Testing method and testing device

Abstract

We provide a testing method that shortens the testing time. [Solution] The inspection method according to the present disclosure is a method for inspecting a cylindrical structure extending in the vertical direction using a first imaging device suspended from an unmanned aerial vehicle, wherein the first imaging device is suspended by a retractable linear member that extends from a winding device located on the outside of the structure when viewed from above and below, and passes through a pulley fixed to the unmanned aerial vehicle, the unmanned aerial vehicle is flown above the structure to position the pulley above the structure, the winding device adjusts the amount of winding of the linear member to raise and lower the first imaging device inside the structure, and the first imaging device takes images of the inner wall surface of the structure at different heights.

Description

Technical Field

[0001] The present disclosure relates to an inspection method and an inspection device using an unmanned aerial vehicle.

Background Art

[0002] For example, Patent Document 1 discloses a method for inspecting the wall surface of a boiler furnace or the like using an unmanned flight inspection machine. The unmanned flight inspection machine includes an unmanned aerial vehicle, an inspection device mounted on the main body of the unmanned aerial vehicle, and a guide mechanism for maintaining a constant distance between the inspection target and the inspection device, and moves along the inspection target while maintaining a constant distance between the inspection target and the inspection device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, it is difficult to perform an inspection using an unmanned aerial vehicle in an environment where wireless communication is obstructed, such as inside a vertical shaft. In such an environment, it is required to perform an inspection by a person, and there is a risk that the inspection time will be prolonged.

[0005] An object of the present disclosure is to solve the above problems and provide an inspection method that shortens the inspection time using an unmanned aerial vehicle.

[0006] An inspection method according to one aspect of the present disclosure is a method for inspecting a vertically extending cylindrical structure using a first imaging device suspended from an unmanned aerial vehicle, wherein the first imaging device is suspended by a retractable linear member extending from a winding device located on the outside of the structure when viewed from above and below, via a pulley fixed to the unmanned aerial vehicle, the unmanned aerial vehicle is flown above the structure to position the pulley above the structure, the winding device adjusts the amount of winding of the linear member to raise and lower the first imaging device inside the structure, and the first imaging device captures images of the inner wall surface of the structure at different heights.

[0007] An inspection device according to one aspect of the present disclosure comprises an unmanned aerial vehicle that flies above a cylindrical structure extending vertically, a pulley fixed to the unmanned aerial vehicle, a first imaging device suspended from the unmanned aerial vehicle, a linear member connected to the first imaging device via the pulley, and a winding device positioned outside the structure when viewed from above and below, and capable of winding up the linear member, wherein the winding device adjusts the amount of winding of the linear member and raises and lowers the first imaging device within the structure, and the first imaging device captures images of the interior wall surface of the structure at different heights.

[0008] According to this disclosure, it is possible to provide an inspection method that shortens the inspection time. [Brief explanation of the drawing]

[0009] [Figure 1] Schematic diagram of the inspection device in Embodiment 1 relating to this disclosure [Figure 2] Schematic diagram of the inspection device in Embodiment 1 [Figure 3] Schematic diagram of the inspection device in Embodiment 1 [Figure 4] Schematic diagram of the inspection device in Embodiment 1 [Figure 5A] Schematic diagram of the first planar image [Figure 5B] Schematic diagram of a reference plane image [Figure 6] Schematic diagram of the inspection device in other operational examples. [Figure 7] Schematic diagram of the inspection device in modified example 1 [Figure 8] Plan view of the first imaging device in modified example 1 [Figure 9] Schematic diagram of the inspection device in modified example 2 [Figure 10] Schematic diagram of the inspection device in modified example 2 [Figure 11] Schematic diagram of the first imaging device in modified example 2 [Modes for carrying out the invention]

[0010] (Embodiment 1) Hereinafter, an exemplary embodiment 1 relating to this disclosure will be described with reference to the attached drawings. However, unnecessarily detailed explanations may be omitted. For example, detailed explanations of already well-known matters or redundant explanations of substantially identical configurations may be omitted. This is to avoid the following explanation becoming unnecessarily verbose and to facilitate understanding by those skilled in the art.

[0011] The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this disclosure, and are not intended to limit the subject matter of the claims to the specific configurations of the following embodiments. Configurations based on the same technical idea as the embodiments are included in this disclosure.

[0012] Furthermore, in this specification, terms such as "first," "second," etc., are used merely to distinguish components for explanatory purposes and are not intended to be interpreted as limiting to any particular component. Therefore, these expressions should be understood to be appropriately reinterpreted depending on the configuration to which the invention relating to this disclosure applies.

[0013] [Overall structure] FIG. 1 is a schematic diagram of the inspection device 1 in Embodiment 1 according to the present disclosure. In a plurality of figures, a three-dimensional orthogonal coordinate system composed of an X-axis, a Y-axis, and a Z-axis is shown, and the directions of each axis are described as corresponding. The X-axis and the Y-axis extend in the horizontal direction, and the Z-axis extends in the vertical direction perpendicular to the horizontal direction.

[0014] As shown in FIG. 1, the inspection device 1 is a device for inspecting a cylindrical structure 50 that extends in the vertical direction (Z direction). In Embodiment 1, the structure 50 is a cylindrical shaft that forms an opening 51 at the upper end and has a central axis R1 extending in the vertical direction. The structure 50 extends in the vertical direction, for example, from the upper end at a height of 10 m above the ground G to the bottom B at a depth of 95 m underground with respect to the ground G. Note that the structure 50 may be a cylindrical chimney installed on the ground.

[0015] The inspection device 1 inspects the inner wall surface of the structure 50 that extends in the circumferential direction C around the central axis R1. Specifically, the inspection device 1 can acquire an image of the inner wall surface of the structure 50 and identify the positions of abnormalities in appearance such as floating of concrete, cracks, peeling of coating films, and rust bumps from the image.

[0016] The inspection device 1 includes an unmanned aerial vehicle 2, a pulley 3, a first imaging device 4, a linear member 6, a winding device 10, a second imaging device 12, a control unit 13, and a transmitter 14.

[0017] The unmanned aerial vehicle 2 is a device that has propellers and flies under remote control via wireless communication. The unmanned aerial vehicle 2 can realize both flight for moving to a predetermined position in the air and flight for maintaining the predetermined position (hereinafter referred to as hovering). In Embodiment 1, the unmanned aerial vehicle 2 is a drone. Note that the unmanned aerial vehicle 2 may be another device capable of unmanned flight such as a multicopter or a radio-controlled helicopter instead of the drone.

[0018] A pulley 3 is fixed to the unmanned aerial vehicle 2. The pulley 3 has a rotating shaft 3A that extends horizontally and a disc 3B that is rotatable around the rotating shaft 3A, and the outer circumference of the disc 3B supports the linear member 6. The rotating shaft 3A of the pulley 3 may be directly attached to the unmanned aerial vehicle 2, or it may be attached to the unmanned aerial vehicle 2 via other members. In Embodiment 1, the rotating shaft 3A is attached to the lower part of the unmanned aerial vehicle 2, and the pulley 3 protrudes downward from the unmanned aerial vehicle 2.

[0019] By flying the unmanned aircraft 2 in the air and making it hover, the pulley 3 can be positioned at a predetermined location in the air.

[0020] The first imaging device 4 is suspended from the unmanned aerial vehicle 2 and captures images or videos of the interior wall surface of the building 50 through an opening 51. Specifically, the first imaging device 4 moves to different heights within the building 50 and captures images or videos of the interior wall surface of the building 50 at each height. The first imaging device 4 may have a camera or video camera that receives light in any wavelength range, such as visible light or infrared light. In Embodiment 1, the first imaging device 4 has a 360° camera capable of capturing a 360° area around the first imaging device 4 using visible light.

[0021] The first imaging device 4 is suspended from the unmanned aerial vehicle 2 by a linear member 6. Specifically, the linear member 6 extends from the winding device 10 and is connected to the first imaging device 4 via a pulley 3 fixed to the unmanned aerial vehicle 2. In Embodiment 1, the tip of the linear member 6 pulled out from the winding device 10 is fixed to the first imaging device 4. The first imaging device 4 is supported by a single linear member 6. Therefore, the first imaging device 4 is suspended directly below the unmanned aerial vehicle 2. That is, the position of the first imaging device 4 in the horizontal direction is determined by the position of the unmanned aerial vehicle 2. On the other hand, the first imaging device 4 is rotatable around a linear member 6 (rotation axis) that extends in the vertical direction, and can have any orientation relative to the building 50 when viewed from above or below.

[0022] The linear member 6 is a flexible linear or strip-shaped member, such as a rope, wire, chain, or belt.

[0023] The winding device 10 is positioned on the outside of the building 50 when viewed from above, and is capable of winding up the linear member 6. Specifically, the winding device 10 is capable of winding up the linear member 6 and also capable of unwinding the wound-up linear member 6. By winding up and unwinding the linear member 6 with the winding device 10, the amount of winding T of the linear member 6 can be adjusted. Therefore, the suspension length L of the linear member 6 between the unmanned aerial vehicle 2 and the first imaging device 4 can also be adjusted. When the winding device 10 winds up the linear member 6, the amount of winding T increases and the suspension length L decreases, and when the linear member 6 is unwinded, the amount of winding T decreases and the suspension length L increases. The height of the first imaging device 4 is determined by the suspension length L.

[0024] In Embodiment 1, the winding device 10 has a rotating shaft 10A and a disc 10B that can rotate around the rotating shaft 10A. When the disc 10B rotates forward, the linear member 6 wound around the outer circumference of the disc 10B is released and pulled out, and when the disc 10B reverses direction, the linear member 6 is wound up around the outer circumference of the disc 10B and recovered. The winding amount T is, for example, the number of times the disc 10B rotates forward or reverses direction relative to a predetermined reference. The winding device 10 is, for example, a reel.

[0025] The winding device 10 has a detection unit 11 capable of detecting the winding amount T. The detection unit 11 may also have a display that shows the winding amount T to the user.

[0026] A second imaging device 12 is further fixed to the unmanned aerial vehicle 2. The second imaging device 12 is a device capable of imaging downwards with its imaging lens facing downwards, and has, for example, a downward-facing camera or video camera. Therefore, the second imaging device 12 can image the first imaging device 4 which is suspended downwards from the unmanned aerial vehicle 2. Specifically, the second imaging device 12 captures a planar image of the first imaging device 4, including its upper surface and a feature point 52. The feature point 52 is a point on an object fixed to the ground G, and may be, for example, a fixed point provided on the wall or bottom B of a building 50, or a fixed point on the outside of the building 50.

[0027] A marker 40 indicating the orientation in the vertical direction is provided on the upper surface of the first imaging device 4, which is rotatable in the vertical direction. The marker 40 is located horizontally away from the axis of rotation of the first imaging device 4 (i.e., the linear member 6). The marker 40 can be photographed by the second imaging device 12 and may be a planar display or pattern on the upper surface, or it may be a three-dimensional shape. For example, the marker 40 may be a pattern printed on the upper surface. If the outer shape of the first imaging device 4 is asymmetrical in the vertical direction, the marker 40 may be part of the contour of the upper surface of the first imaging device 4.

[0028] By comparing the positions of the marker 40 and the feature point 52 in the planar image of the first imaging device 4, the orientation of the first imaging device 4 in the vertical direction relative to the building 50 can be determined. By combining the orientation of the first imaging device 4 in the vertical direction with the height of the first imaging device 4, the position of the interior wall surface in the image captured by the first imaging device 4 can be determined.

[0029] The control unit 13 includes a general-purpose processor such as a CPU, MPU, FPGA, DSP, or ASIC that performs a predetermined function by executing a program. The control unit 13 performs its function by executing a program stored in the memory 13A.

[0030] The control unit 13 controls the imaging devices 4 and 12 and the winding device 10. Specifically, the control unit 13 controls the timing of imaging by the imaging devices 4 and 12. The control unit 13 also controls at least one of the winding amount T, winding speed, and winding time of the winding device 10. In addition, the control unit 13 may control at least one of the winding amount T, winding speed, and winding time of the winding device 10 in response to user operation of the inspection device 1.

[0031] The control unit 13 is configured to calculate a predetermined value based on information acquired from the first imaging device 4 and the winding device 10. Specifically, the control unit 13 acquires the image captured by the first imaging device 4. The control unit 13 receives the image from the first imaging device 4, for example, using a predetermined communication standard. Furthermore, the control unit 13 acquires the winding amount T of the linear member 6 detected by the detection unit 11 of the winding device 10. The control unit 13 receives the winding amount T from the detection unit 11, for example, using a predetermined communication standard. The communication standard used by the control unit 13 may be wired or wireless.

[0032] The memory 13A of the control unit 13 has information about the depth of the structure 50, that is, the height of the bottom B of the structure 50, stored in advance. For example, the memory 13A stores the height of the bottom B relative to the ground G.

[0033] The transmitter 14 is configured to control the unmanned aerial vehicle 2. The transmitter 14 includes a general-purpose processor such as a CPU, MPU, FPGA, DSP, or ASIC that performs predetermined functions by executing a program. The transmitter 14 performs its functions by executing a program stored in memory (not shown). In Embodiment 1, the transmitter 14 is a user-operable controller of the inspection device 1.

[0034] The transmitter 14 communicates wirelessly with the communication unit 21 of the unmanned aerial vehicle 2. Specifically, the transmitter 14 includes a circuit that transmits information in accordance with a predetermined communication standard, and the communication unit 21 of the unmanned aerial vehicle 2 includes a circuit that receives the transmitted information. The transmitter 14 and the communication unit 21 may also include a circuit that enables bidirectional communication of information. For example, the transmitter 14 and the communication unit 21 communicate via a network such as a wireless local area network (LAN) in accordance with standards such as Wi-Fi, IEEE 802.2, IEEE 802.3, third-generation mobile communication system (3G), fourth-generation mobile communication system (4G), fifth-generation mobile communication system (5G), and Long-Term Evolution (LTE).

[0035] (operation) With the above configuration in mind, an example of an inspection method for a building 50 using the inspection device 1 will be described with reference to Figures 2 to 4. Figures 2 to 4 are schematic diagrams of the inspection device 1 in Embodiment 1 during the execution of the inspection method. Note that the following operation is just an example, and the inspection method using the inspection device 1 is not limited to this.

[0036] As shown in Figure 2, first, in response to user input, the transmitter 14 communicates with the communication unit 21 of the unmanned aircraft 2, causing the propellers of the unmanned aircraft 2 to rotate and the unmanned aircraft 2 to take off.

[0037] Next, in response to user input, the transmitter 14 flies the unmanned aerial vehicle 2 to a predetermined position above the building 50, thereby positioning the pulley 3 above the building 50. Specifically, the transmitter 14 flies the unmanned aerial vehicle 2 above the opening 51 of the building 50. The transmitter 14 also flies the unmanned aerial vehicle 2 to a predetermined height to avoid interference between the linear member 6 and the upper end of the building 50. In Embodiment 1, with the linear member 6 separated from the building 50, the transmitter 14 flies the unmanned aerial vehicle 2 such that, when viewed from above, the first imaging device 4 suspended from the unmanned aerial vehicle 2 coincides with the center R0 of the bottom B of the building 50. The transmitter 14 may also use the second imaging device 12 to recognize the positional relationship between the first imaging device 4 and the center R0 while flying the unmanned aerial vehicle 2.

[0038] When the unmanned aerial vehicle 2 reaches a predetermined position above the building 50, it performs a hover to maintain its position. This action also maintains the position of the pulley 3.

[0039] As shown in Figure 3, the winding device 10 then, under the control of the control unit 13, pulls out the linear member 6 to increase the suspension length L, and lowers the first imaging device 4 into the building 50 through the opening 51. The descent speed of the first imaging device 4 may be constant, or it may decrease as it approaches the bottom B.

[0040] Next, the control unit 13 determines whether the first imaging device 4 has reached the bottom B of the building 50. The first imaging device 4 may have a sensor capable of detecting changes in the tension of the linear member 6, and the control unit 13 may make the determination by acquiring information from the sensor. For example, when the linear member 6 begins to sag, the control unit 13 determines that the first imaging device 4 has reached the bottom B of the building 50.

[0041] If it is determined that the first imaging device 4 has not reached the bottom B of the building 50, the extension of the linear member 6 continues.

[0042] On the other hand, when it is determined that the first imaging device 4 has reached the bottom B of the building 50, the winding device 10 stops unwinding the linear member 6 under the control of the control unit 13. The height of the first imaging device 4 in this state (i.e., when the first imaging device 4 has reached the bottom B of the building 50) is defined as the reference height H0. The detection unit 11 detects the reference winding amount T0 when it is located at the reference height H0. The control unit 13 acquires the reference winding amount T0. Based on the reference winding amount T0 and the height of the bottom B which is pre-stored in the memory 13A, the control unit 13 derives a first height relation formula that shows the relationship between the winding amount T and the vertical height of the first imaging device 4, and stores it in the memory 13A.

[0043] While the first imaging device 4 performs ascent and descent, the unmanned aerial vehicle 2 continues to hover, maintaining the positions of the unmanned aerial vehicle 2 and the pulley 3. In addition, depending on user operation, the unmanned aerial vehicle 2 may move horizontally (XY direction) within the range of the opening 51 of the building 50, for example.

[0044] As shown in Figure 4, the winding device 10 then, under the control of the control unit 13, pulls out the linear member 6 to shorten the suspension length L and raises the first imaging device 4 into the building 50 through the opening 51. The rising speed of the first imaging device 4 may be less than the descending speed. Specifically, the average rising speed of the first imaging device 4 may be less than the average descending speed.

[0045] As the first imaging device 4 rises, the first imaging device 4 performs imaging of the interior wall surface of the building 50. In Embodiment 1, the first imaging device 4 continuously captures images (pictures or videos) of the interior wall surface of the building 50 in association with time information. Here, continuously capturing images includes both capturing images at predetermined intervals over a predetermined period and capturing videos over a predetermined period.

[0046] Furthermore, as the first imaging device 4 rises, the second imaging device 12 captures a planar image of the first imaging device 4. In Embodiment 1, the second imaging device 12 continuously captures images of the upper surface of the first imaging device 4 in association with time information.

[0047] Furthermore, the imaging devices 4 and 12 may begin imaging even before the first imaging device 4 rises. Since communication is difficult inside the building 50, the imaging devices 4 and 12 may begin imaging before the first imaging device 4 descends.

[0048] While the imaging devices 4 and 12 are taking images, the detection unit 11 detects the winding amount T, and the control unit 13 acquires the winding amount T in association with time information and stores it in the memory 13A.

[0049] When the first imaging device 4 reaches the top of the building 50 (for example, when the proximity sensor detects the pulley 3), the winding device 10 stops the upward movement of the first imaging device 4 under the control of the control unit 13. The imaging devices 4 and 12 may also stop imaging, and the detection unit 11 may stop detecting the winding amount T.

[0050] Next, in response to user input, the transmitter 14 communicates with the communication unit 21 of the unmanned aircraft 2 and causes the unmanned aircraft 2 to land.

[0051] Next, the control unit 13 acquires the video captured by the shooting devices 4 and 12 via a predetermined communication standard. Then, for a predetermined frame F1 in the video from the first shooting device 4, the control unit 13 acquires the first height H1 of the first shooting device 4 at the time of capturing frame F1. Here, frame F1 may be an image or a frame from a video.

[0052] In acquiring the first height H1, the control unit 13 first acquires the first winding amount T1 at the time of shooting frame F1. Specifically, the control unit 13 refers to the time information associated with frame F1 and acquires the first winding amount T1 corresponding to the time information. Subsequently, the control unit 13 calculates the first height H1 of the first shooting device 4 at the time of shooting frame F1 based on the first winding amount T1 and the first height relation expression stored in memory 13A.

[0053] Next, the control unit 13 acquires a first orientation V1 of the first imaging device 4 in the vertical direction at the time of capturing frame F1 of the image from the first imaging device 4.

[0054] As shown in Figure 5A, in acquiring the first orientation V1, the control unit 13 first acquires a first planar image D1 taken by the second imaging device 12, which shows the first imaging device 4 at the time of frame F1's capture. Specifically, the control unit 13 acquires the first planar image D1 corresponding to the time information by referring to the time information associated with frame F1. Subsequently, the control unit 13 calculates the first orientation V1 of the first imaging device 4 at the time of frame F1's capture based on the position of the marker 40 in the first planar image D1. For example, the control unit 13 uses general-purpose image processing to identify the position of the marker 40 relative to the feature point 52 in the first planar image D1 and calculates the first orientation V1 of the first imaging device 4.

[0055] By obtaining the height and orientation of the first imaging device 4 in the vertical direction when frame F1 is captured, the position of the inner wall surface captured in frame F1 can be determined.

[0056] (effect) The inspection method and inspection device 1 according to Embodiment 1 can achieve the following effects.

[0057] The inspection method of Embodiment 1 is a method for inspecting a cylindrical structure 50 that extends vertically using a first imaging device 4 suspended from an unmanned aerial vehicle 2. The first imaging device 4 is suspended by a retractable linear member 6 that extends from a winding device 10 located on the outside of the structure 50 when viewed from above, and passes through a pulley 3 fixed to the unmanned aerial vehicle 2. The inspection method includes flying the unmanned aerial vehicle 2 above the structure 50 to position the pulley 3 above the structure 50. The inspection method includes the winding device 10 adjusting the winding amount T of the linear member 6 to raise and lower the first imaging device 4 within the structure 50. The inspection method includes capturing images (first images) of the inner wall surface of the structure 50 with the first imaging device 4 at different heights.

[0058] With this configuration, the first imaging device 4 can be raised and lowered inside the building 50 by adjusting the suspension length L of the linear member 6, allowing imaging of any position on the inner wall surface of the building 50. This reduces inspection time compared to when the inner wall surface is imaged by a human worker. Furthermore, because the unmanned aerial vehicle 2 is flown to position the pulley 3 above the building 50, the suspension point of the first imaging device 4 can be freely set compared to when the first imaging device 4 is suspended by a human worker.

[0059] The inspection method of Embodiment 1 further includes obtaining a first height H1 of the first imaging device 4 when capturing a frame F1 of the image of the interior wall surface of the building 50.

[0060] This configuration allows for the identification of the height of the inner wall surface projected onto frame F1. Even when detailed inspection of anomalies is required, the location of the anomaly can be identified, thus shortening inspection time.

[0061] The inspection method of Embodiment 1 further includes detecting a first winding amount T1 of the suspension length L when frame F1 is being photographed. The first height H1 is calculated based on the first winding amount T1.

[0062] This configuration makes it easier to determine the height of the inner wall surface projected onto frame F1.

[0063] The inspection method of Embodiment 1 further includes detecting a reference winding amount T0 of the suspension length L when the first imaging device 4 reaches the bottom B of the building 50. The first height H1 is calculated based on the first winding amount T1 and the reference winding amount T0.

[0064] This configuration makes it easier to determine the height of the inner wall surface projected onto frame F1.

[0065] The inspection method of Embodiment 1 further includes acquiring a first orientation V1 around the vertical direction of the first imaging device 4 when capturing frame F1.

[0066] This configuration allows for the identification of the circumferential (vertical) position of the inner wall surface projected onto frame F1. Even when detailed inspection of an anomaly is required, the circumferential location of the anomaly can be identified, thus shortening the inspection time.

[0067] In the inspection method of Embodiment 1, when viewed from above, the first imaging device 4 has a marker 40 at a position away from the linear member 6. The inspection method further includes capturing a planar image (third planar image) of the first imaging device 4, including the marker 40, when capturing frame F1, using a second imaging device 12 fixed to the unmanned aerial vehicle 2 and capable of capturing images downwards. The first orientation V1 is calculated based on the position of the marker 40 in the planar image.

[0068] This configuration makes it easier to determine the circumferential position of the inner wall surface projected onto frame F1.

[0069] The inspection device of Embodiment 1 comprises an unmanned aerial vehicle 2 that flies above a cylindrical structure 50 extending in the vertical direction, a pulley 3 fixed to the unmanned aerial vehicle 2, a first imaging device 4 suspended from the unmanned aerial vehicle 2, a linear member 6, and a winding device 10. The linear member 6 is connected to the first imaging device 4 via the pulley 3. The winding device 10 is positioned outside the structure 50 when viewed from above and below, and is capable of winding up the linear member 6. The winding device 10 adjusts the winding amount T of the linear member 6, raising and lowering the first imaging device 4 inside the structure 50, so that the first imaging device 4 captures images of the inner wall surface of the structure 50 at different heights.

[0070] With this configuration, the first imaging device 4 can be raised and lowered inside the building 50 by adjusting the suspension length L of the linear member 6, allowing imaging of any position on the inner wall surface of the building 50.

[0071] This disclosure is not limited to Embodiment 1, and can be implemented in various other forms.

[0072] In Embodiment 1, an example was described in which the first imaging device 4 has a 360° camera, but the invention is not limited to this. The first imaging device 4 only needs to be capable of photographing at least a portion of the interior wall surface of the building 50, and may have a camera oriented in a predetermined direction.

[0073] In the first embodiment, the example of operation described was one in which the first imaging device 4 and the second imaging device 12 continuously capture images of the interior wall surface of the building 50, but the invention is not limited to this. The first imaging device 4 and the second imaging device 12 may capture images when the first imaging device 4 is positioned at at least two different heights. In this case, the imaging by the first imaging device 4 and the second imaging device 12 may be synchronized and performed simultaneously. Through such operation, the height and orientation of the first imaging device 4 when it captures an image of the interior wall surface of the building 50 (which may be referred to as the first image) can be obtained.

[0074] In the first embodiment, the example of acquiring the height and orientation of the first imaging device 4 was described, but the invention is not limited to this. For example, only the height or orientation of the first imaging device 4 may be acquired.

[0075] In the first embodiment, the operation example described shows that the control unit 13 calculates the first height H1 of the first imaging device 4 based on the first winding amount T1, but the invention is not limited to this. The control unit 13 may also calculate the height of the first imaging device 4 based on the planar image captured by the second imaging device 12. In this case, as shown in Figure 5B, the second imaging device 12 acquires a reference planar image D0 when the first imaging device 4 reaches the bottom B of the building 50, that is, when it is located at the reference height H0. Based on the size of the first imaging device 4 in the reference planar image D0 and the height of the bottom B pre-stored in the memory 13A, the control unit 13 derives a second height relation expression that shows the relationship between the size of the first imaging device 4 and the actual vertical height, and stores it in the memory 13A.

[0076] In acquiring the first height H1, the control unit 13 first acquires a first planar image D1 taken by the second imaging device 12 at the time of capturing frame F1 in the video of the first imaging device 4. Specifically, the control unit 13 acquires a first planar image D1 corresponding to the time information by referring to the time information associated with frame F1. Subsequently, the control unit 13 calculates the first height H1 of the first imaging device 4 at the time of capturing frame F1 based on the size of the first imaging device 4 in the first planar image D1 and the second height relation formula.

[0077] The control unit 13 calculates the size of the first imaging device 4 in a planar image, for example, using general-purpose image processing. The size of the first imaging device 4 may be the area of ​​the top surface of the first imaging device 4, the maximum dimension passing through the center of the top surface, or the distance between two predetermined positions on the top surface.

[0078] Alternatively, as shown in Figure 6, a scale 16 extending vertically may be pre-installed within the building 50, and the control unit 13 may calculate the height of the first imaging device 4 based on the image of the scale 16 captured by the first imaging device 4. The scale 16 has markings indicating the height within the building 50, and for example, has marks provided at predetermined intervals in the vertical direction. The scale 16 is installed, for example, along the inner wall surface of the building 50. The first imaging device 4 then photographs the scale 16 together with the inner wall surface of the building 50. In other words, the image of the scale 16 is included in the image captured by the first imaging device 4.

[0079] In acquiring the first height H1, the control unit 13 calculates the first height H1 of the first shooting device 4 at the time of shooting frame F1 based on the image of the scale 16 in frame F1 of the video captured by the first shooting device 4. The control unit 13 uses, for example, general-purpose image processing to acquire the height within the building 50 indicated by the image of the scale 16 in frame F1, and calculates the first height H1 of the first shooting device 4 based on that.

[0080] If a camera other than a 360° camera is available, the first shooting device 4 may capture multiple images in the vertical direction, and the image capturing the scale 16 may be a different image from the image capturing the inner wall surface of the building 50.

[0081] [Example 1] The following describes Modification 1. In Modification 1, components that are the same as or equivalent to those in Embodiment 1 are denoted by the same reference numerals and described accordingly, and descriptions that overlap with Embodiment 1 are omitted.

[0082] Figure 7 is a schematic diagram of the inspection device 101 in Modification 1. Figure 8 is a plan view of the first imaging device 104 in Modification 1. The inspection device 101 of Modification 1 differs from the configuration of Embodiment 1 in that it has a first imaging device 104 instead of a first imaging device 4 which has a 360° camera.

[0083] As shown in Figure 7, the first imaging device 104 has multiple imaging devices oriented in different directions around the vertical direction. As shown in Figure 8, in modified example 1, there are four imaging devices 104A to 104D arranged at 90° intervals around the vertical direction. The fields of view of each imaging device 104A to 104D may be arranged to partially overlap with the fields of view of adjacent imaging devices. With this configuration, the inner wall surface of the building 50 can be imaged around its entire circumference. In addition, it becomes easier to combine the images or videos acquired by each imaging device 104A to 104D.

[0084] The images or videos captured by the imaging devices 104A to 104D may be synchronized and performed simultaneously.

[0085] [Differentiation 2] Modification 2 is described below. In Modification 2, components identical or equivalent to those in Embodiment 1 are denoted by the same reference numerals and described accordingly, and descriptions that overlap with Embodiment 1 are omitted.

[0086] Figures 9 and 10 are schematic diagrams of the inspection device 201 in modified example 2. The inspection device 201 in modified example 2 differs from that in embodiment 1 in that it has two unmanned aerial vehicles 202A and 202B.

[0087] As shown in Figures 9 and 10, the inspection device 201 includes unmanned aircraft 202A and 202B, a first imaging device 204, a linear member 206, pulleys 203A and 203B, an illumination device 240, a winding device 10, a control unit 13, and a transmitter 14.

[0088] The unmanned aerial vehicles 202A and 202B are devices equipped with propellers and controlled remotely via wireless communication. Unless otherwise specified, the unmanned aerial vehicles 202A and 202B may have the same configuration as the unmanned aerial vehicle 2 of Embodiment 1.

[0089] The first pulley 203A is fixed to the first unmanned aerial vehicle 202A, and the second pulley 203B is fixed to the second unmanned aerial vehicle 202B. Unless otherwise specified, pulleys 203A and 203B may have the same configuration as pulley 3 in Embodiment 1.

[0090] Each of the pulleys 203A and 203B supports the linear member 206. The linear member 206 passes through the winding device 10, the first pulley 203A, the first imaging device 204, and the second pulley 203B in order from one end (base end) to the other end (tip end). The tip of the linear member 206 pulled out from the winding device 10 is fixed to a fixing point 207, for example, fixed to the ground G. Unless otherwise specified, the linear member 206 may have the same configuration as the linear member 6 of Embodiment 1.

[0091] The first imaging device 204 is suspended from both the unmanned aircraft 202A and 202B by a linear member 206, and moves up and down within the building 50 through the opening 51 to capture images or videos of the interior walls of the building 50. Unless otherwise specified, the first imaging device 204 may have the same configuration as the first imaging device 4 of Embodiment 1.

[0092] Specifically, the first imaging device 204 is suspended from a portion of the linear member 206 located between pulleys 203A and 203B. The first imaging device 204 is suspended from the horizontal center of the unmanned aerial vehicles 202A and 202B, and the horizontal position of the first imaging device 204 is determined by the positions of the unmanned aerial vehicles 202A and 202B.

[0093] By providing pulleys 203A and 203B, the portions of the linear members 206 extending from the first imaging device 204 to each of the pulleys 203A and 203B are separated horizontally from each other, making them less likely to become entangled. As a result, rotation of the first imaging device 204 in the vertical direction can be suppressed.

[0094] Figure 11 is a schematic diagram of the first imaging device 204 in modified example 2. As shown in Figure 11, the first imaging device 204 has a camera 241, a support part 242, and pulleys 243A and 243B.

[0095] The support portion 242 is a plate-shaped or rod-shaped member that supports the camera 241, and in modified example 2, the upper part of the camera 241 is fixed to it. The pulleys 243A and 243B are provided at different positions on the support portion 242 and each supports the linear member 206. Unless otherwise specified, the pulleys 243A and 243B may have the same configuration as the pulley 3 of embodiment 1. In modified example 2, the pulleys 243A and 243B are arranged on both sides of the camera 241 in the horizontal direction. The distance between each of the pulleys 243A and 243B and the center of gravity of the camera 241 is constant. This configuration makes it easy to suspend the camera 241 horizontally.

[0096] The distance between the unmanned aircraft 202A and 202B is greater than the distance between the pulleys 243A and 243B. This configuration ensures that the linear members 206 extending from the first unmanned aircraft 202A and the linear members 206 extending from the second unmanned aircraft 202B are more reliably separated from each other and less likely to become entangled. As a result, the rotation of the first imaging device 204 in the vertical direction can be further suppressed.

[0097] Returning to Figures 9 and 10, the irradiation device 240 is fixed to the first imaging device 204. The irradiation device 240 is a device that irradiates a laser pattern onto the inner wall surface of the building 50 in a horizontal direction. The irradiation device 240 irradiates, for example, a laser pattern having a visible light wavelength band that can be photographed by the first imaging device 204.

[0098] Because the rotation of the first imaging device 204 in the vertical direction is suppressed, the irradiation device 240 can irradiate a laser pattern in a constant direction. By pre-determining the irradiation direction of the irradiation device 240 to the building 50, the orientation of the first imaging device 204 can be determined. Therefore, the position of the interior wall surface captured by the first imaging device 204 can be determined.

[0099] The unmanned aircraft 202A and 202B may be equipped with downward-facing cameras to photograph the building 50 and the illumination device 240 from above, thereby pre-determining the direction of illumination of the illumination device 240 to the building 50.

[0100] Alternatively, both pulleys 203A and 203B may be provided on a single unmanned aircraft.

[0101] While this disclosure is adequately described in relation to preferred embodiments with reference to the accompanying drawings, various modifications and alterations will be obvious to those skilled in the art. Such modifications and alterations should be understood to be included within the scope of the invention as defined by the appended claims. [Industrial applicability]

[0102] The inspection method described herein has the effect of shortening inspection time and is particularly useful in inspection methods for inspecting the inner wall surfaces of structures such as shafts. [Explanation of Symbols]

[0103] 1. Inspection device 2 Unmanned aircraft 3 Pulleys 4. First imaging device 6 Linear members 10. Winding device 11 Detection unit 12. Second imaging device 13 Control Unit 14 Transmitter 40 Landmark 50 Buildings 51 Aperture H1 First Height V1 First orientation

Claims

1. A method for inspecting a cylindrical structure extending vertically using a first imaging device suspended from an unmanned aerial vehicle, The first imaging device is suspended by a retractable linear member that extends from a winding device located on the outside of the building when viewed from above and below, and passes through a pulley fixed to the unmanned aircraft. The unmanned aircraft is flown above the building, and the pulley is positioned above the building. The winding device adjusts the amount of winding of the linear member to raise and lower the first imaging device within the building, This includes taking images of the interior wall surface of the building at different heights using the first imaging device, The aforementioned unmanned aircraft includes a first unmanned aircraft to which a first pulley is fixed, and a second unmanned aircraft to which a second pulley is fixed. An inspection method wherein the linear member passes through, in order, the winding device, the first pulley, the first position of the first imaging device, the second position of the first imaging device which is different from the first position, and the second pulley.

2. The inspection method according to claim 1, further comprising obtaining a first height of the first imaging device when capturing a first image of the interior wall surface of the building.

3. The method further includes detecting a first winding amount at the time of capturing the first image, The inspection method according to claim 2, wherein the first height is calculated based on the first winding amount.

4. The first imaging device further includes detecting a reference winding amount when it reaches the bottom of the building, The inspection method according to claim 3, wherein the first height is calculated based on the first winding amount and the standard winding amount.

5. The method further includes capturing a first planar image of the first imaging device at the time of capturing the first image using a second imaging device fixed to the unmanned aircraft and capable of capturing images downwards, The inspection method according to claim 2, wherein the first height is calculated based on the size of the first imaging device in the first planar image.

6. The second imaging device further includes capturing a reference plane image of the first imaging device that has reached the bottom of the building, The inspection method according to claim 5, wherein the first height is calculated based on the size of the first imaging device in the first planar image and the size of the first imaging device in the reference planar image.

7. The inspection method according to any one of claims 1 to 6, further comprising obtaining a first orientation of the first imaging device in the vertical direction when capturing a first image of the interior wall surface of the building.

8. When viewed from above or below, the first imaging device has a marker at a position away from the linear member, The method further includes capturing a third planar image of the first imaging device, including the marker, at the time of capturing the first image, using a second imaging device fixed to the unmanned aerial vehicle and capable of capturing images downwards. The inspection method according to claim 7, wherein the first orientation is calculated based on the position of the marker in the third planar image.

9. An unmanned aerial vehicle flying above a cylindrical structure extending vertically, A pulley fixed to the aforementioned unmanned aerial vehicle, The first imaging device suspended from the aforementioned unmanned aerial vehicle, A linear member connected to the first imaging device via the aforementioned pulley, A winding device, which is positioned on the outside of the building when viewed from above and below and capable of winding up the linear member, Equipped with, The aforementioned unmanned aircraft includes a first unmanned aircraft to which a first pulley is fixed, and a second unmanned aircraft to which a second pulley is fixed. The linear member passes through, in order, the winding device, the first pulley, the first position of the first imaging device, the second position of the first imaging device which is different from the first position, and the second pulley. The winding device adjusts the amount of winding of the linear member and raises and lowers the first imaging device within the building. The first imaging device is an inspection device that captures images of the interior wall surface of the building at different heights.

Images