In step S11, the calculation device 42 of the work area management device 4 executes the work area management program to realize the processing of the acquisition unit 421, and the acquisition unit 421 acquires position information of the positioning point. More specifically, the acquisition unit 421 controls the communication device 44 to receive the position information transmitted by the on-board terminal 20 via the network 3, and stores it in the storage device 43. The operation of the on-board terminal 20 measuring the position of the work vehicle 2 and acquiring the position information may be executed in step S11 or before step S11.

After step S11, step S12 is executed. In step S12, the calculation device 42 of the work area management device 4 executes the work area management program to realize the processing of the extraction unit 422, and the extraction unit 422 extracts the positioning points to be processed. More specifically, the extraction unit 422 extracts the positioning points related to the work area whose position and shape are to be estimated in this processing from among the multiple positioning points for which position information was obtained in step S11.

A method for extracting positioning points will be described. The multiple positioning points for which position information was acquired in step S11 include positioning points of the working trajectory along which the work vehicle 2 moved while working in the field 9 that includes the target work area, positioning points of other working trajectories along which the work vehicle 2 moved while working in other fields 9, and positioning points of the movement trajectory along which the work vehicle 2 moved outside the field 9 without working.

Here, the movement speed of the work vehicle 2 is slower when it is moving while performing work, and faster when it is moving without performing work. Furthermore, when the in-vehicle terminal 20 measures the position of the work vehicle 2 at regular time intervals, the distance between two positioning points in succession in the positioning order is shorter when the work vehicle 2 is moving while performing work, and longer when it is moving without performing work. By utilizing this, the extraction unit 422 distinguishes and separates the multiple positioning points into a cluster of positioning points of the operating trajectory and a cluster of positioning points of the movement trajectory.

Furthermore, before the work vehicle 2 works in a certain field 9, it moves toward that field 9, and after working in that field 9, it moves away from that field 9 toward another location. Therefore, when multiple positioning points are arranged in the order of positioning, there are clusters of positioning points of the movement trajectory before and after a cluster of positioning points of the operation trajectory. By utilizing this, the extraction unit 422 extracts the positioning points of the operation trajectory that are the target of the current process.

Note that positioning points of the operating trajectory that are different from the positioning points extracted this time may be extracted when step S12 is executed again by the repeated process. Therefore, the extraction unit 422 may store information in the storage device 43 for distinguishing the positioning points extracted this time in step S12 from positioning points that have not yet been extracted.

After step S12, step S13 is executed. In step S13, the calculation device 42 of the work area management device 4 executes the work area management program to realize the processing of the reference polygon calculation unit 423, and the reference polygon calculation unit 423 calculates a reference polygon corresponding to the positioning point extracted in step S12.

The reference polygon is explained below. The reference polygon is a figure that shows the result of estimating the position and shape of the work area where the work vehicle 2 has performed work using a specified method. As described above, the position and shape of the work area can also be estimated using a method that uses the concave hull of a set of positioning points, and multiple results are obtained for each of the different values of the parameter α for calculating the concave hull. In this case, the reference polygon is used as a criterion for selecting the most likely one from the multiple results obtained using the method that uses the concave hull.

The method for calculating the reference polygon will now be described. First, among the positioning points extracted in step S12, the operation trajectory between any two consecutive positioning points in the order of positioning is calculated by approximating the operation trajectory between these two positioning points with a straight line connecting these two positioning points. Figure 6A shows an example of a set of positioning points 91 and a set 88A of operation trajectories 93 calculated from this set of positioning points 91.

Next, the set of areas surrounded by the operation trajectories 93 is calculated. The set of areas calculated in this manner is called the reference area. Figure 6B shows an example of a reference area 88B calculated from the set of operation trajectories 93 shown in the example of Figure 6A.

Next, by referring to map information of the area including the range where the work vehicle 2 has traveled, this area is divided into a mesh to set a number of small areas. This division process may be performed on meshes in a first direction and a second direction different from the first direction. Furthermore, these first and second directions may be, for example, north-south and east-west directions, or latitude and longitude directions. At this time, the shape of each small area is approximated to a rectangle. Furthermore, the mesh spacing may be the same in the first and second directions. At this time, the shape of each small area is approximated to a square of the same size.

Next, from among these multiple small regions, small regions that include at least a portion of the reference region 88B are extracted, and the set of extracted small regions is calculated as a reference polygon. Figure 6C shows an example of a reference polygon 88C calculated from the reference region 88B in Figure 6B.

After step S13 in the flowchart of FIG. 3, step S14 is executed. In step S14, the calculation device 42 of the working area management device 4 executes the working area management program to realize the processing of the concave hull calculation unit 424, and the concave hull calculation unit 424 calculates the concave hull corresponding to the positioning point extracted in step S12. Here, the concave hull calculation unit 424 prepares multiple values as the parameter α, and calculates multiple concave hulls using these multiple parameters α.

Examples of concave hulls calculated from the set of positioning points 91 shown in the example of FIG. 6A are shown in FIG. 7A, FIG. 7B, FIG. 7C, FIG. 7D, and FIG. 7E. The concave hull 89A in FIG. 7A is calculated when the parameter α is 0.2. The concave hull 89B in FIG. 7B is calculated when the parameter α is 0.15. The concave hull 89C in FIG. 7C is calculated when the parameter α is 0.1. The concave hull 89D in FIG. 7D is calculated when the parameter α is 0.05. The concave hull 89E in FIG. 7E is calculated when the parameter α is 0, and is also the convex hull of the positioning points 91.

After step S14, step S15 is executed. In step S15, the calculation device 42 of the working area management device 4 executes the working area management program to realize the processing of the coincidence calculation unit 425, and the coincidence calculation unit 425 calculates the coincidence between the reference polygon and the concave hull. More specifically, the coincidence calculation unit 425 calculates the coincidence between the reference polygon calculated in step S13 and each of the multiple concave hulls calculated in step S14.

A method for calculating the degree of coincidence between a reference polygon and a concave hull is described below. As described above, the reference polygon is a collection of small regions arranged in a mesh pattern. In one embodiment, each of the multiple concave hulls calculated in step S14 is converted into a collection of small regions divided into a mesh pattern under the same conditions as the reference polygon, and the degree of coincidence of each concave hull with the reference polygon is then calculated. Note that, here, a case is described in which these small regions are square, but this is merely an example and does not limit the embodiment.

In one embodiment, the degree of coincidence between a first figure and a second figure consisting of a plurality of small regions arranged in a mesh pattern is described. First, the first figure and the second figure are overlapped so that the positions of the respective small regions are aligned, and a third figure, which is a collection of small regions common to the first figure and the second figure, and a fourth figure included in at least one of the first figure or the second figure are calculated. In other words, the third figure is a collection of small regions included in the first figure and also included in the second figure. Also, the fourth figure is a collection of small regions included in the first figure or included in the second figure. Next, the total number of small regions included in the third figure is divided by the total number of small regions included in the fourth figure to determine the degree of coincidence between the first figure and the second figure. The degree of coincidence described above is merely an example and does not limit the embodiment.

With reference to Figures 8A, 8B, 8C, and 8D, a specific example of a method for calculating the degree of coincidence between two figures according to one embodiment will be described. In order to calculate the degree of coincidence between the first figure 6A shown in Figure 8A and the second figure 6B shown in Figure 8B, a set of small areas included in the first figure 6A and the second figure 6B is calculated, resulting in a third figure 6C shown in Figure 8C. Furthermore, a set of small areas included in at least one of the first figure 6A and the second figure 6B is calculated, resulting in a fourth figure 6D shown in Figure 8D. The total number of small areas included in the third figure 6C in Figure 8C is 11. Furthermore, the total number of small areas included in the fourth figure 6D in Figure 8D is 17. Therefore, the degree of coincidence between the first figure 6A shown in Figure 8A and the second figure 6B shown in Figure 8B is 11/17. Note that in the above method for calculating the degree of coincidence between two figures, the figures shown in Figures 8A to 8D are merely examples and do not limit the embodiment. In particular, the shapes in Figures 8A and 8B do not necessarily limit the characteristics of the contours of the reference polygon and the concave hull.

In one embodiment, the matching calculation unit 425 calculates the matching degree with the reference polygon for each of all concave hulls calculated in step S14 and stores the calculated degree in the storage device 43.

After step S15, step S16 is executed. In step S16, the calculation device 42 of the work area management device 4 executes the work area management program to realize the processing of the selection unit 426, and the selection unit 426 selects the concave hull that has the highest degree of agreement with the reference polygon as the estimated shape of the work area. More specifically, by referring to the degree of agreement calculated in step S15, the concave hull that has the highest degree of agreement with the reference polygon calculated in step S13 is selected as the estimated shape of the work area from among the multiple concave hulls calculated in step S14.

In the example of the concave hull shown in Figures 7A to 7E, the degree of agreement between the concave hull shown in Figure 7B and the reference polygon shown in Figure 6C is the greatest among the degrees of agreement between the concave hulls shown in Figures 7A to 7E and the reference polygon shown in Figure 6C, so the selection unit 426 selects the concave hull in Figure 7B as the estimated shape of the work area.

After step S16, step S17 is executed. In step S17, the calculation device 42 of the work area management device 4 executes the work area management program to realize the processing of the extraction unit 422, and the extraction unit 422 determines whether or not there are any positioning points remaining to be processed in order to infer the shape of another work area among the positioning points whose position information was obtained in step S11. If there are still positioning points remaining to be processed (Yes), the processing of the flowchart in FIG. 3 returns to step S12, and steps S12 to S17 are executed again for the positioning points that have not yet been extracted the previous time step S12 was executed. Conversely, if there are no more positioning points remaining to be processed (No), the processing of the flowchart in FIG. 3 proceeds to step S18.

In step S18, the calculation device 42 of the working area management device 4 executes the working area management program to realize the processing of the output unit 427, and the output unit 427 outputs the estimated shape of the working area. More specifically, the output unit 427 controls the input/output device 45, etc., to output information representing the concave hull selected in step S16 as the estimated shape of the working area to the outside. As an example, a display device or touch panel included in the input/output device 45 may display the estimated shape of the working area so that the user can visually recognize it. At this time, the estimated shape of the working area may be displayed superimposed on map information of the area including the working area so that the user can intuitively understand it. Furthermore, the positioning points included in the working area may be displayed superimposed on the estimated shape and map information.

As described above, according to one embodiment, a reference polygon and multiple concave hulls are calculated using two different methods based on position information measured at multiple positioning points that the work vehicle 2 passes through while moving while performing work, and the concave hull that matches the reference polygon most closely is selected as the estimated shape of the work area. In this way, the work area can be estimated efficiently and accurately.

(Variation 1)
In the above embodiment, a configuration has been described in which the information representing the estimated shape of the work area is output by being displayed by the work area management device 4. As a modified example of this configuration, the information representing the estimated shape of the work area may be output from the external terminal 5. In one modified example, in step S18 of the flowchart in Fig. 3, the calculation device 42 of the work area management device 4 executes the work area management program to realize the processing of the output unit 427, and the output unit 427 controls the communication device 44 to transmit the information representing the estimated shape of the work area to the external terminal 5 via the network 3. The communication device of the external terminal 5 receives this information, and the display device of the external terminal 5 outputs the information representing the estimated shape of the work area by displaying the estimated shape of the work area.

(Variation 2)
In the above embodiment, a configuration has been described in which, when calculating the degree of match between the reference polygon and the concave hull, a process of filling the inside of the contour line of each of the reference polygon and the concave hull is performed in advance. As a variation of this configuration, the degree of match between the reference polygon and the concave hull may be calculated without performing a process of filling the inside of the contour line of each of the reference polygon and the concave hull.

Second Embodiment
In the first embodiment described above, in step S12 of the flowchart in Fig. 3, in order to distinguish between the operating trajectory 93 and the movement trajectory 92, the difference in the movement speed of the work vehicle 2 on the operating trajectory 93 and the movement trajectory 92 is utilized. In this embodiment, whether the positioning point is inside or outside the field is determined based on image information obtained by photographing the field from above. At this time, according to this embodiment, it will be described that even if the image information of the field is incomplete and part of the boundary line of the field cannot be distinguished, it is possible to determine whether the positioning point is inside or outside the field.

The work area management system 1 according to this embodiment is configured similarly to the work area management system 1 according to the first embodiment shown in FIG. 1. Also, the work area management device 4 according to this embodiment is configured similarly to the work area management device 4 according to the first embodiment shown in FIG. 2. However, the work area management method and work area management program according to this embodiment are configured as shown in the flowchart in FIG. 9.

When the processing of the flowchart in FIG. 9 starts, step S21 is executed. In step S21, the calculation device 42 of the work area management device 4 executes the work area management program to realize the processing of the acquisition unit 421, and the acquisition unit 421 acquires the position information of the positioning point and image information of the terrain contour.

More specifically, the acquisition unit 421 acquires position information of the positioning points in the same manner as in step S11 of the flowchart in FIG. 3 in the first embodiment. That is, the acquisition unit 421 controls the communication device 44 to receive position information transmitted by the on-board terminal 20 via the network 3, which measures the position at each of the multiple positioning points that the work vehicle 2 has passed while moving, and stores the information in the storage device 43.

In this embodiment, the acquisition unit 421 further acquires image information of the terrain contour of the area including the field where the work vehicle 2 will be working. The terrain contour is a collection of lines that represent the contours of the terrain, such as fields and roads, included in this area. The image information of the terrain contour may be acquired by performing image processing on a photograph taken from above this area, or by processing map information of this area. The image information of the terrain contour may be stored in the storage device 43 of the work area management device 4 before the flowchart of FIG. 9 starts, and the acquisition unit 421 may acquire the image information of the terrain contour by reading it from the storage device 43.

Figure 10A is a diagram showing an example of positioning points 10A-10I and the topographical contour of a field 90 in one embodiment. Of the boundary lines of the field 90 shown in the example of Figure 10A, the solid line portions are portions that can be determined based on image information of the field 90, and the remaining dashed line portions are portions that cannot be determined. In such a case, it is difficult for the related art method to automatically determine whether each of the multiple positioning points 10A-10I is inside or outside the field 90. In the example of Figure 10A, the work vehicle 2 passes through multiple positioning points 10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, and 10I in this order, as indicated by the arrows. Hereinafter, when the positioning points 10A-10I are not distinguished from one another, they will be collectively referred to as positioning points 10.

After step S21, step S22 is executed. In step S22, the calculation device 42 of the work area management device 4 executes the work area management program, and the reference polygon calculation unit 423 calculates the reference polygon of the terrain contour. The method of calculating the reference polygon may be the same as step S13 of the flowchart in FIG. 3 according to the first embodiment.

In the example shown in FIG. 10A, the reference polygon obtained in step S22 is calculated from the solid line portions of the boundary line of the field 90 that have been determined to be boundary lines based on the image information, and does not include the dashed line portions that have not been determined.

After step S22, step S23 is executed. In step S23, the calculation device 42 of the working area management device 4 executes the working area management program to realize the processing of the concave hull calculation unit 424, and the concave hull calculation unit 424 calculates the convex hull of the positioning point 10. The method of calculating the convex hull may be the same as the method of calculating the convex hull by setting the parameter α to zero, among the methods of calculating the concave hull in step S14 of the flowchart in FIG. 3 according to the first embodiment.

Figure 10B is a diagram showing an example of a convex hull 11A of the positioning points 10A to 10I in Figure 10A.

After step S23, step S24 is executed. In step S24, the calculation device 42 of the working area management device 4 executes the working area management program to realize the processing of the coincidence calculation unit 425, and the coincidence calculation unit 425 calculates the coincidence between the reference polygon and the convex hull. The method of calculating the coincidence may be the same as step S15 in the flowchart of FIG. 3 according to the first embodiment.

After step S24, step S25 is executed. In step S25, the calculation device 42 of the working area management device 4 executes the working area management program to realize the processing of the extraction unit 422, and the extraction unit 422 determines whether or not there are any positioning points 10 remaining to be processed. More specifically, the extraction unit 422 determines whether or not the total number of positioning points 10 that are the basis of the convex hull calculated in step S23 is equal to or greater than the minimum number required to calculate the convex hull, which is three. If it is determined that there are any positioning points 10 remaining (Yes), the process proceeds to step S26. Conversely, if it is determined that there are no positioning points 10 remaining (No), the process proceeds to step S27.

In step S26, the calculation device 42 of the working area management device 4 executes the working area management program to realize the processing of the extraction unit 422, and the extraction unit 422 extracts the positioning points 10 to be processed. More specifically, from among the positioning points 10 currently being processed, the remaining positioning points 10, excluding the positioning point 10 whose position was measured first, are extracted as the next processing target. The extraction unit 422 may generate information for identifying the extracted positioning points 10 and store it in the storage device 43.

In the example shown in FIG. 10A, of the positioning points 10A to 10I that are the targets of processing, the positioning point 10 whose position was measured first is positioning point 10A, so the extraction unit 422 extracts the remaining positioning points 10B to 10I as targets for the next processing.

After step S26, the process returns to step S23, and steps S23 to S25 are executed again.

Figure 10C shows an example of convex hull 11B of positioning points 10B to 10I that are the targets of processing when step S23 is executed for the second time after positioning point 10A is excluded from positioning points 10A to 10I that are the targets of processing in the example shown in Figure 10B. Furthermore, Figure 10D shows an example of convex hull 11C of positioning points 10C to 10I that are the targets of processing when step S23 is executed for the third time after positioning point 10B is excluded from positioning points 10B to 10I that are the targets of processing in the example shown in Figure 10C. When there is no distinction between convex hulls 11A, 11B, and 11C, they are collectively referred to as convex hull 11.

In this way, steps S23 to S25 are repeated to reduce the number of positioning points 10 to be processed one by one, calculate the convex hull 11 of the remaining positioning points 10, and calculate the degree of coincidence between the calculated convex hull 11 and the reference polygon. When the total number of remaining positioning points 10 becomes less than 3, this repeated process ends and the process proceeds to step S27.

In step S27, the calculation device 42 of the working area management device 4 executes the working area management program to realize the processing of the selection unit 426, and the selection unit 426 selects the convex hull 11 that has the highest degree of agreement with the reference polygon as the estimated shape of the area to be processed. The method of selecting the estimated shape may be the same as step S16 of the flowchart in FIG. 3 according to the first embodiment.

After step S27, step S28 is executed. In step S28, the calculation device 42 of the working area management device 4 executes the working area management program to realize the processing of the output unit 427, and the output unit 427 outputs information representing the estimated shape of the area to be processed. The method of outputting the information representing the estimated shape may be the same as step S18 of the flowchart in FIG. 3 according to the first embodiment.

As described above, according to one embodiment, a reference polygon and multiple convex hulls are calculated using two different methods based on position information measured at multiple positioning points that the work vehicle 2 passes through while moving while performing work, and the convex hull that matches the reference polygon most closely is selected as the estimated shape of the work area. In this way, the work area can be estimated efficiently and accurately.

(Variation 3)
The above second embodiment has been described as a configuration that can be used in place of step S12 in the flowchart of Fig. 3 in the first embodiment. As a modification of this configuration, the process of the flowchart of Fig. 9 in the second embodiment may be used in place of the entire working area management method in the first embodiment. In other words, the working area management system 1 and working area management program according to the second embodiment may be used in place of the working area management system 1 and working area management program in the first embodiment, respectively.

(Variation 4)
In the above-described second embodiment, a configuration has been described in which the topographical contour is the boundary line of the field 90. As a modified example of this configuration, the topographical contour may be a boundary line of something other than the field 90, for example, a road.

(Variation 5)
In the above second embodiment, in step S24 of the flowchart in FIG. 9, a configuration has been described in which the degree of coincidence between the reference polygon and the convex hull is calculated in the same manner as step S15 of the flowchart in FIG. 3 according to the first embodiment. According to this configuration, when the distance between the boundary line of the field 90 and the positioning points 10 through which the work vehicle 2 passes during work is sufficiently larger than the dimensions of the small areas arranged in a mesh pattern on the map, there is a possibility that the degree of coincidence will be calculated as zero or a value close to zero no matter how much the set of positioning points 10 to be processed is changed. When such a situation occurs, it may become difficult to estimate the shape of the area to be processed. In order to prevent such a situation from occurring, as a modified example of step S24, a further conversion process may be added to the process of converting the convex hull 11 into a set of small areas. That is, a process is performed in which each of the small areas included in the set of small areas obtained by converting the convex hull 11 is replaced with a block of multiple small areas. As an example, a process is performed in which one black small area shown in the center of the figure 6E in FIG. 11A is replaced with a total of nine blocks of black small areas in three rows and three columns shown in the center of the figure 6F in FIG. 11B. This increases the likelihood that the degree of coincidence between the reference polygon as a collection of small areas and the convex hull 11 as a collection of added small areas will be calculated as a realistic value. As a further modification, a process may be performed in which the single black small area shown in Fig. 11A is replaced with a mass of more black small areas than in the example of Fig. 11B. As another modification, a process may be performed in which each of the small areas included in the reference polygon is replaced with a mass of multiple small areas.

(Variation 6)
In the above second embodiment, a configuration has been described in which, in step S26 of the flowchart in Fig. 9, the remainder, excluding the positioning point 10 whose position was measured the earliest, is extracted from among the positioning points 10 that were the processing targets at that time, and the processing is repeated as the target for the next processing. As a modified example of this configuration, in step S26, the remainder, excluding the positioning point 10 whose position was measured the latest, may be extracted from among the positioning points 10 that were the processing targets at that time, and the processing may be repeated as the target for the next processing. Also, as another modified example combining these configurations, after a first repetitive process in which the remainder, excluding the positioning point 10 whose position was measured the earliest, is extracted and the processing is repeated as the target for the next processing, a second repetitive process in which the remainder, excluding the positioning point 10 whose position was measured the latest, is extracted and the processing is repeated as the target for the next processing may be performed, or the first repetitive process may be performed after the second repetitive process.

The invention made by the inventor has been specifically described above based on the embodiment, but it goes without saying that the present invention is not limited to the embodiment and can be modified in various ways without departing from the gist of the invention. Furthermore, the features described in the embodiment can be freely combined as long as they are not technically inconsistent.

LIST OF SYMBOLS 1 Working area management system 2 Work vehicle 20 On-board terminal 3 Network 4 Working area management device 41 Bus 42 Calculation device 421 Acquisition unit 422 Extraction unit 423 Reference polygon calculation unit 424 Concave hull calculation unit 425 Matching degree calculation unit 426 Selection unit 427 Output unit 43 Storage device 430 Recording medium 431 Working area management program storage unit 44 Communication device 45 Input/output device 5 External terminal 6A, 6B, 6C, 6D, 6E, 6F Figure 71 Point 71A, 71C Point 72A Convex hull 72B, 72C Concave hull 8A, 8B, 8C Working area 81 Convex hull 82, 83 Concave hull 84A, 84B Area 88A Set of working trajectories 88B Reference area 88C Reference polygon 89A, 89B, 89C, 89D Concave hull 89E Concave hull (convex hull)
9, 9A, 9B, 90 Field 91 Positioning point 92 Movement trajectory 93 Operation trajectory 10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 10I Positioning point 11A, 11B, 11C Convex hull

Claims (9)

Acquiring a plurality of pieces of position information measured at a plurality of positioning points passed by a work vehicle performing agricultural work while moving within a predetermined area;
calculating first reference polygon information representing a first reference polygon as a set of small areas included in a work area in which the work vehicle performed the agricultural work, among a plurality of small areas obtained by dividing the area into a mesh shape in a predetermined first direction and a second direction different from the first direction;
calculating a plurality of concave hulls corresponding to the plurality of concave hull calculation parameters, using concave hull calculation parameters that determine a shape of the concave hull calculated from the plurality of positioning points;
selecting, from among the plurality of concave hulls, a concave hull whose relationship with the first reference polygon satisfies a predetermined condition as the estimated shape of the working area;
and outputting information representing the estimated shape of the working area to an external device. 2. The method for managing a work area according to claim 1,
The selecting step comprises:
Calculating a degree of coincidence between the first reference polygon and each of the plurality of concave hulls;
selecting the concave hull with the highest degree of match as the concave hull that satisfies the predetermined condition;
A working area management method, wherein the degree of agreement is a ratio between a first total number of the small areas that include at least one of the first reference polygon or each of the multiple concave hulls, and a second total number of the small areas that include both the first reference polygon and each of the multiple concave hulls. 3. The method for managing a working area according to claim 1, further comprising:
The concave hull calculation parameters are
a threshold value used to determine whether any two positioning points included in the plurality of positioning points are to be connected by a line included in the concave hull. In the working area management method according to any one of claims 1 to 3,
extracting a processing target positioning point that is estimated to be included in the working area from among the plurality of positioning points;
The extracting step comprises:
Calculating a speed of the work vehicle at each of the plurality of positioning points based on the plurality of position information;
and dividing a plurality of trajectories connecting the plurality of positioning points in the order of the measurements into a cluster of working trajectories along which the work vehicle moves while performing the farm work and a cluster of moving trajectories along which the work vehicle moves without performing the farm work, based on the speed;
The determining based on the speed includes:
Among the plurality of positioning points, a positioning point whose speed is slower than a predetermined first threshold speed is determined to be included in the cluster of the operation trajectory, and a positioning point whose speed is faster than a second threshold speed that is faster than the first threshold speed is determined to be included in the cluster of the movement trajectory.
Includes
How to manage your work area. In the working area management method according to any one of claims 1 to 3,
extracting a processing target positioning point that is estimated to be included in the working area from among the plurality of positioning points;
The extracting of the processing target positioning point includes:
acquiring image information of a topographical contour of the area;
calculating second reference polygon information representing a second reference polygon as a collection of small areas included in the topographical contour among the plurality of small areas obtained by dividing the area into a mesh shape in the first direction and the second direction;
calculating, for each of a plurality of sets obtained by extracting a portion of the positioning points whose positions are consecutive in order of measurement from the plurality of positioning points, a plurality of pieces of convex hull information each representing a plurality of convex hulls of the portion of the positioning points;
selecting, from among the plurality of convex hulls, a convex hull whose relationship with the second reference polygon satisfies a predetermined condition as a predicted shape of the working area;
extracting, from the plurality of positioning points, a positioning point that is included in the selected convex hull as the processing target positioning point. 6. The method for managing a working area according to claim 4, further comprising:
extracting a second plurality of positioning points from the plurality of positioning points, excluding positioning points included in a first working area, which is the working area for which the estimated shape has been estimated;
calculating third reference polygon information representing a third reference polygon as a collection of small areas included in a second working area different from the first working area, among the plurality of small areas obtained by dividing the area into a mesh shape in the first direction and the second direction;
calculating a plurality of concave hulls corresponding to the plurality of concave hull calculation parameters from the second plurality of positioning points;
selecting, from among the plurality of concave hulls, a concave hull whose relationship with the third reference polygon satisfies the predetermined condition as an estimated shape of the second working area;
and outputting information representing the estimated shape of the second working area to an external device. The working area management method according to any one of claims 1 to 6,
The outputting step includes:
a display unit configured to display the estimated shape of the work area and a positioning point included in the work area among the plurality of positioning points, superimposed on map information of the region. an acquisition unit that acquires a plurality of pieces of position information measured at a plurality of positioning points passed by a work vehicle performing agricultural work while moving within a predetermined area;
a reference polygon calculation unit that calculates first reference polygon information that represents a first reference polygon as a collection of small areas included in a work area in which the work vehicle performed the agricultural work, among a plurality of small areas obtained by dividing the area into a mesh shape in a predetermined first direction and a second direction different from the first direction;
a concave hull calculation unit that calculates a plurality of concave hulls corresponding to each of the plurality of concave hull calculation parameters by using concave hull calculation parameters that determine a shape of a concave hull calculated from the plurality of positioning points;
a selection unit that selects, from among the plurality of concave hulls, a concave hull whose relationship with the first reference polygon satisfies a predetermined condition as the estimated shape of the working area;
and an output unit that outputs information representing the estimated shape of the work area to an outside. A work area management program for implementing a predetermined process by executing the work area management program,
The process comprises:
Acquiring a plurality of pieces of position information measured at a plurality of positioning points passed by a work vehicle performing agricultural work while moving within a predetermined area;
calculating first reference polygon information representing a first reference polygon as a set of small areas included in a work area in which the work vehicle performed the agricultural work, among a plurality of small areas obtained by dividing the area into a mesh shape in a predetermined first direction and a second direction different from the first direction;
calculating a plurality of concave hulls corresponding to the plurality of concave hull calculation parameters, using concave hull calculation parameters that determine a shape of the concave hull calculated from the plurality of positioning points;
selecting, from among the plurality of concave hulls, a concave hull whose relationship with the first reference polygon satisfies a predetermined condition as the estimated shape of the working area;
and outputting information representing the estimated shape of the work area to an external device.

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