JP2001194318A - Device and method for flaw detection - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device and a method for flaw detection, little affected by disturbing light such as sunlight, capable of discriminating through flaws such as holes and cracks from dirt, recesses, rust, and the like, capable of performing detection without stopping a moving container, capable of detecting small flaws with high accuracy, and little consuming electric power. SOLUTION: This device is equipped with a pulse light source 12 for emitting short pulse light 11, a light transmitting device 14 for transmitting the pulse light to irradiate an inspected surface 13 with higher illuminance than its periphery receives, a CCD camera 16 for taking a picture of the inspected surface in synchronization with the light source, and the device 18 for flaw detection for comparing the illuminance of a dark part in the taken picture with a prescribed threshold and, if lower, issuing a flaw detection signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for detecting damage to a shipping container or the like.

[0002]

2. Description of the Related Art When loading a shipping container on a ship or the like, the container terminal gate provided at the entrance of the container yard is checked for penetration damage such as holes and cracks in the container, and damage to luggage due to intrusion of water or the like. Must be prevented beforehand.

For this reason, in the container terminal gate, a check for damage to the container has been conventionally performed by an inspector visually. However, such a visual inspection requires (1) a large number of inspection factors and one of the factors of high cost. (2) The detection accuracy is easily affected by the skill of the inspector, the weather, and the like. Easy to leak (3)
There is a problem that a considerable amount of time is required for stopping the container, which is a bottleneck in container distribution. (4) Also, especially the ceiling surface of the container (upper surface exterior)
However, since the inspector waits at the upper part of the gate and visually inspects it from above, the workability is poor, and since the visual inspection is performed from a remote position, there is a problem that small damaged parts are easily overlooked.

[0004] In order to solve this problem, some means have been proposed and implemented for taking an image of the top exterior of the container with a damage monitor camera and displaying the image on a CRT or the like for inspection. However, with this method, although a rough inspection can be performed, a skilled inspector can discriminate the penetration damage to be detected, such as holes and cracks, from dirt such as adhered tar, dents, rust, etc. on the image. It was difficult.

[0005] In order to solve the various problems described above,
The inventors of the invention of the present application have previously described "damage detection method and apparatus".
(Japanese Patent Application No. 7-25447) was filed and filed. As shown schematically in FIG. 9, this means includes a light source 2 (LED) for illuminating the inspected portion 1 (damaged portion) and an illuminance detector 4 (CCD camera) for detecting reflected light 3 from the inspected portion. And a calculation control unit (not shown) for generating a damage detection signal when the illuminance of the detected reflected light is lower than the set threshold value compared with the set threshold value. Yes,
The inspected portion 1 is illuminated by the light source 2 and the reflected light 3 from the detected object is detected by the illuminance detector 4. If the illuminance of the detected reflected light is lower than a threshold value, the detected object is damaged. It is determined. By this means, the visual inspection is eliminated, and the damage inspection can be automatically performed in a short time.

[0006]

However, the means of the above-mentioned prior application has the following problems. (1) The light intensity tends to change due to the influence of other ambient light sources or strong disturbance light such as sunlight, and it is difficult to set a stable threshold value. In particular, when the ambient light is strong, the illuminance detector (for example, a CCD camera) becomes saturated and cannot be detected. (2) Since the wavelength range of the light source (for example, light emitting diode) is wide, the resolution of the illuminance detector (CCD camera) is reduced due to chromatic aberration and the like. Therefore, when penetration damage (a hole, a crack, or the like) is small (for example, 5 mm or less), it is difficult to distinguish from dirt, dents, rust, and the like. In order to avoid this, a large number of CCD cameras and the like are required, and the equipment cost is greatly increased. (3) Since reflected light is continuously incident on the illuminance detector (CCD camera), if the container moves during imaging, an image flows and the resolution is greatly reduced. Therefore, it is necessary to stop the container or make it sufficiently slow. (4) Power consumption is large because it is a continuous light source.

The present invention has been made to solve such a problem. That is, an object of the present invention is to reduce the influence of disturbance light such as sunlight, and to reliably identify penetration damage such as holes and cracks and dirt, dents, rust, etc., and to detect without stopping a moving container. Another object of the present invention is to provide a damage detection device and method which can detect small damage with high accuracy and consume less power.

[0008]

According to the present invention, a pulse light source (12) for emitting a short pulse light (11), and the surface to be inspected (13) transmitted with the pulse light with higher illuminance than the surroundings. An optical transmission device (14) for irradiating, a CCD camera (16) for capturing an image of a surface to be inspected in synchronization with a pulse light source, and comparing the illuminance of a dark portion in the captured image with a predetermined threshold value and lowering the illuminance. Damage detection device (1
8), the damage detection device is provided.

According to the structure of the present invention, the damage detection device (1)
According to 8), the illuminance of the dark portion in the captured image is compared with a predetermined threshold value, and if the illuminance is lower than the predetermined threshold value, a damage detection signal is issued, so that penetrating damage such as holes and cracks and dirt, dents, rust, and the like are eliminated. Even if the image can be reliably identified and the imaging range is wide, damage can be detected in a short time. In addition, since the pulse light source (12) emits a short pulse light (11) and the CCD camera (16) captures an image of the surface to be inspected in synchronization with the pulse light source, even if the surface to be inspected (13) moves, the movement of the surface is prevented. Still image can be captured without stopping, and the detection accuracy of small damage can be improved. Furthermore, since the surface to be inspected is illuminated with stronger illuminance than the surroundings using a strong pulsed light source, the influence of disturbance light such as sunlight can be reduced.

According to a preferred embodiment of the present invention, CC
The D camera (16) has a CCD cell width of 1/2 or less of the optical black due to the minimum dark part to be detected, and the predetermined threshold value is set lower than the minimum illuminance of the tar part or the rust part. By setting the optical black in consideration of the aberration of the imaging lens to the size of the image in the image of the minimum dark part by the imaging lens, and further setting the CCD cell width to 1/2 or less, the CCD cell and the optical black are relatively positioned. At least one C in the optical black
A CD cell can be located. Therefore, by setting the threshold value sufficiently low, it is possible to reliably distinguish penetrating damage without reflected light from dirt, dents, rust, and the like with little reflected light.

The pulse light source (12) is a pulse laser light source, and the CCD camera (14) has a high-speed electronic shutter. The combination of the pulse laser light source and the high-speed electronic shutter allows the use of an optical filter having a narrow band (about several nm), and can greatly reduce the influence of disturbance light. Also, since pulsed laser light is a single wavelength light source,
Chromatic aberration in the imaging lens of the CCD camera (16) is eliminated, and a high-resolution captured image can be obtained. Further, since the light emission time of the pulse laser light source is extremely short, that is, 1/1000 second or less, a still image can be obtained even with a high-speed moving object.

The pulse light source (12) has a wavelength of 532 nm.
Nd: YAG laser device, and the optical transmission device (1)
Preferably, 4) includes an optical fiber for transmitting pulsed light. By using pulsed light having a wavelength of 532 nm, transfer of pulsed light to a plurality of locations can be easily and inexpensively performed with a small transfer loss using an optical fiber.

The pulse light source (12) has a wavelength of 35.
The optical transmission device may be a 5 nm Nd: YAG laser device, and the optical transmission device may include an optical mirror system for transmitting pulsed light. By using the pulsed light having the wavelength of 355 nm, the pulsed light can be transmitted by the optical mirror system, so that the eye-safe property can be improved.

Further, the pulse light source (12) may be a flash lamp, and the optical transmission device (14) may include an optical mirror system for transmitting the pulse light. The flash lamp emission time is also short, less than 1 / 10,000 second,
Still images can be acquired even with high-speed moving objects. In addition, since the irradiation angle of the flash lamp is wide, a wide range can be irradiated with a simple optical mirror system, and the system can be made very inexpensive.

According to the present invention, a short pulse light (1
1) emits light, irradiates the moving inspected surface (13) with a higher illuminance than the surroundings by transmitting the pulsed light, and images the inspected surface with the CCD camera (16) in synchronization with the pulsed light; A damage detection method is provided, wherein the illuminance of a dark part in an image obtained by capturing an image of a detection surface is compared with a predetermined threshold value and a damage detection signal is issued when the illuminance is lower than the threshold value.

According to this method, the illuminance of a dark part in a captured image is compared with a predetermined threshold value, and if the illuminance is lower than the predetermined threshold value, a damage detection signal is issued. Therefore, penetration damage such as holes and cracks and dirt, dents, rust And the like, and damage can be detected in a short time even when the imaging range is wide. Also, since the short pulse light (11) is emitted and the surface to be inspected is imaged by the CCD camera (16) in synchronization with the pulse light source, even if the surface to be inspected (13) moves, the movement is not stopped. A still image can be captured, and detection accuracy of small damage can be increased. Furthermore, since the surface to be inspected is illuminated with stronger illuminance than the surroundings using a strong pulsed light source, the influence of disturbance light such as sunlight can be reduced.

Further, according to the present invention, a position detection sensor (20) for detecting a moving detection target surface (13) is provided, and the detection target surface is detected and a short pulse light (11) is repeatedly emitted, and Pulsed light is transmitted to repeatedly irradiate the surface to be inspected (13) with higher illuminance than the surroundings, and the surface to be inspected is repeatedly imaged by a plurality of CCD cameras (16) in synchronization with the pulsed light, and A damage detection method is provided, wherein the illuminance of dark portions in a plurality of images obtained by capturing the entire surface is compared with a predetermined threshold value and a damage detection signal is issued when the illuminance is lower than a predetermined threshold value.

According to this method, the position detecting sensor (20)
The start / stop of the detecting device can be automatically controlled by detecting the surface to be detected (13) which moves by the operation. Also, since the pulsed light (11) is repeatedly emitted and the surface to be inspected is repeatedly imaged by the plurality of CCD cameras (16) in synchronization with the pulsed light, the moving surface to be detected (e.g., a container) is not stopped. Thus, it is possible to image the entire surface to be detected in a short time.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. In addition, the same reference numerals are given to the common parts in the respective drawings, and the duplicate description will be omitted.

FIG. 1 is an overall configuration diagram showing a first embodiment of a damage detection device according to the present invention. In this example, the damage detection device 10 of the present invention includes a pulse light source 12 and an optical transmission device 1.
4. It comprises a CCD camera 16 and a damage detection device 18.

FIG. 2 is a system configuration diagram of the apparatus shown in FIG. The pulse light source 12 is a pulse laser light source, and emits a very short pulse light 11 of 100 millionth of a second or less. In this example, an Nd: YAG laser device is used as a laser oscillator, that is, a laser device, and emits a double-wave pulse light having a wavelength of 532 nm. Incidentally, similarly, Nd: YA
A third laser pulse light having a wavelength of 355 nm may be emitted using a G laser device.

In this example, the optical transmission device 14 includes a main optical fiber 14a, a condenser lens 14b, a branch bundle fiber 14c, and a bare coupling connector 1.
4d, a distribution optical fiber 14e, a collimator 14f, and the like. The pulse light 11 oscillated by the pulse light source 12 is branched and transmitted to a plurality of distribution optical fibers, and the surface to be inspected 13
(Target) is illuminated with stronger illuminance than the surroundings.

FIG. 3 is an arrangement diagram of the irradiation optical system of the apparatus of FIG. In this figure, (A) is the back surface of the container terminal gate, (B) is the side surface, and the inspection surface 13 is shown.
Is a container top (top exterior). The container has a height of about 2.88 m and a height of about 2.58 m.
The irradiation position of the laser beam by the optical transmission device 14 is
3, one inspection area 13a (for example, 0.4 mx 3.0)
m), so that the inspection area 13a is double-irradiated. With this configuration, the inspection area 1
When the light intensity of the laser beam irradiated with the laser beam 3a at about 1.8 m above the ground is set to be equal to or less than the maximum allowable exposure MPE (for example, about 0.18 μJ / cm ^{2 in} the case of 532 nm) which satisfies the eye safety, the inspection area The light intensity of 13a (measurement surface) is a maximum of about 1 μJ / cm ² . This strength is
This corresponds to 10 times or more the light intensity of the wavelength 532 nm included in strong sunlight. Therefore, even when a laser beam of 532 nm is used, the surface 13 to be inspected can be irradiated with a higher illuminance than the periphery.

When a laser beam having a wavelength of 355 nm is used, the maximum allowable exposure MPE that satisfies the eye-safe property is much larger than that at a wavelength of 532 nm (for example, about 41%).
50 μJ / cm ² ). Therefore, in this case, since the eye-safe property can be easily satisfied, it is possible to freely irradiate the inspection target surface 13 with stronger pulse light as needed. Note that the laser light having a wavelength of 355 nm has a large loss in the optical fiber. In this case, it is preferable to use an optical mirror system for transmitting pulse light as the optical transmission device 14.

FIG. 4 is an overall configuration diagram showing a second embodiment of the damage detection device of the present invention. In this figure, a pulse light source 12 is a flash lamp. Further, since the irradiation angle of the flash lamp is wide, it is possible to irradiate a wide range by using a simple optical mirror system as an optical transmission device.

FIG. 5 is a diagram showing the relationship between the received light intensity and the size of the damaged portion. As shown in this figure, the damaged portion (defective portion AB)
Is formed on the CCD by the imaging lens, the ideal image is A ′
In a case where there is no reflected light (scattered light) from the defective portion, the portion corresponding to A'B 'ideally becomes optical black. However, in practice, the width of the optical black is narrowed by the width of the optical aberration because it is affected by the optical aberration of the imaging lens.

FIG. 6 is a diagram showing the relationship between optical black and CCD cell width. In this figure, (A) shows the case where the CCD cell width and the optical black almost match, and (B) shows the CC cell width.
(C) is an example of the present invention when the D cell width is about ／ of the optical black, and the case where the CCD cell width is about の of the optical black.

As is apparent from FIG.
In the case of, when the width of the CCD cell and the position of the optical black are relatively offset, the output is generated in all the CCD cells and the optical black is detected even though the optical black originally exists. It may not be possible. On the other hand, in the present invention, since the CCD camera 16 has a CCD cell width of 以下 or less of the optical black due to the minimum dark part to be detected, the size of the imaging lens at the minimum dark part due to the imaging lens is reduced. By setting the optical black in consideration of the above and further setting the CCD cell width to １ ／ or less thereof, even if the CCD cell and the optical black are relatively offset, at least one A CCD cell can be located. Therefore, by setting the threshold value sufficiently lower than the minimum illuminance of the tar portion or the rust portion, it is possible to reliably distinguish penetrating damage without reflected light from dirt, dents, rust, etc. with little reflected light. Can be.

FIG. 7 is a performance comparison diagram of the imaging lens.
In this figure, the horizontal axis is the optical aperture value, and the vertical axis is the optical center resolution. The thick curve in the figure is a calculation example of the spherical aberration of the biconvex lens, and the thin solid line is a calculation example of the diffraction limit. Further, each broken line in the figure is the actually measured resolution of two types of high performance lenses A and B for a commercially available single-lens reflex camera, and A1 and B1 in the figure are A2 and B when the light source is a fluorescent lamp.
Reference numeral 2 denotes a case where the light source is 532 nm monochromatic light. Also, C
Reference numeral 1 denotes another lens when the light source is a fluorescent lamp. From this figure, it can be seen that the best resolution is about 30 μm for a fluorescent lamp, while it is about 15 μm for a 532 nm monochromatic light.

As shown in FIG. 2, the CCD camera 16
It has a high-performance imaging lens exemplified in FIG. 7, and is configured to image a surface to be inspected in synchronization with a pulse light source. CC
The D camera 16 has, for example, an image size of 8.4 × 6.4 m.
m, SONY XC with effective pixel number H768 × V493
-77RR or PROTEC C with an image size of 8.7 x 6.9 mm and an effective pixel count of H1300 x V1030
VM-M1 or the like can be used.

In the example shown in FIG.
VCR 18a for recording video images from D camera 16, digital oscilloscope 18b for monitoring signal waveform from CCD camera 16, VCR 18a
And a monitor 18d for displaying a defective portion. The illuminance of a dark portion in the captured image is compared with a predetermined threshold value. If the illuminance is lower than a predetermined threshold, a damage detection signal (image display and / or Or an alarm signal).

In the method of the present invention using the above-described apparatus of the present invention, a short pulse light 11 is emitted, and the surface 13 to be inspected that moves by transmitting the pulse light 11 is illuminated with higher illuminance than the surroundings. The inspection target surface 13 is synchronized with the light 11
The illuminance of the dark part in the image captured by the camera 16 and the captured image of the detected surface 13 is compared with a predetermined threshold value, and when the illuminance is lower than a predetermined threshold value, a damage detection signal is issued. In particular, when a large area such as a container top is used as the inspection surface 13, FIG.
As shown in FIG. 2, a position detection sensor 20 for detecting a moving detection target surface 13 is provided. The detection target surface 13 is detected, a short pulse light 11 is repeatedly emitted, the pulse light 11 is transmitted, and the inspection target surface 13 is transmitted. Irradiate repeatedly with stronger illuminance than the surroundings,
The surface to be inspected is repeatedly imaged by the plurality of CCD cameras 16 in synchronization with the pulsed light 11, and the illuminance of dark portions in the plurality of images obtained by imaging the entire surface of the surface to be detected 13 is compared with a predetermined threshold value and is lower than this. In this case, a damage detection signal is issued.

Table 1 shows that the CCD camera 16 is a Sony XC-77RR, and the imaging lens is A (Nikkor) shown in FIG.
It shows the relationship between the required accuracy, the measurement width, the required number, and the speed limit when using 24 mmF2).

[0034]

[Table 1]

From this table, for example, in FIG. 1, one camera captures a measurement width of about 450 mm, and seven cameras are used to cover the width of the container, so that the vehicle travels at about 20 km / h. It can be seen that damage with a required accuracy of 2 mm can be detected without stopping the container to be stopped.

FIG. 8 shows a measurement result obtained by measuring an actual container top using the apparatus of the present invention. In this figure, the horizontal axis is the position of the container top in the width direction, and the vertical axis is CC
This is the output of the D cell. (A) shows four through holes (3.5 mm, 2.5 mm, 2.0 mm, 1.5 mm in diameter from the left).
mm) is detected on the line, and (B) is a case where tar and rust are detected. In the test results of FIG.
In the through hole of (A), when the diameter is 3.5 mm, about 31 m
The optical black value of V was about 31 mV and about 63 mV at 2.5 mm and 2.0 mm, respectively. In contrast, the minimum output in the tar section was about 94 mV. Therefore, the predetermined threshold value is set sufficiently lower than the minimum illuminance of the tar portion or the rust portion (for example, about 70 m).
V) shows that through damage without reflected light can be reliably distinguished from dirt, dents, rust, etc., with less reflected light.

As described above, according to the configuration of the present invention,
The damage detection device 18 compares the illuminance of a dark part in a captured image with a predetermined threshold value and issues a damage detection signal when the illuminance is lower than the predetermined threshold value. Therefore, penetration damage such as holes and cracks and dirt, dents, rust, etc. And damage can be detected in a short time even when the imaging range is wide. In addition, pulse light source 1
2 emits a short pulse light 11, and the CCD camera 16 images the surface to be inspected in synchronization with the pulse light source.
Even when 3 moves, a still image can be captured without stopping the movement, and the detection accuracy of small damage can be improved. Furthermore, since the surface to be inspected is illuminated with stronger illuminance than the surroundings using a strong pulsed light source, the influence of disturbance light such as sunlight can be reduced.

Further, by setting the optical black in consideration of the aberration of the image pickup lens to the size of the image in the image of the minimum dark portion by the image pickup lens, and further setting the CCD cell width to 1/2 or less thereof, Even if the optical black is relatively offset, at least one CCD cell can be located within the optical black. Therefore, by setting the threshold value sufficiently low, it is possible to reliably distinguish penetrating damage without reflected light from dirt, dents, rust, and the like with little reflected light.

Further, by combining the pulse laser light source and the high-speed electronic shutter, an optical filter having a narrow band (about several nm) can be used, and the influence of disturbance light can be greatly reduced. Also, since pulsed laser light is a single wavelength light source,
Chromatic aberration in the imaging lens of the CCD camera 16 is eliminated, and a high-resolution captured image can be obtained. Further, since the light emission time of the pulse laser light source is extremely short, that is, 1/1000 second or less, a still image can be obtained even with a high-speed moving object.

In particular, the pulsed light source 12 is set to a 532 nm wavelength N
d: By using a YAG laser device and using an optical fiber for the optical transmission device 14, pulse light can be easily and inexpensively transferred to a plurality of locations with a small transfer loss.

It should be noted that the present invention is not limited to the above-described embodiments and examples, and it is needless to say that various changes can be made without departing from the spirit of the present invention.

[0042]

As described above, according to the present invention, the inspection of damage to the exterior of a container is performed by combining a pulse light source (particularly, a pulse laser light source) and a CCD camera, thereby being resistant to disturbance light and without stopping the container. This automatically enables detection of a minute damaged portion. That is, a portion where there is no scattered light from the container irradiation surface is determined as a damaged portion using an active pulse light source and an appropriate number and arrangement of CCD cameras. This enables automatic detection of a damaged portion of the container. In addition, since a pulsed light source is used as the illumination light, it is not disturbed by disturbance light such as sunlight by combination with an electronic shutter of a CCD camera.
A clear still image of a moving object can be obtained. In addition, when a pulse laser which is monochromatic light is used as a pulse light source, chromatic aberration in a camera lens system can be excluded, and fine damage can be detected.

Therefore, according to the present invention, visual observation by a human becomes unnecessary, and the time for stopping the container can be shortened, the container distribution can be speeded up, and cost reduction and high efficiency can be expected. That is, the damage detection device and method of the present invention are less affected by disturbance light such as sunlight, can reliably identify penetration damage such as holes and cracks, and dirt, dents, and rust, and stop moving containers. It has excellent effects such as being able to detect without causing damage, and being able to detect small damage with high accuracy, and further reducing power consumption.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing a first embodiment of a damage detection device of the present invention.

FIG. 2 is a system configuration diagram of the apparatus of FIG. 1;

FIG. 3 is a layout diagram of an irradiation optical system of the apparatus of FIG. 1;

FIG. 4 is an overall configuration diagram showing a second embodiment of the damage detection device of the present invention.

FIG. 5 is a diagram illustrating the relationship between the intensity of received light and the size of a damaged portion.

FIG. 6 is a diagram showing the relationship between optical black and CCD cell width.

FIG. 7 is a performance comparison diagram of the imaging lens.

FIG. 8 is a measurement result showing an example of the present invention.

FIG. 9 is a schematic view of the means according to the prior application.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inspection part 2 Light source 3 Reflected light 4 Illuminance detector 10 Damage detection device 11 Pulse light 12 Pulse light source 13 Inspection surface 14 Optical transmission device 16 CCD camera 18 Damage detection device 20 Position detection sensor

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Taketo Yagi 3-1-1-15 Toyosu, Koto-ku, Tokyo Ishikawajima-Harima Heavy Industries, Ltd. Tokyo Engineering Center (72) Inventor Koji Yata Shinnaka, Isogo-ku, Yokohama-shi, Kanagawa No. 1 Haramachi Ishi Kawashima Harima Heavy Industries Co., Ltd. Machinery and Plant Development Center (72) Inventor Naoaki Okamura No. 1 Shinnakaharacho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Ishi Kawashima Harima Heavy Industries Co., Ltd. Machinery and Plant Development Center (72) Inventor Haruyuki Hosaka 573-19 Nakano Hisagi, Nagareyama City, Chiba Prefecture (72) Inventor Kenji Tamura 972 Kamiyabecho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Nice Park Stage Higashi-Totsuka 410 (72) Inventor Isao Ito Aoba-ku, Yokohama-shi, Kanagawa 4-7-17 Eda Nishi Gaso Flat B-403 Yusen City (72) Inventor Yamashita Ichiro 7-1 Tsunashimadai, Eboku-ku, Yokohama-shi, Kanagawa Prefecture Yusen Tsunashima Ryo 304 F-term (reference) 2G051 AA11 AA90 AB07 BA06 BA10 BB02 BC02 CA04 CB01 CC07 CD07 EA16

Claims (8)

[Claims] 1. A pulse light source (12) for emitting a short pulse light (11) and a surface to be inspected (13) by transmitting the pulse light
Transmission device that irradiates light with higher illuminance than its surroundings (14)
A CCD camera (16) for imaging a surface to be inspected in synchronization with a pulse light source; and a damage sensor for comparing the illuminance of a dark portion in the captured image with a predetermined threshold value and generating a damage detection signal when the illuminance is lower than a predetermined threshold value. A damage detection device, comprising: a detection device (18). 2. The CCD camera (16) has a CCD cell width of 1/2 or less of optical black due to a minimum dark part to be detected, and said predetermined threshold value is smaller than a minimum illuminance of a tar part or a rust part. 2. The method according to claim 1, wherein the setting is also made lower.
A damage detection device according to claim 1. 3. The damage detection device according to claim 1, wherein the pulse light source (12) is a pulse laser light source, and the CCD camera (14) has a high-speed electronic shutter. 4. The pulse light source (12) has a wavelength of 532n.
4. Damage detection device according to claim 3, characterized in that the device is a m Nd: YAG laser device, the optical transmission device (14) comprising an optical fiber transmitting pulsed light. 5. The pulse light source (12) has a wavelength of 355n.
4. Damage detection device according to claim 3, characterized in that it is a m Nd: YAG laser device, the optical transmission device (14) comprising an optical mirror system transmitting pulsed light. 6. Damage detection according to claim 3, wherein the pulsed light source (12) is a flash lamp and the optical transmission device (14) comprises an optical mirror system for transmitting the pulsed light. apparatus. 7. A short pulse light (11) is emitted, and the surface to be inspected (13), which moves by transmitting the pulse light, is illuminated with higher illuminance than the surroundings, and the surface to be inspected is synchronized with the pulse light. C
A damage detection method characterized in that an image is picked up by a CD camera (16) and the illuminance of a dark part in the image picked up from the detected surface is compared with a predetermined threshold value, and a damage detection signal is issued when the illuminance is lower than a predetermined threshold value. 8. A position detecting sensor (20) for detecting a moving detection surface (13), detecting the detection surface and repeatedly emitting short pulse light (11), and transmitting the pulse light. The surface to be inspected (13) is repeatedly irradiated with illuminance higher than the surroundings, and the surface to be inspected is synchronized with the pulse light by a plurality of Cs.
The illuminance of a dark part in a plurality of images of the entire surface to be detected is compared with a predetermined threshold value, and a damage detection signal is issued when the illuminance is lower than the predetermined threshold value. Damage detection method.