Landmine detection system and landmine detection method

Abstract

To provide a landmine detection system and a landmine detection method that can improve the accuracy of detecting landmines that are placed on the ground and have metals containing iron on the outer surface, while reducing the risk of injury to an explorer, and can efficiently detect the landmines. [Solution] The mine detection system 1 comprises a first drone device 2 having a first drone 6, a first tank, and a first spraying device 10 that sprays an acidic first solution 52 that dissolves iron on the outer surface of the mine; a second drone device 4 having a second drone 20, a second tank, and a second spraying device 22 that sprays a second solution 54 that functions as a chemical marker that reacts to the iron ions dissolved by the first solution; and a third drone device 40 having a third drone 42 and a camera that captures images or videos of the reaction between the second solution and the iron ions.

Description

[Technical Field]

[0001] The present invention relates to a land mine detection system and a land mine detection method. [Background technology]

[0002] As disclosed in Patent Document 1, a technique for detecting landmines is known in the past, which uses an infrared camera to capture images of the landmine and utilizes the difference in specific heat between the landmine and the area around it. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-155460 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the technology shown in Patent Document 1 has the disadvantage of low measurement accuracy when landmines are hidden in the ground. Also, in order to detect landmines using this technology, measurements must be taken after a large change in temperature, when differences in specific heat can be utilized, which limits the efficiency of landmine detection.

[0005] The present invention has been made to solve these problems, and aims to provide a mine detection system and a mine detection method that improve the accuracy of detecting mines that have an iron-containing metal outer surface and are placed on the ground, while reducing the risk of injury to the detector, and that can detect mines efficiently. [Means for solving the problem]

[0006] In order to achieve the above object, according to one embodiment of the present invention, a mine detection system for detecting mines that use metal containing iron on their outer surface comprises: a first drone apparatus, the first drone apparatus comprising a first drone, a first tank provided on the first drone, and a first spraying device that sprays an acidic first solution that dissolves iron on the outer surface of the mine; a second drone apparatus, the second drone apparatus comprising a second drone, a second tank provided on the second drone, and a second spraying device that sprays a second solution that functions as a chemical marker that reacts with iron ions dissolved by the first solution sprayed by the first spraying device of the first drone apparatus; and a third drone apparatus, the third drone apparatus comprising a third drone and a camera that captures images or videos of the reaction between the second solution sprayed by the second spraying device and the iron ions dissolved by the first solution. According to one embodiment of the present invention configured as described above, the camera of the third drone device can capture images or videos of the reaction between the second solution sprayed by the second spraying device and the iron ions eluted by the first solution. This allows the location of a landmine whose outer surface contains iron to be estimated from the captured images, etc., if one exists underground. This reduces the risk of injury to the explorer when searching from the air using a drone, improving the accuracy of searching for landmines whose outer surface contains iron and enabling efficient landmine searches.

[0007] According to one embodiment of the present invention, a mine detection method for detecting landmines preferably includes a first solution spraying step in which a drone's spraying device sprays an acidic first solution that dissolves iron on the surface of the landmine; a second solution spraying step in which the drone's spraying device sprays a second solution that functions as a chemical marker that reacts to the iron ions eluted by the first solution sprayed in the first solution spraying step; and a photographing step in which a camera captures an image or video of the reaction between the second solution sprayed in the second solution spraying step and the iron ions eluted by the first solution. According to one embodiment of the present invention configured as described above, the reaction between the second solution sprayed in the second-solution spraying step and the iron ions eluted by the first solution can be captured by a camera in the photographing step as an image or video. This allows the location of a landmine whose outer surface contains iron to be estimated from the captured image, etc., when it is present underground. Therefore, the risk of injury to an explorer when searching from the air using a drone can be reduced, while improving the accuracy of searching for landmines whose outer surface contains iron and enabling efficient landmine searches. [Effects of the Invention]

[0008] The mine detection system and mine detection method of the present invention can improve the detection accuracy for mines that are placed on the ground and have an outer surface that contains iron, while reducing the risk of injury to the explorer, and can efficiently search for mines. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a schematic diagram illustrating an overview of a first drone device of a mine detection system according to an embodiment of the present invention. [Figure 2] FIG. 10 is a schematic diagram illustrating an overview of a second drone device of a mine detection system according to an embodiment of the present invention. [Figure 3] FIG. 10 is a schematic diagram illustrating an overview of a third drone device of a mine detection system according to an embodiment of the present invention. [Figure 4]1 is a block diagram showing connections between a first drone device, a second drone device, a third drone device and a control unit in a mine detection system according to one embodiment of the present invention. FIG. [Figure 5] FIG. 2 is a block diagram showing the configuration of a first drone device in the mine detection system according to one embodiment of the present invention. [Figure 6] FIG. 2 is a block diagram showing the configuration of a second drone device in a mine detection system according to one embodiment of the present invention. [Figure 7] FIG. 10 is a block diagram showing the configuration of a third drone device in the mine detection system according to one embodiment of the present invention. [Figure 8] 2 is a block diagram showing the configuration of a control unit in the landmine detection system according to one embodiment of the present invention. FIG. [Figure 9] 2 shows a flowchart of a mine detection method for a mine detection system according to one embodiment of the present invention; [Figure 10] 1 is a diagram showing the course along which a first drone device, a second drone device, and a third drone device move sequentially through search points in a mine detection system according to one embodiment of the present invention. FIG. [Figure 11] This is a diagram illustrating the state in which the second solution reacts and changes color on the ground at a location where a landmine is present, captured by the third drone camera of the third drone device in a landmine detection system according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] A mine detection system 1 according to an embodiment of the present invention will now be described with reference to the accompanying drawings. The embodiments of the present disclosure have been described as examples, and it will be apparent to those skilled in the art that many variations, modifications, and substitutions can be made within the spirit and scope of the present invention. Therefore, the present invention is not limited to the disclosed embodiments, and various variations, modifications, etc. can be made in form and details without departing from the scope of the claims. Furthermore, the components disclosed in the specification can be freely combined.

[0011] As shown in Fig. 1, a mine detection system 1 according to one embodiment of the present invention can detect a mine M. For example, the mine detection system 1 detects a mine M that uses a metal containing iron on its outer surface. The mine detection system 1 includes a first drone device 2, a second drone device 4, and a third drone device 40. In the following description of one embodiment of the present invention, the sky side of the first drone device of the mine detection system 1 as shown in FIG. 1 is referred to as the upper side, and the ground side of the first drone device is referred to as the lower side. Landmines M are present on the surface of the ground G or buried underground near the surface. Landmines M often exist, for example, at a depth of 1 to 10 cm below the surface, or, for example, at a depth of 1 to 5 cm below the surface. There are various types of landmines M, including those with explosives placed inside a metal container, those with explosives placed inside a plastic or other resin container, and those with a plastic or other resin container at the bottom and an iron-containing metal upper section. Anti-personnel landmines M have diameters ranging from 5 to 20 cm, while anti-tank landmines can be as large as a manhole cover. It is important to safely search for, detect, and dispose of landmines M to minimize human casualties. This technology can detect mines M that use iron-containing metal on their outer surface, such as mines in which explosives are placed in an iron-containing metal container, or mines in which most of the bottom is made of a resin container such as plastic, but part of the top is made of iron-containing metal parts or iron-containing metal containers. This technology can detect mines M that use iron-containing metal on their outer surface, regardless of the size of the mine M.

[0012] As shown in Figures 1 and 5, the first drone device 2 includes a first drone 6, a first tank 8 provided on the first drone 6, a first spraying device 10 that sprays an acidic first solution 52 that dissolves iron on the surface of the mine, a first drone camera 11, a first drone altitude measuring device 12, a first drone GPS device 14, a first drone communication unit 15, and a first drone control unit 16.

[0013] The first drone 6 is an unmanned aerial vehicle, such as a multicopter drone, but may be another type of unmanned aerial vehicle. The first drone 6 comprises a main body 6a and six arms extending from the main body 6a. Each arm has a rotor 6b and blades (rotating wings) 6c for rotating the blades. By controlling the rotation speed of each blade 6c, the first drone 6 can move forward and backward, left and right, and up and down. The first drone 6 is configured to generate lift sufficient to fly the first tank 8. In this embodiment, the first drone 6 comprises six arms and one blade attached to each arm (a total of six blades), but other numbers of arms and blades attached to each arm may be used. The first drone 6 can fly to a predetermined location, altitude, and course, and can also take off and land automatically according to a predetermined program, controlled by a control unit 60 (described later). Therefore, the first drone 6 can search for mines M along a predetermined course F from a starting point A (see FIG. 10) and return to a return point, for example, the same point as the starting point. The first drone device 2 may be equipped with a manual operation unit 70, and all or part of the control may be manually operated by the manual operation unit. The first drone 6 may also be changed to another type of flying object that can fly anywhere, for example, an unmanned aerial vehicle (UAV) such as a helicopter.

[0014] The first tank 8 is a tank that can store liquid. The first tank 8 is formed in a generally rectangular shape when viewed from above. The first tank 8 is attached to the lower part of the aircraft body 6a so that the center of gravity of the first tank 8 generally coincides with the center of gravity of the first drone 6 when viewed from above. The first tank 8 forms a box-shaped container. The first tank 8 is made of resin or the like. The first tank 8 has an inlet portion 8a for pouring liquid therein and a supply portion 8b that can supply the liquid to the first spraying device 10. The user can additionally replenish the liquid through the inlet portion 8a. The supply portion 8b and the first spraying device 10 are fluidly connected via a supply pipe.

[0015] The liquid in the first tank 8 is the first solution 52. The first solution 52 is an acidic solution, such as a dilute sulfuric acid solution. The dilute sulfuric acid has a pH value, for example, in the range of 5.5 to 6. The concentration of the dilute sulfuric acid is, for example, in the range of 0.1% to 0.3%. The dilute sulfuric acid is an acidic solution, and when it adheres to the iron-containing metal on the outer surface of the landmine M, it can dissolve the iron from the metal surface. For example, the reaction between the dilute sulfuric acid and iron produces FeSO4, which generates iron ions. The first solution 52 is an acidic solution, such as a solution of dilute sulfuric acid or acetic acid. For example, the reaction between acetic acid and iron produces Fe(CH3COO)2, which generates iron ions. By using the dilute sulfuric acid or acetic acid solution as the first solution 52, landmines can be chemically detected while reducing the impact on future land use. The first solution 52 can be changed to any acidic solution that can dissolve iron.

[0016] As shown in FIG. 1, the first spraying device 10 sprays a first solution 52, which is a liquid in a first tank 8. More specifically, the first spraying device 10 sprays an acidic solution, such as dilute sulfuric acid or acetic acid. The first spraying device 10 is provided at the bottom of the first tank 8 and is configured to spray a liquid downward. The first spraying device 10 includes an electromagnetic valve that opens and closes an internal flow path. The first spraying device 10 can start or stop spraying the first solution 52 from the first spraying device 10 at any timing. The first spraying device 10 has a spraying section 10a at its bottom, which resembles the spout of a watering can pointing downward. The spraying section 10a has a spherical surface and a curved portion that protrudes downward. The spraying section 10a has multiple holes of a predetermined diameter. For example, multiple holes facing downward are formed in the lower end surface of the spraying section 10a. The diameter of the holes in the first spraying device 10 is within a range of 1 mm to 1.5 mm. The spraying unit 10a is configured to spray the acidic solution toward a predetermined area J, for example, a quadrilateral area with four sides measuring 10 cm to 30 cm directly below the first drone 6. For example, FIG. 10 illustrates a predetermined area J as a square with four sides measuring 20 cm. The predetermined area J is illustrated as an area where the main flow of the first solution sprayed from the spraying unit 10a reaches. The spraying unit 10a, which has a large number of holes of a predetermined diameter, allows the first solution 52 to be sprayed in a manner that makes it easy for the solution to adhere to the mines M, thereby increasing the likelihood of eluting iron ions 80.

[0017] By arranging predetermined areas onto which liquid is sprayed by the spraying unit 10a, it becomes possible to search in a search area such as that shown in FIG. 10. Furthermore, for example, by arranging predetermined areas in a continuous line, it becomes possible to search for mines M in a strip-shaped area along course F (see FIG. 10). The first spraying device 10 can be configured to spray fine water droplets and also to form a relatively soft water flow, like water from the spout of a watering can. The solution sprayed from the spraying unit 10a forms a relatively gentle water flow (a water droplet string containing many water droplets). The spraying unit 10a of the first spraying device 10 is directed vertically downward.

[0018] As shown in FIG. 5, the first drone camera 11 is mounted on the main body 6a of the first drone 6, allowing the first drone 6 to capture and view the surroundings. The first drone camera 11 has the ability to capture video and photographs. The first drone camera 11 allows a user to remotely check the surroundings of the first drone camera 11 and also capture and record the ground conditions at the search point (detection point). The first drone camera 11 is also mounted so that it can capture the conditions directly below the first drone 6 in order to confirm the conditions vertically below where the first solution 52 is sprayed. When the first drone device 2 functions as the third drone device 40, the first drone camera 11 functions as the third drone camera 44.

[0019] The first drone altitude measurement device 12 is provided on the airframe main body 6a and can measure the altitude H (distance) of the first drone 6 relative to the ground G, where there may be buried mines M. The first drone altitude measurement device 12 uses, for example, an ultrasonic altimeter that can measure the height to the ground G. The first drone altitude measurement device 12 may be configured with any one of a barometric pressure measurement sensor that can measure flight altitude by measuring air pressure, an ultrasonic sonar that can measure the distance from the first drone 6 to the ground G, a laser measurement sensor that can measure the distance from the first drone 6 to the ground G, a LIDAR sensor that can measure the distance from the first drone 6 to the ground G, or any combination of these. This allows the first drone altitude measurement device 12 to measure the altitude H (distance) from the first drone 6 to the ground G. For example, the first drone altitude measurement device 12 can measure the altitude (distance) H from the first drone 6 to the ground G within a predetermined distance range of 10 cm to 2 m, more preferably an altitude H within a range of 30 cm to 1 m, and more preferably an altitude H within a range of 30 cm to 50 cm, and can fly the first drone 6 at the predetermined altitude H. The first altitude range H1 in which the first drone 6 is flown can be, for example, an altitude range from the first drone 6 to the ground G within a predetermined distance range of 10 cm to 2 m, more preferably an altitude range of 30 cm to 1 m, and more preferably an altitude range of 30 cm to 50 cm.

[0020] The first drone GPS device 14 is capable of using satellites to identify the current location of the first drone 6. The first drone GPS device 14 can acquire location information (e.g., information such as latitude and longitude) of the location where the first spraying device 10 sprayed the first solution 52. Furthermore, the first drone GPS device 14 can recognize the location of the first drone 6 and provide the location information necessary for predetermined flight control of the first drone 6.

[0021] The first drone communication unit 15 can wirelessly communicate data from the first drone device 2 with the control unit 60. For example, the first drone communication unit 15 can transmit information such as the position (coordinates, altitude) of the first drone 6 and the position where the first solution 52 was sprayed by the first spraying device 10 to the control unit 60. In addition, the first drone communication unit 15 can mutually share control information with the control unit 60.

[0022] The first drone device 2 may be equipped with a manual operation unit 70, a monitor 72 for the operation unit 70, etc. as necessary.

[0023] The first drone control unit 16 has a built-in CPU 17 and a storage device 19 such as memory, and controls connected devices to execute predetermined controls based on predetermined control programs stored in the memory, etc. The first drone control unit 16 is electrically connected to the first drone 6, first tank 8, first spraying device 10, first drone camera 11, first drone altitude measuring device 12, first drone GPS device 14, first drone communication unit 15, control unit 60, etc. These electrical connections may be made via wireless communication, etc.

[0024] The first drone control unit 16 can execute flight control of the first drone 6. The first drone control unit 16 is configured to perform predetermined functions in cooperation with the control unit 60. The first drone control unit 16, together with the control unit, controls the first drone device 2 and the flight of the first drone 6. More specifically, the first drone control unit 16 can control the position (coordinates, altitude) at which the first spraying device 10 sprays the first solution 52, attitude control, rotation suppression control in the yawing direction, movement between spraying points, etc. In this way, the first drone control unit 16 can control the flight altitude, flight route, rotation speed of each blade, attitude (including left and right roll and rotational yawing), and operation control of the first spraying device 10 as necessary. The first drone control unit 16 can control the first drone 6 to reach a predetermined altitude above the target point (search point) and the first spraying device 10 to spray the first solution 52 toward the ground G. The first drone-side control unit 16 may be provided integrally with the control unit 60. For example, all or part of the functions of the first drone-side control unit 16 may be provided on the control unit 60 side. All or part of the functions of the first drone-side control unit 16 may be provided in an information terminal device or the like on the operation unit 70 side.

[0025] As shown in Figures 2 and 6, the second drone device 4 includes a second drone 20, a second tank 21 provided on the second drone 20, a second spraying device 22, a second drone side camera 24, a second drone side altitude measurement device 25, a second drone side GPS device 26, a second drone side communication unit 27, and a second drone side control unit 28.

[0026] The second drone 20 is an unmanned aerial vehicle, such as a multicopter drone, but may be another type of unmanned aerial vehicle. The second drone 20 includes a main body 20a and six arms extending from the main body 20a. Each arm has a rotor 20b and blades (rotating wings) 20c for rotating the blades. By controlling the rotation speed of each blade 20c, the second drone 20 can move forward and backward, left and right, and up and down. The second drone 20 is configured to generate lift sufficient to fly with the second tank 21 on board. In this embodiment, the second drone 20 includes six arms and one blade attached to each arm (a total of six blades), but the number of arms and the number of blades attached to each arm may be changed. The second drone 20 can fly to a predetermined location, at a predetermined altitude, and along a predetermined course, and can also take off and land fully automatically according to a predetermined program, controlled by a control unit 60 (described later). Therefore, the second drone 20 can search for mines M along a predetermined course F from a starting point A (see FIG. 10) and return to a return point, for example, the same point as the starting point. The second drone 20 may be equipped with a manual operation unit (not shown), and all or part of the control may be manually operated by the manual operation unit. The second drone 20 may also be changed to another type of flying object that can fly anywhere, for example, an unmanned aerial vehicle (UAV) such as a helicopter.

[0027] The second tank 21 is a tank that can store liquid. The second tank 21 is formed in a generally rectangular shape when viewed from above. The second tank 21 is attached to the lower part of the aircraft body 6a so that the center of gravity of the second tank 21 generally coincides with the center of gravity of the second drone 20 when viewed from above. The second tank 21 forms a box-shaped container. The second tank 21 is made of resin or the like. The second tank 21 has an inlet portion 21a for pouring liquid therein and a supply portion 21b that can supply the liquid to the second spraying device 22. The user can additionally replenish the liquid from the inlet portion 21a. The supply portion 21b and the second spraying device 22 are fluidly connected via a supply pipe.

[0028] The liquid in the second tank 21 is a second solution 54, for example, a solution that acts as a chemical marker that reacts with iron ions, such as a tannic acid solution. The chemical formula of the tannic acid solution is C 76 H 52 O 46 The second tannic acid solution 54 undergoes a visible color change due to a chemical reaction with the iron ions. The unreacted tannic acid solution is, for example, a light yellow-brown color. The tannic acid solution reacts with the iron ions 80 (see FIG. 1 ) to produce a discolored substance 82, for example, a blue-black color. The discolored substance 82 is, for example, a black substance and may be referred to as iron tannin. The second tannic acid solution 54 can function as a marker that produces a visible change in response to the iron ions 80 eluted by the acidic solution. The second solution 54 can be replaced with another solution that functions as a chemical marker that reacts with the iron ions 80 and indicates the presence of the iron ions 80 by a change in color or state, for example, a visible change.

[0029] As shown in FIG. 2, the second spraying device 22 sprays the second solution 54, which is a liquid in the second tank 21. The second spraying device 22 is provided at the bottom of the second tank 21 and is configured to spray the second solution 54 downward. The second spraying device 22 is provided at the bottom of the second tank 21 and is configured to spray the second solution 54 downward. The second spraying device 22 is equipped with an electromagnetic valve that opens and closes an internal flow path. The second spraying device 22 can start or stop spraying the second solution 54 from the second spraying device 22 at any timing. The second spraying device 22 forms a spraying portion 22a on its lower end surface, which resembles the spout of a downward-facing watering can. The spraying portion 22a forms a spherical surface and a curved portion that protrudes downward. The second sprinkling device 22 can form many fine water droplets, and can also form a relatively soft water stream (a string of water droplets containing many water droplets) like water spouting from the spout of a watering can.

[0030] The second spraying device 22 sprays a tannic acid solution that functions as a chemical marker. More specifically, the second spraying device 22 sprays a solution that functions as a chemical marker by reacting with iron ions 80 and indicating the presence of iron ions 80 through a change in color or state. For example, the second spraying device 22 sprays a tannic acid solution from the spraying unit 22a toward the predetermined area J. For example, the spraying unit 22a is oriented vertically downward. By using the tannic acid solution as the second solution 54, landmines can be detected chemically while reducing the impact on future land use. The spraying unit 22a has multiple holes of a predetermined diameter formed therein. For example, multiple holes facing downward are formed on the lower end surface of the spraying unit 22a. The diameter of the holes in the spraying unit 22a is within a range of 1 mm to 1.5 mm. The spraying unit 22a is configured to spray the second solution 54 toward a predetermined area J, for example, a quadrilateral area with four sides measuring 10 cm to 30 cm directly below the first drone 6. For example, FIG. 10 illustrates a predetermined area J that is a square with four sides measuring 20 cm. The predetermined area J is also illustrated as an area reached by the main flow of the second solution 54 sprayed from the spraying unit 22a.

[0031] The second drone camera 24 is provided on the main body 20a of the second drone 20, and allows the surrounding situation to be photographed and confirmed visually from the second drone 20. The second drone camera 24 has the ability to take videos and photos. The second drone camera 24 allows the user to check the situation around the second drone camera 24 from a remote location, and also photograph and record the ground situation at the search point (detection point). The second drone camera 24 is provided so that it can also photograph the situation directly below the second drone 20, in order to confirm the situation vertically below where the acid solution is being sprayed.

[0032] The second drone altitude measurement device 25 is provided on the airframe main body 20a and can measure the altitude H (distance) of the second drone 20 relative to the ground G, where there may be buried mines M. The second drone altitude measurement device 25 uses, for example, an ultrasonic altimeter that can measure the height to the ground G. The second drone altitude measurement device 25 may be configured with any one of a barometric pressure measurement sensor that can measure the flight altitude by measuring the air pressure, an ultrasonic sonar that can measure the distance from the second drone 20 to the ground G, a laser measurement sensor that can measure the distance from the second drone 20 to the ground G, a LIDAR sensor that can measure the distance from the second drone 20 to the ground G, or any combination of these. This allows the second drone altitude measurement device 25 to measure the altitude H (distance) from the second drone 20 to the ground G. For example, the second drone altitude measurement device 25 can measure an altitude (distance) H (e.g., H0 described below) within a predetermined distance range of 10 cm to 2 m from the second drone 20 to the ground G, more preferably an altitude H within a range of 30 cm to 1 m, and more preferably an altitude H within a range of 30 cm to 50 cm, and can fly the second drone 20 at the predetermined altitude H. The first altitude range H1 in which the second drone 20 is flown can be, for example, an altitude range within a predetermined distance range of 10 cm to 2 m from the second drone 20 to the ground G, more preferably an altitude range of 30 cm to 1 m, and more preferably an altitude range of 30 cm to 50 cm.

[0033] The second drone's GPS device 26 is capable of using satellites to identify the current location of the second drone 20. The second drone's GPS device 26 can acquire location information (e.g., information such as latitude and longitude) of the location where the second spraying device 22 sprayed the solution. Furthermore, the second drone's GPS device 26 can recognize the location of the second drone 20 and provide the location information necessary for the specified flight control of the second drone 20.

[0034] The second drone communication unit 27 can wirelessly communicate data on the second drone device 4 side with the control unit 60. For example, the second drone communication unit 27 can transmit information such as the position (coordinates, altitude) of the second drone 20 and the position where the solution was sprayed by the second spraying device 22 to the control unit 60. In addition, the second drone communication unit 27 can mutually share control information with the control unit 60.

[0035] The second drone device 4 may be equipped with a manual operation unit 70, a monitor 72 provided on the manual operation unit 70, etc. as necessary.

[0036] The second drone control unit 28 has a built-in CPU 29 and a storage device 31 such as a memory, and controls connected devices to execute predetermined controls based on predetermined control programs stored in the memory, etc. The second drone control unit 28 is electrically connected to the second drone 20, second tank 21, second spraying device 22, second drone camera 24, second drone altitude measuring device 25, second drone GPS device 26, second drone communication unit 27, etc. These electrical connections may be made via wireless communication, etc.

[0037] The second drone-side control unit 28 can execute flight control of the second drone 20. The second drone-side control unit 28 is configured to perform predetermined functions in cooperation with the control unit 60. The second drone-side control unit 28, together with the control unit, controls the second drone device 4 and the flight of the second drone 20. More specifically, the second drone-side control unit 28 can control the position (coordinates, altitude) at which the second spraying device 22 sprays the solution, attitude control, rotation suppression control in the yawing direction, movement between detection points, etc. In this way, the second drone-side control unit 28 can control the flight altitude, flight route, rotation speed of each blade, attitude (including left and right roll and yawing in the rotational direction), and operation control of the second spraying device 22 as necessary. The second drone-side control unit 28 can control the second drone 20 to reach a predetermined altitude above the target point (search point) and the second spraying device 22 to spray the second solution 54 toward the ground G. The second drone-side control unit 28 may be provided integrally with the control unit 60. For example, all or part of the functions of the second drone-side control unit 28 may be provided on the control unit 60 side. All or part of the functions of the second drone-side control unit 28 may be provided in an information terminal device or the like on the operation unit 70 side.

[0038] As shown in Figures 3 and 7, the third drone device 40 includes a third drone 42, a third drone camera 44 provided on the third drone 42, a third drone altitude measuring device 45, a third drone GPS device 46, a third drone communication unit 47, a floodlight 55, and a third drone control unit 48.

[0039] The third drone 42 is an unmanned aerial vehicle, such as a multicopter drone, but may be another type of unmanned aerial vehicle. The third drone 42 includes a main body 42a and six arms extending from the main body 42a. Each arm has a rotor 42b and blades (rotating wings) 42c for rotating the blades. By controlling the rotation speed of each blade 42c, the third drone 42 can move forward and backward, left and right, and up and down. The third drone 42 is configured to generate lift sufficient to fly a third drone camera 44 mounted thereon. In this embodiment, the third drone 42 includes six arms and one blade attached to each arm (a total of six blades), but the number of arms and the number of blades attached to each arm may be changed. The third drone 42 can fly to a predetermined location, at a predetermined altitude, and along a predetermined course, and can also take off and land fully automatically according to a predetermined program, controlled by a control unit 60 (described later). Therefore, the third drone 42 can search for mines M by photographing the ground G from a starting point A (see FIG. 10) along a predetermined course F with the third drone's camera 44, and return to a return point, for example, the same point as the starting point. The third drone 42 may be equipped with a manual operation unit 70, and all or part of the control may be manually operated by the manual operation unit 70. The third drone 42 may also be changed to another type of flying object that can fly anywhere, for example, an unmanned aerial vehicle (UAV) such as a helicopter.

[0040] The third drone camera 44 captures images or videos of the reaction of the second solution 54 sprayed by the second spraying device 22 of the second drone device 4 to the iron ions 80. The third drone camera 44 has the ability to take videos and photos. The third drone camera 44 is mounted on the body 42a of the third drone 42, and can capture and view the surrounding situation from the third drone 42. The third drone camera 44 is mounted so that it can capture the situation directly below the third drone 42 in order to check the reaction situation of the ground G vertically below. The third drone camera 44 also allows the user to remotely check the surrounding situation and flight status of the third drone camera 44.

[0041] The third drone altitude measurement device 45 is provided on the airframe main body 42a and can measure the altitude H (distance) of the third drone 42 relative to the ground G, where mines M may be buried. The third drone altitude measurement device 45 uses, for example, an ultrasonic altimeter that can measure the height to the ground G. The third drone altitude measurement device 45 may be configured with any one of a barometric pressure measurement sensor that can measure the flight altitude by measuring the air pressure, an ultrasonic sonar that can measure the distance from the third drone 42 to the ground G, a laser measurement sensor that can measure the distance from the third drone 42 to the ground G, a LIDAR sensor that can measure the distance from the third drone 42 to the ground G, or any combination of these. This allows the third drone altitude measurement device 45 to measure the altitude H (distance) from the third drone 42 to the ground G. For example, the third drone altitude measurement device 45 can measure an altitude (distance) H (e.g., H0 described later) within a predetermined distance range of 10 cm to 2 m from the third drone 42 to the ground G, more preferably an altitude H within a range of 30 cm to 1 m, and more preferably an altitude H within a range of 30 cm to 50 cm, and can fly the third drone 42 at the predetermined altitude H. The first altitude band H1 in which the third drone 42 is flown can be, for example, an altitude band within a predetermined distance range of 10 cm to 2 m from the third drone 42 to the ground G, more preferably an altitude band within a range of 30 cm to 1 m, and more preferably an altitude band within a range of 30 cm to 50 cm.

[0042] The third drone's GPS device 46 is capable of using satellites to identify the current position of the third drone 42. The third drone's GPS device 46 can acquire position information (such as latitude and longitude information) of the location where the third drone's camera 44 took the image. Furthermore, the third drone's GPS device 46 can recognize the position of the third drone 42 and provide the position information necessary for predetermined flight control of the third drone 42.

[0043] The third drone communication unit 47 can wirelessly communicate data on the third drone device 40 side with the control unit 60. For example, the third drone communication unit 47 can transmit information such as the position (coordinates, altitude) of the third drone 42 and the position where the image was taken by the third drone camera 44 to the control unit 60. In addition, the third drone communication unit 47 can mutually share control information with the control unit 60.

[0044] The floodlight 55 increases the brightness of the ground imaged by the third drone camera 44. The floodlight 55 is, for example, an LED floodlight. The floodlight 55 can brightly illuminate the ground, making it easier for the third drone camera 44 to check the reaction status of the ground G when clouds appear and the surroundings become dark, when the brightness becomes low such as in the evening, or when it becomes dark at night. Furthermore, the efficiency of mine detection work can be improved without limiting work time to daytime or fine weather.

[0045] The third drone device 40 may be equipped with a manual operation unit 70, a monitor 72 provided on the operation unit 70, etc. as needed.

[0046] The third drone control unit 48 has a built-in CPU 49 and a storage device 51 such as memory, and controls connected devices to execute predetermined controls based on predetermined control programs recorded in the memory, etc. The third drone control unit 48 is electrically connected to the third drone 42, the third drone camera 44, the third drone altitude measuring device 45, the third drone GPS device 46, the third drone communication unit 47, etc. These electrical connections may be made via wireless communication, etc.

[0047] The third drone control unit 48 can execute flight control of the third drone 42. The third drone control unit 48 is configured to perform predetermined functions in cooperation with the control unit 60. The third drone control unit 48, together with the control unit, controls the third drone device 40 and the flight of the third drone 42. More specifically, the third drone control unit 48 can control the position (coordinates, altitude) at which the third drone camera 44 captures images, attitude control, rotation suppression control in the yawing direction, movement between detection points, and the like. In this way, the third drone control unit 48 can control the flight altitude, flight route, rotation speed of each blade, attitude (including left and right roll and yawing in the rotational direction), and operation control of the third drone camera 44 as necessary. The third drone control unit 48 can control the third drone 42 to reach a predetermined altitude above the target point (search point) and the second spraying device 22 to spray the solution toward the ground G. The third drone control unit 48 may be provided integrally with the control unit 60. For example, all or part of the functions of the third drone-side control unit 48 may be provided on the control unit 60 side. All or part of the functions of the third drone-side control unit 48 may be provided on an information terminal device or the like on the operation unit 70 side.

[0048] 1 to 4, the landmine detection system 1 further includes a control unit 60. The control unit 60 is configured to, for example, perform control such as capturing images or videos of the reaction of the second solution 54 sprayed by the second spraying device 22 with the iron ions 80 using the third drone camera 44. The control unit 60 controls, for example, the first drone device 2, the second drone device 4, and the third drone device 40. The control unit 60 is provided, for example, in a computer located away from the first drone device 2, the second drone device 4, the third drone device 40, etc.

[0049] The control unit 60 is electrically connected to the first drone device 2, the second drone device 4, the third drone device 40, etc. via the Internet 3. The control unit 60 may be provided in an electronic device that functions as a computer, such as a smartphone or tablet. The control unit 60 has a built-in CPU 63 and a storage device 65 such as a memory, and controls the connected devices based on a predetermined control program recorded in the memory. Thus, the control unit 60 functions as a computer. The electrical connection between the control unit 60 and other devices may be entirely or partially connected via wireless communication such as infrared communication or other methods. The control unit 60 has a predetermined program for executing a predetermined control function. The control unit 60 may also be composed of multiple devices. The storage device 65 of the control unit 60 stores a predetermined program, but it is not necessarily required to store all of the program. Some or all of the program may be stored separately in multiple devices, or may be stored on a server via the Internet. For example, the first drone control unit 16, the second drone control unit 28, or the third drone control unit 48 mounted on the first drone device 2, the second drone device 4, or the third drone device 40 may be configured to execute some or all of the control functions. The control unit 60 is equipped with an output device 71 such as a monitor and an input device 67 that can be operated, and can set various modes, etc.

[0050] The control unit 60, using each program stored in the memory device 65, has a first solution spraying mode 62 in which the first drone 6 of the first drone device 2 flies within the first altitude zone H1 and sprays the first solution 52 using the first spraying device 10; a second solution spraying mode 64 in which the second drone 20 of the second drone device 4 flies within the first altitude zone H1 and sprays the second solution 54 that functions as a chemical marker using the second spraying device 22; a photography mode 66 in which the third drone 42 of the third drone device 40 flies within the first altitude zone H1 and uses the third drone side camera 44 to take images or videos of the reaction of the second solution 54 sprayed by the second spraying device 22 to iron ions 80; and an analysis mode 68 in which the images and videos of the ground G acquired in the photography mode 66 are analyzed for the presence of areas where the second solution is thought to have turned bluish-black, and the location of the landmine is estimated. The control unit 60 also has a course setting mode 69 for setting a predetermined course F for searching for mines by the first drone device 2, the second drone device 4, and the third drone device 40. In the course setting mode 69, only the predetermined course F may be set, or landmarks such as search points D1 to D16 may be set together with the course F.

[0051] Next, as shown in FIG. 9, a series of operations for detecting a land mine M by the land mine detection system 1 will be described. As shown in FIG. 9, in preparation step S1 of the mine detection system 1, the first drone 2, second drone 4, third drone 40, control unit 60, and other components of the mine detection system 1 are prepared. The first drone 2, second drone 4, and third drone 40 are located at starting point A (see FIG. 10). A first acidic solution 52, such as a dilute sulfuric acid solution, is stored in the first tank 8. The first spraying device 10 is also prepared for use. The control unit 60 prepares or acquires flight data for the first drone 2, second drone 4, and third drone 40 (e.g., coordinates of the search point (see FIG. 10), flight route, flight altitude data (detected altitude data) relative to the ground G at the search point coordinates, etc.). When step S1 is completed, the control unit 60 proceeds to S2.

[0052] In step S2, the control unit 60 executes the first solution spraying mode 62, flies the first drone 6 of the first drone device 2 within the first altitude zone H1, and sprays the first solution 52 using the first spraying device 10. The acidic solution sprayed by the first spraying device 10 dissolves the iron on the surface of the mine, and some of the iron ions are transported to the ground surface near the top of the mine M by capillary action, water diffusion, etc.

[0053] The control unit 60 flies the first drone device 2 from the starting point A to above the search point D1 in the search area D. The search area D is an example provisionally set area in which to search for mines M. The search point D1 is a point that serves as a landmark for executing the mine detection process. Information on the search point D1 is provided to the control unit 60, for example, as coordinate information. The control unit 60 stops the spraying operation by the first spraying device 10 while the first drone device 2 is moving from the starting point A to the search area D. When the first drone device 2 arrives above the search point D1, the control unit 60 executes the first solution spraying mode 62 and causes the first spraying device 10 to spray the first solution 52.

[0054] The control unit 60 can automatically fly the first drone 6 of the first drone device 2 along a predetermined course, such as the course indicated by arrow F, using a predetermined program. The control unit 60, using a course setting mode 69, causes the first drone 6 to fly along the predetermined course F and continuously spray the first solution using the first spraying device 10 during flight. For example, the first drone device 2 continuously sprays the first solution 52 from search point D1 along the predetermined course F to search point D16. This allows the entire strip-shaped area along the predetermined course F to be used as a search area. In this case, search points D1 to D16 are defined as markers indicating the predetermined course F. The predetermined course F can be freely set to correspond to the area in which mines M are to be searched. As a modified example, the control unit 60 may cause the first drone device 2 to spray the first solution 52 at a plurality of predetermined points (for example, each point from search points D1 to D16) along the predetermined course F. In this case, spraying by the first spraying device 10 is stopped between points D1 and D2, D2 and D3, etc. As a further modified example, the control unit 60 may cause the first drone 6 to spray the first solution 52 intermittently, for example, at regularly spaced points, using the first spraying device 10 while flying along a predetermined course F. After setting the course F, spraying may be performed at regularly spaced points.

[0055] For example, while the first drone 6 is hovering in the air, the first spraying device 10 sprays the first solution 52 within a rectangular area with sides of 20 cm on the ground directly below it, for example, within a predetermined period of time until the first spraying device 10 moves to the next location. This allows the first solution 52 to be sprayed within a predetermined area while the first spraying device 10 passes overhead. Therefore, a predetermined amount is sprayed that efficiently wets the mines M, making it easier for the first solution 52 to adhere to mines M that use a metal containing iron on their outer surfaces, and facilitating the elution of iron.

[0056] When the first solution 52 adheres to the mine M, which uses a metal containing iron on the outer surface, iron is eluted. For example, iron is eluted according to the following chemical formula. 1, some of the eluted iron ions are moved to the surface of the ground G by capillary action, water diffusion, etc. When step S2 ends, the control unit 60 proceeds to S3.

[0057] The control unit 60 executes step S3 after 2 to 12 hours have elapsed since the first solution 52 was sprayed in step S2, thereby allowing time for the elution of iron and the movement of iron ions, thereby improving detection accuracy. In step S3, the control unit 60 sprays the second solution 54, which functions as a chemical marker, in a second solution spraying step. The second solution 54 reacts with the iron ions eluted by the first solution 52 and functions as a chemical marker that clearly indicates the location of the iron ions.

[0058] When the control unit 60 starts S3, it causes the second drone device 4 to fly from the starting point A to above the search point D1 in the search area D. The search area D is an example provisionally set area in which to search for mines M. The control unit 60 stops the spraying operation by the second spraying device 22 while the second drone device 4 is moving from the starting point A to the search area D. When the second drone device 4 arrives above the search point D1, the control unit 60 executes the second solution spraying mode 64 and causes the second spraying device 22 to spray the second solution 54.

[0059] The control unit 60 can automatically fly the second drone 20 of the second drone device 4 along a predetermined course, such as the course indicated by arrow F, using a predetermined program. The control unit 60 uses a course setting mode 69 to fly the second drone 20 along the predetermined course F and continuously spray the second solution 54 using the second spraying device 22 during flight. For example, the second drone device 4 continuously sprays the second solution 54 from search point D1 along the predetermined course F to search point D16. This allows the entire strip-shaped area along the predetermined course F to be used as a search area. In this case, search points D1 to D16 are defined as markers indicating the predetermined course F. The control unit 60 may cause the second drone device 4 to spray the second solution 54 at a plurality of predetermined points (for example, each point from search points D1 to D16) along the predetermined course F. In this case, spraying by the first spraying device 10 is stopped between points D1 and D2, D2 and D3, etc. The control unit 60 may cause the second drone 20 to spray the second solution 54 intermittently, for example, at regular intervals, using the second spraying device 22 while flying the second drone 20 along a predetermined course F. After setting the course F, spraying may be performed at regular intervals.

[0060] The control unit 60 executes the second solution spraying mode 64, flying the second drone 20 of the second drone device 4 within the first altitude zone H1 and spraying the second solution 54 using the second spraying device 22. When the second solution 54 sprayed by the second spraying device 22 reacts with iron ions 80 present on the ground surface near the target landmine M, the second solution 54 turns bluish-black. In FIGS. 2 and 3, the bluish-black discoloring substance 82 is indicated by a black circle. Also, in FIG. 11, where an underground mine M (the mine M is indicated by a dashed line in FIG. 11) is located, the bluish-black discoloring substance 82 appears on the ground G, and can be recognized in an image captured by the third drone camera 44. In FIG. 11, the third drone camera 44 captures an aerial image of the ground G. In FIG. 11, two mines M are located close to each other on the same ground G, and a circular area of ​​the discoloring substance 82 is displayed for each mine. Because the mines M are underground, they are difficult to see with the naked eye, and the screen displays the ground G and a circular area of ​​a bluish-black discoloring substance 82 that has emerged above the ground G. The lower part of Figure 11 also illustrates how the bluish-black discoloring substance 82 appears on the ground G even for relatively small mines M that are underground, and can be recognized in the image by the third drone's camera 44. At this time, outside the area where the bluish-black discoloring substance 82 has appeared, there are areas where the second solution 54 has been sprayed on the ground, but no reaction with the iron ions 80 occurs, and the ground G maintains its original color.

[0061] The control unit 60 can automatically fly the second drone 20 of the second drone device 4 along a predetermined course, such as the course indicated by arrow F, using a predetermined program. The control unit 60 uses a course setting mode 69 to fly the second drone 20 along the predetermined course F and continuously spray the second solution using the second spraying device 22 during flight. The control unit 60 may also cause the second drone device 4 to spray the second solution 54 at multiple points along the predetermined course F. The control unit 60 may also cause the second spraying device 22 to spray the second solution 54 intermittently, for example, at regular intervals, while the second drone 20 is flying along the predetermined course F. When the sprayed second solution reacts with iron ions, the second solution 54 changes into a bluish-black discoloration substance 82. After step S3 is completed, the control unit 60 proceeds to step S4.

[0062] The control unit 60 executes step S4 after a time period between 0.5 and 1 hour has elapsed since the second solution was sprayed in step S3. In step S4, the control unit 60 executes the observation step, thereby observing the reaction of the second solution 54 sprayed in the second solution spraying step with the third drone-side camera 44, which is an observation device.

[0063] In the observation step, the control unit 60 switches the camera 44 to the photography mode, flies the third drone 42 within the first altitude range H1, and captures images or videos of the reaction of the second solution 54 sprayed by the second spraying device 22 with the iron ions 80. For example, the third drone camera 44 can recognize, from the RGB camera image, the presence of a color-changing substance 82 on the ground G, which has turned blue-black as a result of the second solution 54 reacting with the iron ions. For example, a circular area on the ground G with a diameter ranging from 10 cm to 20 cm appears to be colored blue-black by the color-changing substance 82, making it easily distinguishable from the surrounding area. In this way, the control unit 60 can observe the reacted portion of the second solution 54 (the visible portion of the color-changing substance 82). FIG. 11 illustrates an example in which a bluish-black discoloring substance 82 appears on the ground G at locations where underground mines M (mines M are indicated by dashed lines in FIG. 11 ) are present, and can be recognized in an image by the third drone camera 44. The lower part of FIG. 11 also illustrates an example in which a bluish-black discoloring substance 82 appears on the ground G at locations where relatively small underground mines M are present, and can be recognized in an image by the third drone camera 44. At this time, outside the area where the bluish-black discoloring substance 82 appears, there are areas where the second solution 54 has been sprayed on the ground, but no reaction with the iron ions 80 occurs, and the ground G maintains its original color. For example, the bluish-black discoloring substance 82 may appear for multiple mines M in a single image, and this may be recognized as a color change.

[0064] When the control unit 60 starts S4, it causes the third drone device 40 to fly from the starting point A to above search point D1 in search area D. Search area D is an example provisionally set area in which to search for mines M. The control unit 60 stops the third drone device 40 from capturing images and videos of the ground G using the third drone camera 44 while the third drone device 40 is moving from the starting point A to the search area D. When the third drone device 40 arrives above search point D1, the control unit 60 executes the photography mode 66 and causes the third drone device camera 44 to start capturing images and videos of the ground G.

[0065] The control unit 60 can automatically fly the third drone 42 of the third drone device 40 along a predetermined course, such as the course indicated by arrow F, using a predetermined program. The control unit 60 can use a course setting mode 69 to fly the third drone 42 along the predetermined course F and continuously capture images and videos of the ground G using the third drone camera 44 during flight. For example, the third drone device 40 continuously captures images using the third drone camera 44 from search point D1 along the predetermined course F to search point D16. This allows the entire strip of land along the predetermined course F to be used as a search area. In this case, search points D1 to D16 are defined as landmarks indicating the predetermined course F. In this way, the control unit 60 can automatically search for mines M at multiple points along the predetermined course F. By searching through search points D1 to D16 along the predetermined course F, screening for the presence of mines within the search area D can be performed, improving the accuracy of the screening.

[0066] For example, the distance K between search point D1 and search point D2 is set to a value ranging from approximately 15 cm to approximately 100 cm, from approximately 15 cm to approximately 50 cm, or approximately 30 cm. The distance K may be set to approximately two or three times the outer width of the mine M to be searched. For example, if the outer width (diameter) of the mine M is approximately 10 cm, the distance K may be set to 20 cm. The distance between search points D1 and D8 (similarly, the distance between search points D2 and D7) is also set to the distance K. Note that the distance between search points D1 and D8 may be set to a value different from the distance K. The search area D to be searched at such distances is, for example, a 5 m square area, a 3 m square area, or the like. The search area D can also be applied to an area with a side length ranging from 1 m to 20 m. The search area D is a virtual area, and its shape and size can be set by setting a course, etc.

[0067] As a modified example, the control unit 60 may cause the third drone camera 44 of the third drone device 40 to capture images and videos of the ground G at a plurality of predetermined points (for example, each point from search points D1 to D16) along the predetermined course F. In this case, the capture by the third drone camera 44 is stopped between points D1 and D2, D2 and D3, etc. As a further modification, the control unit 60 may cause the third drone 42 to intermittently photograph the third drone's camera 44, for example, at regular intervals, while flying the third drone 42 along a predetermined course F. After setting the course F, spraying may be performed at regular intervals, separate from the settings D1 to D16.

[0068] On the ground surface in the portion where the second solution 54 reacts with the iron ions 80, an area appears in which the second solution 54 has changed into a bluish-black discoloration substance 82. The color and appearance of the discoloration substance 82 may vary depending on the environment. When step S4 is completed, the control unit 60 proceeds to S5.

[0069] In step S5, the control unit 60 may include an analysis step in which, using the analysis mode 68, the control unit 60 analyzes the images and videos of the ground G acquired in the observation step S4 for the presence of an area where the second solution 54 is thought to have changed into the bluish-black discoloration substance 82, and estimates the location of the landmine. In this case, the control unit 60 can automatically analyze the images and videos acquired in step S4 for the presence of an area where the second solution 54 is thought to have changed into the bluish-black discoloration substance 82. The control unit 60 has a function to output the analysis results to a monitor. The control unit 60 also has a function to estimate the location of the landmine M based on the change in color of the second solution 54. The control unit 60 has a notification function, such as a function to display the area where the landmine M is thought to be located by surrounding it on the monitor. Note that the control unit 60 is not limited to analyzing the image or the like resulting from step S4, and the user or the like may determine the presence of an area where the second solution 54 appears to have changed into the bluish-black discoloration substance 82 while looking at a monitor or the like. When step S5 is completed, the control unit 60 proceeds to END.

[0070] Examples of an embodiment of the present invention may be provided in each aspect as described below.

[0071] (1) A mine detection system for detecting landmines that use a metal containing iron on their outer surface, comprising: a first drone apparatus comprising a first drone, a first tank provided on the first drone, and a first sprayer that sprays an acidic first solution that dissolves the iron on the outer surface of the landmine; a second drone apparatus comprising a second drone, a second tank provided on the second drone, and a second sprayer that sprays a second solution that functions as a chemical marker that reacts with the iron ions dissolved by the first solution sprayed by the first sprayer of the first drone apparatus; and a third drone apparatus comprising a third drone and a camera that captures images or videos of the reaction between the second solution sprayed by the second sprayer and the iron ions dissolved by the first solution.

[0072] (2) The landmine detection system according to (1), wherein the first solution is a solution of dilute sulfuric acid or acetic acid.

[0073] (3) The landmine detection system according to (1), wherein the second solution is a tannic acid solution.

[0074] (4) The landmine detection system described in (1), wherein the first spraying device has a spraying section having a large number of holes of a predetermined diameter formed therein, and the spraying section sprays the first solution over a predetermined area.

[0075] (5) The mine detection system described in (1), wherein the second drone of the second drone device is configured by a drone common to the first drone of the first drone device, and the second drone device is configured by replacing the first solution in the first tank of the first drone device with the second solution after the first drone device has finished spraying the first solution.

[0076] (6) The second drone of the second drone device and the third drone of the third drone device are configured as a single drone in common with the first drone of the first drone device, and the second drone device is configured by changing the first solution in the first tank of the first drone device to the second solution after the first drone device has finished spraying the first solution.

[0077] (7) The third drone device is equipped with a spotlight that increases the brightness of the ground photographed by the camera.

[0078] (8) The mine detection system described in (1) further includes a control unit that controls the first drone device, the second drone device, and the third drone device, and the control unit has a first solution spraying mode in which the first spraying device of the first drone device sprays the first solution, a second solution spraying mode in which the second spraying device of the second drone device sprays the second solution, and a photographing mode in which the camera of the third drone device captures images or videos of the reaction of the second solution with iron ions.

[0079] (9) A mine detection system as described in (8), wherein the control unit has an analysis mode that analyzes images or video captured in the shooting mode to estimate the location of the mine.

[0080] (10) A mine detection method for detecting landmines, comprising: a first solution spraying step in which a drone's spraying device sprays an acidic first solution that dissolves iron on the surface of the landmine; a second solution spraying step in which the drone's spraying device sprays a second solution that functions as a chemical marker that reacts with the iron ions eluted by the first solution sprayed in the first solution spraying step; and a photographing step in which a camera captures an image or video of the reaction between the second solution sprayed in the second solution spraying step and the iron ions eluted by the first solution.

[0081] The embodiments for carrying out the present invention are not limited to the above, and other modifications may be applied. Various alternative embodiments and examples will be apparent to those skilled in the art based on the disclosed technology. As a modified example, the second drone 20 of the second drone device 4 may be configured by a drone common to the first drone 6 of the first drone device 2. In this case, the second drone device 4 can be configured by changing the first solution 52 in the first tank 8 of the first drone device 2 to the second solution 54 after the first drone device 2 has finished spraying the first solution 52. This allows the first drone device 2 and the second drone device 4 to share a drone body, making it easier to configure the system.

[0082] As another variation, the second drone 20 of the second drone device 4 and the third drone 42 of the third drone device 40 may be configured as a single drone shared with the first drone 6 of the first drone device 2. The second drone device 4 may be configured by replacing the first solution 52 in the first tank 8 of the first drone device 2 with the second solution 54 after the first drone device 2 has finished spraying the first solution 52. This allows the first drone device 2, the second drone device 4, and the third drone device 40 to share the same drone body, making it easier to configure the system. [Explanation of symbols]

[0083] 1: Landmine detection system 2: First drone device 4: Second drone device 6: First drone 8: First Tank 10: 1st spraying device 10a: Spreading part 20: Second drone 21: Second Tank 22:Second spraying device 22a: Spreading part 40: Third drone device 42: Third drone 52: First solution 54: Second solution 60: Control section M:Landmine

Claims

1. A landmine detection system for detecting landmines using a metal containing iron on an outer surface, a first drone device including a first drone, a first tank provided on the first drone, and a first spraying device that sprays a first acidic solution that dissolves iron on the outer surface of a mine; a second drone device including a second drone, a second tank provided on the second drone, and a second spraying device that sprays a second solution that functions as a chemical marker that reacts with iron ions eluted by the first solution sprayed by the first spraying device of the first drone device; A landmine detection system comprising: a third drone device, the third drone device comprising a third drone; and a camera that captures images or videos of the reaction between the second solution sprayed by the second spraying device and the iron ions dissolved by the first solution.

2. 2. The mine detection system of claim 1, wherein the first solution is a solution of dilute sulfuric acid or acetic acid.

3. 2. The mine detection system of claim 1, wherein the second solution is a tannic acid solution.

4. 2. The landmine detection system according to claim 1, wherein the first spraying device includes a spraying section having a large number of holes each having a predetermined diameter formed therein, and the spraying section sprays the first solution over a predetermined area.

5. The second drone of the second drone device is configured by a drone common to the first drone of the first drone device, 2. The mine detection system of claim 1, wherein the second drone device is configured to change the first solution in the first tank of the first drone device to the second solution after the first drone device has finished spraying the first solution.

6. the second drone of the second drone device and the third drone of the third drone device are configured by a single drone common to the first drone of the first drone device, 2. The mine detection system of claim 1, wherein the second drone device is configured to change the first solution in the first tank of the first drone device to the second solution after the first drone device has finished spraying the first solution.

7. 2. The mine detection system of claim 1, wherein the third drone device is equipped with a floodlight that increases the brightness of the ground imaged by the camera.

8. Further, a control unit is provided that controls the first drone device, the second drone device, and the third drone device, The control unit has a first solution spraying mode in which the first spraying device of the first drone device sprays the first solution; a second solution spraying mode in which the second solution is sprayed by the second spraying device of the second drone device; 2. The mine detection system of claim 1, further comprising a photography mode in which the camera of the third drone device captures images or videos of the reaction between the second solution and iron ions.

9. 9. The landmine detection system according to claim 8, wherein the control unit has an analysis mode for analyzing the image or video captured in the imaging mode to estimate the location of the landmine.

10. A mine detection method for detecting a land mine, comprising: a first solution spraying step of spraying an acidic first solution that dissolves iron on the surface of the landmine by a first spraying device provided on a first drone of the first drone device; a second solution spraying step of spraying, by a second spraying device provided on a second drone of a second drone device, a second solution that functions as a chemical marker that reacts with iron ions eluted by the first solution sprayed in the first solution spraying step; A landmine detection method comprising a photographing step of photographing an image or video of the reaction between the second solution sprayed in the second solution spraying step and the iron ions dissolved by the first solution using a camera provided on a third drone of a third drone device.

Images