JP6482248B2 - Narrow gap inspection device - Google Patents

Description

  The present invention relates to a narrow gap inspection device for inspecting a narrow gap, and more particularly to a technique for detecting a crack from a plurality of photographed images of a concrete surface.

  Conventionally, concrete bridges and the like are exemplified as those requiring inspection of narrow gaps. The concrete of such a concrete bridge has cracks on its surface due to aging, alkali-aggregate reaction, or sodium chloride sprayed to prevent freezing on the bridge in the winter and penetrates and corrodes the reinforcing bars. enter. If this crack is left unattended, the width of the crack expands and the concrete is destroyed, and the strength of the bridge is lowered. Therefore, early detection of minute cracks in maintenance inspections of concrete bridges, etc. is very important for preventing accidents and planning repair works.

  By the way, in order to detect fine cracks in concrete at an early stage, it is necessary to inspect the surface state. However, the narrow gap between the bridge base (abut) and the upper work end is 8 m wide and 1 m high, for example. Since the space width is about 20 mm, direct visual observation is impossible.

  In view of the above problems, a photographing apparatus for inspecting a concrete structure has been proposed. This photographing apparatus for inspection has a cart that can move in a horizontal free direction on a floor surface, and a base portion fixed to the cart. A vertical strut with a telescopic drive means that can be expanded and contracted in the vertical direction, a horizontal arm with a telescopic drive means that has one end supported near the upper end of the vertical strut and the free end is extendable in the horizontal direction, A camera unit attached to a free end tip of a horizontal arm or an extension bar attached to a free end tip of the horizontal arm, a vertical column attached to the carriage, and a telescopic drive means for the horizontal arm, and It comprises an operation panel for operating the camera unit (for example, Patent Document 1).

  In addition, for inspection of the lower part of the bridge, although not for gaps, a rail laid on the lower part of the bridge, a patrol robot having a digital wireless device and inspecting the bridge by running on the rail, and a patrol robot In a bridge inspection facility consisting of a robot controller that operates and receives the inspection results, a tightly coupled cable that leaks weak radio waves is laid along the rail, and the patrol robot is contactless with the tightly coupled cable. There has been proposed a bridge inspection facility (for example, Patent Document 2) in which a coupler, which is an adjacent antenna, is provided and a communication signal is transmitted and received between a patrol robot and a robot controller via a tightly coupled cable.

  In the bridge inspection facility of Patent Document 2, the back surface of a bridge such as a viaduct can be automatically inspected, but the narrow gap as described above cannot be inspected.

  On the other hand, in the inspection imaging apparatus of Patent Document 1, the camera unit attached to the free end of the extension bar is attached in a state where it is suspended below the central axis of the extension bar or positioned above the central axis. In such a case, the above-described horizontal cross-sectional structure member of the horizontal arm is used, and the stability is good. In particular, observation and photographing in a deep narrow part can be performed, but the apparatus is complicated. is there. The camera unit has a small CCD video camera equipped with a lens at one end of a flat plate, and a mirror is installed at a central portion so that the mirror is inclined at 45 degrees with respect to the flat plate. Since the image in the range of F1 to F2 in the direction of the front axis F is reflected by the mirror and can be taken into the CCD video camera through the lens, the image can be taken only in a narrow range. There is a problem that it takes time to image the entire narrow gap. In addition, since a small CCD video camera having a lens on a flat plate and a mirror are provided so as to be exposed, there is a risk that clean images cannot be obtained due to dust or the like if it is placed in a narrow gap.

  Furthermore, in order to find minute cracks and increase inspection accuracy, it is necessary to use a high-resolution camera. However, it is difficult to insert a high-resolution camera when photographing a narrow gap such as the upper end of a bridge. Even if the image can be taken with a high-resolution camera, for example, the image that covers the inspection / photographing target surface having a width of 8 m and a height of 1 m becomes a huge amount of data. Searching for fine cracks is inefficient and unreliable.

Japanese Patent Laid-Open No. 2005-24260 JP 2006-37557 A JP 2011-242365 A JP 2014-6222 A

  In order to solve the above problems, the present inventors have developed a narrow gap inspection device that can image a wide range in a narrow gap by an imaging means and can automatically detect fine cracks with high resolution. The purpose is to provide.

The narrow gap inspection device of the present invention has a built-in imaging unit including a mirror that captures the inspection location, an illumination unit that illuminates the inspection location, and an imaging unit that captures the inspection location captured on the mirror. The main body is formed larger in the length direction than in the thickness direction and in the width direction crossing the length direction, the mirror is obliquely arranged with respect to the length direction, and the mirror has a dimension in the length direction. A narrow gap inspection device having a large dimension in the width direction and a plurality of the imaging units arranged in parallel in the width direction, wherein individual images captured by a plurality of the imaging means are combined for each imaging means, and combined extract the crack candidate by the adaptive binarization process from the respective images, after connecting the cracks candidates by combining a plurality of images of cracks candidates are extracted, clutch from the feature quantity of linked cracked candidate Candidate is characterized by comprising an image processing means for detecting cracks by determining whether the crack or otherwise.

  ADVANTAGE OF THE INVENTION According to this invention, the narrow gap inspection apparatus which can image a wide range in a narrow gap with an imaging means can be provided. And since the main body is formed larger in the length direction than the thickness direction and in the width direction intersecting the length direction, it is possible to pick up the inspection point reflected in the mirror by being inserted into the narrow gap by the image pickup means. At this time, since the mirror has a larger length dimension in the width direction than a dimension in the length direction, it is possible to image a large area. Further, by incorporating the image pickup unit, it becomes difficult to be affected by dust and the like. In addition, by arranging a plurality of imaging units in the width direction, it is possible to capture a wide range of images in the width direction. In addition, by providing image processing means for detecting a crack after combining a plurality of images taken by a plurality of imaging means, it is possible to automatically detect a crack taken across a plurality of images.

It is a perspective view which shows the Example of the narrow gap inspection apparatus of this invention. It is a side view of the principal part of a moving body same as the above. It is a sectional view of a mobile object same as the above. It is a perspective view of the principal part of a moving body same as the above. It is a front view of a moving body same as the above. It is explanatory drawing of a drive means and a rail same as the above. It is explanatory drawing of an image processing means same as the above. It is a flowchart which shows the flow of image processing same as the above. It is an image taken by a plurality of image pickup means. It is an image which shows the crack candidate before an image joint same as the above. It is an image which shows the crack candidate after an image joint same as the above.

  A preferred embodiment of the narrow gap inspection device of the present invention will be described in detail with reference to the accompanying drawings.

  1-7 which show the structure of the narrow gap inspection apparatus of a present Example, the narrow gap inspection apparatus moves the moving body 2 which image | photographs an inspection location and the apparatus main body which is not shown in figure which controls this moving body 2. In FIG. I have. The moving body 2 is configured by arranging a plurality of box-shaped main bodies 4 side by side.

  The main body 4 is formed such that the dimension L in the length direction and the dimension W in the width direction intersecting the dimension T are larger than the dimension T in the thickness direction, and the dimension L in the length direction, which is the moving direction, is the dimension in the width direction. It is formed larger than W (L> W> T). Further, the main body 4 includes a front surface portion 5M and a rear surface portion 5K positioned in the front and rear direction, wide side surface portions 6 and 6 positioned on both sides in the thickness direction, and narrow side surface portions 7 and 7 positioned on both sides in the width direction. Have A frame body 8 is provided at the rear part of the main body 4, and the frame body 8 is sandwiched between the wide side surface parts 6 and 6 and the narrow side surface parts 7 and 7, and the rear surface of the frame body 8 constitutes the rear surface part 5K. ing. An opening 8 </ b> A is formed at the center of the frame 8.

  An imaging means 11 such as an endoscope camera or a CCD camera is provided at the center of the front part of the frame body 8, and a lens 11A of the imaging means 11 is arranged in the front, and images the front. Further, a mirror 12 is provided in front of the imaging means 11 at a predetermined distance, and this mirror 12 is arranged at an angle θ with respect to the length direction. The mirror 12 is provided over substantially the entire length in the width direction in the main body 4, and the angle θ is set to 89 degrees or less and 1 degree or more so that the area of the inspection location can be adjusted. The mirror 12 has a length dimension W1 in the width direction larger than a dimension L1 in the length direction. Moreover, the thickness of the main body 4 is 10 mm or less.

  As an example of the imaging means 11, a commercially available endoscope camera having a focal length of about 20 to 50 mm can be used. In this case, for example, by setting the distance between the lens 11A and the mirror 12 to about 77 mm longer than the focal length of the imaging unit 11 and using the mirror 12 that is long in the width direction of the main body 4, a wide range of imaging can be performed. .

  An imaging unit 13 is configured by the imaging means 11 and the mirror 12. In addition to the imaging unit 11 and the mirror 12, the imaging unit 13 includes illumination units 14 and 14A.

  On the front side of the mirror 12, there is provided an illuminating means 14 made up of LEDs or the like that emit light in a bar shape or a plurality of dot shapes. It is provided in an intersecting direction with an angle.

  Further, a circuit board 15 as a main body side control means for controlling the operation of the illumination means 14 is provided at an appropriate place such as the front surface of the frame body 8 or the vicinity thereof, and the circuit board 15 is electrically connected to the illumination means 14. In addition to being connected, the cable 16 is electrically connected to an apparatus main body (not shown). The imaging means 11 is also electrically connected to the apparatus main body by a cable 16, and a groove-like insertion portion 17 through which the cable 16 is inserted is formed in the length direction at the rear portion of the frame body 8. Further, the circuit board 15 is provided with an illuminating unit 14A made of LED, and the mirror 12 can be irradiated with the illumination light of the illuminating unit 14A, and the inspection location can be illuminated with the reflected light of the mirror 12. In addition, what is necessary is just to provide at least one of the illuminating devices 14 and 14A.

  A guide portion 21 is provided in front of the front surface portion 5M of the main body 4, and guide rollers 22 and 22 made of solid tires are rotatably provided on both sides of the guide portion 21 in the width direction. The dimension in the thickness direction of the guide portion 21 is equal to or less than the dimension T in the thickness direction, the outer diameter D of the guide roller 22 is formed slightly larger than the dimension T, and the outer circumference of the guide roller 22 from both sides in the width direction. Is arranged to come out. The focal length is kept constant by the guide rollers 22 and 23. The front end portions 23S and 23S of the support shafts 23 and 23 of the guide rollers 22 and 22 on both sides are formed in a curved surface shape, and the space between the front end portions 23S and 23S is set so as to be within a width dimension W.

  Further, on both sides in the width direction of the rear portion of the main body 4, step portions 24 and 24 for storing the guide roller 22 are provided, and the guide rollers 22 and 22 are rotatably provided in the step portions 24 and 24 on both sides. Yes. The axis of the support shaft 23 of the guide roller 22 is provided in the width direction.

  The main body 4 includes connecting means 26 for connecting in a parallel state. The connecting means 26 includes a locking hole 27 provided on one side of the narrow side surface portion 7 and a locking projection 28 provided on the other side of the narrow side surface portion 7. In the locking hole 27, a large diameter portion 27A and a small diameter portion 27B are continuously formed in the length direction, and a locking projection 28 includes a head portion 28A that passes through the large diameter portion 27A, and a shaft portion 28B that is locked to the small diameter portion 27B. have. Then, with the shaft portion 28B inserted into the small diameter portion 27B, a head portion 28A larger than the small diameter portion 27B is locked to the small diameter portion 27B.

  Rear connection means 31 is provided at the rear of the main body 4. The rear side connecting means 31 includes a rearward connecting arm 32 as a rearward lengthwise connecting portion disposed at intervals in the width direction, and a widthwise connecting arm 33 as a widthwise connecting portion protruding downward. ing.

  Then, plate-like wide side surface parts 6 and 6 are fixed to the openings on both sides in the thickness direction of the main body 4 so as to close the opening. The mirror 12 and the illumination means 14 are provided on the wide side surface part 6 on the reflection surface side of the mirror 12. A transparent window 34 is provided corresponding to the above.

  In addition, a mounting body 35 is used to integrate a plurality of main bodies 4, 4. The attachment body 35 is substantially U-shaped having a rear connection receiving portion 36 for connecting the rear connection means 31 and both end receiving portions 37, 37 sandwiching the plurality of main bodies 4, 4... From both sides in the width direction. There is no.

  Then, the adjacent bodies in the width direction are connected by the connecting means 26, and the plurality of main bodies 4, 4... The rearward connection arm 32 and the width direction connection arm 33 are connected to the rear side connection receiving portion 36 by bolts or the like. Has been. Further, the main bodies 4 and 4 on both sides in the width direction and the both-end receiving portions 37 and 37 are connected by a connecting means (not shown). In this way, the movable body 2 is formed in which a plurality (four in this example) of the main body 4 including the imaging means 11, the mirror 12, and the illumination means 14 and 14A are connected, and the mirrors 12 of the four main bodies 4 are substantially formed. They are continuously aligned. Moreover, the both end receiving part 37 has a substantially U-shaped cross section, and a wire guard is formed through which a string-like body can be inserted.

  Reference numeral 71 denotes a rail, and the movable body 2 is configured to be movable on the rail 71. At one end of the rail 71, a driving means 85 for the moving body 2 is detachably provided. The driving means 85 includes a case 85K, and one end of a rail 71 is connected to the case 85K. A guide wheel 86 and a driven wheel 87 are provided on the other end of the rail 71 so as to be freely rotatable. The guide wheel 86 and the driven wheel 87 are covered with a cover (not shown). In the case 85K, an electric motor 89 for driving the moving wire 88 is built in, and at one end of the rail 71, a driving wheel 87A that is rotationally driven by the motor 89 and a freely rotatable guide wheel 86 are provided. .

  In addition, a moving body receiving member 90 that moves along the rail 71 is provided, and the moving body receiving member 90 has one side portion 90A and the other side portion 90B connected to a central portion 90C along the bottom surface portion 72 of the rail 71. The lower part of the movable body 2 is detachably connected between the one side part 90A and the other side part 90B. Furthermore, wheels (not shown) are provided on both sides of the moving body receiving member 90 or the moving body 2 in the left-right direction.

  The moving wire 88 is disposed along the rail 71. The other end 88 </ b> B of the moving wire 88 passes through the lower portion of the guide wheel 86 on the other end side, is hooked on the driven wheel 87 and is folded back, and the other end 88 </ b> B of the moving wire 88 that is hooked on the driven wheel 87. Is connected to the other end 90B. On the other hand, one end 88A of the moving wire 88 passes through the lower portion of the guide wheel 86 in the case 85K, is hooked on the driving wheel 87A, is folded, and one end 88A of the moving wire 88 is hooked on the driving wheel 87A. Is connected to the one end.

  An encoder 91 that detects the rotational speed of the motor 89 is built in the case 85K. Then, the drive body 87A is rotationally driven by the motor 89 and the moving wire 88 is pulled in one side direction or the other side direction, whereby the moving body 2 moves left and right. The rotation speed of the motor 89 is detected by the encoder 91, the movement amount of the moving body 2 is detected from the rotation speed, and the position of the moving body 2 can be detected from the movement amount.

  Further, in the solid line in FIG. 1, the driving means 85 is provided on one side in the left-right direction of one end of the rail 71, whereas the case 85 </ b> K incorporating the driving means 85 is operated to attach and detach the rail 71. An operation button 85B is provided. Then, by operating this operation button 85B, as shown by the one-dot chain line in FIG. 1, the case 85K is connected to the other side in the left-right direction of one end of the rail 71, and the drive means 85 is connected to the drive wheel 87A. Can be done.

  Referring to FIG. 7, the drive control unit 92 is built in the drive unit 85, controls the moving body 2 that moves along the rail 71, and controls the drive of the motor 89 based on the position information from the encoder 91. Is supposed to do. In addition, the drive control unit 92 sends an imaging command signal to the imaging means 11 at every fixed movement distance interval and sends an image capture command signal to the personal computer 93.

  The image signal distributor 94 distributes image data from the image pickup means 11, specifically, NTSC × 4 channel signals to the personal computer 93 and the moving picture recorder 95. The image capture board 96 is a substrate that captures the NTSC signal from the imaging means 11 into the personal computer 93.

  Image processing software is installed in the personal computer 93, and the personal computer 93 operates as image processing means. This image processing software automatically combines images sequentially in response to the input of a shooting command signal generated at a fixed distance section (capture interval) for each of the plurality of imaging means 11 as the imaging means 11 moves. To save.

  Further, the image processing software has a function of automatically detecting cracks by combining images captured by the plurality of imaging units 11. This function will be described later.

  Next, the operation will be described. The rail 71 is installed close to the inspection point of the narrow gap. The illumination means 14, 14 </ b> A irradiates the inspection location with a light amount suitable for imaging, and the drive control unit 92 captures the inspection location while controlling the position of the moving body 2.

  The drive control unit 92 controls the position of the moving body 2 by performing drive control of the motor 89 based on the position information from the encoder 91. That is, the drive control unit 92 rotates the driving wheel 87A by the motor 89 and moves the moving body 2 by pulling the moving wire 88. At the same time, the encoder 91 detects the rotational speed of the motor 89 and detects the rotational speed. From this, the movement amount of the moving body 2 is detected, and the position of the moving body 2 is controlled. In addition, the drive control unit 92 sends an imaging command signal to the imaging unit 11 at every fixed movement distance interval and sends an image capture command signal to the personal computer 93. Thereby, the image image | photographed for every fixed movement distance interval is obtained.

  The personal computer 93 automatically and sequentially combines a plurality of images for each of the plurality of image pickup means 11.

  Furthermore, the personal computer 93 combines the images captured by the plurality of imaging units 11 with image processing software, and automatically detects cracks.

  A flow of image processing in the personal computer 93 is shown in FIG. Hereinafter, an example of an image obtained by actually photographing the four imaging units 11 side by side will be described.

  In S1 (step 1), images are acquired from a plurality of imaging means 11 (cameras). In step S2 (step 2), the individual images acquired in step S1 are combined for each imaging unit 11 to generate a rectangular image. Here, when there are four imaging means 11, four rectangular images are obtained as shown in FIG. This rectangular image shows the range of the sensor width of the imaging means 11 x the movement distance.

  In the next S3 (step 3), a crack candidate extraction process is performed. That is, an adaptive binarization process for extracting a crack is performed on each rectangular image obtained in S2, and the extracted image is set as a “crack candidate image”. FIG. 10 shows an example of a crack candidate image. The extracted crack candidates are filled and displayed.

  In step S4 (step 4), an image identification process between different image pickup units 11 (cameras) is performed. That is, there is a gap or gap between the crack candidate images obtained in S <b> 3 due to photographing by the plurality of imaging means 11. The gaps and gaps are filled by image processing, and the crack candidates between the different imaging means 11 are made the same one after another. Specifically, a boundary point to be overlapped between different images is detected, the positions thereof are aligned, and then crack candidates are combined. FIG. 11 shows an example of a crack candidate image after the equalization processing.

  Next, in S5 (step), the feature amount is determined. That is, the length, width, area, etc. of the crack candidates connected in S4 are corrected to feature quantities such as length, width, area in the connected state. Then, all of the photographed data is compared with a predetermined condition for determining as a true crack, and finally it is determined whether it is a crack or the other (dirt or the like).

  The crack has a feature of “elongate like a string”. On the other hand, dirt has a feature of “not thin”. These cracks and dirt can be distinguished from each other by distinguishing them as separate lumps (for example, a labeling process) and measuring the feature quantities of the respective lumps. One type of feature quantity is “area”. Another feature amount is “peripheral length”. The elongated one has a long peripheral length with respect to the area, and the thin one has a short peripheral length with respect to the area.

  Here, when it is determined whether it is a crack or the other using the image before the combination treatment (FIG. 10), the accurate determination cannot be made because the lump is divided and only a part of the lump appears in the image. There is a case. On the other hand, according to this method, since the determination is performed using the combined image (FIG. 11), it is less likely that the chunk is divided and only a part of the chunk appears in the image. Automatic and accurate determination can be performed using processing software.

  At the last S6 (step 6), the determination result of S5 is displayed on the display of the personal computer 93 as a crack detection result.

  As described above, the narrow gap inspection device of the present embodiment images on the main body 4 the mirror 12 that captures the inspection location, the illumination means 14 and 14A that illuminate the inspection location, and the inspection location that is captured on the mirror 12. The body 4 is formed larger than the thickness direction in the length direction and in the width direction intersecting the length direction, and the mirror 12 is provided obliquely with respect to the length direction. The mirror 12 has a dimension in the width direction larger than the dimension in the length direction, and an imaging unit 13 including the mirror 12 and the imaging means 11 is built in the main body 4, and the imaging unit 13 is arranged in the width direction. A plurality of narrow gap inspection devices provided with a personal computer 93 as image processing means for detecting cracks after combining a plurality of images picked up by a plurality of the image pickup means 11. . And since the main body 4 is formed larger in the length direction than the thickness direction and in the width direction intersecting the length direction, the inspection portion that is inserted into the narrow gap and reflected on the mirror 12 is imaged by the imaging means 11. At this time, since the mirror 12 has a larger length dimension in the width direction than a dimension in the length direction, it is possible to image a large area. Further, by incorporating the image pickup unit 13, it becomes difficult to be affected by dust and the like. In addition, by arranging a plurality of imaging units 13 in the width direction, it is possible to capture a wide range of images in the width direction. In addition, by providing a personal computer 93 as an image processing means for detecting cracks after combining a plurality of images taken by a plurality of image pickup means 11, cracks taken across a plurality of images are automatically detected. Can be detected.

  Further, by imaging with a plurality of imaging means 11, it is possible to obtain a high resolution and large resolution image that cannot be obtained with a single imaging means, and to perform crack detection with high accuracy. Moreover, since there is no restriction | limiting in the number of the imaging means 11, it also becomes possible to comprise so that a resolution can be raised infinitely.

  And, since cracks can be detected with high accuracy even in narrow gaps where conventional devices cannot enter, the accuracy of maintenance and inspection of concrete structures and the like can be increased, and further inspection can be performed easily. As a result, labor can be saved for inspection workers.

  In addition, crack candidates are detected from a plurality of images obtained from a plurality of different imaging means, boundary points that should be overlapped between different images are detected, their positions are aligned, and then the crack candidates are combined to form a true crack Features such as the width and length of the candidate can be derived. Thereby, even if it is a crack which straddles a plurality of images, it can be judged that it is the same continuous crack, and values such as the size, length, and area of the crack can be measured as those of the crack that is not divided. As a result, cracks can be selected and detected with high accuracy.

4 Main body 11 Imaging means 12 Mirror 13 Imaging units 14, 14A Illumination means 93 Personal computer (image processing means)

Claims (1)

The main body incorporates an imaging unit including a mirror that captures the inspection location, illumination means that illuminates the inspection location, and imaging means that captures the inspection location captured on the mirror, and the main body is longer than the thickness direction. The mirror is formed obliquely with respect to the length direction, and the mirror has a dimension in the width direction larger than a dimension in the length direction, A narrow gap inspection device in which a plurality of imaging units are arranged side by side in the width direction, wherein individual images captured by a plurality of the imaging means are combined for each of the imaging means, and an adaptive two-dimensional image is obtained from the combined images. extract the crack candidate by binarization process, after connecting the cracks candidates by combining a plurality of images of cracks candidates are extracted, cracks or other cracks candidate from the feature quantity of linked cracked candidate Narrow gap inspection device characterized by comprising an image processing means for detecting cracks by determining.