JP6913615B2 - Railroad vehicle visual inspection equipment and its setting method - Google Patents

Description

The present invention relates to an appearance inspection device for a railway vehicle and a method for setting the same.

For some time, there have been devices that use line scan cameras (also called "line sensor cameras") to inspect the appearance of products. Line scan cameras are easier to acquire high-resolution images than area sensors, and are easier to acquire images with less distortion due to lens aberrations, and images with less distortion over the entire area for subjects that are long in one direction. There are advantages.

Patent Document 1 discloses an apparatus for inspecting a substrate using a line sensor. This device makes it possible to inspect a specific defect generated in a predetermined layer by obliquely injecting inspection light from the lighting unit onto the surface of the substrate.

Japanese Unexamined Patent Publication No. 2016-156830

At present, the present inventors are developing a system for visually inspecting a railway vehicle using a line scan camera with high accuracy and high efficiency. Then, the present inventors assume that various structures provided in the lower part of the vehicle body of the railway vehicle are photographed and inspected from the side of the vehicle. However, in the lower part of the vehicle body of the railway vehicle, structures are arranged at a plurality of places from the side to the back. For this reason, when these are photographed from the side of the vehicle, if the lighting is weak, the illuminance of the structure arranged in the back is lowered, and there is a problem that a clear image of this structure cannot be obtained. On the other hand, if the illumination is too strong, for example, the image of the structure arranged in the foreground or the structure that is strongly illuminated is overexposed, which causes a problem that it becomes difficult to grasp the shape of the structure. That is, it has not been easy to properly illuminate a plurality of structures having different arrangements in the depth direction so that a clear image can be obtained from the structure in the back to the structure in the foreground.

It should be noted that such a problem is not limited to the case where the lower part of the vehicle body of the railway vehicle is photographed from the side, and it is considered that the same problem occurs when the appearance inspection of a range having a depth in the photographing direction is performed.

The present invention is a device that acquires an image of a region of a railroad vehicle having a depth in the shooting direction and inspects the appearance of the railroad vehicle. The purpose is to be able to obtain it.

In order to achieve the above object, the present invention
A line scan camera arranged so that the linear shooting area intersects the moving direction of the railroad vehicle,
A floodlight that illuminates the area to be photographed by a railroad vehicle,
An image analysis unit that analyzes an external image of a railroad vehicle obtained by continuous shooting with the line scan camera, and an image analysis unit.
With
The imaging target area has a width in the depth direction at which the distance from the line scan camera is different.
In the floodlight, the light projection direction in which the amount of light is the largest becomes closer to the pixel sequence acquisition plane connecting the center of the light input portion of the line scan camera and the linear photographing region as the distance from the floodlight increases, and the photographing This is an appearance inspection device for a railroad vehicle, characterized in that it faces a direction that does not intersect with the pixel array acquisition plane over the entire depth direction of the target area.

According to such a configuration, by arranging the floodlights in the above-mentioned direction, it becomes easy to uniformly illuminate the entire area in the depth direction of the photographing target area of the railway vehicle. That is, it becomes easy to set the illumination so that there are no parts in the shooting target area where the illuminance is too high and the image is overexposed and where the illuminance is insufficient and the image becomes unclear. .. As a result, it is possible to obtain an image having uniform sharpness over the entire depth direction of the area to be photographed of the railway vehicle, and it is possible to accurately inspect the appearance of the railway vehicle.

Here, the floodlight may have a plurality of light emitting diodes arranged in a long array in one direction, and may be installed so that the longitudinal direction of the array is parallel to the pixel array acquisition plane.

According to such a configuration, it becomes easy to illuminate the area to be photographed with uniform brightness even in the longitudinal direction of the linear image area of the line scan camera, and an image of a railroad vehicle having uniform sharpness can be obtained. Can be done.

Further, the visual inspection device for a railway vehicle according to the present invention is
A frame that holds a relative position and a relative angle between the floodlight and the line scan camera may be further provided.

According to such a configuration, after the relative position and relative angle between the line scan camera and the floodlight are set so that uniform illuminance can be obtained, the relative position and relative angle can be held by the frame. Therefore, for example, by fixing the line scan camera and the floodlight at the optimum relative position and angle in the factory and transporting the frame together to the site, the line scan camera and the floodlight placed at the optimum position can be easily brought to the site. Can be installed.

The method for setting the visual inspection device for a railway vehicle according to the present invention is as follows.
It is a method of setting a railroad vehicle visual inspection device equipped with a line scan camera in which a linear shooting area intersects the moving direction of the railroad vehicle and a floodlight that illuminates the shooting target area of the railroad vehicle.
By operating the floodlight, the illuminance at a plurality of locations having different positions in the depth direction of the imaging target region and overlapping with the pixel array acquisition plane connecting the center of the light input portion of the line scan camera and the linear imaging region. Is measured, and the orientation of the floodlight is determined so that the measured brightness falls within a predetermined range one step lower than the brightness in the light projection direction in which the amount of light is the largest.

According to such a method, the direction of the floodlight can be easily determined so as to uniformly illuminate the entire area in the depth direction with respect to the area to be photographed of the railway vehicle having a depth. As a result, the orientation of the floodlight can be set so that there are places in the imaging target area where the illuminance is too high and the image is overexposed, and where the illuminance is insufficient and the image is unclear. With such a setting, it is possible to obtain an image having uniform sharpness over the entire depth direction of the area to be photographed of the railway vehicle, and it is possible to accurately inspect the appearance of the railway vehicle.

Further, the method of setting the visual inspection device for a railway vehicle according to the present invention is as follows.
In the factory, after measuring the illuminances at the plurality of locations to determine the orientation of the floodlight, the floodlight is adjusted to the determined orientation, and the line scan camera and the floodlight are fixed to a common frame. After that, the line scan camera and the floodlight may be transported and installed at the site together with the frame.

According to such a method, the adjustment work of the arrangement of the line scan camera and the floodlight on the site can be reduced, and the line scan camera and the floodlight can be easily installed on the site with the optimum relative position and relative angle set. be able to. This makes it possible to provide a railroad vehicle visual inspection device capable of acquiring a clear image with high reliability.

According to the present invention, in a device that acquires an image of a region of a railroad vehicle having a depth in the shooting direction and inspects the appearance of the railroad vehicle, uniform sharpness is obtained for a plurality of locations having different positions in the depth direction. Images can be acquired.

It is a figure which shows the appearance inspection apparatus of the railroad vehicle of embodiment of this invention. It is a figure which shows the arrangement relation of a line scan camera and a floodlight, (A) is a side view, (B) is a plan view, (C) is a front view. 3 (A) to 3 (D) are views showing an example of light distribution of a floodlight measured at a plurality of locations having different positions in the depth direction. It is a graph which conceptually showed the relationship between the distance from a line scan camera and the illuminance. It is a perspective view which shows the configuration example which fixed the line scan camera and the floodlight to a frame.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing an appearance inspection device for a railway vehicle according to an embodiment of the present invention. 2A and 2B are views showing the arrangement relationship between the line scan camera and the floodlight, FIG. 2A is a side view thereof, FIG. 2B is a plan view thereof, and FIG. 2C is a front view thereof. ..
The railway vehicle appearance inspection device 1 of the embodiment of the present invention is a part of the device that inspects the appearance of the railway vehicle and determines the presence or absence of an abnormality. Specifically, the visual inspection device 1 photographs the side surfaces of a plurality of structures installed under the vehicle body of the railway vehicle from the side of the railway vehicle, analyzes the photographed appearance image of the railway vehicle, and analyzes the photographed appearance image of the railway vehicle to obtain an abnormality. Check for presence. The area to be photographed by a railroad vehicle has a width in the depth direction.

The visual inspection device 1 includes a line scan camera 10 installed on the side of a railroad track through which the railroad vehicle 100 passes, a floodlight 20 that illuminates an area to be photographed by the railroad vehicle, and an image analyzer 30 that analyzes the captured image. And. The image analyzer 30 corresponds to an example of the image analysis unit according to the present invention.
The line scan camera 10 is a photographing device having a light input unit 11 for incident light and a linear image pickup element, and can repeatedly perform photographing on a linear photographing region. The line scan camera 10 is installed so that a linear shooting area intersects the moving direction of the shooting target, and continuously captures the shot image while the shooting target is moving to capture a two-dimensional shot image of the shooting target. You can get it. In FIGS. 2 (A) and 2 (B), the pixel sequence acquisition plane S1 connecting the center of the light input unit 11 and the linear photographing region is shown by a alternate long and short dash line. Although the pixel sequence acquisition plane S1 is not shown in the entire depth direction in FIG. 2 (A), the pixel sequence acquisition plane S1 is actually a plane extending over the depth range D1 in FIG. 2 (B). .. The line scan camera 10 acquires an image of a portion of the imaging target that overlaps with the pixel sequence acquisition plane S1 in a single capture.

The floodlight 20 is an illumination in which a plurality of high-intensity light emitting diodes 21 are arranged in a plurality of rows and a plurality of columns in a rectangular frame long in one direction. The plurality of high-luminance light emitting diodes 21 have high directivity and are arranged so as to face each other in the same direction. The irradiation light of the floodlight 20 has a light distribution that spreads at a small angle, the illuminance at the center of the irradiation range is the highest, and the illuminance decreases as the distance from the center deviates. In FIGS. 2 (A) and 2 (B), the light distribution center L1 representing the light projecting direction in which the amount of light of the floodlight 20 is the largest is shown by a dashed line.

The image analyzer 30 is a computer, and is a CPU (Central Processing Unit) 31, a RAM (Random Access Memory) 32, a display unit 33, an operation unit 34 such as a mouse or a keyboard, an interface 35 for data input, and a storage device 36. To be equipped. The storage device 36 stores a visual inspection program 361 that compares a captured image with a normal image and inspects the appearance for any abnormality. Further, the storage device 36 stores a normal image database 362 in which past normal images of the railroad vehicle to be inspected are stored, and a captured image stored in the captured image sent from the line scan camera 10 via the communication network N. A storage unit 363 is provided.

The visual inspection program 361 realizes a plurality of functional modules by being executed by the CPU 31. The plurality of functional modules include a captured image generation module, a captured image correction module, a brightness adjustment module, a comparative inspection module, and the like. The captured image generation module generates continuous two-dimensional image data for the imaging target area of the railroad vehicle 100 from the captured image data of the line scan camera 10. The captured image correction module corrects the distortion of the railroad vehicle 100 in the two-dimensional image due to the speed variation or vertical movement of the railroad vehicle 100. The brightness adjustment module adjusts the brightness of the captured image so as to eliminate variations in brightness due to external factors of the captured image. The comparative inspection module compares the past normal image of the same vehicle stored in the normal image database 362 with the captured image, extracts a changed portion, and determines the presence or absence of an abnormality.

Each functional module of the visual inspection program 361 is not particularly limited, but processes the captured image data of the imaging target area of the railway vehicle 100 as grayscale data. When color identification is not performed in this way, it is important to illuminate the object to be photographed with an appropriate illuminance and acquire a clear photographed image.

<How to set the arrangement of the line scan camera and the floodlight>
As shown in FIG. 1, the line scan camera 10 has a shooting direction facing the lower part of the vehicle body at a position separated from the lower part of the railroad vehicle 100 to the side, and a linear shooting area intersects the traveling direction of the railroad vehicle 100 ( For example, they are installed so as to be orthogonal to each other.

The floodlight 20 is installed at a position deviated from the line scan camera 10 in the lateral direction (direction along the railroad track) and at a position deviated from the line scan camera 10 in front (closer to the railroad vehicle 100). Further, in the floodlight 20, the longitudinal direction (longitudinal direction of the arrangement of the light emitting diodes) is parallel to the pixel array acquisition plane S1 of the line scan camera 10, and the projection direction of the illumination is toward the lower part of the vehicle body of the railway vehicle 100. It is installed so that it faces. In the present specification, "parallel" means not only parallel in a strict sense but also a slight error within a range in which the action of being able to illuminate the longitudinal direction of the linear photographing region of the line scan camera 10 almost uniformly can be obtained. It shall also include those having.

In addition, in the floodlight 20, the light distribution center L1 does not intersect with the pixel row acquisition plane S1 of the line scan camera 10 over the entire depth direction of the imaging target area, and the farther away from the floodlight 20, the more the pixel row acquisition plane S1 becomes. It is installed so that it faces the approaching direction. In the present embodiment, the photographing target area has a depth range D1 (see FIG. 1) on the front side from the center of the lower part of the vehicle body of the railway vehicle 100.

Further, the detailed installation angle of the floodlight 20 is determined by finely adjusting the angle while installing the floodlight 20 as described above and then operating the floodlight 20 to measure the illuminance. For example, in the work of determining the installation angle, as shown in FIG. 2B, the illuminance of the floodlight 20 is measured at four locations Pa, Pb, Pc, and Pd whose positions are different in the depth direction of the imaging target area.

3 (A) to 3 (D) are views showing an example of light distribution of a floodlight measured at a plurality of locations having different positions in the depth direction. 3 (A) to 3 (D) correspond to the light distribution of the four locations Pa to Pd in FIG. 2 (B).

In the floodlight 20, the illumination intensity is set so that the range E1 having the highest illuminance becomes higher than the appropriate illuminance value and the range E2 having one step lower illuminance becomes the appropriate illuminance value. The range E2 in which the illuminance is one step lower is a predetermined range in which an appropriate illuminance can be obtained during light distribution. Further, as shown in FIGS. 3A to 3D, the light distribution of the floodlight 20 occupies the center in the range E1 having the highest illuminance, and the illuminance decreases as the distance from the center increases. Further, the farther away from the floodlight 20, the smaller the range E1 having the highest illuminance. Further, the range E2 in which the illuminance is one step lower approaches the center of the light distribution as the distance from the floodlight 20 increases. Therefore, since the orientation of the floodlight 20 is set as described above, the range E2 in which the illuminance is one step lower overlaps with or approaches the pixel sequence acquisition plane S1 of the line scan camera 10. Here, the worker adjusts the angle of the floodlight 20 in detail based on the measurement result of the light distribution at the four locations Pa to Pd, so that the range E2 in which the illuminance is one step lower at the four locations Pa to Pd is line-scanned. The adjustment is made so as to overlap the pixel sequence acquisition plane S1 of the camera 10. That is, the illuminance of the pixel array acquisition plane S1 is adjusted to fall within the range E2 at the four locations Pa to Pd. In this way, the relative angle between the floodlight 20 and the line scan camera 10 is determined.

It is not necessary to adjust the relative angle of the floodlight 20 in detail for each device. For example, when the light distribution variation of each product of the floodlight 20 is very small, if one floodlight 20 is used to determine a detailed relative angle, another device does not adjust the detailed relative angle of the floodlight 20. , The floodlight 20 may only be fixed at a determined relative angle. Even if the floodlight 20 is arranged in this way, the same light distribution setting as in the case of making the above adjustment can be realized.

FIG. 4 is a graph conceptually showing the relationship between the distance from the line scan camera and the illuminance. In FIG. 4, the vertical axis represents the illuminance of the portion overlapping the pixel sequence acquisition plane S1 of the line scan camera 10, and the horizontal axis represents the distance from the line scan camera 10.
As mentioned earlier, the illuminance is too high in the range where overexposure occurs in the image (indicated as "overexposure" in FIG. 4) and too low in the range where the sharpness of the image is reduced (in FIG. 4 "" There is an appropriate range (indicated as "appropriate" in FIG. 4) in which a clear image can be obtained. However, by setting the orientation of the floodlight 20 as described above, as shown in FIG. 4, the illuminance at the portion overlapping the pixel array acquisition plane S1 of the line scan camera 10 is appropriate over the entire depth direction of the imaging target area. It becomes possible to.

<How to install the device>
Next, an example of the procedure for installing the line scan camera 10 and the floodlight 20 in the field will be described. FIG. 5 is a perspective view showing a configuration example in which the line scan camera and the floodlight are fixed to the frame.
The line scan camera 10 and the floodlight 20 are adjusted in the relative positions and relative angles described above at the factory. After the adjustment, the line scan camera 10 and the floodlight 20 are further fixed to the common frame 40 in the factory, and their relative positions and relative angles are maintained.
Subsequently, the line scan camera 10 and the floodlight 20 are transported to the site while being fixed to the frame 40, and are installed on the side of the rail through which the railroad vehicle 100 passes.
With such an installation method, it is possible to reduce the work of adjusting the arrangement of the line scan camera 10 and the floodlight 20 in the field, and it is possible to provide the visual inspection device 1 for a railway vehicle capable of acquiring a clear image with high reliability.

The embodiment of the present invention has been described above. However, the present invention is not limited to the above embodiment. For example, in the above embodiment, a configuration in which one set of floodlights 20 is arranged on one side of the line scan camera 10 has been described as an example, but a configuration in which two sets of floodlights are arranged on both sides of the line scan camera 10 is applied. May be good. Further, in the above embodiment, the configuration in which the structure under the vehicle body of the railway vehicle 100 is photographed by the line scan camera from the side of the railway vehicle 100 has been described as an example, but the present invention is not limited to this. For example, the present invention is effectively applied to a configuration in which the structure at the lower part of the vehicle body is photographed from below the vehicle body, or the upper part of the vehicle body is photographed from the side of the railway vehicle 100, and the depth is generated in the imaging target area. can. In addition, the details shown in the embodiments can be appropriately changed without departing from the spirit of the invention.

1 Railroad vehicle appearance inspection device 10 Line scan camera 11 Incoming light section 20 Floodlight 30 Image analyzer D1 Depth range of the area to be photographed E1 Highest illuminance range E2 One step lower illuminance range

Claims (5)

A line scan camera arranged so that the linear shooting area intersects the moving direction of the railroad vehicle,
A floodlight that illuminates the area to be photographed by a railroad vehicle,
An image analysis unit that analyzes an external image of a railroad vehicle obtained by continuous shooting with the line scan camera, and an image analysis unit.
With
The imaging target area has a width in the depth direction at which the distance from the line scan camera is different.
In the floodlight, the light projection direction in which the amount of light is the largest becomes closer to the pixel sequence acquisition plane connecting the center of the light input portion of the line scan camera and the linear photographing region as the distance from the floodlight increases, and the photographing An visual inspection device for a railroad vehicle, characterized in that it faces a direction that does not intersect with the pixel array acquisition plane over the entire depth direction of the target area. The floodlight has a plurality of light emitting diodes arranged in a long array in one direction, and is installed so that the longitudinal direction of the array is parallel to the pixel array acquisition plane. The described railroad vehicle visual inspection device. The visual inspection device for a railway vehicle according to claim 1 or 2, further comprising a frame for holding a relative position and a relative angle between the floodlight and the line scan camera. It is a method of setting a railroad vehicle visual inspection device equipped with a line scan camera in which a linear shooting area intersects the moving direction of the railroad vehicle and a floodlight that illuminates the shooting target area of the railroad vehicle.
By operating the floodlight, the illuminance at a plurality of locations having different positions in the depth direction of the imaging target region and overlapping with the pixel array acquisition plane connecting the center of the light input portion of the line scan camera and the linear imaging region. The direction of the floodlight is determined so that the measured brightness falls within a predetermined range one step lower than the brightness in the direction of the floodlight where the amount of light is the largest. How to set up the visual inspection device. In the factory, after measuring the illuminances at the plurality of locations to determine the orientation of the floodlight, the floodlight is adjusted to the determined orientation, and the line scan camera and the floodlight are fixed to a common frame. The method for setting a railroad vehicle appearance inspection device according to claim 4, wherein the line scan camera and the floodlight are transported and installed at the site together with the frame.

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