JP2020198608A - Imaging system, imaging method, and program - Google Patents

Abstract

To appropriately perform imaging.SOLUTION: An imaging system according to an aspect of the disclosed technology has an imaging unit that picks up an image of an object in a state where it is installed on a movable body, and an exposure condition determination unit that, based on the distance between the movable body and the object, determines an exposure condition for the imaging unit to be either one of a fixed exposure condition or an automatic exposure condition.SELECTED DRAWING: Figure 15

Description

The present invention relates to imaging systems, imaging methods, and programs.

In the maintenance and management of objects such as tunnels, in order to improve the efficiency of inspection, a method of imaging the wall surface of a tunnel while traveling by a moving body such as a vehicle equipped with an imaging system is known.

Further, it is determined whether or not there is a light change section in which the brightness changes by a predetermined amount or more within a predetermined distance in front of the moving body, and if the light change section exists, it occurs during traveling of the light change section. A technique for controlling the exposure of an imaging system provided in a vehicle according to a change in brightness is disclosed (see, for example, Patent Document 1).

However, with the technique of Patent Document 1, there are cases where proper imaging cannot be performed.

The disclosed technology has an object of appropriately imaging.

The imaging system according to one aspect of the disclosed technique exposes the imaging unit based on the distance between the imaging unit that images an object while installed on the moving object and the moving object and the object. It has an exposure condition determining unit that determines either a fixed exposure condition or an automatic exposure condition.

According to the disclosed technique, an appropriate image can be taken.

It is a perspective view which shows the structural example of the imaging system which concerns on embodiment. It is a perspective view which shows the structural example of the camera unit which concerns on embodiment. It is a perspective view which shows the structural example of the lighting unit which concerns on embodiment. It is a block diagram which shows the hardware configuration example of the image pickup system which concerns on embodiment. It is a figure explaining the imaging when the distance from a vehicle to a tunnel wall surface is short, (a) is a figure which looked at the vehicle from the traveling direction, and (b) is the figure which shows the traveling of the vehicle inside the tunnel. It is a figure explaining the image taking when the distance from a vehicle to a tunnel wall surface is long, (a) is a figure which looked at the vehicle from the traveling direction, and (b) is the figure which shows the traveling of the vehicle inside the tunnel. It is a figure which shows the influence of the position / posture change of a camera unit and a lighting unit, (a) is a figure which shows the case where there is no position / posture change, and (b) is a figure which shows the case where there is a position / posture change. It is a figure which shows the structural example of the guide shaft and the guide shaft holding member. It is a figure which shows the relationship between the imaging area and the illumination area when it is tilted with respect to the wall surface of a tunnel. It is a figure which shows the configuration example of an index plunger. It is a figure explaining the effect example which tilted the illumination direction with respect to the image pickup direction. It is a figure which shows the relationship between the illumination light and the inclination of the image pickup light, the illumination light distribution angle, and the illumination area, (a) is a figure which shows the relationship between a camera unit, an illumination unit, and a wall surface of a tunnel, and (b) is a figure which shows the image area. It is a figure which shows the case where the vehicle is far from the wall surface of a tunnel in a state where the lighting areas overlap. It is a figure which shows the relationship between the illumination light and the inclination of the image pickup light, the illumination light distribution angle, and the illumination area, and (c) shows the case where a vehicle approaches a wall surface of a tunnel in a state where an image pickup area and an illumination area overlap. FIG. 3D is a diagram showing an example in which the imaging light is tilted with respect to the illumination light. It is a figure explaining the relationship example of the meandering of a vehicle, an image pickup area, and an illumination area. It is a flowchart which shows the operation example of the image pickup system which concerns on embodiment. It is a block diagram which shows the functional structure example of the image pickup system which concerns on 1st Embodiment. It is a figure explaining the operation example of the image pickup system which concerns on 1st Embodiment. It is a flowchart which shows the operation example of the image pickup system which concerns on 1st Embodiment. It is a flowchart which shows the processing example by the exposure control unit which concerns on 1st Embodiment. It is a block diagram which shows the functional structure example of the image pickup system which concerns on the modification. It is a flowchart which shows the operation example of the image pickup system which concerns on the modification. It is a block diagram which shows the functional structure example of the image pickup system which concerns on 2nd Embodiment. It is a figure explaining the operation example of the image pickup system which concerns on 2nd Embodiment. It is a flowchart which shows the operation example of the image pickup system which concerns on 2nd Embodiment. It is a flowchart which shows the operation example of the image pickup system which concerns on 3rd Embodiment. It is a figure explaining the relationship example of a vehicle and an emergency parking zone. It is a flowchart which shows the operation example of the image pickup system which concerns on 4th Embodiment. It is a flowchart which shows the operation example at the time of fixed exposure. It is a flowchart which shows the operation example of the image pickup system which concerns on 5th Embodiment.

The embodiment will be described with reference to the drawings. In each drawing, the same components may be designated by the same reference numerals and duplicate description may be omitted.

The imaging system according to the embodiment is a device that images an object for maintenance of an object such as a tunnel. In the embodiment, an imaging system in which an imaging system is mounted on a vehicle and an imaging system is imaged on the inner wall surface of the tunnel (hereinafter referred to as a wall surface of the tunnel) while the vehicle is running will be described as an example. Here, the vehicle is an example of a "moving body", the traveling direction is an example of the "moving direction", and the wall surface of the tunnel is an example of the "object".

<Overall configuration of imaging system>
FIG. 1 is a perspective view illustrating an example of a configuration of an imaging system according to an embodiment. The imaging system 100 includes a slide unit 200, a camera unit 300, and a lighting unit 400.

The camera unit 300 images the wall surface of the tunnel, and the lighting unit 400 illuminates the wall surface of the tunnel with light for imaging by the camera unit 300.

The slide unit 200 is a member for sliding the camera unit 300 and the lighting unit 400 in the direction of the thick arrow in FIG. The positions of the camera unit 300 and the lighting unit 400 can be changed by the slide unit 200 in the direction of the thick arrow in FIG.

Further, the slide unit 200 includes rails 210 and 220, a base 230, a guide shaft 240, guide shaft holding members 251 and 252, and frames 261 and 262.

The camera unit 300 slides on the rail 210 fixed to the frame 261 to change its position in the direction of the thick arrow in FIG. Similarly, the lighting unit 400 makes its position variable in the direction of the thick arrow in FIG. 1 by sliding on the rail 220 fixed to the frame 262.

The rails 210 and 220 are fixed to the frames 261 and 262, respectively, so that the rail axes are substantially parallel to each other. The base 230 is fixed to the frames 261 and 262, connects the two, and serves as the base of the imaging system 100.

The guide shaft 240 is a member used for sliding the camera unit 300 and the lighting unit 400 with stable accuracy, and is a metal round bar or the like. The round bar is installed so that the longitudinal direction of the round bar is along the sliding direction of the camera unit 300 and the lighting unit 400.

The guide shaft 240 is passed through and held through holes provided in the guide shaft holding members 251 and 252 that hold the guide shaft 240, respectively. The configuration and operation of the guide shaft 240 and its peripheral members will be described in detail separately.

Here, FIG. 1 shows a configuration in which both the camera unit 300 and the lighting unit 400 are slid by the slide unit 200, but the present invention is not limited to this. The unit that slides the camera unit 300 and the unit that slides the lighting unit 400 may be separately configured.

The imaging system 100 is attached to the roof of the vehicle or the like so that the sliding directions of the camera unit 300 and the lighting unit 400 intersect the traveling direction of the vehicle. In other words, the direction of the thick arrow in FIG. 1 intersects the traveling direction of the vehicle to which the imaging system 100 is attached. By mounting in this way, the positions of the camera unit 300 and the lighting unit 400 can be changed in a plane intersecting the traveling direction of the vehicle.

The portion of the vehicle to which the imaging system 100 is attached is not limited to the roof. It may be a bonnet or the like in front of or behind the vehicle, or it may be a loading platform or the like if the vehicle is a truck. Further, regarding the attachment of the imaging system 100 to the vehicle, when the imaging system 100 is attached to the roof, hook parts or the like may be used in the same manner as the ski carrier for the vehicle.

<Camera unit configuration>
Next, FIG. 2 is a perspective view illustrating an example of the configuration of the camera unit 300 according to the embodiment.

The camera unit 300 includes a base plate 310, rail connecting portions 321 and 322, cameras 331-334, shaft connecting portions 341 and 342, and an index plunger 350.

The rail connecting portions 321 and 322 are members for connecting the base plate 310 and the rail 210. The rail connecting portions 321 and 322 have a "U" -shaped cross section in the direction orthogonal to the rail axis. When the rail 210 is a double-headed rail, the rail connecting portions 321 and 322 are connected to the rail 210 so that one of the heads of the double-headed rail is covered with a "U" shape.

The rail connecting portions 321 and 322 have the same shape and are connected to the rail 210 at two positions different in the axial direction of the rail. By fixing the base plate 310 to the rail connecting portions 321 and 322, the camera unit 300 can slide in the direction of the rail axis (the direction of the thick arrow in FIG. 1).

The cameras 331 to 334 are fixed to the flat surface portion of the base plate 310. Here, the camera 331 has a lens 331-1 and a line CCD (Charge Coupled Device) 331-2. The lens 331-1 forms an image of a subject in the optical axis direction of the lens 331-1 on the imaging surface of the line CCD331-2. The line CCD331-2 captures an image of the imaged subject.

A diaphragm 331-1a (see FIG. 4) is provided inside the lens 331-1. The diaphragm 331-1a is an iris diaphragm having diaphragm blades, and is an opening having a variable diameter. The diameter of the opening can be changed by connecting a drive source such as a motor to the diaphragm blades and driving the motor based on a control signal. As a result, the amount of light passing through the lens 331-1 can be changed, and the brightness of the image of the subject imaged by the lens 331-1 can be changed.

The line CCD331-2 is a CCD in which pixels are arranged in a one-dimensional shape (line shape), and in the embodiment, the camera 331 has such that the arrangement direction of the pixels of the line CCD331-2 intersects with the traveling direction of the vehicle. Is fixed to the base plate 310. The cameras 332 to 334 also have the same configuration as the camera 331, but since they are the same as those described above, the description thereof will be omitted.

The tunnel has a semicircular cross section that intersects the traveling direction of the vehicle. In line with this, the cameras 331 to 334 are arranged radially so that the optical axes of the lenses possessed by the cameras 331 to 334 intersect the wall surface of the tunnel, as shown in FIG. In other words, the cameras 331 to 334 are arranged radially on the flat surface of the base plate 310 so that each faces the wall surface of the tunnel.

By connecting the line images captured by the cameras 331 to 334 in the arrangement direction of the cameras, the line image of the wall surface of the tunnel can be captured along the shape of the tunnel. Then, while the vehicle is running, the above line images are continuously imaged at predetermined time intervals, and the captured line images are joined in a direction orthogonal to the pixel arrangement direction of the line image to form an area on the wall surface of the tunnel. An image (two-dimensional image) can be acquired. The predetermined time interval is a line image acquisition cycle or the like by the line CCD.

Here, the example in which the number of cameras is four is shown above, but the present invention is not limited to this. The number of cameras may be increased or decreased depending on conditions such as the size of the tunnel. Further, the image magnification, the field of view, the F number, and the like of the lens 331-1 may be determined according to the conditions for which the image is desired.

Further, although the example in which the camera 331 is provided with the line CCD is shown above, the camera 331 may be provided with the area CCD in which the pixels are arranged two-dimensionally. Further, CMOS (Complementary Metal-Oxide-Semiconductor) or the like may be used instead of CCD.

On the other hand, the shaft connecting portions 341 and 342 are members for connecting to the guide shaft 240. The index plunger 350 is a member for fixing the camera unit 300 at a desired position in the sliding direction. The configurations and operations of the shaft connecting portions 341 and 342 and the index plunger 350 will be described in detail separately.

<Structure of lighting unit>
Next, FIG. 3 is a perspective view illustrating an example of the configuration of the lighting unit 400 according to the embodiment.

The illumination unit 400 includes a base plate 410, a rail connection portion, an illumination light source portion 431 to 436, a shaft connection portion 441 and 442, and an index plunger 450. The relationship between the rail connecting portion and the rail 220 is the same as the relationship between the rail connecting portions 321 and 322 and the rail 210 described above.

The illumination light source units 431 to 436 are fixed to the flat surface portion of the base plate 410. The illumination light source unit 431 has a lens 431-1 and a light source 431-2.

The light source 431-2 illuminates the subject in the optical axis direction of the lens 431-1 via the lens 431-1. A diaphragm 431-1a is provided inside the lens 431-1 (see FIG. 4).

The aperture 431-1a is an aperture having a variable diameter, and by changing the diameter of the aperture, the amount (brightness) of the illumination light illuminated by the lens 431-1 can be changed. As the light source 431-2, a metal halide light, an LED (Light Emitting Diode), or the like can be used. The illumination light source unit 432 to 436 also has the same configuration as the illumination light source unit 431, but the description thereof will be omitted because it is the same as the above.

As described above, the tunnel has a semicircular cross section that intersects the traveling direction of the vehicle. In line with this, as shown in FIG. 3, the illumination light source units 431 to 436 are radially arranged so that the optical axes of the lenses provided therein intersect with the wall surface of the tunnel. In other words, the illumination light source units 431 to 436 are radially arranged on the flat surface portion of the base plate 410 so as to face the wall surface of the tunnel. The lighting unit 400 can illuminate the wall surface of the tunnel with line-shaped light along a direction intersecting the traveling direction of the vehicle (arrangement direction of pixels of the line CCD).

In the above description, an example in which the number of illumination light source units is 6 has been described, but the number is not limited to this and may be increased or decreased. Further, the number of illumination light source units does not necessarily match the number of cameras, and the number may be determined according to conditions such as brightness. Further, the angle of view of the lens, the F number, and the like may be determined according to the conditions for imaging.

Further, in the above description, the positions of the illumination light source units 431 to 436 are slightly shifted back and forth in the optical axis direction of the lens, but this is to prevent physical interference between the illumination light source units. Is.

On the other hand, the shaft connecting portions 441 and 442 are members for connecting to the guide shaft 240. The index plunger 450 is a member for fixing the lighting unit 400 at a desired position in the sliding direction. The configuration and operation of the shaft connecting portions 441 and 442 and the index plunger 450 will be described in detail separately.

<Hardware configuration of imaging system>
Next, FIG. 4 is a block diagram showing an example of the hardware configuration of the imaging system 100. The imaging system 100 includes a camera unit 300, a lighting unit 400, a sensor control board 110, a TOF (Time of Flight) sensor 141, an IMU (Inertial Measurement Unit) 170, and a vehicle speed meter / moving distance meter 171. ..

The TOF sensor 141 as an example of the "distance detection unit" can detect the distance from the wall surface of the tunnel 600 to the TOF sensor 141, and can detect the distance from the wall surface of the tunnel 600 to the imaging system 100.

More specifically, the wall surface of the tunnel 600 is irradiated with light from the TOF sensor 141, and the distance to the wall surface of the tunnel 600 is detected based on the time until the reflected light is received. When the TOF sensor 141 using the area sensor is used as the light receiving element, it is possible to obtain a two-dimensional contour line image in which the display color differs depending on the distance.

The IMU 170 can measure the angle / angular velocity and acceleration of the three axes that control the movement of the vehicle 500, and the vehicle speed meter / moving range finder 171 can measure the speed / moving distance of the vehicle 500.

The data measured by the IMU 170 and the vehicle speed meter / moving distance meter 171 is output to the HDD 114 via the sensor control board 110 and stored, and later, the size and inclination of the image on the wall surface are geometrically corrected by image processing. used.

The camera unit 300 includes lenses 331-1, 332-1, 333-1 and 334-1 and lines CCD 331-2, 334-2, 333-2 and 334-2. The lens 331-1 has an aperture 331-1a, the lens 332-1 has an aperture 332-1a, the lens 333-1 has an aperture 333-1a, and the lens 334-1 has an aperture 334-1a inside. There is. However, in FIG. 4, for simplification of the drawing, only the lens 331-1, the diaphragm 331-1a, and the line CCD 331-2 are shown, and the other lenses, the diaphragm, and the line CCD are not shown.

The lighting unit 400 includes lenses 431-1, 432-1, 433-1, 434-1, 435-1 and 436-1, and light sources 431-2, 432-2, 433-2, 434-2, 435- 2 and 436-2 are provided. The lens 431-1 has an aperture 431-1a, the lens 432-1 has an aperture 432-1a, the lens 433-1 has an aperture 433-1a, the lens 434-1 has an aperture 434-1a, and the lens 435-1 has an aperture 435-1a. The aperture 435-1a and the lens 436-1 have an aperture 436-1a inside. However, in FIG. 4, for simplification of the figure, only the lens 431-1, the diaphragm 431-1a, and the light source 431-2 are shown, and the other lenses, the diaphragm, and the light source are not shown.

The sensor control board 110 includes a CPU (Central Processing Unit) 111, a ROM (Read Only Memory) 112, a RAM (Random Access Memory) 113, an HDD (Hard Disk Drive) 114, and an external I / F (Inter / Face). ) 115 and a buzzer 116, each of which is electrically connected to each other by a system bus 117. Here, the sensor control board 110 is an example of a computer.

The ROM 112 stores various programs and data, various setting information, and the like, and the RAM 113 temporarily holds the programs and data. The CPU 111 reads a program, data, setting information, etc. from the ROM 112 or the like onto the RAM 113 and executes processing, thereby realizing control of the entire imaging system 100 and processing of image data. Here, the image data processing includes a process of joining line images captured by the cameras 331 to 334, and a line image continuously captured by the cameras 331 to 334 at predetermined time intervals while the vehicle is running. It refers to the process of connecting in the traveling direction of the vehicle. Further, the CPU 111 can separately realize various functions described in detail with reference to FIGS. 15 and 18.

Note that the control realized by the CPU 111, the processing of image data, and some or all of the various functions may be realized by an FPGA (Field-Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit).

The HDD 114 stores image data input from the camera unit 300, sensor data input from the TOF sensor 141, IMU 170, and the vehicle speed meter / moving distance meter 171.

The external I / F 115 realizes a user interface function for the user to operate the imaging system 100 and an interface function for the imaging system 100 to exchange data and signals with an external device such as a PC (Personal Computer). ..

The buzzer 116 generates a beep sound for notifying the user of a warning.

The sensor control board 110 is connected to an external device such as a PC (Personal Computer) via an external I / F 115 so that data such as image data can be transmitted and received between the sensor control board 110 and the external device. You may.

<Imaging method, action, effect, etc.>
Next, the actions and effects of the configuration of the imaging system 100 according to the embodiment will be described.

In the imaging system 100, the camera unit 300 and the lighting unit 400 are slid by the slide unit 200 and fixed at two positions determined based on the length of a predetermined road structure in a direction intersecting the traveling direction of the vehicle.

The length of the predetermined road structure is the width of the sidewalk in the direction intersecting the traveling direction of the vehicle.

Here, the sidewalk is a road for pedestrians to pass through, and means a part of the road that is attached to a roadway or the like and is structurally partitioned for pedestrians to pass through. The width of the sidewalk varies depending on the traffic volume of pedestrians, but is generally about 1.5 to 3 m.

When the width of the sidewalk is 1.5 m, the distance between the two positions determined based on the width of the sidewalk may be set to 1.5 m. Alternatively, when the width of the sidewalk exceeds the width of the vehicle such as 3 m, the distance between the two positions determined based on the width of the sidewalk may be determined as the maximum width of the vehicle.

If there is an audit road or roadside belt in addition to the sidewalk, the distance between the two positions determined based on the width of the sidewalk is used as the length of the difference between the width of the sidewalk and the width of the audit road or roadside belt. You may decide.

When acquiring images at two positions, first, the camera unit 300 and the lighting unit 400 are fixed at one of the two positions determined based on the width of the sidewalk in the direction intersecting the traveling direction of the vehicle. , Acquire an area image of the tunnel wall surface in the desired area. Next, the camera unit 300 and the lighting unit 400 are fixed at the other position of the two positions, and an area image of the wall surface of the tunnel in a desired area is acquired.

Hereinafter, the details of the method of imaging the wall surface of the tunnel 600 at two positions will be described with reference to FIGS. 5 and 6. 5A and 5B are views for explaining an example of an image pickup when the distance from the image pickup system 100 to the wall surface of the tunnel 600 is short, FIG. 5A is a view of the vehicle 500 from the traveling direction, and FIG. 5B is a view. It is a figure which shows the state that the vehicle 500 travels in the inside of a tunnel 600.

In FIG. 5A, the imaging system 100 is fixed on the roof of the vehicle 500. The camera unit 300 and the lighting unit 400 are slid to the right end of the slide unit 200 in the traveling direction, and are fixed to the slide unit 200 by the index plungers 350 and 450, respectively.

On the other hand, in FIG. 5B, there is a lane 710 on the left side and a lane 720 on the right side with respect to the center of the road 700. The vehicle 500 is traveling in the lane 720 in the direction toward the front of the paper.

In this example, there is a sidewalk 730 on the lane 710 (oncoming lane of vehicle 500) side. Since there is no sidewalk on the lane 720 side, the vehicle 500 is traveling at a position closer to the wall surface on the vehicle 500 side of the tunnel 600 than when there is a sidewalk.

The camera unit 300 and the lighting unit 400 are located at the right end of the slide unit 200 in the traveling direction, that is, at a position away from the wall surface of the tunnel 600 on the vehicle 500 side. The positions of the camera unit 300 and the lighting unit 400 in this case are hereinafter referred to as position A.

The broken line 100A in FIG. 5B represents the imaging range by the imaging system 100. That is, the imaging system 100 images the area 600A (the area indicated by the thick line) within the imaging range indicated by the broken line 100A on the wall surface of the tunnel 600. As shown by the thick line, in the embodiment, the image is taken up to the boundary between the wall surface (lining portion) of the tunnel and the ground.

By performing imaging by the imaging system 100 while the vehicle 500 is running, the wall surface on the right half of FIG. 5B is imaged with respect to the paper surface from the entrance to the exit of the tunnel 600.

On the other hand, FIG. 6 is a diagram for explaining an example of an imaging state when the distance from the imaging system to the wall surface of the tunnel is long, (a) is a diagram of the vehicle 500 viewed from the traveling direction, and (b) is a diagram. It is a figure which shows the state that the vehicle 500 travels in the inside of a tunnel 600. The parts that overlap with FIG. 5 will be omitted from the description, and the differences will be described.

In FIG. 6, the camera unit 300 and the lighting unit 400 are slid to the left end of the slide unit 200 in the traveling direction, and are fixed to the slide unit 200 by the index plungers 350 and 450, respectively.

On the other hand, in FIG. 6B, the vehicle 500 is traveling in the lane 710 in the front direction with respect to the paper surface.

In this example, there is a sidewalk 730 on the lane 710 (the lane in which the vehicle 500 travels). That is, the vehicle 500 is traveling in the opposite lane in the opposite direction to that in the case of FIG. 5B. In this case, the vehicle 500 travels at a position farther from the wall surface of the tunnel 600 on the vehicle 500 side as compared with the case where there is no sidewalk on the traveling lane side.

The camera unit 300 and the lighting unit 400 are located at the left end of the slide unit 200 in the traveling direction, that is, close to the wall surface of the tunnel 600 on the vehicle 500 side. The positions of the camera unit 300 and the lighting unit 400 in this case are hereinafter referred to as position B.

The broken line 100B in FIG. 6B represents the imaging range by the imaging system 100. That is, the imaging system 100 images the area 600B (the area indicated by the thick line) within the imaging range indicated by the broken line 100B on the wall surface of the tunnel 600. As shown by the thick line, in the embodiment, the image is taken up to the boundary between the wall surface (lining portion) of the tunnel and the ground.

By performing imaging by the imaging system 100 while the vehicle 500 is running, the wall surface on the right half of FIG. 6B is imaged with respect to the paper surface from the entrance to the exit of the tunnel 600.

By joining the image of the wall surface captured in the state of FIG. 5 and the image of the wall surface captured in the state of FIG. 6, it is possible to acquire the captured image of the entire wall surface from the entrance to the exit of the tunnel 600.

Here, it is desirable that the images captured by each camera of the camera unit 300 have overlapping imaging regions. Further, in order to create a single developed view image by joining the images, it is desirable that the image on the side without the sidewalk in FIG. 5 and the image on the side with the sidewalk in FIG. 6 are captured so that the ceiling portion overlaps. In other words, when the wall surface of the tunnel 600 is imaged on the way back and forth, the image area on the way back and the image area on the way back intersect with the traveling direction of the vehicle 500 so that an unimaged area is not generated on the wall surface of the tunnel 600. It is desirable to overlap in the direction of the image.

According to the embodiment, the distance from the wall surface on the vehicle 500 side to the imaging system 100, that is, simply by switching and fixing the camera unit 300 and the lighting unit 400 to the positions A and B depending on the presence or absence of the sidewalk. The subject distance can be made substantially constant. As a result, it is possible to perform imaging with common imaging conditions such as focus state, imaging magnification, and illumination brightness regardless of the presence or absence of a sidewalk. In addition, since the wall surfaces of the tunnels on the right half and the left half can be imaged under common imaging conditions, image processing for connecting the two can be easily performed.

As described above, the wall surface of the tunnel can be appropriately imaged without the trouble of adjusting the focus of the camera and measuring the cross-sectional shape of the object.

In addition to the above, the following effects can also be obtained. For example, if the focus of the camera is adjusted while the vehicle is running, the adjustment mechanism may break down due to vibrations associated with the running, irregular movements such as sudden braking and sudden acceleration.

Further, when a cam mechanism that employs a cam groove and a cam follower is used as the adjustment mechanism, the cam follower may gradually move in the cam groove due to vibration caused by the running of the vehicle, and the focus state may change. Furthermore, if dust in the tunnel gets inside the mechanism, it may cause malfunction.

According to the embodiment, since the focus of the camera is not adjusted while the vehicle is running, the possibility of these failures can be reduced. Further, since the slide mechanism is simple, there is an effect that the device cost can be reduced. Further, since it is not necessary to perform complicated image processing such as detecting the contrast of the texture of the subject for the focus adjustment, the calculation cost can be reduced.

Further, when traveling in a tunnel that is dark and has a small amount of features, it is difficult to detect the contrast itself, and if the contrast detection is performed with sufficient accuracy, an expensive image sensor with high sensitivity is required. According to the embodiment, such technical difficulty and the cost of the image sensor can be reduced.

Further, when a line image sensor is used in the camera unit, since only one line of images can be obtained, it becomes difficult to adjust the focus using the captured image. According to the embodiment, since the image captured for focus adjustment is not used, a line image sensor can be used for the camera unit. This enables imaging with high illumination efficiency as described later.

In addition to the above, the following effects can also be obtained. For example, suppose that the camera unit 300 and the lighting unit 400 are placed at positions relatively offset from the center of the tunnel 600 to take an image. Here, the center of the tunnel 600 refers to the substantially center of the semicircle in the semicircular cross-sectional shape of the tunnel 600.

In this case, the image of the wall surface near the ceiling of the tunnel 600 (the image acquired by the camera 331 in FIG. 2) and the image of the wall surface near the ground of the tunnel 600 (the image acquired by the camera 334 in FIG. 2) are used to obtain an imaging magnification. The difference in conditions such as is large. As a result, there are problems such as a large difference in image resolution between the vicinity of the ceiling of the tunnel 600 and the vicinity of the ground.

In addition, in order to eliminate such a problem, there is also a method of imaging the wall surface of the tunnel while ignoring the lane and driving the vehicle in the center of the road so that the distance to the wall surface of the tunnel is substantially constant (). For example, see Japanese Patent Application Laid-Open No. 2011-095222).

However, this method is inconvenient because it may collide with an oncoming vehicle at the time of imaging, and it is necessary to go at night when there is little traffic of the vehicle or to block the road. Further, if a median strip is provided on the road in the tunnel, imaging by the above method is impossible in the first place.

On the other hand, according to the embodiment, the camera unit 300 and the lighting unit 400 can be brought closer to the center of the tunnel 600 regardless of whether the vehicle 500 is near or far from the wall surface of the tunnel 600. Differences in imaging conditions can be suppressed. Therefore, it is possible to perform imaging while suppressing problems such as differences in image resolution between the vicinity of the ceiling of the tunnel 600 and the vicinity of the ground while traveling in the original lane without closing the traffic of the vehicle.

In the embodiment, an example of changing the position of the slide unit 200 in the direction of the thick arrow in FIG. 1 is shown, but the present invention is not limited to this. The position of the slide unit 200 may be changed in an arbitrary direction in a plane intersecting the traveling direction of the vehicle.

Further, in the embodiment, an example is shown in which the camera unit 300 and the lighting unit 400 are fixed by the slide unit 200 at two different positions in the direction of the thick arrow in FIG. 1, but the present invention is not limited to this. The camera unit 300 and the lighting unit 400 may be fixed at two different positions in the plane intersecting the traveling direction of the vehicle and in the direction facing the wall surface of the tunnel.

Here, the "direction facing the wall surface of the tunnel" is supplemented. As described above, the tunnel has a semicircular cross section orthogonal to the traveling direction of the vehicle. Therefore, among the wall surfaces of the tunnel, the wall surface is oriented horizontally near the ground, and the wall surface is oriented vertically downward near the ceiling. The "direction facing the wall surface of the tunnel" means a direction facing the wall surface having a different direction depending on the location. The "direction facing the wall surface of the tunnel" near the ground is a substantially horizontal direction or the like. On the other hand, the "direction facing the wall surface of the tunnel" near the ceiling is substantially vertically upward.

Next, the details of the configuration and operation of the guide shaft 240 according to the embodiment will be described.

The camera unit 300 and the lighting unit 400 are separate components, and each slides independently. Therefore, when the guide shaft 240 is not applied, there is a possibility that each of them independently causes movements such as pitching, yawing, and rolling when sliding.

Further, when the imaging system 100 is attached to and detached from the vehicle, the mutual position or posture (hereinafter referred to as position / posture) between the camera unit 300 and the lighting unit 400 may change. Furthermore, there is a possibility that each position / posture may fluctuate due to vibration during running, or each position / posture may fluctuate due to deformation of members such as frames 261 and 262 and base plates 310 and 410 due to the influence of temperature and the like. is there.

If there is such a fluctuation, the illumination light does not properly hit the imaging region of the camera unit 300, and there may be a problem that imaging cannot be performed due to insufficient brightness.

As an example, FIG. 7 is a diagram illustrating a state in which the positions / orientations of the camera unit 300 and the lighting unit 400 fluctuate and the illumination light does not properly hit the imaging region of the camera unit 300. FIG. 7A is a diagram showing a case where there is no mutual change in position / posture between the camera unit 300 and the lighting unit 400, and FIG. 7B is a diagram showing the mutual position / position of the camera unit 300 and the lighting unit 400. It is a figure which shows the case where there is a change of posture.

FIG. 7A is a view of the vehicle 500 traveling in the direction of the thick arrow in the figure as viewed from above. 600 is the wall surface of the tunnel. The imaging range 361 represents the imaging range of the camera unit 300, and the intersection of the wall surface of the tunnel 600 and the imaging range 361 corresponds to the imaging region of the wall surface of the camera unit 300. The illumination range 461 represents the illumination range by the illumination unit 400, and the intersection of the wall surface of the tunnel 600 and the illumination range 461 corresponds to the illumination area of the wall surface by the illumination unit 400.

In FIG. 7A, since there is no mutual change in position / orientation between the camera unit 300 and the lighting unit 400, the imaging region by the camera unit 300 and the lighting region by the lighting unit 400 overlap. That is, the illumination light appropriately illuminates the imaging region.

On the other hand, in FIG. 7B, the postures of the camera unit 300 and the lighting unit 400 change independently, so that the imaging range 362 and the lighting range 462 change from the state shown in FIG. 7A, and the wall surface of the tunnel 600 is formed. The imaging area and the illumination area in the above do not overlap. That is, the illumination light does not properly illuminate the imaging region due to the mutual change in position / orientation between the camera unit 300 and the illumination unit 400.

In particular, in the embodiment, a line CCD is used as the image sensor, and the image pickup range (region) in the traveling direction of the vehicle 500 is narrowed. In this case, since it is sufficient to concentrate the illumination light in a narrow area, there is an effect that the illumination efficiency is good, and a sufficient amount of illumination light is required inside the dark tunnel, which is more preferable. However, on the other hand, since the imaging region in the traveling direction of the vehicle 500 is narrow, if the mutual position / orientation of the camera unit 300 and the lighting unit 400 fluctuates, the illumination light does not properly hit the imaging region of the camera unit 300. Is likely to occur.

Therefore, the imaging system 100 of the embodiment includes a guide shaft 240 in order to suppress a problem that the illumination light does not properly illuminate the imaging region. Hereinafter, a specific description will be given with reference to FIG. FIG. 8 is a diagram illustrating an example of the configuration of the guide shaft and the guide shaft holding member according to the embodiment.

In FIG. 8, the guide shaft 240 is held by the guide shaft holding members 251 and 252. The shaft connecting portions 341 and 342 are fixed to the base plate 310 of the camera unit 300.

Further, the shaft connecting portions 341 and 342 are provided with through holes 341-1 and 342-1, respectively. The guide shaft 240 and the camera unit 300 are connected by passing the guide shaft 240 through the through holes 341-1 and 342-1. Similarly, the guide shaft 240 and the lighting unit 400 are connected by passing the guide shaft 240 through the through holes provided in the shaft connecting portions 441 and 442, respectively.

The camera unit 300 and the lighting unit 400 slide while being connected to the guide shaft 240, respectively. That is, a common member can be used as a guide to slide.

Therefore, when the position / orientation of either the camera unit 300 or the lighting unit 400 changes, the other also changes accordingly. That is, the camera unit 300 and the lighting unit 400 can be slid or stationary while maintaining the relative position / orientation relationship between the two. As a result, it is possible to suppress fluctuations in the relative position / orientation of the camera unit 300 and the lighting unit 400, and to suppress a problem that the illumination light does not properly illuminate the imaging region.

Next, FIG. 9 shows an example of an imaging area of the camera unit 300 when the camera unit 300 is tilted with respect to the wall surface of the tunnel, and an illumination area of the lighting unit 400 when the lighting unit 400 is tilted with respect to the wall surface of the tunnel. It is a figure explaining an example.

In FIG. 9, the illumination unit 400 irradiates the wall surface of the tunnel 600 with illumination light 466, which is divergent light having the optical axis 465 as the optical axis. The light distribution angle (divergence angle) α of the illumination light 466 is 1.65 degrees or the like. The camera unit 300 images the wall surface of the tunnel 600. The optical axis 365 is the optical axis of the camera unit 300.

When the positions of the camera unit 300 and the lighting unit 400 fluctuate due to meandering operation of the vehicle 500 or the like, the camera unit 300 and the lighting unit 400 may be tilted toward the wall surface in the tunnel as shown in FIG. In this case as well, the relative position / orientation relationship between the camera unit 300 and the lighting unit 400 is maintained. Therefore, as shown in the figure, the imaging area by the camera unit 300 and the lighting area by the lighting unit 400 overlap. It is possible to maintain the state of being.

In this way, even when the positions of the camera unit 300 and the lighting unit 400 change due to meandering operation of the vehicle 500 or the like, the lighting unit 400 can appropriately illuminate the imaging region of the camera unit 300. Although the case where the line CCD is used is particularly shown in this embodiment, the same effect can be obtained even when the area CCD or the like is used.

Next, the details of the configuration and operation of the index plungers 350 and 450 according to the embodiment will be described with reference to FIG. FIG. 10 is a diagram illustrating an example of the configuration of the index plungers 350 and 450.

In FIG. 10, the index plunger 350 is fixed to the flat surface portion of the base plate 310 of the camera unit 300, and the index plunger 450 is fixed to the flat surface portion of the base plate 410 of the lighting unit 400.

As described above, the camera unit 300 slides on the rail 210 and the lighting unit 400 slides on the rail 220. Since the index plungers 350 and 450 have the same configuration and operation, the index plunger 450 will be described here as an example.

The index plunger 450 has a plunger 451 and a plunger holding portion 452. The plunger 451 has a round bar-shaped pin protruding toward the ground, a spring that gives the pin a biasing force toward the ground, and a spring holding portion that presses the pin and the spring. The plunger holding unit 452 holds the plunger 451.

On the other hand, the base 230 of the slide unit 200 is provided with a fitting hole 231 for fitting the lighting unit 400 with the pin at a position where the lighting unit 400 is desired to be fixed in the sliding direction of the lighting unit 400. Therefore, when the lighting unit 400 slides, the pin is in a state of hitting the base 230 at a position where there is no fitting hole 231 and does not act to fix the lighting unit 400.

When the lighting unit 400 slides to the position where the fitting hole 231 is located, the pin protrudes toward the fitting hole 231 by the urging force of the spring and fits into the fitting hole 231. As a result, the lighting unit 400 cannot slide, and the lighting unit 400 is fixed. When it is desired to release the fixing and slide the lighting unit 400 again, the fixing release mechanism is manually operated to release the fixing.

In the embodiment, the base 230 is provided with fitting holes at positions corresponding to positions A and B in the sliding direction, respectively. As a result, the lighting unit 400 can be fixed at two different positions in the plane intersecting the traveling direction of the vehicle. Similarly, the camera unit 300 can also be fixed at two different positions in the plane intersecting the traveling direction of the vehicle by the index plunger 350.

In the embodiment, an example is shown in which a pin is fitted into a fitting hole 231 provided in the base 230 to fix the lighting unit 400 or the like, but the present invention is not limited to this. A pin may be fitted into a fitting hole provided in the frame 262, the rail 220, or the like to fix the lighting unit, or the lighting unit or the like may be positioned by abutting and then clamped by a bolt or the like. ..

Next, in the embodiment, an example of the effect of tilting the illumination direction of the illumination light by the illumination unit 400 with respect to the imaging direction (image acquisition direction) by the camera unit 300 will be described with reference to FIG.

FIG. 11 is a view of the vehicle 500 traveling in the direction of the thick arrow as viewed from above, as in FIG. 7. The imaging direction 363 is the imaging direction by the camera unit 300, and is synonymous with the optical axis direction of the lens of the camera unit. The imaging range 364 represents a range imaged by the camera unit 300. The portion where the wall surface of the tunnel 600 and the imaging range 364 intersect corresponds to the imaging region of the wall surface by the camera unit 300.

The illumination direction 463 is the illumination direction by the illumination unit 400, and is synonymous with the optical axis direction of the lens of the illumination unit. The illumination range 464 represents a range illuminated by the illumination unit 400. The portion where the wall surface of the tunnel 600 and the lighting range 464 intersect corresponds to the lighting area of the wall surface by the lighting unit 400.

As described above, when the positions / postures of the camera unit 300 and the lighting unit 400 fluctuate due to vibration or the like while the vehicle 500 is running, the illumination light does not properly hit the imaging region of the camera unit 300, and the image is captured due to insufficient brightness. There is a problem that cannot be done.

Therefore, in the embodiment, the illumination unit 400 is illuminated by tilting the illumination direction of the illumination unit 400 with respect to the imaging direction of the camera unit 300 toward the imaging region of the wall surface of the tunnel 600. In the example of FIG. 11, a state of being illuminated with an inclination of an angle θ is shown.

By tilting the illumination in this way and setting the vicinity close to the center of the illumination region in the traveling direction of the vehicle as the imaging region, it is possible to suppress the problem that the illumination light does not hit the imaging region.

Here, FIGS. 12A and 12B show the tilt angle θ of the optical axis 365 of the camera unit 300 and the optical axis 465 of the lighting unit 400, the light distribution angle α of the illumination light, and from the camera unit 300 to the wall surface of the tunnel 600, respectively. It is a figure explaining an example of the relationship between the distance L of, and the illumination area S.

FIG. 12A (a) is a diagram illustrating an example of the relationship between the camera unit 300, the lighting unit 400, and the wall surface of the tunnel 600. In FIG. 12A (a), the optical axis 365 of the camera unit 300 is perpendicular to the wall surface of the tunnel 600, and the optical axis 465 of the illumination light 466 by the illumination unit 400 is tilted with respect to the optical axis 365 of the camera unit 300. It is tilted at an angle θ. Note that this "vertical" does not strictly mean 90 degrees, and may deviate slightly from 90 degrees depending on the inclination of the wall surface of the tunnel 600, the meandering of the vehicle 500, and the like. This point is the same in the following.

The illumination light 466 illuminates the wall surface of the tunnel 600 with a light distribution angle α. It is assumed that the distance L from the camera unit 300 to the wall surface of the tunnel 600 fluctuates from Lmin to Lmax due to meandering operation of the vehicle 500 or the like. The illumination area S is an illumination area of the tunnel 600 by the illumination light 466. The illumination light is light that illuminates a circular region, and the illumination region S indicates the diameter of this circular region. However, the illumination light is not limited to the light that illuminates the circular region, and may be the light that illuminates the rectangular region or the light that illuminates the elliptical region.

On the other hand, FIG. 12A (b) is a diagram showing a case where the vehicle 500 is farthest from the wall surface of the tunnel 600 in a state where the imaging region by the camera unit 300 and the illumination region by the lighting unit 400 overlap.

As an example, if the tilt angle θ is 2.5 degrees and the light distribution angle α is 1.65 degrees, the illumination area S is 330 mm. In this case, when the distance from the camera unit 300 to the wall surface of the tunnel 600 is 5200 mm, the optical axis 365 of the camera unit 300 is the endmost portion of the illumination region S on the wall surface of the tunnel 600 (the rightmost end in FIG. 12A (b)). Located in. Therefore, the distance of 5200 mm from the camera unit 300 to the wall surface of the tunnel 600 is an example of the maximum distance Lmax that can maintain a state in which the imaging region of the camera unit 300 and the illumination region of the illumination unit 400 overlap.

FIG. 12B (c) is a diagram showing a case where the vehicle 500 is closest to the wall surface of the tunnel 600 in a state where the imaging region by the camera unit 300 and the illumination region by the lighting unit 400 overlap.

As an example, similarly to the above, when the angle θ is 2.5 degrees and the light distribution angle α is 1.65 degrees, the illumination area S is 330 mm. In this case, when the distance from the camera unit 300 to the wall surface of the tunnel 600 is 2600 mm, the optical axis 365 of the camera unit 300 is the leftmost portion of the illumination region S on the wall surface of the tunnel 600 (the leftmost end in FIG. 12B (c)). Located in. Therefore, the distance of 2600 mm from the camera unit 300 to the wall surface of the tunnel 600 is an example of the minimum distance Lmin capable of maintaining a state in which the imaging region of the camera unit 300 and the illumination region of the illumination unit 400 overlap.

In the above description, the lighting unit 400 illuminates the wall surface of the tunnel 600 with divergent light having a light distribution angle α, but the divergent light is not limited to the divergent light and may be illuminated by parallel light.

When illuminating the divergent light, the illumination area on the wall surface of the tunnel 600 can be changed according to the distance from the lighting unit 400 to the wall surface of the tunnel 600. The longer the distance L from the lighting unit 400 to the wall surface of the tunnel 600, the wider the area can be illuminated.

On the other hand, when illuminating parallel light, a certain area can be illuminated on the wall surface of the tunnel 600 regardless of the distance L from the illumination unit 400 to the wall surface of the tunnel 600.

Further, in the above description, the direction of the optical axis 365 of the camera unit 300 is perpendicular to the wall surface of the tunnel 600, and the optical axis 465 of the lighting unit 400 is tilted with respect to the optical axis 365 of the camera unit 300. It is not limited to this. As shown in FIG. 12B (d), the direction of the optical axis 465 of the lighting unit 400 is perpendicular to the wall surface of the tunnel 600, and the optical axis 365 of the camera unit 300 is set to the optical axis 465 of the lighting unit 400. You may tilt it against it. FIG. 12B (d) shows an example in which the optical axis 365 of the camera unit 300 is tilted by an inclination angle θ with respect to the optical axis 465 of the lighting unit 400. In other words, the optical axis 465 of the lighting unit 400 and the optical axis 365 of the camera unit 300 need only be relatively tilted at the tilt angle θ.

By tilting the optical axis 465 of the lighting unit 400 and the optical axis 365 of the camera unit 300 relatively in this way, the light can be illuminated toward the imaging region of the camera unit 300. Even when the horizontal imaging region (horizontal imaging field of view) on the wall surface of the tunnel 600 is narrow, the imaging region by the camera unit 300 can be appropriately illuminated by the light from the illumination unit 400.

Further, the effect is more remarkable by combining a configuration in which the guide shaft 240 is used to maintain the relative position / orientation relationship between the camera unit 300 and the lighting unit 400 and a configuration in which the illumination direction is tilted for illumination. It becomes. In other words, even when a line CCD is used as the image sensor and imaging is performed in a state where the illumination efficiency is good, the problem that the illumination light by the illumination unit 400 does not properly illuminate the imaging area by the camera unit 300 is further improved. It can be remarkably suppressed.

Further, even when the distance between the tunnel and the wall surface fluctuates due to the meandering of the car or the tunnel size is different, it is possible to suppress the problem that the illumination light by the illumination unit 400 does not properly illuminate the imaging area by the camera unit 300. ..

FIG. 13 is a diagram illustrating an example of the relationship between the meandering of the vehicle 500, the imaging region of the camera unit 300, and the lighting region of the lighting unit 400. The vehicle 500 is traveling in the direction indicated by the arrow in FIG. 13 while meandering.

As shown on the right side of FIG. 13, when the maximum distance Lmax from the camera unit 300 to the wall surface of the tunnel 600 is 5200 mm, the optical axis 365 of the camera unit 300 is the end of the illumination region S on the wall surface of the tunnel 600. It is located in the section (far left in FIG. 13). That is, it is one of the limits that the imaging region of the camera unit 300 and the illumination region of the illumination unit 400 can be maintained to overlap.

On the other hand, as shown on the left side of FIG. 13, when the minimum distance Lmin from the camera unit 300 to the wall surface of the tunnel 600 is 2600 mm, the optical axis 365 of the camera unit 300 is located in the illumination region S on the wall surface of the tunnel 600. It is located at the farthest end (the rightmost end in FIG. 13). That is, it is the other limit that can maintain the state in which the imaging region of the camera unit 300 and the illumination region of the illumination unit 400 overlap.

Under the conditions that the angle θ is 2.5 degrees and the light distribution angle α is 1.65 degrees (see FIG. 12A), the distance L from the camera unit 300 to the wall surface of the tunnel 600 is in the range of 2600 mm to 5200 mm, and the vehicle 500 It turns out that meandering is acceptable.

<Operation of imaging system>
Next, the operation of the imaging system 100 according to the embodiment will be described with reference to FIG. FIG. 14 is a flowchart showing an example of the operation of the imaging system 100.

First, in step S141, the imaging system 100 is attached to the vehicle 500.

Subsequently, in step 142, the camera unit 300 and the lighting unit 400 are fixed to the position A by the slide unit 200. In this case, the user manually performs the sliding of the camera unit 300 and the lighting unit 400 and the fixing at the position A.

Subsequently, in step S143, while the vehicle 500 is driven from the entrance to the exit of the tunnel 600, the area 600A of the wall surface on the side of the tunnel 600 where the sidewalk 730 is not present is imaged. In this case, imaging is started when the vehicle 500 enters the entrance of the tunnel 600. The user gives an instruction to start imaging.

When the vehicle 500 reaches the exit of the tunnel 600, the imaging is stopped. The user gives an instruction to stop imaging. Up to this point, image data of half of the entire wall surface of the tunnel 600 is stored in the HDD 114.

Subsequently, in step S144, the camera unit 300 and the lighting unit 400 are fixed to the position B by the slide unit 200. In this case, the user manually performs the sliding of the camera unit 300 and the lighting unit 400 and the fixing at the position B.

Subsequently, in step S145, while the vehicle 500 is traveling from the entrance to the exit of the tunnel 600 in the direction opposite to the traveling direction in step S1103, the area 600B of the wall surface on the side of the sidewalk 730 of the tunnel 600 is imaged. Will be Similar to the above, the user gives an instruction to start / stop imaging. As a result, the other half of the entire wall surface of the tunnel 600 is imaged and stored in the HDD 114.

Subsequently, in step S146, the user confirms that there is no problem with the captured image, and if there is no problem (step S146, No), the imaging ends. On the other hand, if there is a problem (step S146, Yes), the process returns to step S1102, and imaging is performed again.

As described above, it is possible to image an object such as a tunnel wall surface without taking time and effort such as adjusting the focus of the camera and measuring the cross-sectional shape of the object.

In the embodiment, an example of fixing the camera unit 300 and the lighting unit 400 at positions A and B to the slide unit 200 has been described, but such fixing may be performed to the vehicle 500. .. The configuration will be described below.

The camera unit 300 and the lighting unit 400 are attached to the vehicle fixing base plate. In the case of position A, the camera unit 300 and the lighting unit 400 are fixed by fixing the vehicle fixing base plate to the right end of the vehicle roof in the traveling direction using hook parts.

In the case of position B, the camera unit 300 and the lighting unit 400 are fixed by fixing the vehicle fixing base plate to the left end of the vehicle roof in the traveling direction using hook parts.

Further, the guide shaft 240 and the same parts as the guide shaft holding members 251 and 252 are provided on the vehicle fixing base plate, and the shaft connecting portions 341 and 342, and 441 and 442 are connected to the guide shaft 240. As a result, the influence of fluctuations in the position / orientation of the camera unit 300 and the lighting unit 400 can be suppressed.

In the case of this example, the imaging system 100 does not have to have the slide unit 200. Further, the camera unit 300 and the lighting unit 400 do not have to have the index plungers 350 and 450, respectively.

As described above, even when the camera unit 300 and the lighting unit 400 are fixed to the vehicle 500, the same effect as when the camera unit 300 and the lighting unit 400 are fixed to the slide unit 200 can be obtained.

[First Embodiment]
Next, the imaging system 100a according to the first embodiment will be described.

In imaging in a tunnel, it is preferable to perform exposure control that matches the exposure amount of light in the imaging system with the brightness in the tunnel (imaging light amount). However, when imaging the wall surface of a tunnel, the distance between the imaging system and the wall surface of the tunnel may change significantly due to an emergency parking zone or the like provided on the side of the road. When the distance between the image pickup system and the wall surface of the tunnel changes, the illumination distance and the like change, and the amount of image pickup light changes significantly. Then, the exposure cannot be appropriately controlled due to the delay in following the control of the change in the amount of imaged light, and overexposure or underexposure may occur, so that the image may not be properly imaged.

On the other hand, in the present embodiment, the exposure condition at the time of imaging is either a fixed exposure condition or an automatic exposure condition (AE: Auto Exposure) based on the distance between the imaging system 100a and the wall surface of the tunnel. To decide. Then, by performing exposure control according to the determined exposure conditions, even when the amount of imaging light changes depending on the distance between the imaging system 100a and the wall surface of the tunnel, an imaging system that images with an appropriate exposure is provided.

Here, overexposure refers to a phenomenon in which gradation is lost in a bright portion of a captured image and becomes pure white (overexposure), and underexposure refers to a phenomenon in which gradation is lost in a dark portion of a captured image and becomes pure black. It refers to a phenomenon (underexposure). In addition, the emergency parking zone refers to an emergency stop space provided on the left side or the right side of a road such as an expressway or a bypass at regular intervals. Further, the exposure condition refers to a condition for determining the exposure (exposure amount) at the time of imaging. Further, the fixed exposure condition means a fixed exposure condition regardless of the amount of imaging light, and the automatic exposure condition means an exposure condition that changes according to the detected amount of imaging light.

The details of the imaging system 100a according to the present embodiment will be described below.

<Functional configuration of the imaging system according to the first embodiment>
First, the functional configuration of the imaging system 100a will be described. FIG. 15 is a block diagram illustrating an example of the functional configuration of the imaging system 100a. As shown in FIG. 15, the image pickup system 100a includes a distance detection unit 120, a light amount detection unit 130, an image pickup unit 140, an illumination unit 150, and a control unit 160.

Of these, the distance detection unit 120 detects the distance between the imaging system 100a and the wall surface of the tunnel 600 in the direction intersecting the traveling direction of the vehicle 500, and determines the exposure condition provided by the control unit 160 with the detected distance data. Output to unit 161. The distance detection unit 120 is realized by a TOF sensor 141 or the like.

The light amount detection unit 130 detects the image pickup light amount at the time of imaging by the image pickup system 100a, and outputs the detected image pickup light amount data to the exposure control unit 162. Here, the amount of imaged light in the tunnel 600 includes the light reflected by the wall surface of the tunnel 600 of the illumination light by the lighting unit 400 and the light reflected by the wall surface of the tunnel 600 of natural light such as sunlight. Further, when the wall surface of the tunnel 600 is illuminated with light for exposure control separately from the illumination by the illumination unit 400, the imaged light amount of the wall surface of the tunnel 600 includes the reflected light.

The light amount detection unit 130 is realized by a line CCD331-2 or the like provided in the camera unit 300. However, the present invention is not limited to this, and may be realized by at least one of the lines CCD331-2, 332-2, 333-2 and 334-2. Further, apart from the camera unit 300, an optical sensor for detecting the amount of light such as PD (Photo Diode) may be provided to realize the function of the light amount detecting unit 130.

The imaging unit 140 is realized by a camera unit 300 or the like, and images the wall surface of the tunnel 600 to acquire an captured image.

The illumination unit 150 is realized by an illumination unit 400 or the like, and illuminates the wall surface of the tunnel 600 in order to secure the amount of imaging light at the time of imaging by the imaging unit 140.

The control unit 160 mainly determines the exposure conditions of the imaging unit 140 and controls the exposure of the imaging unit 140. Specifically, the control unit 160 includes an exposure condition determination unit 161, an exposure control unit 162, a storage unit 163, an input / output unit 164, and an end determination unit 165.

Of these, the exposure condition determination unit 161 determines the exposure condition of the imaging unit 140 as either a fixed exposure condition or an automatic exposure condition based on the distance data detected by the distance detection unit 120.

More specifically, when the detected distance is equal to or less than a predetermined first threshold value, the exposure condition determination unit 161 determines the exposure condition of the imaging unit 140 as an automatic exposure condition, and the distance is a predetermined first threshold value. If not the following, the exposure condition of the imaging unit 140 is determined to be a fixed exposure condition. Then, after the determination, the determination result is output to the exposure control unit 162. Here, the predetermined first threshold value is a predetermined value based on the dynamic range of the line CCD in the imaging unit 140 and the like. Further, when the detected distance is equal to or less than the first threshold value, the value is determined based on the fact that the captured image does not overexpose or underexpose.

Next, the exposure control unit 162 will be described. In the embodiment, at least one of the exposure time (shutter speed) of the line CCD, the amplification factor (gain) of the output voltage with respect to the light received by the line CCD, the diameter of the aperture provided by the camera unit 300, and the amount of illumination light by the illumination unit 400. Is the exposure condition.

The exposure control unit 162 includes an exposure time control unit 1621, an amplification factor control unit 1622, an aperture control unit 1623, and an illumination control unit 1624, and the image pickup unit 140 is made to take an image under fixed exposure conditions by using these. Alternatively, the image pickup unit 140 is made to take an image under automatic exposure conditions.

In imaging under the automatic exposure condition, the exposure control unit 162 calculates the exposure condition based on the imaged light amount detected by the light amount detection unit 130, and performs automatic exposure control to expose under the calculated exposure condition. Since a known exposure program or the like that automatically determines the exposure control value can be applied to the calculation of the automatic exposure condition, detailed description thereof will be omitted here.

The exposure time control unit 1621 controls the exposure time of each of the lines CCD331-2, 332-2, 333-2 and 334-2 based on the image capture light amount data detected by the light amount detection unit 130.

Further, the amplification factor control unit 1622 controls the amplification factors of the lines CCD331-2, 332-2, 333-2 and 334-2 based on the above-mentioned imaging light amount data, and the aperture control unit 1623 controls the above-mentioned aperture control unit 1623. The diameter of each of the diaphragms 331-1a, 332-1a, 333-1a and 334-1a is controlled based on the imaged light intensity data of. Further, the illumination control unit 1624 controls the illumination light amounts of the light sources 431-2, 432-2, 433-2 and 434-2 included in the illumination unit 400 based on the above-mentioned imaging light amount data.

The exposure times of the lines CCD331-2, 332-2, 333-2 and 334-2 may be equal or different. Further, the amplification factors of the lines CCD331-2, 332-2, 333-2 and 334-2 may be equal or different. Further, the diameters of the diaphragms 331-1a, 332-1a, 333-1a and 334-1a may be the same or different. Further, the illumination light amounts of the light sources 431-2, 432-2, 433-2 and 434-2 may be equal or different.

The storage unit 163 is realized by a storage device such as the RAM 113 of FIG. 4, and stores the exposure condition data calculated by the exposure control unit 162.

The input / output unit 164 is an interface unit for inputting / outputting data and signals, and is realized by an external I / F 115 or the like.

The end determination unit 165 determines whether or not the imaging of the wall surface of the tunnel 600 by the imaging system 100a has been completed. As an example, the end determination unit 165 compares the mileage based on the measured value by the vehicle speed meter / moving distance meter 171 with the length of the tunnel 600 stored in advance in the storage device such as the HDD 114 of FIG. 4, and the mileage is the tunnel. When the length reaches 600, the end of imaging is determined. Alternatively, the end determination unit 165 may receive the end instruction of the operator (operator) of the imaging system 100a via the input / output unit 164 and determine the end of imaging in response to the end instruction.

<Operation of the imaging system according to the first embodiment>
Next, the operation of the imaging system 100a will be described with reference to FIGS. 16 to 17.

16A and 16B are views for explaining an example of the operation of the imaging system 100a, FIG. 16A is a diagram showing a positional relationship between the imaging system 100a and the wall surface of the tunnel 600, and FIG. 16B is a diagram showing a positional relationship between the imaging system 100a and the wall surface of the tunnel 600. It is a figure which shows the relationship between the detection distance with, and the mileage of a vehicle 500.

In FIG. 16A, the vehicle 500 on the left side in the drawing is equipped with an imaging system 100a including a camera unit 300, a lighting unit 400, and a TOF sensor 141, and roads 700 in the directions indicated by thick arrows 151 and 152. Is running. The vehicle 500a shown in the center of the figure shows the state after the vehicle 500 has traveled in the direction of the thick arrow 151, and the vehicle 500b shown on the right side of the figure is a state in which the vehicle 500 is further thickened from the state of the vehicle 500a. It shows the state after traveling in the direction of 152.

Here, the camera unit 300 is an example of the image pickup unit 140, the illumination unit 400 is an example of the illumination unit 150, and the TOF sensor 141 is an example of the distance detection unit 120.

The imaging range 364 shown in FIG. 16A shows the imaging range by the camera unit 300, and the illumination range 464 shown by the broken line indicates the illumination range by the illumination unit 400. As shown in the figure, the lighting unit 400 illuminates the wall surface of the tunnel 600 in a direction intersecting the traveling direction of the vehicle 500, and the camera unit 300 images the wall surface of the tunnel 600.

In FIG. 16A, the laser beam 142 shown by the one-point chain line indicates the laser beam that is irradiated from the TOF sensor 141 to the wall surface of the tunnel 600, reflected by the wall surface of the tunnel 600, and returned to the TOF sensor 141. The TOF sensor 141 uses the laser beam 142 to detect the distance between the imaging system 100 and the wall surface of the tunnel 600 at a sufficient sampling rate.

In FIG. 16A, the wall surface of the tunnel 600 is shown on the lower side in the drawing of the vehicle 500, and the wall surface of the tunnel 600 at the position of the vehicle 500 on the left side in the drawing is shown as the wall surface 601.

At the position of the vehicle 500a in the center of the figure, there is a step on the wall surface of the tunnel 600 due to the emergency parking zone 701 provided on the side of the road 700, and the distance between the image pickup system 100a and the wall surface 602 is the same as that of the image pickup system 100a. It is longer than the distance to the wall surface 601. As the distance becomes longer, the illumination light from the lighting unit 400 to the wall surface 602 spreads, so that the amount of reflected light on the wall surface 602 decreases. Therefore, at the position of the vehicle 500a, the amount of captured light decreases, and the image of the wall surface 602 imaged by the camera unit 300 becomes darker than the image of the wall surface 601.

Since the emergency parking zone 701 is not provided at the position of the vehicle 500b on the right side in the figure, the distance between the imaging system 100a and the wall surface 603 is equivalent to the distance between the imaging system 100a and the wall surface 601. .. In addition, the amount of imaged light is the same as when the wall surface 601 is imaged.

On the other hand, in FIG. 16B, the horizontal axis represents the mileage of the vehicle 500. This mileage corresponds to the mileage of the vehicle 500 in FIG. 16A. The vertical axis indicates the detection distance from the imaging system 100a to the wall surface of the tunnel 600 by the TOF sensor 141, and the upper part in the figure indicates that the detection distance is longer.

Section 153 shown in FIG. 16B shows a section in which the distance to the wall surface 601 is detected by the TOF sensor 141. Similarly, section 154 indicates a section in which the distance to the wall surface 602 is detected, and section 155 indicates a section in which the distance to the wall surface 603 is detected. In section 154, the detection distance is longer by the amount of the emergency parking zone 701 as compared with sections 153 and 155. Further, the detection distance in the section 153 and the detection distance in the section 155 are equivalent.

The imaging system 100a starts imaging the wall surface 601 from the position of the vehicle 500 on the left side of the drawing in FIG. 16A. In the section 153, the exposure condition determination unit 161 determines the exposure condition of the camera unit 300 as the automatic exposure condition. The camera unit 300 takes an image of the wall surface 601 under automatic exposure conditions while being moved in the direction of the thick arrow 151 as the vehicle 500 travels.

When the vehicle 500 enters the section 154, the detection distance by the TOF sensor 141 changes abruptly. Based on this change, the exposure condition determination unit 161 detects that the vehicle 500 has entered the section 154 of the emergency parking zone 701, switches the exposure condition from the automatic exposure condition to the fixed exposure condition, and immediately before entering the section 154. Fixed to exposure conditions. After that, the camera unit 300 images the wall surface 602 under fixed exposure conditions. At this time, the exposure control unit 162 exposes the camera unit 300 under a fixed exposure condition, but at the same time, automatically calculates the exposure condition and stores the calculated exposure condition data in the storage unit 163.

After that, when the vehicle 500 enters the section 154 from the section 154, the detection distance by the TOF sensor 141 changes rapidly again, and becomes equivalent to the detection distance in the section 153. Based on this change, the exposure condition determination unit 161 detects that the vehicle 500 has left the section 154 and switches the exposure condition from the fixed exposure condition to the automatic exposure condition. Further, the exposure control unit 162 stops the storage of the exposure condition data in the storage unit 163. After that, the camera unit 300 images the wall surface 603 under the automatic exposure condition.

After that, when the vehicle 500 exits the tunnel 600, the imaging system 100a ends the imaging. Here, in one imaging, the fixed exposure condition in the section 154 is not appropriate, and the captured image of the wall surface 602 may include overexposed areas or blackened areas. In that case, the imaging system 100a performs a second imaging in order to image the wall surface 602 under appropriate exposure conditions.

In the second imaging, the exposure control unit 162 reads out the exposure condition data stored in the storage unit 163 in the first imaging, and takes an image under the exposure conditions based on the read exposure condition data. In the exposure condition data, the exposure condition data in the section 154 immediately after the vehicle 500 enters the section 154 and immediately before the vehicle 500 exits the section 154 may not be appropriate for calculating the automatic exposure condition due to a follow-up delay or the like. It is preferable to replace it with the average value of the data.

Next, FIG. 17 is a flowchart showing an example of the operation of the imaging system 100a.

First, in step S171, the vehicle 500 starts traveling.

Subsequently, in step S172, the exposure condition determination unit 161 determines the exposure condition to the automatic exposure condition, and the imaging unit 140 images the wall surface of the tunnel 600 under the automatic exposure condition.

Subsequently, in step S173, the distance detection unit 120 detects the distance between the imaging system 100a and the wall surface of the tunnel 600 in the direction intersecting the traveling direction of the vehicle 500, and uses the detected distance data as the exposure condition determination unit 161. Output to.

The order of steps S172 and S173 can be changed as appropriate, and both may be performed in parallel.

Subsequently, in step S174, the exposure condition determination unit 161 determines whether or not the detected distance is equal to or less than a predetermined first threshold value.

When it is determined in step S174 that the distance is equal to or less than a predetermined first threshold value (step S174, Yes), the exposure condition determination unit 161 determines the exposure condition as the automatic exposure condition, and the determination result is transmitted to the exposure control unit 162. Output.

Then, in step S175, the imaging unit 140 images the wall surface of the tunnel 600 under automatic exposure conditions.

On the other hand, when it is determined in step S174 that the distance is not equal to or less than a predetermined first threshold value (step S174, No), the exposure condition determination unit 161 determines the exposure condition as the fixed exposure condition, and determines the determination result as the exposure control unit 162. Output to.

Then, in step S176, the imaging unit 140 images the wall surface of the tunnel 600 under fixed exposure conditions.

Subsequently, in step S177, the exposure control unit 162 calculates the automatic exposure condition.

Subsequently, in step S178, the exposure control unit 162 stores the calculated exposure condition data in the storage unit 163.

Subsequently, in step S179, the end determination unit 165 determines whether or not the imaging of the wall surface of the tunnel 600 by the imaging system 100 has been completed.

When it is determined in step S179 that the imaging is completed (step S179, Yes), the imaging system 100a ends the imaging. On the other hand, when it is determined in step S179 that the imaging is not completed (step S179, No), the imaging system 100a returns to step S173 and repeats the operations after step S173.

In this way, the imaging system 100a can image the wall surface of the tunnel 600.

<Processing by the exposure control unit according to the embodiment>
Next, FIG. 18 is a flow chart showing an example of processing by the exposure control unit 162.

First, in step S181, the light amount detection unit 130 detects the imaged light amount data I and outputs the detected imaged light amount data I to the exposure control unit 162.

Subsequently, in step S182, the exposure control unit 162 determines whether or not the captured light amount data I is larger than the predetermined target value Ig.

If it is determined in step S182 that the imaged light amount data I is larger than the target value Ig (steps S182, Yes), in step S183, the aperture control unit 1623 stops down until the imaged light amount data I reaches the target value Ig. It is determined whether or not the diameters of 331-1a, 332-1a, 333-1a and 334-1a can be reduced.

When it is determined in step S183 that the aperture can be reduced (steps S183, Yes), the aperture control unit 1623 reduces the diameter of each aperture in step S184 until the imaged light amount data I reaches the target value Ig. After that, the exposure control unit 162 ends the process.

On the other hand, when it is determined in step S183 that the reduction is not possible (step S183, No), in step S185, the exposure time control unit 1621 performs the line CCD331-2,332 until the imaged light amount data I reaches the target value Ig. It is determined whether or not the exposure time of -2, 333-2 and 334-2 can be shortened.

When it is determined in step S185 that the exposure can be shortened (steps S185, Yes), in step S186, the exposure time control unit 1621 shortens the exposure time of each line CCD until the imaged light amount data I reaches the target value Ig. After that, the exposure control unit 162 ends the process.

On the other hand, when it is determined in step S185 that the shortening is not possible (step S185, No), in step S187, the amplification factor control unit 1622 increases the amplification factor of each line CCD until the imaged light amount data I reaches the target value Ig. Is determined whether or not can be reduced.

If it is determined in step S187 that the reduction is possible (step S187, Yes), in step S188, the amplification factor control unit 1622 lowers the amplification factor of each line CCD until the imaged light amount data I reaches the target value Ig. After that, the exposure control unit 162 ends the process.

On the other hand, when it is determined in step S187 that the reduction is not possible (step S187, No), in step S189, the illumination control unit 1624 uses the light sources 431-2, 432- until the imaged light amount data I reaches the target value Ig. It is determined whether or not the illumination light amount of 2, 433-2, 434-2, 435-2 and 436-2 can be reduced.

When it is determined in step S189 that the reduction is possible (step S189, Yes), in step S190, the illumination control unit 1624 reduces the illumination light amount of each light source until the imaged light amount data I reaches the target value Ig. After that, the exposure control unit 162 ends the process.

On the other hand, if it is determined in step S189 that the reduction is not possible (step S189, No), in step S191, the exposure control unit 162 generates a beep sound in the buzzer 116 (see FIG. 4) and is out of the investigation range. The warning is notified, and then the process returns to step S181 to continue the process. Instead of generating the beep sound, a warning message may be displayed on the user interface screen via the external I / F 115 to notify the user.

On the other hand, if it is determined in step 182 that the imaged light amount data I is not larger than the predetermined target value Ig (steps S182, No), in step S192, the illumination control unit 1624 targets the imaged light amount data I. It is determined whether or not the illumination light amount of each light source can be increased until the value Ig is reached.

When it is determined in step S192 that the light intensity can be increased (step S192, Yes), in step S193, the illumination control unit 1624 increases the illumination light amount of each light source until the imaged light amount data I reaches the target value Ig. After that, the exposure control unit 162 ends the process.

On the other hand, when it is determined in step S192 that the increase is not possible (step S192, No), in step S194, the amplification factor control unit 1622 increases the amplification factor of each line CCD until the imaged light amount data I reaches the target value Ig. Is determined whether or not it can be increased.

When it is determined in step S194 that the increase is possible (step S194, Yes), in step S195, the amplification factor control unit 1622 determines the amplification factor of each line CCD until the imaged light amount data I reaches the target value Ig. Raise it and then end the process.

On the other hand, when it is determined in step S194 that the increase is not possible (step S194, No), in step S196, the exposure time control unit 1621 takes the exposure time of each line CCD until the imaged light amount data I reaches the target value Ig. Is determined whether or not can be extended.

When it is determined in step S196 that the extension is possible (step S196, Yes), in step S197, the exposure time control unit 1621 determines the exposure time of each line CCD until the imaged light amount data I reaches the target value Ig. After the extension, the exposure control unit 162 ends the process.

On the other hand, if it is determined in step S196 that the extension is not possible (step S196, No), in step S198, the aperture control unit 1623 can increase the diameter of each aperture until the imaged light amount data I reaches the target value Ig. It is determined whether or not it is.

If it is determined in step S198 that the aperture can be expanded (step S198, Yes), in step S199, the aperture control unit 1623 expands the diameter of each aperture until the imaged light amount data I reaches the target value Ig. After that, the process ends.

On the other hand, if it is determined in step S198 that the image cannot be expanded (step S198, No), in step S191, the exposure control unit 162 generates a beep sound in the buzzer 116 to notify a warning outside the investigation range. After that, the process returns to step S181 to continue the process. In the same manner as described above, instead of generating the beep sound, a warning message may be displayed on the user interface screen via the external I / F 115 to notify the user.

In this way, the exposure control unit 162 can execute the exposure control process based on the image pickup light amount data I. In FIG. 18, in steps S183 to S190, the aperture diameter is reduced (steps S183 to S184), the exposure time is shortened (steps S185 to S186), the amplification factor is reduced (steps S187 to S188), and the amount of illumination light is reduced (steps S189 to S190). An example of controlling in the order of) is shown, but this order can be changed as appropriate. Similarly, in steps S192 to S199, the illumination light amount is increased (steps S192 to S193), the amplification factor is increased (steps S194 to S195), the exposure time is extended (steps S196 to S197), and the aperture diameter is increased (steps S198 to S199). An example of control is shown, but the order can be changed as appropriate.

<Operation and effect of the imaging system according to the first embodiment>
As described above, in the present embodiment, when the distance between the imaging system 100a and the wall surface of the tunnel 600 is equal to or less than a predetermined first threshold value, the exposure condition at the time of imaging is determined as the automatic exposure condition. When the distance is not equal to or less than a predetermined first threshold value, the exposure condition at the time of imaging is determined to be a fixed exposure condition.

As a result, when the distance between the imaging system 100a and the wall surface of the tunnel 600 changes significantly due to an emergency parking zone or the like provided on the side of the road, the wall surface of the tunnel 600 can be imaged under fixed exposure conditions. Then, it is possible to prevent the exposure from being unable to be appropriately controlled due to the delay in following the change in the amount of imaged light, and to prevent overexposure and underexposure and to appropriately take an image.

Further, in the present embodiment, in order to determine the exposure condition by comparing the absolute value of the distance between the imaging system 100a and the wall surface of the tunnel 600 with the first threshold value, the wall surface in the section 154 provided with the emergency parking zone Even when the step is not steep, it is possible to accurately detect entering the section 154 and accurately detecting exiting the section 154.

Further, when the image is taken under the fixed exposure condition in the section 154, the fixed exposure condition may not be appropriate and the image may not be taken properly in the section 154 with only one image taken by traveling the vehicle 500. On the other hand, in the present embodiment, the exposure control unit 162 calculates the exposure based on the amount of imaged light when the image capturing unit 140 is imaging the wall surface of the tunnel 600 under the fixed exposure condition in the first imaging by traveling. The condition data is output to the storage unit 163 and stored. Then, in the second imaging by traveling the vehicle 500, the section 154 is imaged under the exposure condition based on the exposure condition data stored in the storage unit 163. As a result, a section where the fixed exposure condition is not appropriate and an appropriate image cannot be taken in the first image can be appropriately imaged in the second image.

However, if the exposure conditions in the section 154 are known by prior experiments or the like, by imaging the section 154 under the known exposure conditions, it is appropriate to take an image once by traveling the vehicle 500 without overexposure or underexposure. Imaging can be performed.

<Modification example>
Here, since the embodiment can be variously modified, the imaging system 100b according to the modified example will be described.

FIG. 19 is a block diagram illustrating an example of the functional configuration of the imaging system 100b. As shown in FIG. 19, the imaging system 100b has an exposure condition determination unit 161b included in the control unit 160b.

Here, in the above-mentioned imaging system 100a, when the detected distance is equal to or less than a predetermined first threshold value, the exposure condition determination unit 161 determines the exposure condition to the automatic exposure condition and is not equal to or less than the predetermined first threshold value. In this case, it was detected that the vehicle entered the section where the emergency parking zone was provided, and the exposure condition was determined to be the fixed exposure condition. On the other hand, the exposure condition determination unit 161b according to the present modification calculates the amount of change in the distance from the difference between the detected distance data and the distance data detected immediately before. Then, when the amount of change in distance is equal to or less than the second threshold value, the exposure condition is determined as the automatic exposure condition, and when the amount of change in distance is not a predetermined second threshold value, the section where the emergency parking zone is provided is entered. Detecting that, the exposure condition is determined to be a fixed exposure condition. The details will be described below.

In FIG. 19, the exposure condition determination unit 161b includes a third threshold value determination unit 1611 and a section passage detection unit 1612.

The third threshold value determination unit 1611 determines a third threshold value for detecting that the user has exited the section provided with the emergency parking zone. The third threshold value determination unit 1611 determines the third threshold value by adding a predetermined margin to the distance data detected immediately before it is detected that the user has entered the section provided with the emergency parking zone.

The section passage detection unit 1612 compares the distance data obtained by the distance detection unit 120 with the above-mentioned third threshold value, and when the distance data exceeds the third threshold value, the section passage detection unit 1612 indicates that the vehicle has exited the section provided with the emergency parking zone. Detect.

Next, FIG. 20 is a flowchart showing an example of the operation of the imaging system 100b.

Since steps S201 to S203 are the same as steps S171 to S173 in FIG. 17, description thereof will be omitted here.

In step S204, the exposure condition determination unit 161b determines whether or not the amount of change in the distance calculated from the difference between the detected distance data and the distance data detected immediately before is equal to or less than the second threshold value.

When it is determined in step S204 that the amount of change in distance is equal to or less than the second threshold value (step S204, Yes), the exposure condition determination unit 161b determines the exposure condition as the automatic exposure condition and controls the determination result by exposure control. Output to unit 162.

Then, in step S205, the imaging unit 140 images the wall surface of the tunnel 600 under the automatic exposure condition.

On the other hand, when it is determined in step S204 that the amount of change in distance is not equal to or less than a predetermined second threshold value (step S204, No), the exposure condition determination unit 161b determines the exposure condition as a fixed exposure condition and determines the determination result. Output to the exposure control unit 162.

Subsequently, in step S206, the third threshold value determination unit 1611 determines a third threshold value for detecting that the user has exited the section provided with the emergency parking zone.

Since steps S207 to S209 are the same as steps S176 to S178 in FIG. 17, description thereof will be omitted here.

In step S210, the distance detection unit 120 detects the distance between the imaging system 100b and the wall surface of the tunnel 600 in the direction intersecting the traveling direction of the vehicle 500, and outputs the detected distance data to the exposure condition determination unit 161b. ..

Subsequently, in step S211 the section passage detection unit 1612 compares the distance data obtained by the distance detection unit 120 with the third threshold value, and determines whether or not the distance data exceeds the third threshold value.

If it is determined in step S211 that the distance data exceeds the third threshold value (steps S211 and Yes), the process proceeds to step S212. On the other hand, when it is determined that the distance data does not exceed the third threshold value (steps S211 and No), the process returns to step S207, and the operations after step S207 are performed again.

Since step S212 is the same as step S179 in FIG. 17, description thereof will be omitted here.

In this way, the imaging system 100b can image the wall surface of the tunnel 600.

As described above, in this modification, the amount of change in distance is calculated from the difference between the detected distance data and the distance data detected immediately before, and the exposure condition is fixedly exposed based on the calculated amount of change in distance. Determine either the condition or the automatic exposure condition. Since it is based on the amount of change in distance, it is possible to determine either the fixed exposure condition or the automatic exposure condition regardless of the diameter of the tunnel.

Moreover, although the absolute value of the wall surface distance or the amount of change thereof was used for determining the exposure condition, both of these can also be used. By using both, it is possible to make more robust decisions regarding disturbances such as lighting in tunnels and emergency telephone boxes.

The other effects are the same as those described in the first embodiment.

[Second Embodiment]
Next, the imaging system 100c according to the second embodiment will be described.

<Functional configuration of the imaging system according to the second embodiment>
FIG. 21 is a block diagram illustrating an example of the functional configuration of the imaging system 100c. As shown in FIG. 21, the imaging system 100c includes a first distance detection unit 121, a second distance detection unit 122, and a control unit 160c. Further, the control unit 160c has an exposure condition determination unit 161c.

The first distance detection unit 121 is realized by a TOF sensor or the like provided on the front side of the vehicle 500 in the traveling direction of the vehicle 500, and is between the imaging system 100c in the direction intersecting the traveling direction of the vehicle 500 and the wall surface of the tunnel 600. Detect the distance of. Then, the detected distance data is output to the exposure condition determination unit 161c included in the control unit 160c.

The second distance detection unit 122 is realized by a TOF sensor or the like provided on the rear side of the vehicle 500 in the traveling direction of the vehicle 500, and is formed by the imaging system 100c in the direction intersecting the traveling direction of the vehicle 500 and the wall surface of the tunnel 600. Detect the distance between. Then, the detected distance data is output to the exposure condition determination unit 161c included in the control unit 160c.

The exposure condition determination unit 161b sets the exposure condition of the imaging unit 140 to either a fixed exposure condition or an automatic exposure condition based on the distance data detected by each of the first distance detection unit 121 and the second distance detection unit 122. Decide on one side. Further, the exposure condition determination unit 161c includes a fourth threshold value determination unit 1613 and a section passage detection unit 1614.

The fourth threshold value determination unit 1613 determines a fourth threshold value for detecting that the user has exited the section provided with the emergency parking zone. The fourth threshold value determination unit 1613 determines the fourth threshold value by adding a predetermined margin to the distance data by the second distance detection unit 122 when it is detected that the user has entered the section provided with the emergency parking zone. ..

The section passage detection unit 1614 compares the distance data obtained by the second distance detection unit 122 with the fourth threshold value, and when the distance data exceeds the fourth threshold value, the section passage detection unit 1614 determines that the vehicle has exited the section provided with the emergency parking zone. Detect.

<Operation of the imaging system according to the second embodiment>
Next, FIG. 22 is a diagram illustrating an example of the operation of the imaging system 100c, (a) is a diagram showing the positional relationship between the imaging system 100c and the wall surface of the tunnel 600, and (b) is a diagram showing the positional relationship between the imaging system 100c and the tunnel. It is a figure which shows the relationship between the detection distance with the wall surface of 600, and the mileage of a vehicle 500. Since the view of FIG. 22 and the like are the same as those of FIG. 16, the description of the overlapping portion will be omitted, and the differences from FIG. 16 will be mainly described.

In FIG. 22A, the vehicle 500 shown on the left side in the drawing is equipped with an imaging system 100c including a camera unit 300, a lighting unit 400, a TOF sensor 141a, and a TOF sensor 141b, and has a thick arrow 151 and a thick arrow 151. The vehicle is traveling on the road 700 in the direction indicated by 152.

The TOF sensor 141a is provided on the front side of the vehicle 500 in the traveling direction of the vehicle 500, and is an example of the first distance detection unit 121. The laser beam 142a shown by the alternate long and short dash line indicates the laser beam emitted from the TOF sensor 141a and reflected by the wall surface of the tunnel 600.

Further, the TOF sensor 141b is provided on the rear side of the vehicle 500 in the traveling direction of the vehicle 500, and is an example of the second distance detection unit 122. The laser beam 142b shown by the alternate long and short dash line indicates the laser beam emitted from the TOF sensor 141b and reflected by the wall surface of the tunnel 600.

The imaging system 100c starts imaging the wall surface of the tunnel 600 by traveling the vehicle 500 from the position of the vehicle 500 on the left side in the drawing. Then, in the section 153, the exposure condition determination unit 161c determines the exposure condition of the camera unit 300 as the automatic exposure condition, and the camera unit 300 moves on the wall surface 601 in the direction of the thick arrow 151 by the traveling of the vehicle 500. Take an image.

When the vehicle 500 enters the section 154, the detection distance by the TOF sensor 141a changes abruptly. Further, with a slight delay, the detection distance by the TOF sensor 141b changes abruptly. The exposure condition determination unit 161c detects that the vehicle 500 has entered the section 154 of the emergency parking zone 701 based on the change in the detection distance by the TOF sensor 141a among them, and changes the exposure condition from the automatic exposure condition to the fixed exposure condition. Switch to. Then, the exposure condition is fixed immediately before entering the section 154. After that, the camera unit 300 images the wall surface 602 under fixed exposure conditions.

After that, when the vehicle 500 leaves the section 154 and enters the section 155, the detection distance by the TOF sensor 141a changes rapidly again and becomes equivalent to the detection distance in the section 153. Further, with a slight delay, the detection distance by the TOF sensor 141b also changes abruptly, and becomes equivalent to the detection distance in the section 153.

The exposure condition determination unit 161c detects that the vehicle 500 has left the section 154 of the emergency parking zone 701 based on the change in the detection distance by the TOF sensor 141b, and changes the exposure condition from the automatic exposure condition to the fixed exposure condition. Switch to. After that, the camera unit 300 images the wall surface 603 under the automatic exposure condition.

Next, FIG. 23 is a flowchart showing an example of the operation of the imaging system 100c.

Since steps S231 to S232 are the same as steps S171 to S172 in FIG. 17, description thereof will be omitted here.

In step S233, each of the first distance detection unit 121 and the second distance detection unit 122 detects and detects the distance between the image pickup system 100c and the wall surface of the tunnel 600 in the direction intersecting the traveling direction of the vehicle 500. The distance data is output to the exposure condition determination unit 161c.

The order of steps S232 and S233 can be changed as appropriate, and both may be performed in parallel.

Subsequently, in step S234, the exposure condition determination unit 161c determines whether or not the distance detected by the first distance detection unit 121 is equal to or less than a predetermined first threshold value.

When it is determined in step S234 that the distance is equal to or less than a predetermined first threshold value (step S234, Yes), the exposure condition determination unit 161c determines the exposure condition as the automatic exposure condition, and determines the determination result to the exposure control unit 162. Output.

Then, in step S235, the imaging unit 140 images the wall surface of the tunnel 600 under automatic exposure conditions.

On the other hand, when it is determined in step S234 that the distance detected by the first distance detection unit 121 is not equal to or less than a predetermined first threshold value (step S234, No), the exposure condition determination unit 161c sets the exposure condition to a fixed exposure condition. And output the decision result to the exposure control unit 162.

Then, in step S236, the fourth threshold value determination unit 1613 determines the fourth threshold value for detecting that the user has left the section where the emergency parking zone is provided.

Since the operations of steps S237 to S239 are the same as those of steps S176 to S178 of FIG. 17, description thereof will be omitted here.

In step S240, the second distance detection unit 122 detects the distance between the imaging system 100c and the wall surface of the tunnel 600 in the direction intersecting the traveling direction of the vehicle 500, and transmits the detected distance data to the exposure condition determination unit 161c. Output.

Subsequently, in step S241, the section passage detection unit 1614 compares the distance data by the second distance detection unit 122 with the fourth threshold value, and determines whether or not the distance data exceeds the fourth threshold value.

If it is determined in step S241 that the distance data exceeds the fourth threshold value (steps S241, Yes), the process proceeds to step S242. On the other hand, when it is determined that the distance data does not exceed the fourth threshold value (step S241, No), the process returns to step S237, and the operations after step S237 are performed again.

Since the operation of step S242 is the same as that of step S179 of FIG. 17, description thereof will be omitted here.

In this way, the imaging system 100c can image the wall surface of the tunnel 600.

As described above, in the present embodiment, when entering the section 154 in which the emergency parking zone 701 is provided, it is detected that the section 154 has been entered based on the detection distance by the first distance detection unit 121, and the section 154 When exiting from the section 154, it is detected based on the detection distance by the second distance detection unit 122. As a result, it is possible to detect that the vehicle 500 has entered the section provided with the emergency parking zone 701 before the emergency parking zone 701 is included in the imaging angle of view of the camera unit 300, and the emergency parking zone 701 is the camera. It can be detected that the vehicle 500 has left the section provided with the emergency parking zone 701 after it is no longer included in the imaging angle of view of the unit 300. As a result, it is possible to reliably detect entering the emergency parking zone 701 and exiting the emergency parking zone 701 with a margin with respect to the imaging angle of view of the camera unit 300.

The other effects are the same as those described in the first embodiment.

[Third Embodiment]
Since the functional configurations of the imaging system 100d according to the third embodiment, the imaging system 100e according to the fourth embodiment, and the imaging system 100f according to the fifth embodiment described below are the same as those of the imaging system 100a, they are duplicated thereafter. The explanation given is omitted.

First, the imaging system 100d according to the third embodiment will be described. Here, in the first embodiment, an example in which the imaging system 100a determines the exposure condition to the fixed exposure condition in the section of the emergency parking zone 701 has been described. On the other hand, in the present embodiment, imaging is continued under the automatic exposure condition in the section of the emergency parking zone 701, and the calculated exposure condition data is stored in the storage unit. As a result, exposure conditions such as appropriate lighting and increase / decrease rate are acquired as compared with the case of imaging under fixed exposure conditions.

FIG. 24 is a flowchart showing an example of the operation of the imaging system 100d.

First, in step S281, the vehicle 500 starts running imaging.

Subsequently, in step S282, the exposure condition determination unit 161 determines the exposure condition to the automatic exposure condition, and the imaging unit 140 images the wall surface of the tunnel 600 under the automatic exposure condition (first AE processing).

Subsequently, in step S283, the distance detection unit 120 detects the distance between the imaging system 100d and the wall surface of the tunnel 600 in the direction intersecting the traveling direction of the vehicle 500, and uses the detected distance data as the exposure condition determination unit 161. Output to. Further, the detected distance data is stored in the storage unit 163.

The order of steps S282 and S283 can be changed as appropriate, and both may be performed in parallel.

Subsequently, in step S284, the exposure condition determination unit 161 determines whether or not the detected distance is equal to or less than a predetermined first threshold value.

When it is determined in step S284 that the distance is equal to or less than a predetermined first threshold value (step S284, Yes), the exposure condition determination unit 161 determines the exposure to be automatic exposure and outputs the determination result to the exposure control unit 162. ..

Subsequently, in step S285, the imaging unit 140 images the wall surface of the tunnel 600 under automatic exposure (AE processing).

On the other hand, when it is determined in step S284 that the distance is not equal to or less than a predetermined first threshold value (step S284, No), in step S286, the exposure condition determination unit 161 stores the data of the exposure condition immediately before entering the emergency parking zone. It is stored in the part 163.

Subsequently, in step S287, the imaging unit 140 images the wall surface of the tunnel 600 under automatic exposure (AE processing).

Subsequently, in step S288, the exposure control unit 162 calculates the automatic exposure and records the calculated exposure condition data in the log.

Subsequently, in step S289, the distance detection unit 120 detects the distance between the imaging system 100d and the wall surface of the tunnel 600 in the direction intersecting the traveling direction of the vehicle 500, and uses the detected distance data as the exposure condition determination unit 161. Output to.

Subsequently, in step S290, the exposure condition determination unit 161 determines whether or not the detected distance exceeds a predetermined first threshold value.

If it is determined in step S290 that the amount is not exceeded (step S290, No), the operations after step S287 are performed again.

On the other hand, if it is determined that the value has been exceeded (step S290, Yes), in step S291, the exposure condition determination unit 161 locks the AE under the immediately preceding exposure condition.

Subsequently, in step S292, the exposure condition determination unit 161 determines whether or not the emergency parking zone 701 has escaped from the imaging range of the camera unit 300. In other words, it is determined whether or not the emergency parking zone 701 is no longer included in the imaging range of the camera unit 300.

If it is determined in step S292 that the device has not escaped (step S292, No), the operations after step S287 are performed again.

On the other hand, if it is determined in step S292 that the vehicle has escaped (step S292, Yes), the operation proceeds to step S293.

Subsequently, in step S293, the end determination unit 165 determines whether or not the imaging of the wall surface of the tunnel 600 by the imaging system 100d has been completed.

When it is determined in step S293 that the imaging is completed (step S293, Yes), the imaging system 100d ends the imaging. On the other hand, when it is determined in step S293 that the imaging is not completed (step S293, No), the operations after step S283 are performed again.

In this way, the imaging system 100d can image the wall surface of the tunnel 600.

As described above, in the present embodiment, by imaging the emergency parking zone 701 under the condition that the lighting and the increase / decrease rate are actually controlled by the automatic exposure control, the second imaging is performed as compared with the case where the image is taken with the fixed exposure. It is possible to obtain appropriate exposure conditions such as lighting and increase / decrease rate.

[Fourth Embodiment]
Next, the imaging system 100e according to the fourth embodiment will be described.

Here, FIG. 25 is a diagram illustrating an example of the relationship between the vehicle 500 and the emergency parking zone 701. As shown in FIG. 25, the vehicle 500 is traveling along the traveling direction 153. The emergency parking zone 701 is a recess provided in the wall surface of the tunnel 600 on the side close to the vehicle 500. Further, the distance between the TOF sensor 141 mounted on the vehicle 500 and the camera unit 300 in the direction along the traveling direction 153 will be referred to as a distance M in the following description.

When the vehicle 500 enters the section of the emergency parking zone 701, the detection distance (distance from the vehicle 500 to the wall surface of the tunnel 600) by the TOF sensor 141 changes abruptly. Since the TOF sensor 141 is installed in front of the camera unit 300 in the traveling direction of the vehicle 500, the wall surface before entering the emergency parking zone 701 is imaged by the camera unit 300 at this timing, and the lighting, increase / decrease rate, etc. are exposed. The condition is also a value suitable for the wall surface before entering the emergency parking zone 701. Therefore, if the exposure condition data is started to be stored from this timing, the exposure condition that is not suitable for photographing the emergency parking zone 701 may be acquired in the second photographing.

Therefore, in the present embodiment, after the detection distance suddenly changes, the vehicle speed / movement distance meter 171 detects that the vehicle 500 has advanced by at least the distance M, and then the data of the exposure condition is started to be stored. As a result, the exposure conditions suitable for the second shooting of the emergency parking zone 701 are acquired. It is preferable that the exposure in this case remains the automatic exposure. Here, the vehicle speed / moving distance meter 171 is an example of the "moving distance detecting unit", and the distance detected by the vehicle speed / moving distance meter 171 is an example of the "moving distance of the moving body".

After that, when the vehicle 500 begins to exit the section of the emergency parking zone 701, the detection distance by the TOF sensor 141 changes rapidly again. If you exit the section of the emergency parking zone 701 with automatic exposure, the lighting and tracking control from the state of increase / decrease rate according to the wall surface of the remote emergency parking zone 701 will not be in time, and the wall surface immediately after exiting the emergency parking zone 701 will be It may be overexposed.

Therefore, in the present embodiment, the exposure is switched to the fixed exposure within the period in which the image pickup range of the camera unit 300 includes the wall surface of the emergency parking zone 701. By doing so, overexposure can be avoided. In this case, it is preferable to use the values immediately before entering the emergency parking zone 701 for the lighting, the rate of increase / decrease, and the like. The timing of switching to fixed exposure may be the timing at which the detection distance suddenly changes. Further, it may be at this timing that the storage of the data of the exposure conditions suitable for the second shooting of the emergency parking zone or the like is finished.

After that, after the vehicle speed / movement distance meter 171 detects that the vehicle 500 has advanced by at least the distance M, the automatic exposure is returned again, so that the wall surface after exiting the section of the emergency parking zone 701 is also exposed appropriately. Can be imaged.

Next, FIG. 26 is a flowchart showing an example of the operation of the imaging system 100e.

Since the operations other than step S312 in FIG. 26 are the same as the operations other than step S292 in FIG. 24, duplicate description will be omitted here.

In step S312, the exposure condition determining unit 161 determines whether or not the output of the vehicle speed / moving distance meter 171 exceeds the distance M.

If it is determined in step S312 that the amount is not exceeded (step S312, No), the operations after step S307 are performed again.

On the other hand, if it is determined in step S312 that the amount has been exceeded (step S312, Yes), the operation proceeds to step S313.

In this way, the imaging system 100e can image the wall surface of the tunnel 600.

As described above, in the present embodiment, when the vehicle 500 enters the section of the emergency parking zone 701, the exposure condition data is obtained after the vehicle speed / movement distance meter 171 detects that the vehicle 500 has advanced by the distance M. Begin to remember. By doing so, it is possible to obtain exposure conditions suitable for taking a second picture of the emergency parking zone 701.

Further, when the vehicle 500 starts to exit the section of the emergency parking zone 701, the exposure is switched to the fixed exposure within the period in which the image pickup range of the camera unit 300 includes the wall surface of the emergency parking zone 701. By doing so, it is possible to avoid overexposure due to the inability to follow and control a sudden change in exposure.

Further, after the vehicle 500 exits the section of the emergency parking zone 701, after the vehicle speed / movement distance meter 171 detects that the vehicle 500 has advanced by at least the distance M, the automatic exposure is returned to the emergency parking zone 701. The wall surface after exiting the section can also be imaged with appropriate exposure.

In this way, the exposure control before and after the vehicle 500 enters the section of the emergency parking zone 701 can be appropriately performed.

It is also possible to set the exposure when shooting the emergency parking zone 701 as a fixed exposure. Here, FIG. 27 is a flowchart showing an example of the operation of the imaging system 100e when the exposure when the emergency parking zone 701 is being photographed is a fixed exposure.

As shown in FIG. 27, in step S327, the imaging unit 140 fixes (locks) the exposure.

Further, in step S330, the exposure condition determination unit 161 determines whether or not the detected distance exceeds a predetermined first threshold value, and if it is determined that the detected distance is exceeded (step S330, Yes), in step S331. The exposure condition determination unit 161 determines whether or not the output of the vehicle speed / movement distance meter 171 exceeds the distance M.

Since the operations other than these are the same as the operations shown in FIG. 26, duplicate description will be omitted here.

[Fifth Embodiment]
Next, the imaging system 100f according to the fifth embodiment will be described.

In the fourth embodiment, the output of the vehicle speed / moving distance meter 171 determines the timing for storing the exposure condition data and the timing for switching to the automatic exposure based on the distance M. However, in the present embodiment, such a determination is made. This is performed based on the brightness of the image captured by the camera unit 300.

Specifically, in the fourth embodiment, from the detection of a sudden change in the wall surface distance by the TOF sensor until the imaging range of the camera unit 300 includes only the emergency parking zone 701, or the vehicle 500 The period of exiting the section of the emergency parking zone 701 was performed by detecting the distance M with the vehicle speed / moving distance meter 171. In the present embodiment, since the amount of change in the brightness of the captured image by the camera unit 300 is equal to or less than the predetermined brightness threshold value, only the emergency parking zone 701 is included in the imaging range of the camera unit 300. It is detected that the user has exited the emergency parking zone 701 due to exceeding a predetermined brightness threshold value.

Here, FIG. 28 is a flowchart showing an example of the operation of the imaging system 100f.

In step S350, the exposure condition determination unit 161 determines whether or not the detected distance exceeds a predetermined first threshold value, and if it is determined that the detected distance is exceeded (step S350, Yes), the exposure is exposed in step S351. The condition determination unit 161 determines whether or not the amount of change in the brightness of the captured image by the camera unit 300 is equal to or less than a predetermined brightness threshold value. The amount of change in the brightness of the captured image can be detected by the amount of change in the average brightness of all the pixels constituting the captured image.

Since the operations other than this are the same as the operations shown in FIG. 27, duplicate description will be omitted here.

By using the amount of change in the brightness of the captured image by the camera unit 300 in this way, the same effect as that of the imaging system 400e of the fourth embodiment can be obtained.

In the above-described embodiment, the emergency parking zone 701 provided on the wall surface of the tunnel 600 has been described as an example. However, even when the wall surface of the tunnel 600 is provided with a recess other than the emergency parking zone 701, emergency parking is performed. The above-described embodiment can be applied to a depression other than the band 701.

Although examples of embodiments of the present invention have been described above, the present invention is not limited to such specific embodiments, and various aspects are described within the scope of the gist of the present invention described in the claims. It can be transformed and changed.

Specifically, the vehicle equipped with the camera may be a two-wheeled vehicle, a four-wheeled vehicle such as a general vehicle, a construction / agricultural / industrial vehicle, a railroad vehicle, a special vehicle, or an air vehicle such as a drone. There may be. These are collectively referred to as a moving body.

Further, in the embodiment, the tunnel has been described as an example of the object, but the object is not limited to this, and the object also includes a pipe used for transporting gas, liquid, powder, and granular material. In addition, the object also includes a hoistway (elevator shaft) such as a vertical hole-shaped reinforced concrete structure in which an elevator (elevator) travels.

The embodiment also includes an imaging method. For example, in the imaging method, the exposure condition in the imaging step is set to a fixed exposure condition based on the imaging step of imaging the object while being installed on the moving object and the distance between the moving object and the object. , Or an exposure condition determination step of determining one of the automatic exposure conditions. By such an imaging method, the same effect as that of the above-mentioned imaging system can be obtained. Such an imaging method may be realized by a circuit such as a CPU and an LSI, an IC card, a single module, or the like.

The embodiment also includes a program. For example, the program images an object while it is installed on a moving object, and based on the distance between the moving object and the object, the exposure condition in the imaging is set to a fixed exposure condition or an automatic exposure condition. Have the computer execute the process of determining one of them. With such a program, the same effect as that of the above-mentioned imaging system can be obtained.

100 Imaging system 110 Sensor control board 111 CPU
112 ROM
113 RAM
114 HDD
115 External I / F
116 Buzzer 117 System bus 120 Distance detection unit 121 First distance detection unit 122 Second distance detection unit 130 Light intensity detection unit 140 Imaging unit 141 TOF sensor (an example of distance detection unit)
141a TOF sensor (an example of the first distance detection unit)
141b TOF sensor (an example of the second distance detection unit)
150 Lighting unit 153 to 155 section 160 Control unit 161 Exposure condition determination unit 1611 Third threshold value determination unit 1612 Section passage detection unit 1613 Fourth threshold value determination unit 1614 Section passage detection unit 162 Exposure control unit 1621 Exposure time control unit 1622 Amplification rate control Unit 1623 Aperture control unit 1624 Lighting control unit 163 Storage unit 164 Input / output unit 165 End judgment unit 170 IMU
171 Vehicle speed meter / moving distance meter 200 Slide unit 210, 220 Rail 230 Base 231 Fitting hole 240 Guide shaft 251, 252 Guide shaft holding member 261, 262 Frame 300 Camera unit 310, 410 Base plate 321, 322 Rail connection 331-334 Camera 331-1, 334-1 Lens 331-1a Aperture 331-2, 334-2 Line CCD
341, 342, 441, 442 Shaft connection part 341-1, 342-1 Through hole 350, 450 Index plunger 361, 362, 364 Imaging range 363 Imaging direction 400 Illumination unit 431-436 Illumination light source 431-1 Lens 431-1a Aperture 431-2 Light source 451 Plunger 452 Plunger holder 461, 462, 464 Lighting range 463 Lighting direction 500 Vehicle 600 Tunnel 601 to 603 Wall surface 700 Road 701 Emergency parking zone 710, 720 Lane 730 Sidewalk I Imaged light amount data Ig Target value M

JP-A-2010-239479

Claims (13)

An imaging unit that captures an object while it is installed on a moving object,
An imaging system including an exposure condition determining unit that determines the exposure condition of the imaging unit to either a fixed exposure condition or an automatic exposure condition based on the distance between the moving body and the object. When the imaging unit is imaging the object under the fixed exposure condition, the data of the automatic exposure condition calculated based on the amount of imaged light is output to the storage unit, and then when the object is imaged, the said The imaging system according to claim 1, further comprising an exposure control unit that controls exposure based on the data stored in the storage unit. The exposure condition determination unit
The imaging system according to claim 1 or 2, wherein the exposure condition is set to the automatic exposure condition when the distance is equal to or less than a predetermined first threshold value. The exposure condition determination unit
The imaging system according to claim 1 or 2, wherein the exposure condition is set to the automatic exposure condition when the amount of change in the distance is equal to or less than a predetermined second threshold value. A first distance detecting unit provided on the front side in the moving direction of the moving body and detecting the distance,
It has a second distance detecting unit which is provided on the rear side in the moving direction of the moving body and detects the distance.
The exposure condition determination unit
Any of claims 1 to 4 that determines the exposure condition as either the fixed exposure condition or the automatic exposure condition based on the distance detected by each of the first and second distance detection units. The imaging system according to item 1. The imaging system according to any one of claims 1 to 5, further comprising a storage unit that stores a range of the exposure conditions determined based on the distance between the moving body and the object. The imaging system according to claim 6, wherein the exposure condition determining unit determines the exposure condition based on the distance between the moving body and the object. A first distance detecting unit provided on the front side in the moving direction of the moving body and detecting the distance,
A moving distance detection unit that detects the moving distance of the moving body,
The imaging system according to any one of claims 1 to 4, further comprising a storage unit that stores a range of the exposure conditions determined based on the distance and the moving distance. The imaging system according to claim 8, wherein the exposure condition determining unit determines the exposure condition based on the distance between the moving body and the object. A first distance detecting unit provided on the front side in the moving direction of the moving body and detecting the distance,
The imaging system according to any one of claims 1 to 4, further comprising a storage unit that stores the range of the exposure conditions determined based on the distance and the brightness of the image captured by the imaging unit. .. The imaging system according to claim 10, wherein the exposure condition determining unit determines the exposure condition based on the distance and the brightness of the captured image. An imaging process that images an object while it is installed on a moving object,
An imaging method including an exposure condition determining step of determining an exposure condition in the imaging step as either a fixed exposure condition or an automatic exposure condition based on a distance between the moving body and the object. Image the object while it is installed on a moving object,
A program that causes a computer to execute a process of determining an exposure condition in imaging to either a fixed exposure condition or an automatic exposure condition based on the distance between the moving object and the object.

Images