Weed removal device

Abstract

To provide a technique capable of suppressing absorption of a laser beam, by smoke generated from a radiation object by radiation of the laser beam.SOLUTION: A weeder comprises: an acquiring unit; an identifying unit; a determining unit; and a radiating unit. The acquiring unit acquires a picked up image including a plant. The identifying unit identifies a plurality of radiation objects which exists in the picked up image to which a laser beam is radiated. The determining unit determines a radiation order of the laser beam, so as to radiate the laser beam from the plurality of radiation objects which exists downstream of an air flow direction in the picked up image, on the basis of the air flow direction in the surrounding of the plant. The radiating unit radiates the laser beam to the plurality of radiation objects, according to the radiation order.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a weeding device. [Background technology]

[0002] Patent documents 1 to 3 disclose weeding devices that remove unwanted plants, i.e., weeds, from farmland. These weeding devices are configured to be mobile on farmland, detect weeds from captured images of plants generated by a three-dimensional imager, and remove the weeds by damaging them with laser light emitted from a laser device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-53941 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-53942 [Patent Document 3] Japanese Patent Application Laid-Open No. 2015-62412 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with the above-mentioned removal device, smoke is generated when the weeds, which are the irradiation targets, are removed by irradiating them with laser light. When removing multiple weeds consecutively, if the smoke generated from the weeds due to the irradiation with laser light gets between the next weed to be irradiated with laser light and the laser light irradiation position, there is a problem in that the next laser light to be irradiated may be absorbed by the smoke.

[0005] An object of one aspect of the present disclosure is to provide a technology for suppressing absorption of laser light by smoke generated from an object to be irradiated by laser light. [Means for solving the problem]

[0006] One aspect of the present disclosure is a weeding device comprising an acquisition unit, an identification unit, a determination unit, and an irradiation unit. The acquisition unit is configured to acquire a captured image including a plant captured by an imaging device. The identification unit is configured to identify multiple irradiation targets present in the captured image to which laser light is to be irradiated by the laser irradiator. The determination unit is configured to determine an irradiation order of the laser light based on the air flow direction around the plant so that the laser light is irradiated from the multiple irradiation targets present downstream in the air flow direction in the captured image. The irradiation unit is configured to irradiate the multiple irradiation targets with laser light in accordance with the irradiation order.

[0007] In this configuration, the order of laser light irradiation for multiple irradiation targets is determined based on the air flow direction, with priority given to irradiation targets located downstream in the air flow direction in the captured image. Smoke generated from the irradiation targets by laser light irradiation rises and flows downstream. Therefore, the smoke is less likely to get between the next irradiation target to be irradiated with laser light, which is located upstream in the air flow direction from the irradiation target previously irradiated with laser light, and the laser light irradiation position. Therefore, absorption of the laser light by smoke generated from the irradiation targets by laser light irradiation can be suppressed. As a result, the irradiation intensity required for removal can be easily obtained without increasing the output intensity of the laser light in consideration of absorption of the laser light by smoke.

[0008] According to an aspect of the present disclosure, a sensor for detecting an air flow direction may be further provided. With this configuration, the downstream side in the captured image is determined based on the air flow direction detected by the sensor, thereby improving the accuracy of determining the irradiation order.

[0009] In one aspect of the present disclosure, the captured image may be divided into a downstream region and an upstream region by a first reference line, which is a line extending substantially perpendicular to the air flow direction. The determination unit may determine the irradiation order so that the laser light is irradiated first from downstream objects present in the downstream region among the multiple irradiation objects. In this configuration, the irradiation order of the laser light is determined by giving priority to downstream objects present in the downstream region in the captured image divided by the first reference line. In other words, the irradiation order is determined so that, in the two regions, the downstream region is given priority over the upstream region. Therefore, the irradiation order of the multiple irradiation objects can be easily determined according to the priority order determined for each divided region in the captured image.

[0010] In one aspect of the present disclosure, the determination unit may determine the irradiation order such that, among the downstream objects, the laser light is irradiated in order from the downstream object farthest from the first reference line. Furthermore, the determination unit may determine the irradiation order such that, among the multiple irradiation objects, upstream objects present in the upstream region are irradiated in order from the upstream object farthest from the first reference line. In this configuration, if there are multiple downstream objects present in the downstream region, the irradiation order is determined in order from the downstream object farthest from the first reference line. If there are multiple upstream objects present in the upstream region, the irradiation order is determined in order from the upstream object farthest from the first reference line. Therefore, even if there are multiple irradiation objects in each region, it is possible to determine an irradiation order such that smoke generated from the irradiation objects due to irradiation with the laser light is less likely to get between the irradiation object to be next irradiated with the laser light and the irradiation position of the laser light.

[0011] In one aspect of the present disclosure, a line extending in the air flow direction in the captured image may be the second reference line. When the distances from the first reference line to multiple irradiation targets are approximately the same, the determination unit may determine the irradiation order such that the laser light is irradiated to multiple irradiation targets in order starting from the irradiation target farthest from the second reference line. With this configuration, for irradiation targets in both the downstream region and the upstream region that are approximately the same distance from the first reference line, it is possible to determine the irradiation order based on the distance from the second reference line so that smoke is less likely to get between the irradiation target to be next irradiated with the laser light and the irradiation position of the laser light.

[0012] In one aspect of the present disclosure, the captured image may be an image of a plant captured from above. The laser light may be irradiated toward the plant from above. The second reference line may be a line passing through an irradiation point, which is a point on the captured image corresponding to a position extending directly downward in the vertical direction from the irradiation position of the laser light. In this configuration, since the second reference line is a line passing through the irradiation point, the second reference line divides the area in the captured image while more accurately considering the irradiation position of the laser light. Therefore, it is possible to determine an irradiation order that makes it less likely for smoke to get between the irradiation target to be next irradiated with the laser light and the irradiation position of the laser light.

[0013] In one aspect of the present disclosure, the captured image may be an image of a plant captured from above. The laser light may be irradiated toward the plant from above. The first reference line may be a line passing through an irradiation point, which is a point on the captured image corresponding to a position extending directly downward in the vertical direction from the irradiation position of the laser light. In such a configuration, since the first reference line is a line passing through the irradiation point, the downstream region and the upstream region in the captured image are separated by the first reference line while more accurately considering the irradiation position of the laser light. Therefore, it is possible to determine an irradiation order that makes it less likely for smoke to get between the irradiation target to be next irradiated with the laser light and the irradiation position of the laser light.

[0014] In one aspect of the present disclosure, the acquisition of captured images and the irradiation of laser light may be performed while the weeding device is stopped. The air flow direction may be determined taking into account at least the wind direction in the environment where the weeding device is used. With this configuration, when the weeding device is used outdoors and there is natural wind outdoors, the order of irradiation of laser light can be determined based on the wind direction of the natural wind.

[0015] An aspect of the present disclosure may further include a movement mechanism that enables movement of the weeding device. When laser light irradiation is performed while the weeding device is moving using the movement mechanism, the air flow direction may be determined taking into account at least a direction opposite to the direction of movement. With this configuration, the order of laser light irradiation can be determined based on the direction of traveling wind that flows in the opposite direction to the direction of movement, which is generated as the weeding device moves.

[0016] According to an aspect of the present disclosure, the laser beam irradiation sequence can be determined based on the horizontal direction of the air blown by the blower.

[0017] According to an aspect of the present disclosure, the laser beam irradiation sequence can be determined based on the direction of the diffusing airflow that flows in a radial direction from the center of the blower. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic diagram of a weeding device. [Figure 2] FIG. 2 is a schematic plan view of a weeding device in which a portion of the configuration is omitted. [Figure 3] 10 is a flowchart of a weeding process. [Figure 4]FIG. 10 is a diagram showing the order of irradiation of laser light onto weeds present in a captured image determined based on wind direction. [Figure 5] FIG. 1 is a schematic diagram of a weeding device equipped with a blower that blows wind in a horizontal direction into an irradiation space. [Figure 6] FIG. 7 is a schematic plan view of the weeding device shown in FIG. 6 in which part of the configuration is omitted. [Figure 7] FIG. 1 is a schematic diagram of a weeding device equipped with a blower that blows wind vertically downward into an irradiation space. [Figure 8] FIG. 8 is a schematic plan view of the weeding device shown in FIG. 7, with some of the components thereof not shown. [Figure 9] This figure shows the order in which laser light is irradiated onto weeds in a captured image, determined based on the direction of the diffused wind flowing radially from the center of the air blown by a blower that blows wind vertically downward into the irradiation space. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings. [1. Configuration] The weeding device 1 shown in FIG. 1 is a device for removing weeds 32, which are unwanted plants other than the crop 31, that have grown around the crop 31 in farmland, particularly in cultivated land 3 where the crop 31 is cultivated. The weeding device 1 detects the weeds 32 and performs weeding work by irradiating the detected weeds 32 with laser light L. The weeding device 1 is self-propelled and travels across the cultivated land 3 to perform weeding work. The weeding device 1 travels, for example, along ridges 30 formed in the cultivated land 3. In the ridges 30, multiple crops 31 are grown at set positions spaced apart at regular intervals, for example, 60 cm apart.

[0020] The weeding device 1 includes a control unit 10, a power supply 11, a laser oscillator 12, a laser head 13, an optical system 14, a camera 15, lighting 16, a traveling unit 17, a housing 18, a shielding wall 19, and a sensor 20.

[0021] A rectangular work area 1A is formed on the ground directly below the weeding device 1 in the cultivated land 3. In other words, the work area 1A is formed on the ground directly below the housing 18. Then, while the weeding device 1 is stopped from traveling, it detects weeds 32 in the work area 1A and irradiates the weeds 32 with laser light L. The shape of the work area 1A is not particularly limited.

[0022] The control unit 10 is a part that performs overall control of the weeding device 1 and is equipped with a CPU and memory. The CPU executes programs stored in the memory, thereby realizing various functions of the weeding device 1. Specifically, the control unit 10 executes the weeding process described below. The control unit 10 also executes travel control processing, for example, to cause the weeding device 1 to travel along the ridges 30, according to route information stored in the memory. Note that the various functions realized by the control unit 10 are not limited to being realized by executing programs, and some or all of them may be realized using one or more pieces of hardware.

[0023] The power source 11 includes a rechargeable battery and supplies power to each part of the weeding device 1. The laser oscillator 12, the laser head 13, and the optical system 14 constitute a laser irradiator for outputting laser light L for removing weeds 32. Specifically, the laser light L is generated by laser oscillation in the laser oscillator 12, and the path of the laser light L is adjusted by the laser head 13 and the optical system 14. The laser light L is irradiated onto the weeds 32 from above the weeds 32. Irradiating the weeds 32 with the laser light L damages the weeds 32, specifically by burning them, causing the weeds 32 to wither and die.

[0024] The housing 18 houses the control unit 10, the power supply 11, the laser oscillator 12, the laser head 13, and the optical system 14. Camera 15 is an imaging device that captures images of plants such as crops 31 and weeds 32 that are present within its imaging range. Camera 15 is provided at the bottom of housing 18, and captures images of work area 1A below housing 18. That is, camera 15 acquires captured images of work area 1A, i.e., crops 31 and weeds 32, captured from above.

[0025] Lighting 16 is provided at the bottom of housing 18 and illuminates work area 1A. The shielding wall 19 is a cylindrical member arranged to surround the irradiation space of the laser light L. Specifically, the shielding wall 19 is arranged to protrude downward from the bottom surface of the housing 18 and surrounds the work area 1A from the side. This maintains the brightness of the work area 1A illuminated by the lighting 16. The shielding wall 19 is made of a light-blocking material such as a steel plate or resin. However, the shielding wall may be made of a material that does not have light-blocking properties. The shielding wall 19 is arranged so that a vertical gap S is provided between the shielding wall 19 and the ground in the work area 1A when the laser light L is irradiated. Specifically, the lower end of the shielding wall 19 is arranged away from the ground so as to be located above the crops 31.

[0026] The traveling unit 17 is provided below the shielding wall 19 and includes tires and a motor as a movement mechanism for moving the weeding device 1. The sensor 20 is a wind direction sensor that detects the direction of air flow. The sensor 20 is preferably provided on the weeding device 1 near the crop 31 to detect the direction of air flow around the crop 31. Specifically, as shown in FIGS. 1 and 2 , the sensor 20 is attached to the lower end of the outer surface of the shielding wall 19. The sensor 20 may also be attached to a location other than the shielding wall 19, for example, a location that does not interfere with the travel of the traveling unit 17. In this embodiment, the sensor 20 detects the wind direction in the environment in which the weeding device 1 is used. For example, when the weeding device 1 is used outdoors, the sensor 20 detects the wind direction W shown in FIG. 2, which is the direction in which natural wind flows outside the shielding wall 19. That is, in this embodiment, the air flow direction is the direction along the wind direction W in the environment in which the weeding device 1 is used.

[0027] [2. Processing] Next, the weeding process executed by the control unit 10 of the weeding device 1 will be described using the flowchart in Figure 3. This weeding process may be executed by a user's operation while the weeding device is stopped above the crops 31, for example. This weeding process may also be executed repeatedly while the weeding device is being controlled to travel according to route information stored in the memory of the control unit 10. In this case, the weeding control may be controlled so that the weeding device temporarily stops above multiple crops 31 lined up at regular intervals on the ridges 30, and the weeding process may be executed automatically when this stopping is detected.

[0028] First, in S101, the control unit 10 acquires a captured image including plants such as crops 31 and weeds 32. Specifically, the control unit 10 turns on the light 16 to illuminate the work area 1A, and also captures an image of the work area 1A with the camera 15, thereby acquiring a captured image including the plants present in the work area 1A.

[0029] Next, in S102, the control unit 10 identifies an irradiation target, which is a target for irradiating the laser light L, from among the plants present in the captured image. Specifically, the control unit 10 performs image recognition based on the captured image and detects weeds 32 that are the irradiation target. Note that, if there are multiple weeds 32, all of the multiple weeds 32 are detected.

[0030] Next, in S103, the control unit 10 detects the wind direction W shown in FIG. 2 as the direction of air flow around the plant using the sensor 20. Next, in S104, the control unit 10 determines, based on the air flow direction, the order in which the laser light L is irradiated onto the plurality of irradiation targets. Specifically, the control unit 10 determines, based on the wind direction W, the order in which the laser light L is irradiated onto the weeds 32 located downstream of the wind direction W in the captured image.

[0031] Here, using the captured image 4 shown in Figure 4, we will explain in detail an example of how to determine the order in which laser light L is irradiated, starting from weeds 32 located downstream of the wind direction W in the captured image 4.

[0032] In this embodiment, the captured image 4 is first divided into a downstream region W1 on the lee side and an upstream region W2 on the wind side by a first reference line L1, which is a line extending substantially perpendicular to the wind direction W. The captured image 4 is further divided by a second reference line L2, which is a line extending along the wind direction W. The first reference line L1 passes through an irradiation point 41, which is a point on the captured image 4 corresponding to a position extending directly downward in the vertical direction from the irradiation position of the laser light L. The second reference line L2 also passes through the irradiation point 41. In the following description, of the multiple weeds 32 present in the captured image 4, the three weeds 32 present in the downstream region W1 will be referred to as downstream weeds 32a1, 32a2, and 32a3, and the three weeds 32 present in the upstream region W2 will be referred to as upstream weeds 32b1, 32b2, and 32b3.

[0033] Next, a process is executed to determine the order in which the laser light L is applied to the multiple downstream weeds 32a1-32a3 in the downstream region W1 in the captured image 4. In the downstream region W1 in the captured image 4, the application order is determined so that, of the three downstream weeds 32a1-32a3 present in the downstream region W1, the laser light L is applied to the downstream weed 32a1 in order of distance from the first reference line L1. Specifically, in the downstream region W1, the application order is determined so that the laser light L is applied first to the downstream weed 32a1, then to the downstream weed 32a2, and then to the downstream weed 32a3.

[0034] Thereafter, a process is executed to determine the order in which the laser light L is applied to the plurality of upstream weeds 32b1-32b3 in the upstream region W2 in the captured image 4. The order in which the laser light L is applied to the upstream weeds 32b1-32b3 in the upstream region W2 in the captured image 4 is also determined so that the laser light L is applied to the upstream weeds 32b1-32b3 in the upstream region W2 in order of the farthest distance from the first reference line L1.

[0035] As shown in the upstream region W2 in the captured image 4 of FIG. 4, when upstream weeds 32b2 and 32b3 exist at approximately the same distance from the first reference line L1, the irradiation order is determined so that the weed farthest from the second reference line L2 is irradiated first. "Approximately the same" is intended to include "completely the same" and "within a predetermined error range." Specifically, in the upstream region W2, the irradiation order is determined so that the laser beam L is irradiated first onto the upstream weed 32b1, then onto the upstream weed 32b2, and then onto the upstream weed 32b3. In other words, it is determined that the laser beam L is irradiated in the captured image 4 in the order of the downstream weeds 32a1, 32a2, and 32a3, followed by the upstream weeds 32b1, 32b2, and 32b3. Similarly, if there are multiple downstream weeds in the downstream region W1 that are approximately the same distance from the first reference line L1, the irradiation order is determined so that the downstream weed that is farthest from the second reference line L2 is irradiated first.

[0036] It is also possible to execute the process of determining the irradiation order in the upstream region W2 first, and then execute the process of determining the irradiation order in the downstream region W1. In this case, too, a process of determining the final irradiation order may be executed so that the order is downstream region W1, then upstream region W2, so that the laser light L is irradiated starting from downstream weeds present in the downstream region W1 for which the process of determining the irradiation order has been executed later.

[0037] Next, in S105, the control unit 10 irradiates the laser light L onto the plurality of irradiation targets in accordance with the determined irradiation order of the laser light L. In the captured image 4, the laser light L is irradiated onto downstream weeds 32a1, downstream weeds 32a2, downstream weeds 32a3, upstream weeds 32b1, upstream weeds 32b2, and upstream weeds 32b3 in this order as shown in Fig. 4. Thereafter, the control unit 10 ends the weeding process of Fig. 3.

[0038] [3.Effects] According to the embodiment described above in detail, the following effects can be obtained. (3a) In this embodiment, the order of irradiating the weeds 32 present in the captured image 4 with the laser beam L is determined based on the wind direction W, with priority given to the downstream weeds 32a1-32a3 present on the downwind side of the wind direction W in the captured image 4, i.e., the downstream region W1. Smoke K generated from the weeds 32 by irradiation with the laser beam L rises and flows toward the downwind side. Therefore, for example, the smoke K is less likely to get between the upstream weeds 32b1-32b3 to be irradiated next with the laser beam L, which are located upwind of the wind direction W relative to the downstream weeds 32a1-32a3 previously irradiated with the laser beam L, and the irradiation position of the laser beam L. This prevents the smoke K generated from the weeds 32 by irradiation with the laser beam L from absorbing the laser beam L. As a result, the irradiation intensity required for removing the weeds 32 can be easily achieved without increasing the output intensity of the laser beam L in consideration of the absorption of the laser beam L by the smoke K.

[0039] (3b) In this embodiment, the order of irradiation of the laser light L is determined by giving priority to weeds 32 present in the downstream region W1 in the captured image 4, which is divided by the first reference line L1. That is, in the two regions W1 and W2, the order of irradiation is determined so that the downstream region W1 is given priority over the upstream region W2. Therefore, the order of irradiation of the multiple weeds 32 can be easily determined according to the priority order determined for each divided region in the captured image 4.

[0040] (3c) In this embodiment, the downstream side in the captured image 4 is determined based on the wind direction W detected by the sensor 20, so that the accuracy of determining the irradiation order can be improved. (3d) In this embodiment, when there are multiple weeds 32 in the downstream region W1, the irradiation order is determined in descending order of distance from the first reference line L1, and when there are multiple weeds 32 in the upstream region W2, the irradiation order is determined in descending order of distance from the first reference line L1. Therefore, even when there are multiple weeds 32 in each of the regions W1 and W2, it is possible to determine an irradiation order that makes it difficult for smoke K generated from the weeds 32 by irradiation with the laser light L to get between the weed 32 to be next irradiated with the laser light L and the irradiation position of the laser light L.

[0041] (3e) In this embodiment, for weeds 32 in either the downstream region W1 or the upstream region W2 that are at approximately the same distance from the first reference line L1, the irradiation order can be determined based on the distance from the second reference line L2 so as to make it less likely for smoke K to enter between the weed 32 to be next irradiated with the laser light L and the irradiation position of the laser light L.

[0042] (3f) In this embodiment, the first reference line L1 and the second reference line L2 are lines that pass through the irradiation point 41, and therefore the first reference line L1 and the second reference line L2 divide the area in the captured image 4 with more accurate consideration of the irradiation position of the laser light L. Therefore, it is possible to determine the irradiation order that makes it more difficult for smoke K to get between the weed 32 to be next irradiated with the laser light L and the irradiation position of the laser light L.

[0043] (3g) In this embodiment, the weeding device 1 is used outdoors, and the capture of the captured images 4 and the irradiation of the laser light L are performed while the weeding device 1 is stopped. Therefore, in a situation where natural wind is present outdoors, the order of irradiation of the laser light L can be determined based on the wind direction W of the natural wind.

[0044] The crop 31 and the weeds 32 correspond to plants, the weeds 32 correspond to the irradiation target, the downstream weeds 32a1 to 32a3 correspond to the downstream target, and the upstream weeds 32b1 to 32b3 correspond to the upstream target. Furthermore, S101 corresponds to an example of processing as an acquisition unit, S102 corresponds to an example of processing as an identification unit, S104 corresponds to an example of processing as a determination unit, and S105 corresponds to an example of processing as an irradiation unit.

[0045] 4. Other Embodiments Although the embodiments of the present disclosure have been described above, it goes without saying that the present disclosure is not limited to the above-described embodiments and can take on various forms.

[0046] (4a) In the above embodiment, a configuration is illustrated in which the irradiation order is determined based on the wind direction W detected by the sensor 20. However, the air flow direction that serves as the basis for determining the irradiation order is not limited to the wind direction W detected by the sensor 20. In other embodiments described below, the air flow direction is detected by a method other than the sensor 20. However, in other embodiments, the detection value of the sensor 20 may also be taken into consideration to determine the air flow direction. Note that the air flow direction may include the flow direction relative to the weeding device 1.

[0047] In the above embodiment, the weeding process is performed while the weeding device 1 is stopped. That is, in the above embodiment, the capture of the captured image 4 and the irradiation of the laser light L are performed while the weeding device 1 is stopped. However, the irradiation of the laser light L may be performed, for example, while the weeding device 1 is traveling. In this way, when the irradiation of the laser light L is performed while the weeding device 1 is traveling, traveling wind flowing in the direction opposite to the direction of movement is generated around the crops 31. For this reason, when the weeding device 1 is configured to be movable, the air flow direction can be estimated to be the direction opposite to the direction of movement.

[0048] The air flow direction may be determined solely from the moving direction of the weeding device 1, or may be determined taking into consideration the detection value of the sensor 20. When the detection value of the sensor 20 is not used to detect the air flow direction, the irradiation order of the laser light L may be determined solely based on the direction of traveling wind generated as the weeding device 1 moves, in the same manner as the method of determining the irradiation order based on the wind direction W described above. When the air flow direction is detected using the detection value of the sensor 20 in addition to the moving direction of the weeding device 1, the irradiation order of the laser light L may be determined based on the air flow direction taking into consideration the wind direction W and traveling wind, in the same manner as the method of determining the irradiation order based on the wind direction W described above. Note that even when the air flow direction is detected using the detection value of the sensor 20, the irradiation order of the laser light L may be based on the traveling wind if there is no natural wind.

[0049] The weeding device 1 may also include a blower that blows horizontal air into the irradiation space where the laser light L is irradiated. As shown in FIGS. 5 and 6, the weeding device 1a may also include a blower 21a attached to the side of the shielding wall 19a and generating horizontal air. The blower 21a generates a horizontal air flow in the irradiation space, i.e., around the crops 31. Therefore, when the weeding device 1a includes the blower 21a that blows horizontal air, the air flow direction can be estimated as the airflow direction Y1 of the blower 21a. The blower 21a is a known device that generates air by rotating multiple blades driven by a motor. The blower 21a introduces outside air, which is air outside the irradiation space where the laser light L is irradiated, into the irradiation space. The introduced outside air then flows along the airflow direction Y1 and is discharged from an opening 191 provided in the side wall of the shielding wall 19a to the outside of the irradiation space, i.e., outside the shielding wall 19a. The opening 191 is a slit that is provided at least on the side surface of the shielding wall 19a opposite to the side surface on which the blower 21a is attached, and that connects the inside and outside of the shielding wall 19a.

[0050] The air flow direction may be determined solely from the airflow direction Y1 of the blower 21a, or may be determined taking into consideration the detection value of the sensor 20. When the detection value of the sensor 20 is not used to detect the airflow direction, the irradiation order of the laser light L may be determined solely based on the airflow direction Y1 of the blower 21a, in the same manner as the method of determining the irradiation order based on the wind direction W described above. Furthermore, when the airflow direction is detected using not only the airflow direction Y1 of the blower 21a but also the detection value of the sensor 20, the irradiation order of the laser light L may be determined based on the airflow direction taking into consideration the wind direction W and the airflow direction Y1, in the same manner as the method of determining the irradiation order based on the wind direction W described above. Note that even when the airflow direction is detected using the detection value of the sensor 20, if there is no natural wind, the irradiation order of the laser light L may be based on the airflow direction Y1. Furthermore, the irradiation order of the laser light L may be determined based on the airflow direction taking into consideration the wind direction W, the running wind, and the airflow direction Y1, in the same manner as the method of determining the irradiation order based on the wind direction W described above.

[0051] The weeding device 1 may also be provided with a blower that blows wind directed vertically downward into the irradiation space where the laser light L is irradiated. As in the weeding device 1b shown in FIGS. 7 and 8, the weeding device 1b may also be provided with a blower 21b that is housed in a housing 18 and generates wind directed vertically downward. The blower 21b generates a radially expanding air flow in the lower part of the shielding wall 19 from the air flowing from above downward in the irradiation space. Therefore, when the weeding device 1b is provided with the blower 21b that blows wind directed vertically downward, the direction of the air flow can be estimated as a direction that radially expands from the blowing center of the blower 21b. The blower 21b introduces outside air, which is air outside the irradiation space of the laser light L, into the irradiation space. The introduced outside air flows from top to bottom within the irradiation space, diffuses radially in the lower part of the shielding wall 19, and is discharged outside the irradiation space, i.e., outside the shielding wall 19, through the gap S below the shielding wall 19.

[0052] The air flow direction may be determined only from the direction radially expanding from the airflow center of the fan 21 b. In other words, the irradiation order of the laser light L may be determined as shown in the captured image 4 b in FIG. 9 based on the diffused air Y2 shown in FIGS. 7 and 8 that flows in the direction radially expanding from the airflow center of the fan 21 b.

[0053] Here, using the captured image 4b ​​shown in Figure 7, we will explain in detail an example of how to determine the order in which laser light L is irradiated, starting from weeds 32 located downstream of the diffused wind Y2 in the captured image 4b.

[0054] In this example, first, the captured image 4b ​​is divided into multiple regions from the upstream side to the downstream side by multiple circular first reference lines L3a to L3c spaced at predetermined intervals from the center point 41b, which is the airflow center of the blower 21b. Next, the irradiation order is determined so that the laser light L is irradiated to the three weeds 32c1-32c3 present in the captured image 4b ​​in descending order of distance from the center point 41b. Specifically, priority is given to the weed 32c1 present in the first region X1 outside the outermost first reference line L3c among the multiple first reference lines L3a-L3c. Next, priority is given to the weed 32c2 present in the second region X2 between the first reference line L3b and the first reference line L3c, which are located inside the first reference line L3c. Next, priority is given to the weed 32c3 present in the third region X3 between the innermost first reference line L3a and the first reference line L3b among the multiple first reference lines L3a-L3c. Finally, if there is a weed 32 present in the fourth region X4 inside the first reference line L3a, that weed 32 is given next priority. In the captured image 4b, the irradiation order is determined so that first the weeds 32c1, then the weeds 32c2, and then the weeds 32c3 are irradiated with the laser light L. That is, in the captured image 4b, it is determined that the laser light L is irradiated to the weeds 32c1, 32c2, and 32c3 in this order.

[0055] The smoke K generated from the weeds 32 by the irradiation of the laser light L rises and flows downstream. Therefore, for example, the smoke K is unlikely to get between the irradiation position of the laser light L and the weed 32c3 to be next irradiated with the laser light L, which is located upstream of the diffused wind Y2 from the weed 32c1 that was previously irradiated with the laser light L. This makes it possible to prevent the laser light L from being absorbed by the smoke K generated by the irradiation of the laser light L. As a result, it is easy to obtain the irradiation intensity required to remove the weeds 32 without increasing the output intensity of the laser light L in consideration of the absorption of the laser light L by the smoke K.

[0056] In addition, in the captured image 4b, the area of ​​the captured image 4b ​​may be further divided using a second reference line that passes through the center point 41b and extends radially perpendicular to the first reference lines L3a to L3c, and the order of irradiation of the laser light L may be determined taking into consideration the priority of each area divided by the second reference line.

[0057] (4b) In the above embodiment, the sensor 20 for detecting the air flow direction is provided, but a configuration without a sensor is also possible. In a configuration without a sensor, the order of irradiation of the laser light L may be determined based on the air flow direction, which is defined as the air flow direction of the running wind, the blown air Y1 direction, and the diffused wind Y2 as described above.

[0058] (4c) The laser light L is irradiated in order from the weeds 32 located downstream of the wind direction W in the captured image 4. The method for determining the irradiation order of the laser light L is not limited to the above-described method. In the above embodiment, the configuration in which the irradiation order of the laser light L is determined using the first reference line L1 and the second reference line L2 has been exemplified, but, for example, the irradiation order of the laser light L may be determined using only the first reference line L1. Also, for example, the irradiation order of the laser light L may be determined in order from the downstream side without using either the first reference line L1 or the second reference line L2, that is, without dividing the captured image 4 into the downstream region W1 and the upstream region W2.

[0059] Furthermore, for example, when the downstream region W1 has priority over the upstream region W2, even if there are multiple downstream weeds 32a1-32a3 in the downstream region W1, the order of irradiation of the multiple downstream weeds 32a1-32a3 in the downstream region W1 does not have to be from the downstream side. The same applies to the upstream region W2.

[0060] Furthermore, for example, the captured image 4 may be divided into smaller sections by a plurality of first reference lines L1. In this case, the order of irradiation of the laser light L may be determined based on the order of regions located downstream among the regions divided by the plurality of first reference lines L1. Furthermore, for example, the first reference line L1 and the second reference line L2 may be lines that do not pass through the irradiation point 41. In this case, the area of ​​the captured image 4 may be divided based on the center of the captured image 4.

[0061] (4d) In the above embodiments, the weeding devices 1, 1a, and 1b are configured to perform weeding work in cultivated land 3, but the locations where the weeding devices 1, 1a, and 1b are used are not limited to this. For example, the weeding devices 1, 1a, and 1b may be used to remove unwanted plants such as weeds 32 in locations other than cultivated land 3 where crops 31 are cultivated or where the crops 31 grow naturally, such as parks and gardens. Furthermore, for example, the weeding devices 1, 1a, and 1b may be used to remove unwanted plants in locations where no crops 31 exist. In other words, all plants present in a specific location may be considered unwanted plants, and the weeding devices 1, 1a, and 1b may be used to remove all such unwanted plants.

[0062] (4e) The weeding devices 1, 1a, and 1b in each of the above embodiments are self-propelled and configured to travel automatically according to route information stored in the memory of the control unit 10. However, the weeding devices 1, 1a, and 1b may move along a route according to user operation, or may be moved by other devices or manually to perform weeding work in the same manner. Furthermore, for example, when traveling within a predetermined area surrounded by a fence or the like, automatic operation may be performed without route information.

[0063] (4f) Although the weeding devices 1, 1a, and 1b in the above embodiments are illustrated as moving by the traveling unit 17, the moving mode for weeding work is not limited to this. For example, the weeding device may move by flying. Also, for example, the weeding device may be configured without a moving mechanism such as a traveling unit.

[0064] (4g) The function of one component in the above embodiments may be distributed among multiple components, or the functions of multiple components may be integrated into one component. Also, part of the configuration of the above embodiments may be omitted. Furthermore, at least part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments. All aspects included in the technical idea identified by the wording of the claims are embodiments of the present disclosure. [Explanation of symbols]

[0065] 1, 1a, 1b... weeding device, 1A... working area, 3... cultivated land, 4, 4b... captured image, 10... control unit, 11... power supply, 12... laser oscillator, 13... laser head, 14... optical system, 15... camera, 16... lighting, 17... traveling unit, 18... housing, 19, 19a... shielding wall, 20... sensor, 21a, 21b... blower, 30... ridge, 31... crop, 32, 32c1 to 32c3... weeds, 3 2a1 to 32a3...downstream weeds, 32b1 to 32b3...upstream weeds, 41...irradiation point, 41b...center point, 191...opening, K...smoke, L...laser light, L1, L3a to L3c...first reference line, L2...second reference line, S...gap, W...wind direction, W1...downstream area, W2...upstream area, Y1...air blowing, Y2...diffused wind, X1...first area, X2...second area, X3...third area, X4...fourth area.

Claims

1. A weeding device comprising: an acquisition unit configured to acquire a captured image including a plant captured by an imaging device; an identification unit configured to identify a plurality of irradiation targets present in the captured image that are to be irradiated with laser light by a laser irradiator; a determination unit configured to determine an irradiation order of the laser light based on an air flow direction around the plant so that the laser light is irradiated from the plurality of irradiation targets present downstream in the air flow direction in the captured image; and an irradiation unit configured to irradiate the laser light onto the plurality of irradiation objects in accordance with the irradiation order; A weeding device comprising:

2. The weeding device according to claim 1, The weeding device further comprises a sensor for detecting the air flow direction.

3. The weeding device according to claim 1 or 2, The captured image is divided into a downstream region and an upstream region by a first reference line that is a line extending substantially perpendicular to the air flow direction, The weeding device, wherein the determination unit determines the irradiation order so that the laser light is irradiated starting from a downstream object that is present in the downstream region among the plurality of irradiation objects.

4. The weeding device according to any one of claims 1 to 3, a line in the captured image extending along the air flow direction is defined as a second reference line; The determination unit determines the irradiation order so that the laser light is irradiated in order from the object that is farthest from the second reference line when the distances from the upstream end of the air flow direction in the captured image of the multiple objects to be irradiated are approximately the same.

5. The weeding device according to claim 4, the captured image is an image of the plant captured from above, the laser light is irradiated onto the plant from above the plant, A weeding device, wherein the second reference line is a line passing through an irradiation point, which is a point on the captured image corresponding to a position extending directly downward in the vertical direction from the irradiation position of the laser light.

6. The weeding device according to claim 3, the captured image is an image of the plant captured from above, the laser light is irradiated onto the plant from above the plant, A weeding device, wherein the first reference line is a line passing through an irradiation point, which is a point on the captured image corresponding to a position extending directly downward in the vertical direction from the irradiation position of the laser light.

7. A weeding device according to any one of claims 1 to 6, The acquisition of the captured image and the irradiation of the laser light are performed while the weeding device is stopped, A weeding device, wherein the air flow direction is determined taking into consideration at least a direction along a wind direction in an environment in which the weeding device is used.

8. A weeding device according to any one of claims 1 to 7, Further provided is a movement mechanism that enables movement of the weeding device, A weeding device, wherein the air flow direction is determined taking into consideration at least a direction opposite to the movement direction when the laser light irradiation is performed while the movement mechanism is moving.

9. A weeding device according to any one of claims 1 to 8, Further provided is a blower that blows air in a horizontal direction, The weeding device, wherein the air flow direction is determined taking into consideration at least the blowing direction of the blower.

10. The weeding device according to claim 1, Further provided is a blower that blows air in a vertically downward direction, A weeding device, wherein the air flow direction is a direction that spreads radially from the blowing center of the blower.

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