Mobile weeding device

Abstract

To provide a mobile weeder capable of efficiently removing unnecessary plants.SOLUTION: A mobile weeder includes: a camera configured so as to acquire an image of a plant taken from above; a laser irradiation device configured so as to radiate laser beams onto the plant from above the plant; a control device for determining characteristics of the plant on the basis of the image, which is configured so as to adjust a laser beam irradiation amount on the basis of the characteristics; and a device body for holding the camera and the laser irradiation device, which includes a moving mechanism.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Weeding devices that remove unwanted plants (i.e., weeds) in farmland by irradiating them with laser light are known (see Patent Documents 1 to 3). These weeding devices irradiate unwanted plants with laser light from above, thereby damaging and killing the plants. [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] It is preferable to remove unwanted plants from farmland at a stage where they are as young as possible. Therefore, from the viewpoints of battery capacity, power saving, safety against excessive irradiation, etc., the irradiation amount of laser light is set to match such relatively small unwanted plants.

[0005] However, if the amount of laser light irradiation is limited in this way, when unwanted plants grow larger than expected, there is a risk that the unwanted plants will not be sufficiently removed due to insufficient laser light output.

[0006] One aspect of the present disclosure aims to provide a mobile weeding device that can efficiently remove unwanted plants. [Means for solving the problem]

[0007] One aspect of the present disclosure is a mobile weeding device that includes a camera configured to acquire an image of a plant photographed from above, a laser irradiator configured to irradiate the plant with laser light from above, a control device configured to determine characteristics of the plant based on the image and adjust the amount of laser light irradiation based on the characteristics, and a device main body that holds the camera and the laser irradiator and has a movement mechanism.

[0008] This configuration allows the amount of laser light irradiation to be adjusted based on the characteristics of the plants determined by image analysis, so that the plants can be irradiated with just the right amount of laser light. As a result, unwanted plants can be efficiently removed while suppressing increases in battery capacity, power consumption, and excessive laser light irradiation.

[0009] In one aspect of the present disclosure, the control device may adjust the amount of laser light irradiation by adjusting the irradiation output of the laser light. With this configuration, the amount of laser light irradiation can be adjusted relatively easily.

[0010] In one aspect of the present disclosure, the control device may adjust the irradiation amount of the laser light by adjusting the irradiation time of the laser light. This configuration also makes it possible to adjust the irradiation amount of the laser light relatively easily.

[0011] In one aspect of the present disclosure, the characteristics may include a size of the plant. With this configuration, it is possible to adjust the amount of laser light irradiation according to the size of the plant.

[0012] In one aspect of the present disclosure, the characteristics may include the type of plant. With this configuration, it is possible to adjust the amount of laser light irradiation according to the shape of the plant. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram of a mobile weeding device according to an embodiment. [Figure 2]FIG. 2 is a block diagram showing the configuration of the control device in the mobile weeding device of FIG. [Figure 3] 3A and 3B are schematic diagrams illustrating the procedure for determining the size of a plant in the control device of FIG. [Figure 4] 4A, 4B, and 4C are schematic diagrams showing the procedure for irradiating unwanted plants with laser light. [Figure 5] FIG. 5 is a schematic diagram showing an example of the irradiation locus of the laser light. [Figure 6] FIG. 6 is a flow chart schematically showing the process executed by the control device of FIG. [Figure 7] FIG. 7 is a flow chart schematically showing the process executed by the control device of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments to which the present disclosure is applied will be described with reference to the drawings. [1. First embodiment] [1-1.Configuration] The mobile weeding device 1 shown in Figure 1 is a device for removing unwanted plants P (i.e., weeds) that have grown around crops in farmland. The mobile weeding device 1 includes a device main body 2, a laser irradiator 3, a camera 4, and a control device 5.

[0015] <Device body> The device main body 2 is a housing that holds the laser irradiator 3, the camera 4, and the control device 5. The device main body 2 also has a movement mechanism.

[0016] The movement mechanism of this embodiment is composed of a plurality of wheels 21. The device body 2 is configured to travel on farmland using the plurality of wheels 21. The movement mechanism may be an electric type in which the wheels 21 are rotated by a motor, or a manual type in which the device body 2 is moved by an operator pushing or pulling it. Furthermore, the device body 2 may be equipped with one or more electric crawlers instead of the wheels 21 as the movement mechanism.

[0017] <Laser irradiator> The laser irradiator 3 is configured to irradiate the unwanted plant P with laser light L from above the unwanted plant P identified by the control device 5. The laser irradiator 3 may be configured to irradiate the laser light L from above the unwanted plant P2 by changing the direction of the laser light L using an optical element such as a mirror.

[0018] The laser irradiator 3 uses laser light L to damage (specifically burn) the unwanted plants P, thereby causing the unwanted plants P to wither and die. The laser light L is irradiated onto the growth point or the roots of the unwanted plants P. The growth point and the roots of the unwanted plants P are determined by the control device 5 based on the image captured by the camera 4.

[0019] A known laser irradiation device including a battery (not shown), an oscillator 31, and a reflection control unit 32 (e.g., a galvanometer scanner, MEMS, etc.) can be used as the laser irradiator 3. The frequency of the laser light from the laser irradiator 3 is, for example, 430 nm or more and 675 nm or less.

[0020] The laser irradiator 3 is configured to be able to change the irradiation direction, irradiation output, and irradiation time of the laser light L. The irradiation output is changed by a signal (for example, an analog input voltage) output from the control device 5 to the oscillator 31.

[0021] The laser irradiator 3 may irradiate the laser while the device main body 2 is moving, or may irradiate the laser while the device main body 2 is stationary. The laser irradiator 3 sequentially irradiates the laser onto the plurality of unwanted plants P identified by the control device 5.

[0022] <Camera> The camera 4 is configured to acquire an image of farmland containing at least one crop and at least one unwanted plant P from above.

[0023] The images captured by camera 4 include at least one crop, at least one unwanted plant P, and other objects (for example, structures such as fences, obstacles such as stones, etc.). The imaging range of camera 4 changes as device main body 2 moves.

[0024] <Control device> The control device 5 mainly controls the laser irradiator 3. The control device 5 is configured by a computer including, for example, a processor, a storage medium such as RAM and ROM, a communication unit, and an input / output unit. As shown in Fig. 2, the control device 5 has an image processing unit 51, a laser control unit 52, and a database 53.

[0025] The image processing unit 51 is configured to identify unwanted plants P from the image captured by the camera 4. The image processing unit 51 identifies unwanted plants P using AI (artificial intelligence) constructed using a known statistical method.

[0026] Statistical methods include, for example, supervised machine learning, multivariate analysis, etc. In supervised machine learning, a decision formula (i.e., a classifier) ​​is constructed by analyzing a large number of labeled plant images (i.e., training data) using a machine learning circuit.

[0027] After identifying the unwanted plants P, the image processing unit 51 is configured to further determine the characteristics of the unwanted plants P. The characteristics of the unwanted plants P include the size and type of the unwanted plants P.

[0028] 3A and 3B, the image processing unit 51 determines, for example, the area of ​​a rectangle S circumscribing the unwanted plant P in the image captured by the camera 4 as the size of the unwanted plant P. In other words, the image processing unit 51 calculates the size of the unwanted plant P as the product of the width X of the unwanted plant P in the reference direction and the width Y in the direction perpendicular to the reference direction.

[0029] Furthermore, the image processing unit 51 refers to the plant data stored in the database 53 to determine the type (i.e., category) of the unwanted plant P. Specifically, the image processing unit 51 recognizes the shape, number, position, etc. of the leaves of the unwanted plant P from the image, and determines the type of the unwanted plant P based on this.

[0030] For example, the image processing unit 51 determines the unwanted plant P in Fig. 4A as a "two-leaf weed," the unwanted plant P in Fig. 4B as a "multi-leaf weed," and the unwanted plant P in Fig. 4C as a "grass weed." Note that the image processing unit 51 may classify the unwanted plants P into four or more categories.

[0031] 2 instructs the laser irradiator 3 to irradiate the coordinates of the unwanted plants P identified by the image processing unit 51 with laser light. The laser control unit 52 is also configured to adjust the irradiation amount and irradiation trajectory of the laser light based on the characteristics of the unwanted plants P determined by the image processing unit 51.

[0032] Specifically, the laser control unit 52 determines the amount of laser light irradiation (i.e., the irradiation energy to the unwanted plants P) based on the size and type of the unwanted plants P. The amount of laser light irradiation is proportional to the irradiation output and irradiation time of the laser light.

[0033] The laser control unit 52 increases the amount of laser light irradiation the larger the unwanted plants P, and decreases the amount of laser light irradiation the smaller the unwanted plants P. Furthermore, the laser control unit 52 increases the amount of laser light irradiation the larger the resistance to laser light (i.e., difficulty in removal by laser light) of the type of unwanted plants P, and decreases the amount of laser light irradiation the smaller the resistance to laser light.

[0034] The amount of laser light irradiation is adjusted by changing at least one of the irradiation power and irradiation time of the laser light. In order to increase the amount of laser light irradiation, one of the following adjustments is performed: increasing only the irradiation power without changing the irradiation time, increasing only the irradiation time without changing the irradiation power, or increasing both the irradiation power and the irradiation time.

[0035] The irradiation time of the laser light is adjusted by the number of revolutions of the irradiation point of the laser light, for example, as shown in Figures 4A, 4B, and 4C. The irradiation point of the laser light moves in a circle around the growth point or the root of the unwanted plant P.

[0036] The laser light irradiation output and irradiation time corresponding to the size and type of unwanted plants P are stored in database 53 as a table or function describing these relationships. When the size and type of unwanted plants P are input as variables into the table or function, the corresponding irradiation output and irradiation time are output. Table 1 below is an example of a table. By adjusting both the irradiation output and irradiation time in this way, the degree of freedom in adjusting the irradiation amount is increased.

[0037] [Table 1]

[0038] The laser control unit 52 also has a function of setting the irradiation trajectory (i.e., irradiation pattern) of the laser light on the unwanted plants P. As shown in Fig. 5, examples of the irradiation trajectory R include geometric patterns such as a circle, a square, and a triangle, letters such as "Z" and "V," and hieroglyphic patterns such as a star shape and a cup shape.

[0039] These irradiation trajectories R are the paths of the irradiation points moving over the unwanted plants P, and are continuous patterns without interruption. The speed at which the irradiation points move when forming the irradiation trajectory R is adjusted based on the total length and number of repetitions of the irradiation trajectory R, ​​and the irradiation time.

[0040] The laser control unit 52 inputs the irradiation coordinates, irradiation output, irradiation time, irradiation trajectory, etc. adjusted as described above to the laser irradiator 3. The laser irradiator 3 irradiates the unwanted plants P with laser light along the irradiation trajectory at the irradiation output and irradiation time instructed by the laser control unit 52.

[0041] <Controller processing> An example of the processing executed by the image processing unit 51 and the laser control unit 52 of the control device 5 will be described below with reference to the flow chart of FIG.

[0042] In this process, first, the image processing unit 51 acquires an image captured by the camera 4 (step S110). Next, the image processing unit 51 identifies unwanted plants from the image and determines the characteristics of the unwanted plants (step S120). After determining the characteristics of the unwanted plants, the laser control unit 52 adjusts the amount of laser light irradiation (step S130).

[0043] 7, the laser control unit 52 determines whether the size of the unwanted plant is equal to or larger than a threshold value (step S210). If the size of the unwanted plant is equal to or larger than the threshold value (S210: YES), the laser control unit 52 determines whether the type of the unwanted plant is "A" (step S220). If the type of the unwanted plant is "A" (S220: YES), the laser control unit 52 sets the irradiation amount for "Pattern 1" in Table 1 (step S230).

[0044] If the type of unwanted plant is not "A" (S220: NO), the laser control unit 52 determines whether the type of unwanted plant is "B" (step S240). If the type of unwanted plant is "B" (S240: YES), the laser control unit 52 sets the irradiation amount for "Pattern 2" in Table 1 (step S250). On the other hand, if the type of unwanted plant is not "B" (S240: NO), the laser control unit 52 sets the irradiation amount for "Pattern 3" in Table 1 (step S260).

[0045] Similarly, when the size of the unwanted plant is less than the threshold value (S210: NO), the laser control unit 52 determines whether the type of the unwanted plant is "A" (step S270) and whether the type of the unwanted plant is "B" (step S290), and sets the irradiation amount for "Pattern 4," "Pattern 5," or "Pattern 6" in Table 1 (steps S280, S300, and S310).

[0046] [1-2.Effects] According to the embodiment described above in detail, the following effects can be obtained. (1a) The amount of laser light irradiation can be adjusted based on the characteristics of unwanted plants determined by image analysis, so that the laser light can be applied to unwanted plants in just the right amount. As a result, unwanted plants can be efficiently removed while suppressing increases in battery capacity, power consumption, and excessive laser light irradiation.

[0047] (1b) The amount of laser light irradiation can be adjusted relatively easily by adjusting the irradiation output of the laser light. (1c) The amount of laser light irradiation can be adjusted relatively easily by adjusting the irradiation time of the laser light.

[0048] (1d) The size of the unwanted plants is included in the characteristics of the unwanted plants determined by the image processing unit 51, so that the amount of laser light irradiation can be adjusted according to the size of the plants. (1e) By including the type of unwanted plant in the characteristics of the unwanted plant determined by the image processing unit 51, it is possible to adjust the amount of laser light irradiation in accordance with the shape of the plant.

[0049] 2. 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.

[0050] (2a) In the mobile weeding device of the above embodiment, the control device does not necessarily have to be attached to the device body. For example, the control device may be installed on farmland or in a facility away from farmland, and configured to wirelessly communicate with the camera and the laser illuminator.

[0051] (2b) In the mobile weeding device of the above embodiment, the control device may adjust the irradiation amount of the laser light according to only the size or type of the plant. Also, the control device may adjust the irradiation amount of the laser light based on characteristics of the plant other than the size and type of the plant.

[0052] (2c) In the mobile weeding device of the above embodiment, the mode of movement of the device body is not limited to traveling. The mobile weeding device may move by flying, for example.

[0053] (2d) 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]

[0054] 1...mobile weeding device, 2...device body, 3...laser irradiator, 4...camera, 5...control device, 21...wheel, 31...oscillator, 32...reflection control unit, 51...image processing unit, 52...Laser control unit, 53...Database.

Claims

1. a camera configured to acquire images of the plant taken from above; a laser irradiator configured to irradiate the plant with laser light from above the plant; a control device configured to determine characteristics of the plant based on the image and adjust the amount of irradiation of the laser light based on the characteristics; an apparatus main body that holds the camera and the laser irradiator and has a movement mechanism; Equipped with The control device detects at least one of the growth point and the root of the plant based on the image, and controls the laser irradiator so that the irradiation point of the laser light orbits around the growth point or the root of the plant.

2. The mobile weeding device according to claim 1, The control device adjusts the irradiation amount of the laser light by adjusting the irradiation output of the laser light.

3. The mobile weeding device according to claim 1 or 2, The control device adjusts the irradiation amount of the laser light by adjusting the irradiation time of the laser light.

4. A mobile weeding device according to any one of claims 1 to 3, The mobile weeding device, wherein the characteristics include a size of the plant.

5. A mobile weeding device according to any one of claims 1 to 4, The mobile weeding device, wherein the characteristics include the type of the plant.

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