Imaging device, imaging method, and program

Abstract

Provided are: an imaging device that, by use of a first camera unit and a second camera unit each comprising a plurality of cameras, acquires images with which inspection can be performed appropriately; an imaging method; and a program. An imaging device (1) comprises: a first camera unit (101) which has a plurality of first cameras (107) arranged in a first-circular-arc (C1) configuration and in which the first cameras (107) are arranged so as to have the respective shooting directions oriented toward the radially outer side of the first circular arc (C1); and a second camera unit (111) which has a plurality of second cameras (107) arranged in a second-circular-arc (C2) configuration and in which the second cameras (107) are arranged so as to have the respective shooting directions oriented toward the radially outer side of the second circular arc (C2). A first axis (R1) that passes through the center of the first circular arc (C1) and that is orthogonal to a plane including the first circular arc (C1) is parallel to but does not overlap with a second axis (R2) that passes through the center of the second circular arc (C2) and that is orthogonal to a plane including the second circular arc (C2).

Description

Imaging device, imaging method, and program

[0001] The present invention relates to an imaging device, an imaging method, and a program.

[0002] Traditionally, tunnel interior walls have been visually inspected periodically to check for damage, etc. However, in recent years, this visual inspection has been replaced by technology that uses images taken with cameras to detect damage, etc.

[0003] For example, Patent Document 1 describes an inspection system that uses multiple video cameras to capture images of the inner wall surface of a tunnel for inspection. In the inspection system described in Patent Document 1, the entire inner wall surface of the tunnel is captured by the multiple video cameras for inspection.

[0004] JP 2011-95222 A

[0005] One embodiment of the technology disclosed herein provides an imaging device, an imaging method, and a program that acquire images that can be used for appropriate inspection using a first camera unit and a second camera unit composed of multiple cameras.

[0006] A first aspect of the present invention is an imaging device that includes a first camera unit having a plurality of first cameras arranged in a first arc, with the shooting direction of the plurality of first cameras facing radially outward of the first arc, and a second camera unit having a plurality of second cameras arranged in a second arc, with the shooting direction of the plurality of second cameras facing radially outward of the second arc, wherein a first axis that passes through the center of the first arc and is perpendicular to a plane that includes the first arc, and a second axis that passes through the center of the second arc and is perpendicular to the plane that includes the second arc, are parallel to and do not overlap.

[0007] The imaging device of the second aspect of the present invention includes an illumination unit in the first aspect, which has a plurality of illumination devices arranged in a third arc shape, and the illumination directions of the plurality of illumination devices are arranged facing radially outward of the third arc.

[0008] In a third aspect of the present invention, in the imaging device of the second aspect, the first axis or the second axis is the same as a third axis that passes through the center of the third arc and is perpendicular to a plane that includes the third arc.

[0009] The imaging device according to a fourth aspect of the present invention is the imaging device according to the second or third aspect, wherein the illumination unit is disposed at the same height as the first camera unit or at a position lower than the first camera unit.

[0010] The imaging device according to a fifth aspect of the present invention is the imaging device according to the fourth aspect, which includes a support member provided between the first camera unit and the second camera unit, and supporting the first camera unit and the second camera unit.

[0011] The imaging device according to a sixth aspect of the present invention is the imaging device of the fifth aspect, wherein a first camera unit is connected to one end of the support member and a second camera unit is connected to the other end.

[0012] The seventh aspect of the present invention is an imaging device according to the second or third aspect, which includes a processor that controls the first camera, the second camera, and the lighting device, and the processor acquires information about the subject being photographed by the first camera and the second camera and / or information about the shooting environment, and sets the light intensity of the lighting device based on the acquired information about the subject being photographed and / or information about the shooting environment.

[0013] An eighth aspect of the present invention is an imaging device in which, in the seventh aspect, the shutter speeds and F-values ​​of the first camera and the second camera are set within a predetermined range, and the first camera and the second camera perform a first photograph.

[0014] A ninth aspect of the present invention is an imaging device according to the eighth aspect, in which a processor determines the ISO sensitivity of the first camera and the ISO sensitivity of the second camera based on the amount of light, and if the ISO sensitivity of the first camera and the ISO sensitivity of the second camera are below a threshold, causes the first camera and the second camera to perform a first photograph.

[0015] In a tenth aspect of the present invention, in the imaging device of the ninth aspect, the processor determines whether the pixel signal values ​​constituting the image acquired in the first photograph by the first camera and the second camera are within a reference range, and if the pixel signal values ​​are outside the reference range, changes the light intensity setting of the lighting device.

[0016] An eleventh aspect of the present invention is an imaging method for an imaging device including: a first camera unit having a plurality of first cameras arranged in a first arc shape, with the imaging directions of the plurality of first cameras facing outward in a radial direction of the first arc; a second camera unit having a plurality of second cameras arranged in a second arc shape, with the imaging directions of the plurality of second cameras facing outward in a radial direction of the second arc; an illumination unit having a plurality of lighting devices arranged in a third arc shape, with the lighting directions of the plurality of lighting devices facing outward in a radial direction of the third arc; and a processor controlling the first camera unit, the second camera unit, and the illumination unit, wherein the first imaging is performed by the processor. The method includes the steps of acquiring information about the subject to be photographed by the camera and the second camera and / or information about the photographing environment, setting the light intensity of the lighting device based on the acquired information about the subject to be photographed and / or information about the photographing environment, determining the ISO sensitivity of the first camera and the ISO sensitivity of the second camera based on the light intensity, causing the first camera and the second camera to perform a first photograph if the ISO sensitivity of the first camera and the ISO sensitivity of the second camera are equal to or lower than a threshold value, determining whether pixel signal values ​​constituting the image acquired in the first photographing by the first camera and the second camera are within a reference range, and changing the light intensity setting of the lighting device if the pixel signal values ​​are outside the reference range.

[0017] A twelfth aspect of the present invention is a program for causing an imaging method of an imaging device including: a first camera unit having a plurality of first cameras arranged in a first arc, the imaging directions of the plurality of first cameras facing outward in a radial direction of the first arc; a second camera unit having a plurality of second cameras arranged in a second arc, the imaging directions of the plurality of second cameras facing outward in a radial direction of the second arc; an illumination unit having a plurality of lighting devices arranged in a third arc, the lighting directions of the plurality of lighting devices facing outward in a radial direction of the third arc; and a processor for controlling the first camera unit, the second camera unit, and the lighting unit, the program causing the processor to The system executes the following steps: acquiring information about the subject to be photographed by the first camera and the second camera and / or information about the photographing environment; setting the light intensity of the lighting device based on the acquired information about the subject to be photographed and / or information about the photographing environment; determining the ISO sensitivity of the first camera and the ISO sensitivity of the second camera based on the light intensity; causing the first camera and the second camera to perform a first photograph if the ISO sensitivity of the first camera and the ISO sensitivity of the second camera are equal to or lower than a threshold value; determining whether pixel signal values ​​constituting the image acquired in the first photographing by the first camera and the second camera are within a reference range; and changing the light intensity setting of the lighting device if the pixel signal values ​​are outside the reference range.

[0018] FIG. 1 is a front view of a multi-eye imaging device. FIG. 2 is a side view of the multi-eye imaging device. FIG. 3 is a diagram illustrating a case where the multi-eye imaging device captures an image of the inner wall surface of a tunnel. FIG. 4 is a front view of a first camera unit, a lighting unit, and a LIDAR unit. FIG. 5 is a side view of the first camera unit, a lighting unit, and a LIDAR unit. FIG. 6 is a front view of a second camera unit. FIG. 7 is a side view of the second camera unit. FIG. 8 is a block diagram illustrating an embodiment of the hardware configuration of a control device. FIG. 9 is a block diagram illustrating functions realized by a processor. FIG. 10 is a flowchart illustrating an imaging method for capturing an image of the inner wall surface of a tunnel using a multi-eye imaging device. FIG. 11 is a diagram illustrating a specific example of determination of the illumination irradiation distance by the processor. FIG. 12 is a diagram illustrating control of the imaging conditions of the multi-eye imaging device.

[0019] Preferred embodiments of an imaging device, an imaging method, and a program according to the present invention will be described below with reference to the accompanying drawings.

[0020] 1 and 2 are diagrams illustrating a multi-eye imaging device according to an embodiment of the present invention. Fig. 1 is a front view of the multi-eye imaging device 1, and Fig. 2 is a side view of the multi-eye imaging device 1. The multi-eye imaging device 1 corresponds to the imaging device of the present invention.

[0021] The multi-lens imaging device 1 photographs the inner wall surface of, for example, a subway tunnel. Damage such as cracks can then be detected from the photographed images, allowing inspection of the inner wall surface of the subway tunnel. The following description will primarily focus on photographing the inner wall surface of a subway tunnel. However, the use of the multi-lens imaging device 1 of the present invention is not limited to inspection of the inner wall surface of a subway tunnel. For example, the multi-lens imaging device 1 can also be used to inspect the inner wall surfaces of automobile tunnels, chimneys, and silos. The multi-lens imaging device 1 can also be used to photograph the inner wall surface of a tunnel from high and low positions, in addition to photographing the inner wall surface of a tunnel. In the following description, a subway tunnel will simply be referred to as a tunnel.

[0022] The multi-eye imaging device 1 is mounted on a cart 3 and travels through the tunnel to be inspected, capturing images of the inner wall surface without omission. The traveling direction C of the cart 3 is shown in FIG.

[0023] The multi-eye imaging device 1 includes a first camera unit 101 on the vertically lower side, a second camera unit 111 on the vertically upper side, a LIDAR unit 103, a camera unit support member D, and an illumination unit 125.

[0024] The first camera unit 101 is located vertically below, i.e., at a lower height than the second camera unit 111. The first camera unit 101 is mainly responsible for capturing images of the inner wall surface at the bottom of the tunnel (see the capturing range F1 in FIG. 3 ). The first camera unit 101 is composed of multiple cameras 107 (first cameras). In the first camera unit 101, the cameras 107 are arranged in the shape of a first arc C1. The capturing direction of the cameras 107 is arranged so that they face radially outward from the first arc C1. Note that, taking into consideration variations in the capturing angle of view, the width of the cracks to be detected (for example, cracks with a width of 1 mm or less may also be detected), and countermeasures against vibrations during travel of the bogie 3, it is preferable to use a high-performance single-lens reflex camera (or a high-performance single-lens mirrorless camera) as the camera 107.

[0025] The second camera unit 111 is provided vertically above, i.e., at a higher position than the first camera unit 101. The second camera unit 111 is mainly responsible for capturing images of the inner wall surface on the ceiling side of the tunnel (see the capturing range F2 in FIG. 3). The second camera unit 111 is composed of multiple cameras 107 (second cameras). In the second camera unit 111, the cameras 107 are arranged in the shape of a second arc C2. The capturing direction of the arranged cameras 107 is arranged so as to face radially outward from the second arc C2.

[0026] An axis R1 that passes through the center of the first arc C1 of the first camera unit 101 and is perpendicular to the plane including the first arc C1, and an axis R2 that passes through the center of the second arc C2 of the second camera unit 111 and is perpendicular to the plane including the second arc C2, are parallel to each other and do not overlap with each other. As a result, the first camera unit 101 and the second camera unit 111 are positioned as shown in FIGS. 1 and 2 .

[0027] The lighting unit 125 is disposed at the same height as the first camera unit 101 or at a lower position than the first camera unit 101. By disposing the lighting unit 125 at the same height as or lower than the first camera unit 101, which has a low height, the center of gravity of the multi-eye imaging device 1 is lowered, and the multi-eye imaging device 1 is stabilized and can avoid tipping over when traveling on the dolly 3. This is because the lighting unit 125 is heavier than the first camera unit 101, the second camera unit 111, etc. The lighting unit 125 is responsible for providing illumination for the first camera unit 101 and the second camera unit 111 (see the illumination range F3 in FIG. 3 ). The lighting unit 125 is composed of multiple lighting devices 105. In the lighting unit 125, the lighting devices 105 are arranged in the shape of a third arc C3. The lighting direction of the arranged lighting devices 105 is arranged so as to face radially outward from the third arc C3.

[0028] 1 and 2, axis R3, which passes through the center of third arc C3 of illumination unit 125 and is perpendicular to the plane including third arc C3, overlaps with axis R1 of first camera unit 101. Note that although height is described in the vertical direction in this description, the height of multi-eye imaging device 1 is not limited to the height in the vertical direction. The height of multi-eye imaging device 1 also includes the height in the direction of a straight line perpendicular to axis R1 and axis R2.

[0029] The camera unit support member D (support member) extends in the vertical direction, and has one end connected to the first camera unit 101 and the other end connected to the second camera unit 111. The camera unit support member D may have a function of extending and contracting in the vertical direction.

[0030] The cart 3 carries the multi-eye imaging device 1 and travels through the tunnel in a traveling direction C. The cart 3 also carries a control device 5 that is connected to the multi-eye imaging device 1 and controls the multi-eye imaging device 1. The control device 5 is configured, for example, by a computer. The cart 3 may be moved manually by an operator (manual type), or may be moved by controlling a drive device (not shown) with the control device 5 (automatic type).

[0031] FIG. 3 is a diagram illustrating a case where the multi-eye imaging device 1 captures an image of the inner wall surface of a tunnel.

[0032] The multi-eye imaging device 1 photographs the inner wall surface of tunnel E while traveling in the positive Z direction. The first camera unit 101 photographs the inner wall surface on the bottom side within its photographing range F1. The second camera unit 111 photographs the inner wall surface on the top side within its photographing range F2. In other words, the multi-eye imaging device 1 is divided into two units arranged in the height direction, with the first camera unit 101 on the bottom side and the second camera unit 111 on the top side, and these units share the corresponding photographing ranges. This makes it possible to reduce the tilted photographing angle when photographing with the cameras 107 of the multi-eye imaging device 1. Specifically, the multi-eye imaging device 1 photographs the inner wall surface of the tunnel E using a first camera unit 101 and a second camera unit 111 that are at different heights. Therefore, even if the distance from the center of the multi-eye imaging device 1 (for example, on the subway tracks) to the top of the tunnel is far (for example, 6 m) and the side wall is close (for example, 1 m), there is no need to perform tilted photography, and images with guaranteed resolution can be obtained.

[0033] <First Camera Unit> Next, the first camera unit 101, the illumination unit 125, and the LIDAR unit 103 will be described in detail.

[0034] FIG. 4 is a front view of the first camera unit 101, the lighting unit 125, and the LIDAR unit 103, and FIG. 5 is a side view of the first camera unit 101, the lighting unit 125, and the LIDAR unit 103.

[0035] The first camera unit 101 has multiple cameras 107 arranged on a first arc C1, with the shooting direction facing radially outward from the first arc C1. The first camera unit 101 has a maximum of nine cameras 107. Each camera 107 is attached to the tip of an arm 143 connected to a disk-shaped camera rotation base 137. Two camera rotation bases 137 are provided facing each other. One camera rotation base 137 (front side in the traveling direction) has five cameras 107 attached to it, and the other camera rotation base 137 (rear side in the traveling direction) has four cameras 107 attached to it. The two camera rotation bases 137 are attached to a camera unit support member D. The attachment angles of the cameras 107 constituting the first camera unit 101 can be freely adjusted as long as adjacent cameras 107 do not interfere with each other. Furthermore, by rotating the camera rotation base 137, it is also possible to rotate all of the cameras 107 that make up the first camera unit 101 at once.

[0036] The lighting unit 125 has a plurality of lighting devices 105 arranged on a third arc C3, with the lighting direction facing radially outward from the third arc C3. The lighting unit 125 has a maximum of 18 lighting devices 105. Each lighting device 105 is attached to the tip of an arm 141 connected to a disk-shaped lighting rotation base 139. The lighting unit 125 has four lighting rotation bases 139, and each of the four lighting rotation bases 139 is attached to a lighting support member 133 that is provided perpendicular to the base plate 131. Two lighting rotation bases 139 are attached on the positive Z-axis side and two on the negative Z-axis side, sandwiching the first camera unit 101 between them. Furthermore, five lighting devices 105 are attached to the lighting rotation base 139 (inner lighting rotation base 139) closest to the first camera unit 101 on the positive Z-axis side and the negative X-axis side, and four lighting devices 105 are attached to the lighting rotation base 139 (outer lighting rotation base 139) farthest from the first camera unit 101 on the positive Z-axis side and the negative X-axis side. In this way, by attaching more lighting devices 105 to the inner lighting rotation base 139, the weight of the lighting devices 105 can be concentrated as much as possible at the center of the multi-eye imaging device 1, thereby stabilizing the multi-eye imaging device 1. Note that the attachment angle of the lighting devices 105 is fixed. Furthermore, multiple lighting devices 105 attached to the same lighting rotation base 139 can be rotated together at the same time.

[0037] The LIDAR unit 103 is composed of a LIDAR (LiDAR) 121 and a LIDAR unit support member 123. The LIDAR unit support member 123 is attached to a base plate 131, and the LIDAR 121 is positioned at the front of the multi-eye imaging device 1 in the traveling direction, and measures the shape of the object (tunnel) to be photographed by the camera 107. The LIDAR 121 is an example of a distance measurement sensor. As a distance sensor, it is sufficient to obtain information on the distance to the inner surface of the tunnel, and a specific example of the LIDAR 121 is a TOF (Time Of Flight) camera. Note that the center position of the LIDAR 121 is preferably located on axis R1.

[0038] Here, the camera unit support member D is composed of a first camera unit support member D1 and a second camera unit support member D2 (see FIG. 5). The lower end of the first camera unit support member D1 is placed on a pedestal 135 that is formed higher than the base plate 131. The first camera unit support member D1 is fastened to the pedestal 135 by a toggle clamp 155. Two camera rotation bases 137 are held facing each other at the upper end of the first camera unit support member D1. A second camera unit support member D2 is also placed at the upper end of the first camera unit support member D1. The lower end of the second camera unit support member D2 is fastened to the upper end of the first camera unit support member D1 by a toggle clamp 157. Two camera rotation bases 151 are held at the upper end of the second camera unit support member D2 (see FIGS. 1 and 2). The illumination support member 133 is fastened to the base plate 131 by a toggle clamp 159. The LIDAR unit support member 123 is fastened to the base plate 131 by a toggle clamp 161. As such, the first camera unit 101 is detachable by the toggle clamp 155, the second camera unit 111 is detachable by the toggle clamp 157, the lighting unit 125 is detachable by the toggle clamp 159, and the LIDAR unit 103 is detachable by the toggle clamp 161. It is preferable that the first camera unit 101, the second camera unit 111, the lighting unit 125, and the LIDAR unit 103 be unitized while being wired (USB, power cable, etc.) as much as possible. For this unitization, the multi-eye imaging device 1 includes a power plug G for the lighting device 105 (the cord connected to the plug is not shown) and a power hub H for the first camera unit 101 on the first camera unit support member D1, as shown in FIG. 5, and a power hub H for the second camera unit 111, as shown in FIG. 7.By dividing the devices into units in this way and fastening each unit to a toggle clamp, even when only about 5 to 10 minutes is available for installing and removing the multi-eye imaging device 1 on the tracks during tunnel inspections, etc., the multi-eye imaging device 1 can quickly install and remove each unit. Note that, although the above description has been given with respect to the case where toggle clamps are used as a specific example of the fastening members for each unit, this is not limiting. Other fastening members capable of fastening each unit may also be used.

[0039] <Second Camera Unit> Next, the second camera unit will be described in detail.

[0040] 6 and 7 are diagrams illustrating the second camera unit 111. Fig. 6 is a front view of the second camera unit 111, and Fig. 7 is a side view of the second camera unit 111.

[0041] The second camera unit 111 has multiple cameras 107 arranged on a second arc C2, with the shooting direction facing radially outward from the second arc C2. The second camera unit 111 has a maximum of nine cameras 107. Each camera 107 is attached to the tip of an arm 153 connected to a disk-shaped camera rotation base 151. Two camera rotation bases 151 are provided facing each other, with five cameras 107 attached to one camera rotation base 151 (front side in the traveling direction) and four cameras 107 attached to the other camera rotation base 151 (rear side in the traveling direction). The two camera rotation bases 151 are attached to a camera unit support member D. The attachment angles of the cameras 107 constituting the second camera unit 111 can be freely adjusted as long as adjacent cameras 107 do not interfere with each other. Moreover, by rotating the camera rotation base 151, it is also possible to rotate all of the cameras 107 constituting the second camera unit 111 at once.

[0042] <Controller> FIG. 8 is a block diagram showing an embodiment of the hardware configuration of the controller 5 shown in FIG.

[0043] The control device 5 shown in FIG. 8 includes a processor 200 , a memory 210 , a database 220 , a display unit 230 , an input / output interface 240 , and an operation unit 250 .

[0044] The processor 200 is composed of a CPU (Central Processing Unit) and the like, and controls the overall operations of each part of the control device 5 and also controls the imaging of the tunnel by the multi-eye imaging device 1 .

[0045] The memory 210 includes flash memory, read-only memory (ROM), random access memory (RAM), a hard disk drive, etc. The flash memory, ROM, or hard disk drive is a non-volatile memory that stores various programs including an operating system. The RAM functions as a working area for processing by the processor 200 and temporarily stores programs stored in the flash memory, etc. Note that the processor 200 may have a portion of the memory 210 (RAM) built in.

[0046] The database 220 stores images captured by the multi-eye imaging device 1. The images captured by the multi-eye imaging device 1 may be stored in association with the distance traveled by the dolly 3 obtained by a positioning sensor (not shown). In addition, a planar development obtained by combining the images captured by each camera 107 may be stored.

[0047] 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 various types of information are received from the operation unit 250.

[0048] The input / output interface 240 includes a connection unit connectable to an external device and a communication unit connectable to a network. The input / output interface 240 can connect to the external device and the network via a wired or wireless connection. For example, the input / output interface 240 is communicatively connected to the first camera unit 101, the second camera unit 111, and the lighting unit 125, and transmits and receives signals. The input / output interface 240 is also communicatively connected to the lidar 121 and the positioning sensor (not shown) of the bogie 3, and acquires output data from each of them.

[0049] The operation unit 250 includes a pointing device such as a mouse, a keyboard, etc., and functions as part of a GUI that accepts input of various information and instructions by user operation. The operation unit 250 may also be configured with a joystick or the like to control the travel of the cart 3.

[0050] Furthermore, when a user (inspector) visually finds a defect during a tunnel inspection, the location of the defect, the positioning data obtained by the positioning sensor, and an image are stored in association with each other by operating the voice input device or switch that constitutes the operation unit 250. This allows the visual inspection information and the image to be stored in association with each other, preventing defects from being overlooked.

[0051] FIG. 9 is a block diagram illustrating the functions implemented by the processor 200. The processor 200 is composed of an illumination control unit 200A, which mainly controls the illumination device 105, and a camera control unit 200B, which mainly controls the camera 107. The illumination control unit 200A acquires the illumination irradiation distance and performs settings such as increasing or decreasing the illumination light intensity. The camera control unit 200B sets the shooting conditions for the camera 107, issues shooting instructions, and determines the image quality of the acquired image. Meanwhile, the processor 200 acquires information about the subject and / or information about the shooting environment (indicated by reference numeral 202). The information about the subject includes, for example, dimension information about the tunnel being the subject of shooting, computer-aided design (CAD) information about the tunnel, and information about the tunnel's interior wall surface (information about the wall's reflectivity and wall surface irregularities). Here, since the reflectivity increases when the wall surface is wet, this information is useful for suppressing overexposed areas when controlling the light intensity of the illumination device 105, which will be described later. The information about the shooting environment includes, for example, information about dust particles and dirt present in the air inside the tunnel, which is the shooting location. Information about the subject to be photographed and information about the photographing environment are input from the input / output interface 240. For example, information about the subject to be photographed, such as information about the distance to the inner wall surface of a tunnel, is input from the lidar 121 to the processor 200 via the input / output interface 240.

[0052] The LIDAR 121 outputs point cloud information of the distance to the inner wall surface of the tunnel to the processor 200. Then, the processor 200 controls the shooting conditions of the camera 107 of the first camera unit 101 and the camera 107 of the second camera unit 111 and the lighting conditions of the lighting device 105 of the lighting unit 125 based on the information about the distance to the inner wall surface output from the LIDAR 121.

[0053] <Control of Illumination Unit> Next, a description will be given of an imaging method involving control of the illumination unit 125 using the multi-eye imaging device 1. Note that the imaging method described below is performed by the processor 200 executing a dedicated program.

[0054] Fig. 10 is a flowchart showing an imaging method for capturing an image of the inner wall surface of a tunnel using the multi-eye imaging device 1. Fig. 10 explains a case in which the processor 200 sets the imaging conditions for one camera 107 constituting the first camera unit 101 or the second camera unit 111, and uniformly sets the lighting conditions for all lighting devices 105 constituting the lighting unit 125. Note that the cameras 107 and lighting devices 105 of the multi-eye imaging device 1 can be controlled individually, or they can be controlled for each unit or for a predetermined number of units.

[0055] First, the processor 200 acquires information about the tunnel to be inspected (step S01). Specifically, the processor 200 acquires information about the distance from the lidar 121 to the inner wall surface. The processor 200 may acquire information about the distance to the inner wall surface by acquiring CAD information about the tunnel.

[0056] Thereafter, the processor 200 acquires the illumination irradiation distance of the lighting device 105 based on the acquired information on the distance, and determines the acquired illumination irradiation distance (step S02).

[0057] FIG. 11 is a diagram illustrating a specific example of how the processor 200 determines the illumination irradiation distance.

[0058] The lighting irradiation distance a shown in FIG. 11 indicates the shortest distance between the lighting device 105 and the ceiling of the tunnel E. This is the lighting irradiation distance when the lighting device 105 illuminates the ceiling of the tunnel E. The lighting irradiation distance b shown in FIG. 11 indicates the shortest distance between the lighting device 105 and the side of the tunnel E. This is the lighting irradiation distance when the lighting device 105 illuminates the side of the tunnel E. The processor 200 then determines whether the lighting irradiation distance a / lighting irradiation distance b is equal to or less than 4 or exceeds 4. If the lighting irradiation distance a / lighting irradiation distance b exceeds 4, the processor 200 increases the height of the cart 3, for example, to shorten the lighting irradiation distance a, thereby increasing the height of the cart 3 so that the lighting irradiation distance a / lighting irradiation distance b does not exceed 4 (step S03). The height of the cart 3 can be controlled by changing the height of the lighting support member 133 by the processor 200 or manually changing the height of the lighting support member 133.

[0059] On the other hand, if the processor 200 determines that the ratio of illumination projection distance a / illumination projection distance b is 4 or less, it sets the light intensity of the illumination device 105 (step S04). For example, the processor 200 sets the illumination light intensity associated with the illumination projection distance a, the illumination projection distance b, or the illumination projection distance a / illumination projection distance b as the light intensity of the illumination device 105 in advance. The processor 200 then causes the camera 107 to perform photometry using its photometry function (step S05). Here, the F-number of the camera 107 is set within a predetermined range. For example, when photographing a tunnel, a curved surface may be the subject, so a deep depth of field is required, and the F-number is set large (darker). The shutter speed of the camera 107 is also set within a predetermined range. For example, when photographing a tunnel, the vehicle 3 is used to move the vehicle while shooting, so it is necessary to suppress image blurring that occurs during moving photography. For this reason, the shutter speed of the camera 107 is set high.

[0060] After the photometry is performed as described above, the processor 200 provisionally determines the ISO sensitivity of the camera 107 (step S06). This provisional determination of the ISO sensitivity is performed automatically based on the photometry information. The processor 200 determines whether the provisionally determined ISO sensitivity exceeds the ISO sensitivity threshold (threshold) (step S07). If the determined ISO sensitivity exceeds the ISO sensitivity threshold, the processor 200 increases the amount of illumination light (step S13) and performs photometry again (step S05).

[0061] On the other hand, if the determined ISO sensitivity is equal to or less than the ISO sensitivity threshold, the processor 200 causes the camera 107 to take a provisional photograph (first photograph) (step S08). The processor 200 then determines whether or not there are any blown-out highlights in the image obtained by the provisional photograph (step S09). Specifically, the processor 200 determines whether or not the pixel signal values ​​constituting the image acquired by the provisional photograph are within a reference range, and if they are within the reference range, determines that there are no blown-out highlights, and if they are outside the reference range, determines that there are any blown-out highlights.

[0062] If the processor 200 determines that there is a whiteout portion in the image, it reduces the amount of illumination light from the lighting device 105 (step S10). On the other hand, if the processor 200 determines that there is no whiteout portion, it determines the amount of illumination light and the ISO sensitivity (step S11) and causes the camera 107 to perform actual photography (step S12).

[0063] As described above, the cameras 107 and lighting devices 105 of the multi-eye imaging device 1 are controlled by the control device 5 under shooting conditions and lighting conditions to perform actual shooting. This allows the multi-eye imaging device 1 to capture images of the tunnel's inner wall surface that are appropriately illuminated. Furthermore, because the images captured by the multi-eye imaging device 1 are acquired by the first camera unit 101 and the second camera unit 111, the images are acquired with a reduced tilt shooting angle and have appropriate resolution.

[0064] <Control of Camera Units> Next, the control of the shooting conditions of the cameras 107 constituting the first camera unit 101 and the second camera unit 111, which is performed by the processor 200, will be described.

[0065] Fig. 12 is a diagram illustrating the control of the shooting conditions of the multi-eye imaging device 1. Fig. 12 is a diagram that schematically shows a plan view as viewed from the positive Y-axis direction, and schematically shows the adjacent cameras 107 that make up the first camera unit 101.

[0066] The case shown by the reference numeral 280 indicates a case where the LIDAR 121 is not mounted on the multi-eye imaging device 1. The case shown by the reference numeral 282 indicates a case where the LIDAR 121 is mounted on the multi-eye imaging device 1.

[0067] The diameter of tunnel 290 increases at point K. Although the multi-eye imaging device 1 travels in a straight line, the increase in the tunnel diameter causes a change in the quality of the captured image after passing point K. In the case shown by reference numeral 280, the increased distance to the inner wall surface of tunnel 290 causes the pixel density in the captured image to be insufficient, making it difficult to properly detect damage such as cracks.

[0068] On the other hand, in the case indicated by the reference numeral 282, the fact that the distance to the inner surface of the tunnel 290 has increased at point K is detected from distance information output by the LIDAR 121 mounted on the multi-eye imaging device 1. As a result, the processor 200 changes the AF (Auto Focus) and focal length of the camera 107 based on the distance information obtained from the LIDAR 121. Therefore, in this case, insufficient pixel density in the acquired image is suppressed, and damage such as cracks can be appropriately detected.

[0069] As described above, the processor 200 controls the imaging conditions of the camera 107 based on information about the distance to the inner wall surface obtained from the lidar 121. This allows the multi-eye imaging device 1 to stably acquire appropriate images of the inner wall surface even when the shape of the tunnel changes.

[0070] <Others> In the above embodiment, the hardware structure of the processing units (e.g., the illumination control unit 200A and the camera control unit 200B) that perform various processes is the following various processors. The various processors include a CPU (Central Processing Unit), which is a general-purpose processor that executes software (programs) and functions as various processing units, a programmable logic device (PLD), such as an FPGA (Field Programmable Gate Array), whose circuit configuration can be changed after manufacture, and a dedicated electrical circuit, such as an ASIC (Application Specific Integrated Circuit), which is a processor with a circuit configuration designed specifically for performing specific processes.

[0071] A single processing unit may be configured with one of these various processors, or may be configured with two or more processors of the same or different types (e.g., multiple FPGAs, or a combination of a CPU and an FPGA). Multiple processing units may also be configured with a single processor. Examples of multiple processing units configured with a single processor include: a first configuration, as typified by client or server computers, in which a single processor is configured with a combination of one or more CPUs and software, and this processor functions as multiple processing units; and a second configuration, as typified by system-on-chip (SoC), in which a processor is used to realize the functions of an entire system including multiple processing units on a single IC (Integrated Circuit) chip. In this way, the various processing units are configured with one or more of the above-mentioned various processors as a hardware structure.

[0072] Furthermore, the hardware structure of these various processors is, more specifically, an electric circuit made up of a combination of circuit elements such as semiconductor elements.

[0073] The above-described configurations and functions can be realized by any hardware, software, or a combination of both. For example, the present invention can be applied to a program that causes a computer to execute the above-described processing steps (processing procedures), a computer-readable recording medium (non-transitory recording medium) on which such a program is recorded, or a computer on which such a program can be installed.

[0074] <Additional Notes> The above disclosure includes, for example, the following inventions.

[0075] (Aspect 1) An imaging device comprising: a first camera unit having a plurality of first cameras arranged in a first arc, the imaging directions of the plurality of first cameras being arranged facing radially outward of the first arc; and a second camera unit having a plurality of second cameras arranged in a second arc, the imaging directions of the plurality of second cameras being arranged facing radially outward of the second arc; wherein a first axis passing through the center of the first arc and perpendicular to a plane including the first arc, and a second axis passing through the center of the second arc and perpendicular to the plane including the second arc, are parallel to and do not overlap.

[0076] (Aspect 2) The imaging device according to Aspect 1, further comprising: an illumination unit having a plurality of illumination devices arranged in a third arc, the illumination directions of the plurality of illumination devices being arranged facing radially outward of the third arc.

[0077] (Aspect 3) The imaging device according to aspect 1 or 2, wherein the first axis or the second axis is the same as a third axis that passes through a center of the third arc and is perpendicular to a plane that includes the third arc.

[0078] (Aspect 4) The imaging device according to any one of Aspects 1 to 3, wherein the illumination unit is disposed at the same height as the first camera unit or at a position lower than the first camera unit.

[0079] (Aspect 5) The imaging device according to any one of Aspects 1 to 4, further comprising a support member provided between the first camera unit and the second camera unit, the support member supporting the first camera unit and the second camera unit.

[0080] (Aspect 6) The imaging device according to aspect 5, wherein the first camera unit is connected to one end of the support member, and the second camera unit is connected to the other end.

[0081] (Aspect 7) An imaging device according to Aspect 2 or 3, including a processor that controls the first camera, the second camera, and the lighting device, wherein the processor acquires information on the subject being photographed by the first camera and the second camera and / or information on the shooting environment, and sets the light intensity of the lighting device based on the acquired information on the subject being photographed and / or information on the shooting environment.

[0082] (Aspect 8) The imaging device according to Aspect 7, wherein the shutter speeds and F-numbers of the first camera and the second camera are set within a predetermined range, and the first camera and the second camera perform a first image capture.

[0083] (Aspect 9) The imaging device according to Aspect 8, wherein the processor determines the ISO sensitivity of the first camera and the ISO sensitivity of the second camera based on the amount of light, and causes the first camera and the second camera to perform the first image capture if the ISO sensitivity of the first camera and the ISO sensitivity of the second camera are equal to or lower than a threshold value.

[0084] (Aspect 10) The imaging device according to Aspect 9, wherein the processor determines whether pixel signal values ​​constituting the image acquired by the first photographing of the first camera and the second camera are within a reference range, and if the pixel signal values ​​are outside the reference range, changes the light intensity setting of the lighting device.

[0085] (Aspect 11) An imaging method for an imaging device including: a first camera unit having a plurality of first cameras arranged in a first arc, the imaging directions of the plurality of first cameras being arranged to face radially outward of the first arc; a second camera unit having a plurality of second cameras arranged in a second arc, the imaging directions of the plurality of second cameras being arranged to face radially outward of the second arc; a lighting unit having a plurality of lighting devices arranged in a third arc, the lighting directions of the plurality of lighting devices being arranged to face radially outward of the third arc; and a processor controlling the first camera unit, the second camera unit, and the lighting unit, the method comprising the steps of: acquiring information on subjects to be photographed by the first camera and the second camera and / or information on the imaging environment; setting light amounts of the lighting devices based on the acquired information on the subject to be photographed and / or the information on the imaging environment; and determining an ISO sensitivity of the first camera and an ISO sensitivity of the second camera based on the light amount. An imaging method comprising: a step of causing the first camera and the second camera to perform a first image capture when the ISO sensitivity of the first camera and the ISO sensitivity of the second camera are equal to or lower than a threshold value; a step of determining whether pixel signal values ​​constituting an image acquired by the first image capture of the first camera and the second camera are within a reference range; and a step of changing the light intensity setting of the lighting device when the pixel signal values ​​are outside the reference range.

[0086] (Aspect 12) A program causing the processor to execute an imaging method for an imaging device including: a first camera unit having a plurality of first cameras arranged in a first arc, the plurality of first cameras being arranged with imaging directions facing outward in a radial direction of the first arc; a second camera unit having a plurality of second cameras arranged in a second arc, the plurality of second cameras being arranged with imaging directions facing outward in a radial direction of the second arc; a lighting unit having a plurality of lighting devices arranged in a third arc, the plurality of lighting devices having lighting directions facing outward in a radial direction of the third arc; and a processor to control the first camera unit, the second camera unit, and the lighting unit, the program causing the processor to execute an imaging method for an imaging device including: a first camera unit having a plurality of first cameras arranged in a first arc, the plurality of first cameras being arranged with imaging directions facing outward in a radial direction of the first arc; a second camera unit having a plurality of second cameras arranged in a second arc, the plurality of second cameras being arranged with imaging directions facing outward in a radial direction of the second arc; A program that executes the steps of: causing the first camera and the second camera to perform a first photograph when the ISO sensitivity of the first camera and the ISO sensitivity of the second camera are equal to or lower than a threshold value; determining whether pixel signal values ​​constituting an image acquired by the first camera and the second camera in the first photograph are within a reference range; and changing the light intensity setting of the lighting device when the pixel signal values ​​are outside the reference range.

[0087] Although examples of the present invention have been described above, it goes without saying that the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the present invention.

[0088] 1: Multi-eye imaging device 3: Cart 5: Control device 101: First camera unit 103: LIDAR unit 105: Lighting device 107: Camera 111: Second camera unit 121: LIDAR 123: LIDAR unit support member 125: Lighting unit 131: Base plate 133: Lighting support member 135: Base 137: Camera rotation base 139: Lighting rotation base 141: Arm 143: Arm 151: Camera rotation base 153: Arm 200: Processor 200A: Lighting control unit 200B: Camera control unit 210: Memory 220: Database 230: Display unit 240: Input / output interface 250: Operation unit

Claims

1. a first camera unit having a plurality of first cameras arranged in a first arc shape, the imaging directions of the plurality of first cameras being arranged facing outward in a radial direction of the first arc; a second camera unit including a plurality of second cameras arranged in a second arc shape, the imaging directions of the plurality of second cameras being arranged facing outward in a radial direction of the second arc; Including, an imaging device, wherein a first axis that passes through the center of the first arc and is perpendicular to a plane that includes the first arc, and a second axis that passes through the center of the second arc and is perpendicular to a plane that includes the second arc are parallel to and do not overlap with each other.

2. 2. The imaging device according to claim 1, further comprising: an illumination unit having a plurality of illumination devices arranged in a third arc, the illumination directions of the plurality of illumination devices being arranged facing radially outward of the third arc.

3. The imaging device according to claim 2 , wherein the first axis or the second axis is the same as a third axis that passes through a center of the third arc and is perpendicular to a plane that includes the third arc.

4. The imaging device according to claim 2 , wherein the illumination unit is disposed at the same height as the first camera unit or at a position lower than the first camera unit.

5. The imaging device according to claim 4 , further comprising a support member provided between the first camera unit and the second camera unit, for supporting the first camera unit and the second camera unit.

6. 6. The imaging device according to claim 5, wherein the first camera unit is connected to one end of the support member, and the second camera unit is connected to the other end of the support member.

7. a processor that controls the first camera, the second camera, and the lighting device; The processor: acquiring information on a subject to be photographed by the first camera and the second camera and / or information on a photographing environment; The imaging device according to claim 2 , wherein the light amount of the lighting device is set based on the acquired information about the subject and / or the acquired information about the imaging environment.

8. The imaging device according to claim 7 , wherein the shutter speeds and F-numbers of the first camera and the second camera are set within predetermined ranges, and the first camera and the second camera perform a first image capture.

9. The processor: determining an ISO sensitivity of the first camera and an ISO sensitivity of the second camera based on the amount of light; The imaging device according to claim 8 , wherein when the ISO sensitivity of the first camera and the ISO sensitivity of the second camera are equal to or lower than a threshold, the first camera and the second camera are caused to perform the first imaging.

10. The processor: determining whether pixel signal values ​​constituting the images acquired by the first photographing of the first camera and the second camera are within a reference range; The imaging device according to claim 9 , wherein when the pixel signal value is outside the reference range, the setting of the light amount of the lighting device is changed.

11. 1. An imaging method for an imaging device including: a first camera unit having a plurality of first cameras arranged in a first arc shape, with imaging directions of the plurality of first cameras facing outward in a radial direction of the first arc; a second camera unit having a plurality of second cameras arranged in a second arc shape, with imaging directions of the plurality of second cameras facing outward in a radial direction of the second arc; a lighting unit having a plurality of lighting devices arranged in a third arc shape, with lighting directions of the plurality of lighting devices facing outward in the radial direction of the third arc; and a processor controlling the first camera unit, the second camera unit, and the lighting unit, performed by the processor, acquiring information about a subject to be photographed by the first camera and the second camera and / or information about a photographing environment; setting the light intensity of the lighting device based on the acquired information on the subject and / or the acquired information on the shooting environment; determining an ISO sensitivity of the first camera and an ISO sensitivity of the second camera based on the amount of light; When the ISO sensitivity of the first camera and the ISO sensitivity of the second camera are equal to or lower than a threshold, causing the first camera and the second camera to perform a first photographing operation; determining whether pixel signal values ​​constituting the images acquired by the first photographing of the first camera and the second camera are within a reference range; changing the light intensity setting of the lighting device when the pixel signal value is outside the reference range; An imaging method comprising:

12. a first camera unit having a plurality of first cameras arranged in a first arc shape, with the imaging directions of the plurality of first cameras facing outward in a radial direction of the first arc; a second camera unit having a plurality of second cameras arranged in a second arc shape, with the imaging directions of the plurality of second cameras facing outward in a radial direction of the second arc; a lighting unit having a plurality of lighting devices arranged in a third arc shape, with the lighting directions of the plurality of lighting devices facing outward in a radial direction of the third arc; and a program for executing an imaging method for an imaging device including a processor for controlling the first camera unit, the second camera unit, and the lighting unit; the processor, acquiring information about a subject to be photographed by the first camera and the second camera and / or information about a photographing environment; setting the light intensity of the lighting device based on the acquired information on the subject and / or the acquired information on the shooting environment; determining an ISO sensitivity of the first camera and an ISO sensitivity of the second camera based on the amount of light; When the ISO sensitivity of the first camera and the ISO sensitivity of the second camera are equal to or lower than a threshold, causing the first camera and the second camera to perform a first photographing operation; determining whether pixel signal values ​​constituting the images acquired by the first photographing of the first camera and the second camera are within a reference range; changing the light intensity setting of the lighting device when the pixel signal value is outside the reference range; A program that executes the following.

13. A non-transitory computer-readable recording medium having the program according to claim 12 recorded thereon.