WO2024062896A1

WO2024062896A1 - Imaging device

Info

Publication number: WO2024062896A1
Application number: PCT/JP2023/031846
Authority: WO
Inventors: 大樹吉田
Original assignee: 富士フイルム株式会社
Priority date: 2022-09-22
Filing date: 2023-08-31
Publication date: 2024-03-28

Abstract

Provided is an imaging device that includes: a plurality of cameras; and a plurality of illumination devices. The plurality of cameras are disposed in an arc shape in different radial directions. The imaging device (10) comprises: at least two first holding members (105a(105b)); and a plurality of cameras (101). The first holding members (105a(105b)) are disposed facing each other. The plurality of cameras (101) are disposed on the first holding members (105a(105b)) in an arc shape. The imaging direction of each of the plurality of cameras faces outward in a radial direction of an arc. Among the plurality of cameras (101), the imaging directions of at least adjacent cameras are different.

Description

Imaging device

The present invention relates to an imaging device, and more particularly, to an imaging device that acquires an image of the inner surface of a tunnel.

Conventionally, visual inspections of the inner surfaces of hydroelectric power generation facilities' headrace channels and subway tunnels have been conducted on a regular basis. Recently, this visual inspection has come to be performed using images captured by a camera. An image of the inner surface of the tunnel to be inspected is acquired by an imaging device that can efficiently image the entire circumference of the inner surface of the tunnel. The imaging device has a plurality of cameras and a plurality of lighting devices, and is laid out so that it can photograph the entire circumference of the inner surface of the tunnel. When imaging the inner surface of a tunnel, an imaging device is mounted on a manual or electrically assisted trolley, and while the trolley is running inside the tunnel, still images or videos are taken at regular intervals and images used for inspection. (moving image).

For example, Patent Document 1 describes an imaging device that includes a plurality of cameras and a plurality of illumination devices that image the inner surface of a tunnel for inspecting the tunnel.

Japanese Patent Application Publication No. 2020-155902

One embodiment according to the technology of the present disclosure provides an imaging device that includes a plurality of cameras and a plurality of illumination devices, and in which the plurality of cameras are arranged in an arc shape in different radial directions.

An imaging device that is one aspect of the present invention includes at least two first holding members and a plurality of cameras, the first holding members are arranged to face each other, and the plurality of cameras are arranged to face each other. The plurality of cameras are arranged in an arc shape on the holding member, the shooting directions of the plurality of cameras are directed outward in the radial direction of the arc, and the shooting directions of at least adjacent cameras among the plurality of cameras are different.

Preferably, the photographic fields of view of at least adjacent cameras among the plurality of cameras partially overlap.

Preferably, the two first holding members have a plurality of first attachment parts arranged on the same circumference to which the plurality of second holding members are attached, and the plurality of second holding members each has a second mounting part to which a camera is attached, and by attaching the plurality of second holding members to which at least the cameras are attached to the two first holding members, the plurality of second holding members The plurality of cameras respectively attached to the first holding member are arranged in an arc shape and in different radial directions with respect to the center of the first holding member, and are further arranged in different radial directions between the two first holding members. be done.

Preferably, the plurality of second holding members each have a second mounting portion to which a camera and a lighting device are attached.

Preferably, the radius of the arc can be changed by moving a plurality of cameras arranged in an arc.

Preferably, the second mounting section includes at least a first camera mounting section and a second camera mounting section, and when a camera is attached to the first camera mounting section, the second camera mounting section The cameras are arranged in an arc with a larger radius than if the cameras were attached to the

Preferably, the second mounting section includes a first lighting device mounting section, a second lighting device mounting section, a first camera mounting section, and a second camera mounting section, and the first camera mounting section When the camera is attached to the first lighting device mounting section and the second lighting device mounting section, the lighting device is attached to the first lighting device mounting section, and when the camera is mounted to the second camera mounting section, the lighting device is attached to the first lighting device mounting section. Attach the lighting device to the mounting section.

Preferably, when the camera is attached to the second camera attachment part, the distance and arc between the cameras disposed on the two first holding members are smaller than when the camera is attached to the first camera attachment part. The distance between the cameras in the circumferential direction becomes shorter.

Preferably, the first attachment part is configured with an elongated hole extending along the circumferential direction of the arc in the first holding member, and the second holding member moves along the elongated hole to form an arc shape. The spacing between placed cameras is changed.

Preferably, the plurality of second holding members have a third mounting portion that is attached to the first mounting portion of the first holding member, the third mounting portion being configured as an elongated hole extending along the radial direction, and the second holding members slide radially relative to the first holding member.

Preferably, it is mounted on a trolley that travels in the tunnel, and at least one wheel of the trolley is provided with a sensor that detects the number of revolutions.

Preferably, a distance sensor is provided to obtain information regarding the distance between the camera and the inner surface.

Preferably, the distance sensor is held by a third holding member, and the third holding member is attached to the first holding member.

Preferably, a control device having a processor is provided, and the processor controls the camera's shooting based on the distance information output from the distance sensor.

FIG. 1 is a front perspective view of the imaging device. FIG. 2 is a side view of the imaging device. FIG. 3 is a front view of the imaging device. FIG. 4 is a rear view of the imaging device. FIG. 5 is a diagram showing the camera unit. FIG. 6 is a front perspective view of the first holding member. FIG. 7 is a diagram illustrating how the camera unit and the first holding member are attached. FIG. 8 is a front perspective view of the imaging device. FIG. 9 is a diagram showing the camera unit. FIG. 10 is a conceptual diagram showing a tunnel inspection device. FIG. 11 is a diagram illustrating a camera unit for downward photography. FIG. 12 is a conceptual diagram illustrating wheels. FIG. 13 is a block diagram showing an embodiment of a hardware configuration of a control device. FIG. 14 is a block diagram illustrating functions implemented by the processor. FIG. 15 is a diagram illustrating a specific example of inspecting a subway tunnel. FIG. 16 is a diagram illustrating a specific example of inspecting a tunnel of a headrace. FIG. 17 is a flow diagram illustrating a tunnel inspection method. FIG. 18 is a diagram illustrating a tunnel inspection device according to modification 1. FIG. 19 is a diagram illustrating a rotary arm according to modification 2.

Hereinafter, preferred embodiments of an imaging device according to the present invention will be described with reference to the accompanying drawings.

First, the background that led to the present invention will be explained. When inspecting the inner surface of a tunnel using images, images are taken of the inner surface of the tunnel using multiple cameras, and feature points are extracted within the overlap between adjacent images and combined. Generate a continuous plan development view. Then, inspection is performed using the developed plan view. Investigators visually check the floor plans to detect cracks, etc., and use the floor plans to draw up repair plans. In addition, cracks may be detected by applying the plan development view to a detector configured with AI (artificial intelligence). Therefore, when inspecting the inner surface of a tunnel, it is necessary to efficiently obtain a developed plan view that can detect damage such as cracks.

Here, the camera used in the imaging device should take into account variations in the shooting angle of view, the width of the crack to be detected (for example, cracks with a width of 1 mm or less may also be detected), vibration countermeasures when the trolley is running, etc. , a high-performance single-lens reflex camera (or a high-performance single-lens reflex camera) is preferably used. Additionally, since there are many dark places inside the tunnel, it is necessary to install a lighting device for each camera. Therefore, if the required number of cameras and illumination devices are laid out in an arcuate or circular shape so that the entire circumference or substantially the entire circumference of the inner surface of the tunnel can be imaged, the external size of the imaging device becomes large.

Here, if the diameter of the tunnel exceeds 6 m, sufficient space can be secured for the delivery route for the imaging device and the assembly work space on site. On the other hand, in the case of small-diameter headrace tunnels with a diameter of 2 m or less, the delivery route is too narrow to pass through, or the assembly space is too narrow to carry out work. Furthermore, in the case of a small-diameter headrace tunnel with a tunnel diameter of 2 m or less, there may be a problem that when the bogie is running, it meanderes and interferes with the inner surface of the tunnel. Therefore, conventionally, when inspecting small-diameter tunnels, workers would lie on their backs on a trolley while carrying a handheld camera to take images.

In view of the above, the present disclosure described below proposes an imaging device that can efficiently image the inner surface of tunnels from large diameters to small diameters.

<Imaging device for imaging large diameter tunnels>
First, an imaging apparatus for imaging a tunnel with a relatively large diameter (large diameter) will be described. Note that the large diameter tunnel here refers to a tunnel with a diameter of 3 m to 10 m, for example.

FIGS. 1 to 4 are diagrams illustrating an imaging device for imaging a large-diameter tunnel. FIG. 1 is a front perspective view of the imaging device, FIG. 2 is a side view of the imaging device, FIG. 3 is a front view of the imaging device, and FIG. 4 is a rear view of the imaging device. In the following description, the front is a surface viewed from the plus Z-axis side, the side surface is a surface viewed from the X-axis direction, and the back surface is a surface viewed from the minus Z-axis side. Note that the imaging device 10 is mounted on a trolley 260 (see FIG. 10), and while moving in the traveling direction W, acquires an image of the inner surface of the tunnel to be inspected. Thereafter, a developed plan view of the inner surface of the tunnel is generated from the acquired images.

The imaging device 10 mainly includes a first holding member 105a on the front side, a first holding member 105b on the back side, and a plurality of camera units 12 (see FIG. 5) attached to the

first holding members

105a and 105b. configured. When capturing an image of the inner surface of a large-diameter tunnel, the camera unit 12 includes two lighting devices 103, one camera 101, and a second holding member 125 (see FIG. 5).

In the imaging device 10, four (4 types) camera units 12 are provided on the first holding member 105a on the front side (see FIG. 3), and five (5 types) are provided on the first holding member 105b on the back side. A camera unit 12 is provided (see FIG. 4). The camera 101 attached to the camera unit 12 is arranged in an arc shape with respect to the center O (center portion) of the rotation base 111a and the rotation base 111b. In this case, the camera 101 is arranged so that the photographing direction of the camera 101 is in the radial direction of the arc. Further, like the camera 101, the illumination device 103 attached to the camera unit 12 is also arranged in an arc shape with respect to the center O (center portion) of the rotation base 111a and the rotation base 111b. In addition, in the following description, the circular arc (circular arc shape) formed by the camera 101 mentioned above is simply described as a circular arc (circular arc shape). Furthermore, the radial direction and circumferential direction of the arc (circular arc shape) formed by the camera 101 described above are simply referred to as the radial direction and circumferential direction.

Furthermore, the photographing direction of the camera 101 (optical axis direction of the camera 101) is different between at least adjacent cameras 101. Furthermore, the camera 101 attached to the first holding member 105a on the front side and the camera 101 attached to the first holding member 105b on the back side are provided so as to have different photographing directions. Similarly, the lighting device 103 is provided so that the irradiation direction is along the radial direction of the arc, and the lighting device 103 is attached to the first holding member 105a on the front side and the first holding member 105a on the back side. The lighting devices 103 attached to the holding member 105b are provided so as to have different irradiation directions.

By arranging the camera 101 in this way, as shown in FIGS. 1 and 2, the camera 101 provided on the first holding member 105a on the front side and the first holding member 105b on the back side are connected to each other. Together with the provided camera 101, it forms a zigzag shape (staggered shape) (see line L in FIGS. 1 and 2). That is, as shown by the line L shown in FIGS. 1 and 2, the cameras 101 have a zigzag shape, and the cameras 101 connected by the line L have side overlaps S and overlaps T, so that the captured images are Partial overlap (the photographic fields of view partially overlap). This means that in each of the cameras 101, the photographing fields of adjacent cameras 101 partially overlap. In this way, by acquiring images so that they have partially overlapping parts, it is possible to synthesize a plurality of acquired images and generate a continuous plan development view.

Similarly, the lighting device 103 has a zigzag shape (zigzag shape) with the lighting device 103 provided on the first holding member 105a on the front side and the lighting device 103 provided on the first holding member 105b on the back side. shape).

As explained above, by arranging the camera 101 and the illumination device 103 in a zigzag shape, the external size of the imaging device 10 can be reduced, and a planar development view can also be generated from the acquired images.

Next, the camera unit 12 will be explained in detail.

FIG. 5 is a diagram showing the camera unit 12 attached to the imaging device 10 when imaging a large-diameter tunnel. The camera unit 12 includes one camera 101, two lighting devices 103, and a second holding member 125. The second holding member 125 includes a frame member 123 and a rotating arm 121.

The camera 101 is preferably configured with a high-performance single-lens reflex camera or a high-performance single-lens reflex camera, but the camera used is not particularly limited. By changing the sensor size and lens focal length of the camera 101, it is possible to adjust the pixel resolution according to the shooting angle of view and the minimum crack width that is desired to be confirmed during inspection.

The illumination device 103 has a light distribution angle that exceeds the angle of view of the camera 101 attached thereto. Further, the illumination device 103 needs not to have flicker at the same frequency as the photographing shutter speed of the camera 101.

The second holding member 125 is composed of a rotating arm 121 and a frame member 123. The rotating arm 121 is inserted into and fixed to the window portion of the frame member 123. The frame member 123 has a rectangular shape, and has a first lighting device mounting portion 123a and a second lighting device mounting portion 123b at opposite ends of the rectangular shape. It is preferable that a plurality of mounting holes be provided in the first lighting device mounting portion 123a and the second lighting device mounting portion 123b so that various types of lighting devices can be mounted depending on the required illuminance. Further, the lighting device 103 is detachably attached to the first lighting device mounting portion 123a and the second lighting device mounting portion 123b. Depending on the tunnel to be inspected, the lighting device 103 may not be necessary, and in that case, the lighting device 103 can be removed to reduce the weight of the imaging device 10.

The rotating arm 121 is connected to the frame member 123. Further, the rotating arm 121 has a screw 121a, and is attached to the rotating base 111a or the rotating base 111b by being tightened by the screw 121a (see FIG. 7). Further, the rotating arm 121 has a first camera attachment part 121b on one of both ends, to which the camera 101 is attached. The camera 101 is attached to the first camera attachment part 121b using a tripod screw provided on the bottom of the camera 101. By attaching the camera 101 to the first camera attachment part 121b, the layout is such that the battery cover and rear operation system of the camera 101 are accessible.

Note that the first camera mounting portion 121b, the first lighting device mounting portion 123a, and the second lighting device mounting portion 123b constitute a second mounting portion of the second holding member 125.

Next, the first holding member 105a (105b) will be described in detail.

6 and 7 are diagrams explaining the first holding member 105a (105b). FIG. 6 is a front perspective view of the first holding member 105a (105b), and FIG. 7 is a diagram illustrating a state in which the camera unit 12 and the first holding member 105a are attached.

The first holding member 105a on the front side and the first holding member 105b on the back side are connected to each other by the connecting member 113 and the base plate 107 while facing each other and being spaced apart in the traveling direction W.

The base plate 107 is a plate on which the first holding member 105a on the front side and the first holding member 105b on the back side are mounted, and is connected to the trolley 260 (see FIG. 10). The carriage 260 and the base plate 107 are fixed by manually tightening a knob (not shown). Thereby, the work of fixing the imaging device 10 to the trolley 260 can be completed manually without preparing any tools or the like.

The first holding member 105a on the front side is composed of a leg portion 109a, a rotation base 111a, and an angle adjustment plate 119a. Further, the first holding member 105b on the back side includes a leg portion 109b, a rotation base 111b, and an angle adjustment plate 119b (not shown). In the following description, the first holding member 105a on the front side will be explained, but the first holding member 105b on the back side has a similar configuration.

The leg portion 109a is attached perpendicularly to the base plate 107 at the lower end, and attached to the connecting member 113 at the upper end. The rotation base 111a is attached to the upper end of the leg portion 109a together with the angle adjustment plate 119a. The angle adjustment plate 119a can adjust the rotation angle of the rotation base 111a. The adjustment angle pitch is determined from the viewpoint of workability and rigidity, and can be set arbitrarily or every several degrees. Further, the rotary base 111a is provided with a scale so that the angle adjustment amount can be visually confirmed.

The first holding member 105a and the camera unit 12 are connected by attaching the rotating arm 121 to the elongated hole 112 (first attachment part) of the rotating base 111a. Specifically, the first holding member 105a and the camera unit 12 are connected by an elongated hole 112 extending along the circumferential direction of the rotation base 111a and a screw 121a of the rotation arm 121. The screw 121a has a structure that can be tightened manually without the need for tools. This makes it possible to connect the first holding member 105a and the camera unit 12 even in locations where inspection work is to be performed, where there is water or the like underneath and where it is difficult to perform work using tools. Further, by moving the rotating arm 121 along the elongated hole 112, the camera unit 12 can adjust the angle in the circumferential direction of the arc on the rotating base 111a. Thereby, the distance between the cameras 101 arranged in an arc shape can be changed.

A maximum of nine camera units 12 can be mounted in the circumferential direction of the imaging device 10. Moreover, the rotation base 111a and the rotation base 111b are installed in an offset state along the traveling direction W of the trolley 260. Further, in order to obtain high running stability of the trolley 260, it is preferable that the rotation base 111a and the rotation base 111b are laid out as low as possible in the center of gravity. Furthermore, although the illustrated rotating base 111a and rotating base 111b have a disk shape, they are not limited to this. For example, the rotation base 111a and the rotation base 111b may be formed of rectangular plate members.

As explained above, when imaging a large-diameter tunnel, the imaging device 10 attaches the camera 101 to the first camera attachment part 121b, and attaches the camera 101 to the first illumination device attachment part 123a and the second illumination device attachment part 123a. The illumination device 103 is attached to the section 123b to image the inner surface of the tunnel. This makes it possible to efficiently image the inner surface of a large-diameter tunnel. Moreover, the acquired image can generate a plan development view that allows for appropriate inspection.

<Imaging device for imaging a small tunnel>
Next, the imaging device 10 when imaging a tunnel with a relatively small diameter (small diameter) will be described. Note that a small diameter tunnel here refers to a tunnel with a diameter of, for example, 1.5 m to 2 m. Also, the description of the same parts as those of the imaging device 10 when imaging a large diameter tunnel described above will be omitted.

FIGS. 8 and 9 are diagrams illustrating the imaging device 10 when imaging a small diameter tunnel. FIG. 8 is a front perspective view of the imaging device 10 when capturing an image of a small-diameter tunnel, and FIG. 9 is a diagram showing the camera unit 12 when capturing an image of a small-diameter tunnel.

The imaging device 10 is equipped with nine camera units 12 as in the case of imaging a large-diameter tunnel. Specifically, four types of camera units 12 are provided on the first holding member 105a on the front side, and five types of camera units 12 are provided on the first holding member 105b on the back side.

The camera 101 attached to the camera unit 12 is arranged in an arc shape with respect to the center O (center portion) of the rotation base 111a and the rotation base 111b. Further, like the camera 101, the illumination device 103 attached to the camera unit 12 is also arranged in an arc shape with respect to the center O (center portion) of the rotation base 111a and the rotation base 111b. Furthermore, the photographing directions of the cameras 101 are arranged in different radial directions, and further, the two

first holding members

105a and 105b are arranged in different radial directions.

The camera unit 12 includes one camera 101, one lighting device 103, and a second holding member 125. The second holding member 125 includes a frame member 123, a rotating arm 121, and an auxiliary member 203.

When photographing the inner surface of a small-diameter tunnel, the camera 101 is removed from the first camera attachment part 121b and attached to the auxiliary member 203. Furthermore, the lighting device 103 that was attached to the second lighting device attachment portion 123b is removed, and the auxiliary member 203 is attached to the second lighting device attachment portion 123b. One end of both ends of the auxiliary member 203 is connected to the second lighting device attachment part 123b, and the camera 101 is attached to the other end (second camera attachment part) of the auxiliary member 203. In this way, by attaching the camera 101 to the second camera attachment part, the radius of the arc formed by the camera 101 is shortened compared to when the camera 101 is attached to the first camera attachment part 121b. Ru. Furthermore, by attaching the camera 101 to the second camera attachment part, the camera 101 is placed on the first holding member 105a on the front side, compared to when the camera 101 is attached to the first camera attachment part 121b. The distance between the camera 101 and the camera 101 disposed on the first holding member 105b on the back side, and the distance between the cameras 101 in the circumferential direction are shortened. Note that the second camera attachment portion constitutes a second attachment portion of the second holding member 125. Moreover, as the auxiliary member 203, members of various shapes are employed. For example, an L-shaped plate member is used as the auxiliary member 203.

In this way, when photographing a tunnel with a small diameter, the illumination device 103 attached to the second illumination device attachment part 123b is removed and the camera 101 is attached to the auxiliary member 203 (second camera attachment part). Accordingly, the radius of the arc formed by the camera 101 can be shortened, and the imaging device 10 is configured with a size that can image a tunnel with a small diameter. As a result, the imaging device 10 can image the inner surface of the tunnel while ensuring the angle of view and minimum object distance (MOD) of the camera 101 even in a small diameter tunnel. Furthermore, the obtained image makes it possible to generate a plan development view that can be properly inspected.

In addition, in the above, the assembly conditions of the imaging device 10 such as the imaging device 10 when imaging a large-diameter tunnel and the imaging device 10 when imaging a small-diameter tunnel are calculated based on the automatic calculation results using the "parameter calculation file". It's okay. For example, the parameter calculation file automatically outputs the type of lens (focal length, etc.), the number of cameras 101 installed, the mounting angle, etc. when the tunnel shape, the width of the crack to be detected, and the running conditions of the trolley 260 are input. do. The diameter of the tunnels to be inspected varies from 1.5 to 10 m, so the photographing conditions of the camera 101 (lens type/number of units installed/installation angle) must be determined in advance. However, if the imaging center is not located at the center of the tunnel, the condition settings will vary for each camera 101, resulting in a very labor-intensive and time-consuming task. Therefore, by using software such as a parameter calculation file, even a user who does not have much knowledge about setting the camera 101 can easily set the camera 101 in a short time.

<Tunnel inspection device>
Next, the tunnel inspection device 11 equipped with the imaging device 10 will be explained. The imaging device 10 is mounted on a trolley 260 that runs inside the tunnel and constitutes the tunnel inspection device 11, and images the inner surface of the tunnel. Note that the tunnel inspection device 11 is also one form of an imaging device.

FIG. 10 is a conceptual diagram showing the tunnel inspection device 11.

The tunnel inspection device 11 mainly includes an imaging device 10, a trolley 260, and a control device 20. Further, a third holding member 254 is attached to the imaging device 10. One end of the third holding member 254 is attached to the rotating base 111a, and the rider 252 is attached to the other end. The lidar 252 is an example of a ranging sensor. The distance sensor only needs to be able to acquire information on the distance to the inner surface of the tunnel, and in addition to the lidar 252, a TOF (Time Of Flight) camera or the like can be used. Further, the camera unit 12 including the camera 101 for photographing the downward direction (minus Y-axis direction) is attached to the third holding member 254.

FIG. 11 is a diagram illustrating the camera unit 12 for downward photography.

The camera unit 12 for downward photography includes a camera 101 and two lighting devices 103. The camera 101 images the area below (for example, the ground) when the tunnel inspection device 11 travels. The configuration of the camera unit 12 has already been explained with reference to FIG. 5, so a detailed explanation will be omitted here.

The truck 260 has four wheels 270. By driving the wheels 270, the tunnel inspection device 11 travels inside the tunnel to be inspected. Note that, although the traveling of the trolley 260 in this example is controlled by the control device 20, it is not limited to this. For example, traveling of the trolley 260 may be controlled manually.

FIG. 12 is a conceptual diagram explaining the wheel 270. Note that in FIG. 12, only one wheel 270 is schematically illustrated. Furthermore, illustrations of a mechanism for attaching the positioning sensor 272 to the trolley 260 are omitted.

A positioning sensor 272 is attached to the wheel 270, and the moving distance of the trolley 260 is measured. Specifically, a magnetic body 270a is arranged on the circumferential surface of the wheel 270, and the magnetic body 270a is detected by a positioning sensor 272 provided on the main body of the cart 260. Thereby, the magnetic body 270a is detected every time the wheel 270 rotates, and the number of rotations of the wheel 270 can be measured from the number of pulses that rise each time the wheel 270 rotates, and the distance traveled can be calculated. Note that by associating the moving distance of the trolley 260 estimated by the positioning sensor 272 with the image acquired by the imaging device 10, it is possible to improve the efficiency of the inspection work. For example, when displaying a combined plan development view, coordinate position information of the displayed location can also be displayed. In addition, the information from the positioning sensor 272 can be used as supplementary information for fine-tuning the synthesis position and extracting feature points when feature points cannot be extracted when composing a developed plan view. Furthermore, by positioning the trolley 260 using the positioning sensor 272 provided on the wheels 270, positioning is possible even in environments where GPS (Global Positioning System) cannot be used, and the position corresponding to the acquired image can be grasped. Can be done. Note that the positioning sensor 272 may be attached to at least one wheel 270, or may be attached to a plurality of wheels 270. By attaching positioning sensors 272 to a plurality of wheels 270, a more accurate moving distance of trolley 260 can be obtained. Furthermore, the positioning sensor 272 is configured with, for example, an electromagnetic proximity sensor.

FIG. 13 is a block diagram showing an embodiment of the hardware configuration of the control device 20 shown in FIG. 10.

The control device 20 shown in FIG. 13 includes a processor 200, a memory 210, a database 220, a display section 230, an input/output interface 240, and an operation section 250.

The processor 200 is composed of a CPU (Central Processing Unit), etc., and performs overall control of each part of the control device 20, as well as controlling photographing of a tunnel by the imaging device 10.

The memory 210 includes a flash memory, a ROM (Read-only Memory), a RAM (Random Access Memory), a hard disk device, and the like. A flash memory, ROM, or hard disk device is a nonvolatile memory that stores various programs including an operating system. The RAM functions as a work area for processing by the processor 200 and temporarily stores programs and the like stored in a flash memory or the like. Note that the processor 200 may include a part of the memory 210 (RAM).

The database 220 stores images captured by the imaging device 10. The image acquired by the imaging device 10 may be stored in association with the moving distance of the trolley 260 acquired by the positioning sensor 272. Further, a plan development view obtained by combining images acquired by each camera 101 may be stored.

The display unit 230 displays images under the control of the processor 200. The display unit 230 is also used as part of a GUI (Graphical User Interface) when receiving various information from the operation unit 250.

The input/output interface 240 includes a connection unit that can be connected to an external device, a communication unit that can be connected to a network, and the like. The input/output interface 240 can connect to external devices and networks by wire or wirelessly. In addition, the input/output interface 240 connects with the lidar 252 of the tunnel inspection device 11 and the positioning sensor 272 of the trolley 260, and acquires the output data of each.

The operation unit 250 includes a pointing device such as a mouse, a keyboard, and the like, and functions as part of a GUI that accepts input of various information and instructions by user operations. Further, the operation unit 250 may be configured with a joystick or the like to control the running of the trolley 260.

Further, when inspecting a tunnel, when a user (inspector) visually finds a deformation, the user (inspector) can check the position of the deformation by operating the voice input device or switch that constitutes the operation unit 250. The positioning data obtained by the positioning sensor 272 and the image are stored in association with each other. Thereby, visual inspection information and images can be stored in association with each other, and it is possible to prevent deformities from being overlooked.

FIG. 14 is a block diagram illustrating functions implemented by the processor 200. The processor 200 constitutes an imaging condition control section 202. Furthermore, the processor 200 obtains information regarding the distance to the inner surface of the tunnel to be inspected, which is output from the lidar 252. Further, the processor 200 controls the camera 101. The processor 200 controls, for example, AF (Auto Focus) and focal length of the camera 101.

The lidar 252 outputs point cloud information on the distance to the tunnel inner surface to the processor 200. Then, the photographing condition control unit 202 corrects the photographing conditions of the plurality of cameras 101 based on the information regarding the distance to the inner surface output from the lidar 252. Specifically, the photographing condition control unit 202 controls photographing conditions such as AF of the plurality of cameras 101 mounted on the imaging device 10 and focal length of the lens of the camera 101. This prevents the shooting distance from changing due to meandering of the trolley 260 or sudden changes in the tunnel cross section, and from insufficient pixel density based on the amount of overlap between adjacent images and the size of the crack to be inspected. , images suitable for inspection can be obtained. Note that image capturing by the camera 101 is performed under the control of the processor 200. Image capture by the camera 101 is performed at regular time intervals. Further, the image capturing by the camera 101 may be performed based on positioning data output from the positioning sensor 272.

15 and 16 are diagrams illustrating a specific example of controlling the photographing conditions of the tunnel inspection device 11.

FIG. 15 is a diagram illustrating a specific example of inspecting a subway tunnel.

The case indicated by reference numeral 280 shows a case where the rider 252 is not mounted on the tunnel inspection device 11. Further, a case indicated by reference numeral 282 shows a case where a rider 252 is mounted on the tunnel inspection device 11.

The diameter of the subway tunnel 290 increases at point D. The tunnel inspection device 11 travels in a straight line, but as the diameter of the tunnel increases, the quality of the image it obtains changes after passing point D. In the case indicated by reference numeral 280, the distance to the inner surface of the tunnel 290 is increased, resulting in insufficient pixel density in the acquired image, making it difficult to appropriately detect damage such as cracks.

On the other hand, in the case indicated by reference numeral 282, it is detected that the distance to the inner surface of the tunnel 290 has become longer at point D based on the distance information output by the lidar 252 mounted on the tunnel inspection device 11. Thereby, the photographing condition control unit 202 can change the AF and focal length of the camera 101 based on the information regarding the distance. Therefore, in this case, insufficient pixel density in the acquired image is suppressed, and damage such as cracks can be appropriately detected.

FIG. 16 is a diagram illustrating a specific example of inspecting the tunnel of the headrace.

The case indicated by reference numeral 284 shows a case where the rider 252 is not mounted on the tunnel inspection device 11. Further, a case indicated by reference numeral 286 shows a case where the rider 252 is mounted on the tunnel inspection device 11.

In the headrace tunnel 292, the tunnel inspection device 11 is running in a meandering manner. As the tunnel inspection device 11 meanderes, the distance from the tunnel 292 becomes shorter as shown in the figure, and the overlapping portions in the images acquired by each camera 101 become insufficient. That is, in adjacent images, areas that overlap each other end up being absent or small. In such a case, there will be parts in the acquired image that cannot be photographed, making it impossible to properly inspect the tunnel. Furthermore, it is not possible to generate an appropriate plan development view from the acquired image.

On the other hand, in the case indicated by reference numeral 286, it is detected that the distance to the inner surface of the tunnel 292 has become longer based on the information regarding the distance outputted by the lidar 252, and the photographing condition control unit 202 controls the camera 101 based on the information regarding the distance. Change AF and focal length. Thereby, it is possible to suppress the lack of overlapping portions in the acquired images, and to comprehensively acquire images of the tunnel 292.

Next, a tunnel inspection method using the tunnel inspection device 11 will be explained. Note that the tunnel inspection method is performed by the processor 200 of the control device 20 executing a program stored in the memory 210.

FIG. 17 is a flow diagram illustrating a tunnel inspection method performed by the tunnel inspection device 11.

First, the distance to the inner surface of the tunnel is measured by the rider 252 (step S01). After that, the imaging condition control unit 202 determines whether the distance to the inner surface of the tunnel has been changed (step S02). When the distance to the inner surface of the tunnel changes, the camera 101 is controlled to change the photographing conditions (step S05). After that, an image of the inner surface of the tunnel is acquired by the camera 101 (step S03). On the other hand, if the distance to the inner surface of the tunnel has not changed, the image is acquired by the camera 101 without changing the photographing conditions. Thereafter, the processor 200 determines whether the tunnel inspection has been completed (step S04), and if the tunnel inspection has not been completed, the distance to the inner surface of the tunnel is measured again.

As explained above, the tunnel inspection device 11 acquires information regarding the distance from the lidar 252 to the inner surface of the tunnel, and controls the photographing conditions of the camera 101 based on the information regarding the distance to acquire images. . Thereby, even if the distance to the inner surface of the tunnel changes, it is possible to obtain an image with an image quality that allows damage such as cracks to be detected. Furthermore, even if the distance to the inner surface of the tunnel changes, this makes it possible to comprehensively image the inner surface of the tunnel and generate a developed plan view.

In the above embodiment, the hardware structure of the processing unit (for example, the imaging condition control unit 202) that executes various processes is the following various processors. Various types of processors include CPUs (Central Processing Units) and FPGAs (Field Programmable Gate Arrays), which are general-purpose processors that execute software (programs) and function as various processing units.The circuit configuration can be changed after manufacturing. This includes programmable logic devices (PLDs), which are processors, and dedicated electric circuits, which are processors with circuit configurations specifically designed to execute specific processes, such as ASICs (Application Specific Integrated Circuits). It will be done.

One processing unit may be composed of one of these various processors, or may be composed of two or more processors of the same type or different types (for example, multiple FPGAs, or a combination of a CPU and FPGA). It's okay. Further, the plurality of processing units may be configured with one processor. As an example of configuring multiple processing units with one processor, first, one processor is configured with a combination of one or more CPUs and software, as typified by computers such as clients and servers. There is a form in which a processor functions as multiple processing units. Second, there are processors that use a single IC (Integrated Circuit) chip to implement the functions of the entire system, including multiple processing units, as typified by System On Chip (SoC). be. In this way, various processing units are configured using one or more of the various processors described above as a hardware structure.

More specifically, the hardware structure of these various processors is an electrical circuit that combines circuit elements such as semiconductor elements.

Each of the configurations and functions described above can be realized as appropriate using any hardware, software, or a combination of both. For example, a program that causes a computer to execute the above-mentioned processing steps (processing procedures), a computer-readable recording medium (non-temporary recording medium) recording such a program, or a computer capable of installing such a program. It is possible to apply the present invention to any case.

<Modification 1>
Next, Modification 1 will be explained. The tunnel inspection device 11 described in FIG. 10 is an example in which the imaging device 10 is attached to the trolley 260. In the tunnel inspection device 11 of this example, the height from the cart 260 to the center of the rotating base 111a can be changed by arranging the spacer P. For example, in the tunnel inspection device 11 of this example, the height from the trolley 260 to the center of the rotating base 111a can be adjusted within a range of 1 to 2.5 m.

FIG. 18 is a diagram illustrating the tunnel inspection device 11 of Modification 1. Note that in FIG. 18, illustration of the cart 260 that constitutes the tunnel inspection device 11 is omitted.

In the tunnel inspection device 11 of this example, spacers P made of aluminum frames are stacked. The spacers P have a rectangular parallelepiped shape and have a structure that allows them to be stacked upward. Furthermore, the pitch can be adjusted by adjusting the height of the spacer P. For example, if the height of one spacer P is 150 mm, the adjustment pitch can be 150 mm.

As explained above, by arranging the spacer P between the imaging device 10 and the trolley 260 and making the height adjustable, it is possible to correspond to inspections of tunnels of various shapes.

<Modification 2>
Next, modification 2 will be explained. In the second modification, a long hole 294 is provided in the rotary arm 121. Thereby, the rotary arm 121 can be slid in the radial direction, and the diameter of the circumference can be changed.

FIG. 19 is a diagram illustrating the rotating arm 121 of Modification 2.

The rotating arm 121 has an elongated hole 294 (third mounting portion) into which the screw 121a is tightened. The rotating arm 121 is attached to the first holding member 105a (105b) by tightening the screw 121a into the elongated hole 294. This allows the rotating arm 121 to slide relative to the rotating base 111a (rotating base 111b) using the elongated hole 294, and the radial position of the camera 101 attached to the first camera mounting portion 121b can be adjusted.

As explained above, by providing the elongated hole 294 in the rotary arm 121, the radial position of the camera 101 can be adjusted.

<Additional notes>
The content disclosed above includes, for example, the content of the following inventions.

(First invention)
comprising at least two first holding members and a plurality of cameras;
the first holding members are arranged to face each other,
The plurality of cameras are arranged in an arc shape on the first holding member, and the photographing directions of the plurality of cameras are directed outward in the radial direction of the arc,
Among the plurality of cameras, at least adjacent cameras have different shooting directions;
Imaging device.

(Second invention)
at least two first holding members and a plurality of cameras, the first holding members are arranged to face each other, and the plurality of cameras are arranged in an arc shape on the first holding member, An imaging device, wherein the photographing directions of the plurality of cameras face outward in the radial direction of the circular arc, and the photographing directions of at least adjacent cameras among the plurality of cameras are different,
a distance sensor that acquires information regarding the distance between the camera and the inner surface of the tunnel;
a control device having a processor;
An imaging device, wherein the processor controls photographing by the camera based on distance-related information output from the distance sensor.

(Third invention)
An imaging device that is mounted on a trolley running in a tunnel and captures an image of an inner wall surface of the tunnel,
The imaging device includes two first holding members, a plurality of second holding members, a plurality of cameras, and a plurality of illumination devices,
The two first holding members are a pair of plate-shaped members facing each other, and are arranged on the cart apart from each other in the running direction of the cart, and the plurality of second holding members are attached to the same plate. having a plurality of first attachment parts arranged on the circumference of the
The plurality of second holding members each include a second mounting part to which the camera and the lighting device are mounted, and a third mounting part to be mounted to the first mounting part of the first holding member. have,
By attaching the plurality of second holding members to which at least the cameras are attached to the two first holding members, the cameras respectively attached to the plurality of second holding members can be attached to the first holding members. are arranged in an arc shape and in different radial directions with respect to the central part of the holding member, and further arranged in different radial directions between the two first holding members,
Imaging device.

Although examples of the present invention have been described above, it goes without saying that the present invention is not limited to the embodiments described above, and that various modifications can be made without departing from the spirit of the present invention.

10: Imaging device 11: Tunnel inspection device 12: Camera unit 14: First holding member 20: Control device 101: Camera 103: Illumination device 105a: First holding member 105b: First holding member 107: Base plate 109a: Legs 109b: Legs 111a: Rotating base 111b: Rotating base 112: Elongated hole 113: Connection member 119a: Angle adjustment plate 119b: Angle adjustment plate 121: Rotating arm 121a: Screw 121b: First camera mounting portion 123: Frame Member 123a: First lighting device mounting section 123b: Second lighting device mounting section 125: Second holding member 200: Processor 202: Photographing condition control section 203: Auxiliary member 210: Memory 220: Database 230: Display section 240 : Input/output interface 250 : Operation unit 252 : Rider 254 : Third holding member 260 : Dolly 270 : Wheel 270a : Magnetic body 272 : Positioning sensor 294 : Oblong hole

Claims

comprising at least two first holding members and a plurality of cameras;
the first holding members are arranged to face each other,
The plurality of cameras are arranged in an arc shape on the first holding member, and the photographing directions of the plurality of cameras are directed outward in the radial direction of the arc,
Among the plurality of cameras, at least adjacent cameras have different shooting directions;
Imaging device.
The imaging device according to claim 1, wherein the fields of view of at least adjacent cameras of the plurality of cameras overlap partially.
The two first holding members have a plurality of first attachment parts arranged on the same circumference to which the plurality of second holding members are attached,
Each of the plurality of second holding members has a second attachment portion to which the camera is attached,
By attaching the plurality of second holding members to which at least the cameras are attached to the two first holding members, the plurality of cameras respectively attached to the plurality of second holding members can be attached to the plurality of second holding members. Claim 2: The first holding member is arranged in the arc shape and in different radial directions with respect to the center portion of the first holding member, and further arranged in different radial directions between the two first holding members. The imaging device described in .
The imaging device according to claim 1, wherein the plurality of second holding members each have a second attachment portion to which the camera and the lighting device are attached.
The imaging device according to claim 1, wherein the radius of the arc can be changed by moving the plurality of cameras arranged in an arc shape.
the second mounting portion includes at least a first camera mounting portion and a second camera mounting portion;
4. The imaging device of claim 3, wherein when the camera is attached to the first camera mounting portion, the camera is arranged on an arc having a larger radius than when the camera is attached to the second camera mounting portion.
The second mounting section includes a first lighting device mounting section, a second lighting device mounting section, a first camera mounting section, and a second camera mounting section,
When the camera is attached to the first camera attachment section, the illumination device is attached to the first illumination device attachment section and the second illumination device attachment section,
The imaging device according to claim 4, wherein when the camera is attached to the second camera attachment section, the illumination device is attached to the first illumination device attachment section.
When the camera is attached to the second camera attachment part, the distance between the cameras arranged on the two first holding members is greater than when the camera is attached to the first camera attachment part. The imaging device according to claim 6 or 7, wherein the distance and the distance between the cameras in the circumferential direction of the arc are shortened.
The first attachment part is configured with an elongated hole extending along the circumferential direction of the arc in the first holding member,
The imaging device according to claim 3, wherein the interval between the cameras arranged in the arc shape is changed by moving the second holding member along the elongated hole.
The plurality of second holding members have a third attachment part attached to the first attachment part of the first holding member,
The third attachment portion is configured with an elongated hole extending along the radial direction,
The imaging device according to claim 3, wherein the second holding member slides in the radial direction with respect to the first holding member.
The imaging device according to claim 1, wherein the imaging device is mounted on a truck that travels in a tunnel, and at least one wheel of the truck is provided with a sensor that detects the number of revolutions.
The imaging device according to claim 1, further comprising a distance sensor that acquires information regarding the distance between the camera and the inner surface.
The distance sensor is held by a third holding member,
The imaging device according to claim 12, wherein the third holding member is attached to the first holding member.
comprising a control device having a processor;
The processor controls photographing by the camera based on information regarding the distance output from the distance sensor.
The imaging device according to claim 12 or 13.