Gas leakage detector and gas leakage detection method

Abstract

To provide a gas leakage detector and a gas leakage detection method for accurately grasping an irradiation position of an infrared ray, when detecting gas leakage using infrared radiation.SOLUTION: A gas leakage detector comprises: a first irradiation part for irradiating an object portion in an inspection object with an infrared ray; a second irradiation part for irradiating the object portion with visible light for projecting a marker, so that a center position of the marker is irradiated with the infrared ray; and a calculation part for calculating a concentration of an object gas, at the object portion, according to the infrared ray radiated to the object portion.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a gas leak detection device and a gas leak detection method for detecting a target gas leak at a target portion of an inspection object by irradiating the target portion with infrared rays. [Background technology]

[0002] When measuring gas concentration using infrared rays, it is difficult to identify the infrared irradiation position because infrared rays are invisible, and even if a gas leak occurs and the gas concentration becomes an abnormal value, it is difficult to determine the leak location. In particular, when detecting gas leaks at high altitudes using a mobile object such as a UAV (Unmanned Aerial Vehicle), for the above reasons, it is difficult to determine the infrared irradiation position and find the gas leak location.

[0003] One possible solution to the above problem is to irradiate a visible guide light for the purpose of indicating the irradiation position of the infrared light that is the detection light (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-169202 Summary of the Invention [Problem to be solved by the invention]

[0005] According to the technology described in Patent Document 1, infrared light (infrared laser light) as detection light and guide light as visible light are irradiated with their optical axes parallel to each other. At this time, the guide light is irradiated near the irradiation position of the infrared light. However, with the technology described in Patent Document 1, the irradiation position of the guide light is shifted from the irradiation position of the infrared light, so it is difficult to accurately grasp the irradiation position of the infrared light just by looking at the irradiation position of the guide light.

[0006] The present invention has been made in consideration of the above circumstances, and aims to provide a gas leak detection device and a gas leak detection method for accurately determining the infrared radiation irradiation position when detecting a gas leak using infrared rays. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention has the following configurations [1] to

[10] . [1] A gas leak detection device comprising: a first irradiation unit that irradiates a target area in an inspection object with infrared rays; a second irradiation unit that irradiates the target area with visible light for projecting a marker so that the infrared rays are irradiated at the center position of the marker; and a calculation unit that calculates the concentration of a target gas in the target area using the infrared rays irradiated to the target area. [2] The gas leak detection device according to [1], comprising a moving body that moves to a position facing the object to be inspected while holding the first irradiation unit and the second irradiation unit. [3] The gas leak detection device according to [1] or [2], further comprising an imaging unit that captures an image of the target area with the marker projected thereon. In this case, if the gas leak detection device is equipped with a mobile body, it is more preferable that the imaging unit be mounted on the mobile body. [4] The gas leak detection device described in [3] further includes a memory unit that, when the concentration calculated for the target area is equal to or greater than a set value, captures an image using the imaging unit and stores the image in association with the concentration calculated for the target area. [5] A gas leak detection device as described in [4], which is provided with a position identification unit that identifies the position of the target area, and a memory unit that stores the image in association with the concentration calculated for the target area and the position of the target area identified by the position identification unit. [6] A gas leak detection device described in any one of [1] to [5], wherein the second irradiation unit has a direction change mechanism that changes the irradiation direction of visible light, and is equipped with a control unit that controls the direction change mechanism to change the irradiation direction so that infrared light is irradiated to the center position of the marker. [7] A gas leak detection device according to any one of [1] to [5], wherein the position of the second irradiating unit relative to the first irradiating unit is set to a position where infrared light is irradiated onto the center position of the marker. [8] A gas leak detection method comprising the steps of: irradiating a target area in an inspection object with infrared light from a first irradiation unit; irradiating the target area with visible light for projecting a marker from a second irradiation unit so that the infrared light is irradiated onto the center position of the marker; and calculating the concentration of a target gas in the target area using the infrared light irradiated onto the target area. [9] The gas leak detection method according to [8], further comprising the step of moving a moving body holding the first irradiation unit and the second irradiation unit to a position facing the object to be inspected.

[10] The gas leak detection method according to [8] or [9], comprising the steps of: taking an image of the target area with the marker projected thereon when the concentration calculated for the target area is equal to or greater than a set value; and storing the image in a storage unit in association with the concentration calculated for the target area. Here, if the gas leak detection method comprises the step of moving a mobile body holding the first irradiation unit and the second irradiation unit to a position facing the inspection target, it is more preferable that the image be taken by an imaging unit mounted on the mobile body. [Effects of the Invention]

[0008] According to the gas leak detection device and gas leak detection method of the present invention, when detecting a gas leak using infrared rays, it is possible to identify the infrared irradiation position and accurately determine the target area where the gas leak inspection is to be performed. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram showing an example of the appearance of a gas leak detection device according to an embodiment of the present invention; [Figure 2] 1 is a block diagram showing the configuration of a gas leakage detection device according to one embodiment of the present invention. [Figure 3] 1 is a front view of a main body of a gas leak detection device according to an embodiment of the present invention. [Figure 4] 1 is a side view of a main body of a gas leak detection device according to an embodiment of the present invention. [Figure 5] FIG. 10 is a diagram showing an example of a marker projected onto a target region. [Figure 6] FIG. 10 is a diagram showing another example of a marker projected onto a target region. [Figure 7] 10A and 10B are diagrams illustrating how the irradiation direction of visible light by the second irradiator is changed. [Figure 8] FIG. 3 is a diagram showing an image of a target region photographed by an imaging unit. [Figure 9] 1 is a diagram showing the flow of a gas leak detection method according to an embodiment of the present invention. [Figure 10] FIG. 4 is a diagram showing a gas leakage detection device according to a modified example of the present invention, and corresponds to FIG. 3. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, one embodiment of the present invention (hereinafter referred to as the present embodiment) will be described with reference to the drawings. In the drawings referred to below, the devices are shown somewhat simplified and schematic to make the explanation easier to understand. Furthermore, the dimensions of the devices and the spacing between the devices shown in the drawings may differ from the actual dimensions. Furthermore, in the following, when describing the position, posture, state, etc. of each device, unless otherwise specified, the description will be of the position, posture, state, etc. when the device is in use. In addition, in this invention, the concept of "device" includes a single device that performs a specific function by itself, as well as a combination of multiple devices that are distributed and exist independently but work together (in cooperation) to perform a specific function. In addition, in this specification, the meanings of the terms "same," "identical," and "equal" may include a range of error generally accepted in the technical field to which the present invention belongs.

[0011] <<Configuration of the gas leak detection device according to this embodiment>> The gas leak detection device according to this embodiment (hereinafter, gas leak detection device 10) is a device used to conduct gas leak inspections. Gas leak inspections are performed on an inspection object To, such as a reservoir or structure that stores a target gas, a pipe or duct that forms a flow path for transporting the target gas, or a gas generating device that generates the target gas. Specifically, as shown in FIG. 1 , infrared rays I are irradiated onto each portion of the outer surface of the inspection object To (hereinafter, also referred to as the target portion Pa), and the concentration of the target gas along the irradiation light path of the infrared rays I is calculated based on the amount of infrared rays I reflected and absorbed by the target portion Pa. The presence or absence of a gas leak at the target portion Pa is determined from the calculated concentration. Known methods and procedures can be used to calculate the gas concentration using infrared rays I. The wavelength of the infrared ray I may be set to a wavelength suitable for calculating the gas concentration depending on the type of target gas.

[0012] 1, the gas leak detection device 10 is mounted on an unmanned aerial vehicle 100 such as a drone, flies to the vicinity of the inspection target, and performs a gas leak inspection while flying. Therefore, by using the gas leak detection device 10, it is possible to perform a gas leak inspection on an inspection target that is located in a place that is difficult for people to approach, such as a high place or a dangerous area. Furthermore, because the gas leak detection device 10 is mounted on the unmanned aerial vehicle 100 and is movable, it is possible to inspect the inspection target To over a wider area than with a fixed device.

[0013] As shown in FIG. 2, the gas leak detection device 10 includes a first irradiation unit 11, a light receiving unit 12, a second irradiation unit 13, a drive unit 14, an angle measurement unit 15, a distance measurement unit 16, a position information acquisition unit 17, an image capture unit 18, a control unit 19, and a memory unit 22. As described above, the gas leak detection device 10 also includes an unmanned aerial vehicle 100 (see FIG. 1). The unmanned aerial vehicle 100 is configured, for example, as a known multicopter, and is remotely operable by a remote controller (not shown). During a gas leak inspection, the unmanned aerial vehicle 100 flies and moves to a position facing the inspection target To. Here, the unmanned aerial vehicle 100 facing the inspection target To means that the unmanned aerial vehicle 100 is directly facing the inspection target To, which is located in front of the unmanned aerial vehicle 100. The configuration of the unmanned aerial vehicle 100 and its flight control mechanism (for example, a flight controller) are similar to known configurations and control mechanisms, and therefore will not be described here.

[0014] 3 and 4, a main body of the gas leak detection device 10 is provided at the bottom of the unmanned aerial vehicle 100. Specifically, a box-shaped casing 104 is supported at the bottom of the unmanned aerial vehicle 100 via a holder 102, and the casing 104 houses a first irradiator 11, a light-receiving unit 12, a second irradiator 13, an angle measuring unit 15, a distance measuring unit 16, a position information acquiring unit 17, an image capturing unit 18, a control unit 19, and a calculation unit 20. In other words, the unmanned aerial vehicle 100 flies while holding the above-mentioned components of the gas leak detection device 10 during a gas leak inspection. The casing 104 is attached to the gas leak detection device 10 in a manner that allows it to rotate around the pitch axis of the unmanned aerial vehicle 100. Here, the pitch axis refers to an axis extending in the left-right direction of the unmanned aerial vehicle 100 when viewed from the front.

[0015] The first irradiating unit 11 focuses the infrared rays I emitted from the light source using optical components, and irradiates the infrared rays I (strictly speaking, infrared laser light) onto a target area Pa in the inspection object To. The target area Pa is irradiated with the infrared rays I in a spot shape, for example, as shown in FIGS. 5 and 6. Hereinafter, the irradiated position on the target area Pa will also be referred to as the irradiation spot Sp, but this irradiation spot Sp cannot be recognized by the human eye because the infrared rays I are invisible.

[0016] The light receiving section 12 is configured with a photoelectric conversion element such as a photodiode and a drive detection circuit, receives infrared rays I reflected by the target site Pa, and outputs a signal (light receiving signal) according to the intensity of the received light.

[0017] The second irradiator 13 irradiates the target area Pa with visible light H for projecting a marker Mk, as shown in FIG. 1, simultaneously with the first irradiator 11 irradiating the infrared light I. The marker Mk is a pattern surrounding the infrared irradiation spot Sp, and is visible to a person when projected onto the target area Pa. The marker Mk may be circular as shown in FIG. 5, square as shown in FIG. 6, or a regular polygon other than a rectangle. The size of the marker Mk is not particularly limited. For example, if the irradiation spot Sp is a spot with a diameter of approximately 1 mm, a circular marker Mk with a diameter of approximately 1 cm may be projected. The marker Mk may be formed by a continuous line as shown in FIG. 5, or may be formed by an intermittent line (dashed line) as shown in FIG. 6. The wavelength of the visible light H forming the marker Mk is preferably set to a wavelength range with a relatively high luminosity factor, specifically, 490 nm to 550 nm, i.e., the wavelength range of green light.

[0018] In this embodiment, the second irradiator 13 also has a direction change mechanism 30 that changes the irradiation direction of the visible light H. The direction change mechanism 30 is configured with a movable galvanometer mirror, polygon mirror, or the like that forms a light irradiation surface, and changes the irradiation direction of the visible light H by changing the orientation of the light irradiation surface. This changes the projection position of the marker Mk on the inspection object To, and in this embodiment, it changes in the up-down direction (vertical direction). Then, by controlling the direction change mechanism 30 by the control unit 19, the second irradiator 13 irradiates the visible light H so that the infrared ray I from the first irradiator 11 is irradiated onto the center position of the marker Mk.

[0019] The configuration of the second irradiator 13 will be described in light of the positional relationship between the first irradiator 11 and the second irradiator 13. As shown in FIG. 7, the first irradiator 11 and the second irradiator 13 each irradiate light toward the target location Pa from an opening provided on the front surface of the casing 104. On the front surface of the casing 104, as shown in FIG. 3, the area through which the infrared light I emitted by the first irradiator 11 passes and the area through which the visible light H emitted by the second irradiator 13 passes are aligned in the vertical direction of the unmanned aerial vehicle 100 and are at the same position in the horizontal direction of the unmanned aerial vehicle 100. The function of the direction change mechanism 30 described above can change the irradiation direction of the visible light H in the rotational direction about the pitch axis of the unmanned aerial vehicle 100, as shown in FIG. 7. This allows the second irradiator 13 to irradiate the infrared light I onto the center position of the marker Mk, in other words, to irradiate the visible light H onto the target location Pa so that the irradiation spot Sp coincides with the center position of the marker Mk.

[0020] The drive unit 14 rotates the casing 104 in a rotational direction about the pitch axis (i.e., the direction indicated by the arrow in FIG. 4 ) and is configured with a known drive motor or actuator. The drive unit 14 rotates the casing 104 at a constant speed, moving it from one end position to the other end position within its rotation range. Accordingly, the position at which the first irradiator 11 irradiates infrared light, i.e., the irradiation spot Sp, changes in the vertical direction of the unmanned aerial vehicle 100. In other words, as the drive unit 14 rotates the casing 104, infrared light for gas leak detection is scanned in the vertical direction of the unmanned aerial vehicle 100. Furthermore, when the infrared light irradiation position (i.e., the irradiation spot Sp) is displaced by a certain amount, the target area Pa of the inspection object To changes. Here, the target area Pa corresponds to one area when the outer surface (inspection target surface) of the inspection object To is partitioned into a grid pattern, and each area has a predetermined height in the vertical direction and a predetermined width in the horizontal direction. Furthermore, as the casing 104 of the drive unit 14 rotates, the position where the second irradiator 13 irradiates the visible light H, i.e., the projection position of the marker Mk, also switches. At this time, the position of the marker Mk switches while maintaining the irradiation spot Sp aligned with the center position of the marker Mk.

[0021] The angle measurement unit 15 measures the angle of the casing 104 at each point in time during the gas leak inspection based on the drive amount of the drive unit 14, and is configured with a known rotation amount measurement device such as a rotary encoder. The angle of the casing 104 is the tilt angle of the casing 104, and more specifically, it is the amount of rotation, expressed in degrees, when the casing 104 is rotated from a reference position (for example, a horizontal position) to the current position in the rotation direction around the pitch axis.

[0022] The distance measurement unit 16 measures the distance from the gas leak detection device 10 (more specifically, the front surface of the casing 104) to the target location Pa during the gas leak inspection, and is configured with a known distance measurement device such as a distance sensor. The distance measured by the distance measurement unit 16 corresponds to the optical path length of the infrared ray I emitted by the first irradiator 11 from the front surface of the casing 104 to reach the target location Pa.

[0023] The position information acquisition unit 17 acquires information related to the position of the gas leak detection device 10 during a gas leak inspection. More specifically, the position information acquisition unit 17 uses the function of a GPS (Global Positioning System) installed in the unmanned aerial vehicle 100 to identify the horizontal position, i.e., the latitude and longitude, of the unmanned aerial vehicle 100 during flight, and acquires these identification results. Furthermore, the position information acquisition unit 17 identifies the vertical position, i.e., the altitude, of the unmanned aerial vehicle 100 during flight, based on the measurement value of a barometer installed in the unmanned aerial vehicle 100, and acquires these identification results. Furthermore, the position information acquisition unit 17 identifies the orientation of the unmanned aerial vehicle 100 during flight, i.e., the direction of the unmanned aerial vehicle 100 in the direction of rotation about the yaw axis, based on the measurement result of a magnetic direction sensor (compass) installed in the unmanned aerial vehicle 100, and acquires these identification results. In addition, the means and methods for obtaining information regarding the location of the gas leak detection device 10 are not limited to those described above, and means and methods other than those described above can be used as long as they can obtain the location of the gas leak detection device 10.

[0024] The photographing unit 18 is configured, for example, by a camera mounted on the unmanned aerial vehicle 100, and photographs an image of the target area Pa during a gas leak inspection. In this embodiment, the photographing unit 18 photographs an image of the target area Pa (the area surrounded by a dashed line in the figure) with the marker Mk projected thereon, as shown in FIG. The photographing unit 18 is housed in the casing 104, and photographs an image of the target site Pa through a photographing lens attached to the front of the casing 104. Therefore, when the driving unit 14 rotates the casing 104, the photographing range (angle of view) of the photographing unit 18 is accordingly displaced in the rotation direction of the casing 104.

[0025] The control unit 19 is configured by a small computer mounted on the unmanned aerial vehicle 100 and controls each component of the gas leak detection device 10. Specifically, during a gas leak inspection, the control unit 19 controls the drive unit 14 to rotate the casing 104 at a constant speed, while controlling the first irradiator 11 to irradiate the target area Pa with infrared light I from the first irradiator 11. At the same time, the control unit 19 controls the second irradiator 13 to irradiate the target area Pa with visible light H, which projects a marker Mk. At this time, as shown in FIG. 7 , the control unit 19 controls the direction change mechanism 30 to change the irradiation direction so that the infrared light I is irradiated onto the center position of the marker Mk. In this way, by projecting a visible marker Mk with the infrared light I irradiated at the center of the irradiation spot Sp, the position of the irradiation spot Sp can be accurately identified, even if the irradiation spot Sp is invisible.

[0026] 2, the control unit 19 includes a calculation unit 20 and a position identification unit 21. The calculation unit 20 calculates the concentration of the target gas (hereinafter also referred to as gas concentration) for the target location Pa using infrared light I irradiated onto the target location Pa, and more specifically, calculates the gas concentration based on the light reception signal output from the light receiving unit 12. Then, the control unit 19 determines that a gas leak has occurred in the target location Pa when the calculation result of the gas concentration is equal to or greater than a predetermined set value. The set value is a value that is set in advance as a criterion for determining whether or not a gas leak has occurred, and is stored in the memory of a small computer that constitutes the control unit 19.

[0027] Furthermore, when the gas concentration calculated for the target location Pa is equal to or greater than the set value, that is, when it is determined that a gas leak is occurring in the target location Pa, the control unit 19 controls the photographing unit 18 to cause the photographing unit 18 to photograph an image of the target location Pa. At this time, since a marker Mk is projected onto the target location Pa, the photographing unit 18 photographs an image of the target location Pa with the marker Mk projected, as shown in FIG. 8. In this way, by photographing an image of the target location Pa in which it has been determined that a gas leak is occurring, it is possible to obtain information for identifying the location of the gas leak. Furthermore, since an image of the target location Pa with the marker Mk projected is photographed, the location of the gas leak can be clearly identified in the image.

[0028] The position identifying unit 21 identifies the position of the target area Pa based on the measurement results by the angle measuring unit 15, the measurement results by the distance measuring unit 16, and information about the position of the gas leak detection device 10 acquired by the position information acquiring unit 17. The position of the target area Pa refers to the absolute position of the target area Pa, i.e., the latitude, longitude, and altitude. In this embodiment, the position identifying unit 21 identifies the position of the target area Pa sequentially during the gas leak inspection. Therefore, when the target area Pa is switched due to the drive unit 14 rotating the casing 104 to change the irradiation spot Sp of the infrared rays I or the unmanned aerial vehicle 100 moving, the position identifying unit 21 identifies the position of the target area Pa after the switch each time.

[0029] The memory unit 22 is configured by a storage device mounted on the unmanned aerial vehicle 100, and for each target portion Pa of the inspection target To, the gas concentration calculated by the calculation unit 20 and the position of the target portion Pa identified by the position identification unit 21 are stored in association with each other for each target portion. In addition, the determination result of the presence or absence of gas leakage based on the gas concentration is also stored in the memory unit 22 in association with the position of the target portion Pa identified by the position identification unit 21. This makes it possible to confirm the gas leakage inspection result for each target portion Pa by checking it against the position of the target portion Pa.

[0030] Furthermore, when the imaging unit 18 captures an image of the target area Pa (more specifically, an image of the target area Pa with the marker Mk projected), the storage unit 22 stores the image in association with the gas concentration calculated by the calculation unit 20 and the position of the target area Pa identified by the position identification unit 21. This makes it possible to confirm the position and current appearance of a part of the inspection target To that has been determined to have a gas leak.

[0031] <<Gas Leak Detection Method According to This Embodiment>> A gas leak detection method using the gas leak detection device 10 according to this embodiment will be described with reference to Fig. 9. Note that the procedure shown in Fig. 9 is merely an example, and new steps may be added or the order of steps may be changed without departing from the spirit of the present invention.

[0032] The gas leak detection method according to this embodiment is used in a series of steps in a gas leak inspection (hereinafter referred to as a gas leak inspection flow). That is, each step in the gas leak inspection flow corresponds to a corner step constituting the gas leak detection method according to this embodiment. The gas leak inspection flow proceeds as shown in Fig. 9. Specifically, after starting up each part of the gas leak detection device 10, the unmanned aerial vehicle 100 constituting the gas leak detection device 10 is remotely controlled to fly and move to a position facing the inspection object To (S001). Furthermore, during the gas leak inspection, the control unit 19 controls the drive unit 14 to rotate the casing 104 and position it at a preset position in the rotation direction (S002). This sets the main body of the gas leak detection device 10 housed in the casing 104 to its initial position.

[0033] Upon completion of the above two steps S001 and S002, the gas leak detection device 10 starts the gas leak inspection. That is, the gas leak detection device 10 causes the first irradiator 11 to irradiate the target area Pa in the inspection target To with infrared rays I (S003). At the same time as step S003, the gas leak detection device 10 causes the second irradiator 13 to irradiate the target area Pa with visible light H for marker projection so that the infrared rays I are irradiated onto the center position of the marker Mk (S004). Specifically, the direction change mechanism 30 of the second irradiator 13 is controlled by the control unit 19, thereby changing the irradiation direction of the visible light H so that the infrared irradiation spot Sp coincides with the center position of the marker Mk. As a result, the marker Mk is projected onto the target area Pa, and the infrared irradiation position on the target area Pa can be accurately identified from the center position of the marker Mk.

[0034] Furthermore, while performing the above two steps S003 and S004, the gas leak detection device 10 measures the angle of the casing 104 at any time using the angle measurement unit 15 (S005), measures the distance from the gas leak detection device 10 to the target location Pa using the distance measurement unit 16 (S006), and acquires information related to the location of the gas leak detection device 10 using the position information acquisition unit 17 (S007). Then, the gas leak detection device 10 identifies the location of the target location Pa using the position identification unit 21 of the control unit 19 based on the measurement results in S005 and S006 and the information acquired in S007 (S008).

[0035] Furthermore, the gas leak detection device 10 calculates the gas concentration in the target location Pa using the calculation unit 20 of the control unit 19 based on the intensity of reflected light of the infrared rays I irradiated onto the target location Pa in the above-mentioned step S003 (S009). If the calculated gas concentration is equal to or greater than the set value (Yes in S010), the gas leak detection device 10 determines that there is a gas leak in the target location Pa (S011), and causes the imaging unit 18 to capture an image of the target location Pa (S012). At this time, markers Mk are projected onto the target location Pa, and the imaging unit 18 captures an image of the target location Pa with the markers Mk projected thereon.

[0036] The captured image of the target site Pa is stored in the storage unit 22 in association with the position of the target site Pa identified in step S008 and the gas concentration calculated in step S009 (S013). If the calculated gas concentration is less than the set value (No in S010), S011 to S013 are omitted and the process proceeds to step S014, which will be described later.

[0037] At this point, if an instruction to end the gas leak inspection has not been given to the gas leak detection device 10 (No in S014), the control unit 19 of the gas leak detection device 10 controls the drive unit 14 to rotate the casing 104 by a predetermined amount around the pitch axis (S015). This switches (i.e., scans) the target area Pa to be irradiated with the infrared rays I, and the gas leak detection device 10 repeats the series of steps from S003 onwards for the target area Pa after the switch. The end instruction is given by turning on an end button (not shown), for example. On the other hand, if an instruction to end the gas leak inspection is given (Yes in S014), the gas leak inspection flow ends at that point.

[0038] <<Other embodiments>> The embodiments described above are merely examples given to facilitate understanding of the present invention and are not intended to limit the present invention. That is, the present invention may be modified or improved from the embodiments described below without departing from the spirit of the present invention. Furthermore, the present invention includes equivalents thereof.

[0039] In the above embodiment, the direction of the visible light H emitted from the second irradiator 13 is changed by controlling the direction change mechanism 30 of the second irradiator 13 so that the infrared light I is emitted to the center position of the marker Mk. However, the configuration for irradiating the visible light H so that the infrared light I is emitted to the center position of the marker Mk is not limited to the above configuration, and for example, the configuration shown in FIG. 10 (hereinafter also referred to as a modified example) is possible. In the modified example, the first irradiator 11 and the second irradiator 13 are housed in the casing 104 and irradiate light from openings provided on the front surface of the casing 104, as in the above embodiment. Meanwhile, in the modified example, the area on the front surface of the casing 104 through which the infrared light I emitted by the first irradiator 11 passes and the area through which the visible light H emitted by the second irradiator 13 passes overlap in the vertical and horizontal directions of the unmanned aerial vehicle 100, and are arranged concentrically as shown in FIG. 10. With this configuration, the optical axis of the infrared light I irradiated from the first irradiating unit 11 coincides with the optical axis of the visible light H irradiated from the second irradiating unit 13. That is, in the modified example shown in Fig. 10, the position of the second irradiating unit 13 relative to the first irradiating unit 11 is set to a position where the infrared light I is irradiated onto the center position of the marker Mk, and therefore, the marker Mk can be projected onto the target site Pa with the infrared irradiation spot Sp at the center without adjusting the irradiation position of the visible light H.

[0040] Furthermore, in the above-described embodiment, the mobile body is an unmanned aerial vehicle 100, and each part of the gas leak detection device 10, such as the first irradiation unit 11 and the second irradiation unit 13, is held in the unmanned aerial vehicle 100. However, the mobile body is not limited to the unmanned aerial vehicle 100, and may be an air vehicle other than an aircraft, or a mobile body other than an aircraft or an air vehicle, for example, a vehicle that can run unmanned (including a self-propelled cart and vehicle, etc.) or a ship. The mobile body may also be a manned vehicle.

[0041] Furthermore, in the above-described embodiment, a small computer mounted on unmanned aerial vehicle 100 functions as control unit 19. However, this is not limited to this, and for example, control unit 19 may be configured by a computer that is separate from the equipment mounted on unmanned aerial vehicle 100, that is capable of communicating with unmanned aerial vehicle 100 (more specifically, a control circuit on the unmanned aerial vehicle 100 side), and that is used to remotely operate unmanned aerial vehicle 100. [Explanation of symbols]

[0042] 10 Gas leak detection device 11 1st irradiation section 12 Light receiving section 13 Second irradiation section 14 Drive unit 15 Angle measurement unit 16 Distance measurement unit 17 Location information acquisition section 18 Photography Department 19 Control Unit 20 Calculation section 21 Location identification part 22 Memory section 30 Direction change mechanism 100 Unmanned aerial vehicle (mobile) 102 Holder 104 Casing H visible light I Infrared Mk Marker Pa target area Sp Irradiation spot (irradiation position) To be inspected

Claims

1. a first irradiation unit that irradiates a target portion of an inspection object with infrared rays; a second irradiating unit that irradiates the target area with visible light for projecting a marker such that the infrared light is irradiated onto a center position of the marker; a calculation unit that calculates the concentration of a target gas in the target location using infrared rays irradiated onto the target location.

2. The gas leak detection device according to claim 1 , further comprising a moving body that moves to a position facing the inspection object while holding the first irradiation unit and the second irradiation unit.

3. The gas leak detection device according to claim 1 , further comprising an image capturing unit that captures an image of the target portion with the marker projected thereon.

4. When the calculated concentration for the target site is equal to or greater than a set value, the imaging unit captures the image; The gas leak detection device according to claim 3 , further comprising a storage unit that stores the image in association with the concentration calculated for the target portion.

5. a position specifying unit that specifies the position of the target site, The gas leak detection device according to claim 4 , wherein the storage unit stores the image in association with the concentration calculated for the target portion and the position of the target portion identified by the position identification unit.

6. the second irradiator has a direction change mechanism that changes the irradiation direction of the visible light, The gas leak detection device according to claim 1 , further comprising a control unit that controls the direction changing mechanism to change the irradiation direction so that the infrared ray is irradiated onto a center position of the marker.

7. The gas leak detection device according to claim 1 , wherein the second irradiating unit is disposed at a position relative to the first irradiating unit such that the infrared light is irradiated onto a center position of the marker.

8. a step of irradiating a target portion of an object to be inspected with infrared light from a first irradiation unit; a step of irradiating the target site with visible light for projecting a marker from a second irradiating unit such that the infrared light is irradiated onto a center position of the marker; and calculating a concentration of the target gas at the target location using infrared light irradiated onto the target location.

9. 9. The gas leakage detection method according to claim 8, further comprising the step of moving a moving body holding the first irradiation unit and the second irradiation unit to a position facing the inspection object.

10. capturing an image of the target site with the marker projected thereon when the calculated density of the target site is equal to or greater than a set value; 10. The gas leakage detection method according to claim 8, further comprising the step of: storing the image in a storage unit in association with the concentration calculated for the target portion.

Images