JP6515344B2 - Defect detection apparatus and defect detection method - Google Patents

Description

  The present invention relates to a defect detection apparatus and a defect detection method.

  For example, inspection of a tubular body such as a steel pipe is performed by visual inspection by an inspector, but such visual inspection largely depends on the skill of the inspector. In particular, the inspection of the inner surface of the tubular body may result in a shameful hemorrhage or serious claims due to insufficient visual inspection.

  As a defect inspection method for defects such as wrinkles on the inner surface of the tubular body, a detection probe consisting of an optical device such as an imaging device or an illumination device for imaging the inner surface of the tubular body all around is moved in the axial direction in the tubular body. Optical inspection is conducted.

  For example, Patent Document 1 below proposes an apparatus for observing the inner surface of a tube by including an imaging device in which a mirror for receiving light in all directions is disposed at the tip of the camera and diffusion ring illumination. ing.

  Further, Patent Document 2 and Patent Document 3 below propose a method for detecting a defect in the inner surface of a pipe from an image obtained by imaging the inner surface with an imaging device disposed on one open end side of the pipe. There is.

  Furthermore, in Patent Document 4 below, a light-cut image is obtained from an annular beam image obtained by irradiating an inner surface of a tubular body with an annular laser beam while moving along the axial direction of the tubular body. As a result, an apparatus has been proposed that simultaneously detects the uneven wrinkles on the inner surface and the wrinkles in the pattern system.

JP 2004-354525 A JP, 2011-69616, A JP 2012-242233 A JP, 2012-159491, A

  According to the technique disclosed in Patent Document 1 described above, it is possible to obtain a captured image of the omnidirectional direction of the surface of the inner surface of the tube. However, there is a problem that it is difficult to select from the captured image whether it is a rough or patterned wrinkle or a background pattern, because it depends only on the image brightness information. .

  Further, in the techniques disclosed in Patent Document 2 and Patent Document 3, the deep portion inside the tubular body is a low resolution image in which imaging pixels become rough, so detection of micro wrinkles becomes difficult. In addition, the imaging field of view changes from the tube opening to the back of the tube, and the angle of the reflected light from the inspection surface and the angle of the illumination light change, so the imaging resolution changes. However, the appearance may change as a result of different luminance. That is, when the entire inner surface of the tubular body is dirty, or when there is roughness on the inner surface of the tube, it may be determined whether the shading of the uneven surface or the density change due to the contamination or roughness of the surface normal portion. There was a problem that it became difficult.

  Further, by using the technology disclosed in Patent Document 4 described above, a depth image representing the uneven state of the inner surface of the tube and a luminance image representing a luminance distribution can be obtained. Therefore, the technique disclosed in Patent Document 4 can perform the inspection of the inner surface of the tubular body with high accuracy, and is excellent in separately detecting the wrinkles having the unevenness and the wrinkles in the pattern shape. . However, the technique disclosed in Patent Document 4 has a problem that it is difficult to determine harm / no harm for wrinkles having no unevenness.

  Even if there is no unevenness, as a highly harmful flaw, for example, a tread on an inner surface of a steel pipe can be mentioned. This treadle often occurs due to foreign substances such as spatter generated in a welding process in manufacturing a steel pipe by forming a steel plate into a tubular shape. In particular, a roller supporting the internal cutting mandrel steps on the spatter generated during welding in the electric resistance welded tube manufacturing process, and the wrinkle generated by the pressed spatter biting into the inner surface of the steel pipe as a base material Example. In this case, the surface is leveled in a state where the spatter is crushed by a roller and bites into the base material. Therefore, the spattered surface which has bitten is flat and in a state of being covered. Since the sputtered surface is worn by being crimped to the roller, the change in unevenness becomes minute, and detection is difficult with the conventional means for detecting the uneven shape. Such a cocoon is hereinafter referred to as "a covered bite".

  FIG. 24 shows an example of the cross-sectional profile of the lidded bite weir generated on the inner surface of the ERW pipe by the above mechanism. Such a cross-sectional profile is obtained by measuring a portion where it is known that a covered bite has occurred with a known surface roughness meter. In the cross-sectional profile shown in FIG. 24, the region surrounded by the broken line is a portion where a covered and bite-in is generated. In this portion, the unevenness of the surface is flat as compared with the surroundings, and there is a cut whose cross section changes sharply at both ends of the flat portion. As a result, the height of such a covered bite and eyebrow is about 20 μm, and the size is 1 mm or less in diameter.

  The above-mentioned cap-and-tack bite with a lid has a high degree of harmfulness because the thickness of the steel pipe is reduced by the amount of spatter biting and the thickness of the steel pipe is not guaranteed, and it should be detected. However, in the method of detecting from a luminance image according to the prior art, such a covered bite may be minute, and it is difficult to distinguish and detect formation and dirt on the inner surface. Moreover, the above-mentioned lidded bite-in-the-basket may be in a state where the bite-in lid is removed. If the lid is removed, the wrinkle after the lid is removed needs to be detected as a normal dent.

  That is, it is necessary to detect with high accuracy both the flat shape in the state with the lid and the shape of the recess in the state with the lid removed with high accuracy. is there.

  Therefore, for the purpose of quality inspection and control of the inner surface of the steel pipe over the entire length, for the purpose of quantitatively inspecting flaws, it is needless to say that the detection of irregularities is no harm, no harmful flaws without irregularities, etc. It is necessary to sort out and detect.

  Therefore, the present invention has been made in view of the above problems, and the object of the present invention is not only the unevenness wrinkle accompanied by the unevenness change which may occur on the inner surface of the tubular body but also the unevenness change. An object of the present invention is to provide a defect detection apparatus and a defect detection method capable of accurately detecting harmful flaws by sorting them with harmless dirt and the like.

  In order to solve the above problems, according to one aspect of the present invention, while moving along the axial direction of the tubular body, annular laser light and conical shape with respect to the entire circumferential direction of the inner surface of the tubular body. The illumination light of each is illuminated, and the imaged image of the annular laser light and the conical illumination light on the inner surface by imaging the inner surface irradiated with the annular laser light and the conical illumination light A tubular body imaging device that generates a plurality of in-pipe surface images along the axial direction of the tubular body, and performing image processing on the in-pipe surface image generated by the tubular body imaging device; An arithmetic processing unit that determines whether there is a defect on the surface, and the tubular body imaging device includes an annular laser light source that emits the annular laser beam to the entire circumferential direction of the inner surface of the tubular body; , Circumferential direction of the inner surface of the tubular body A conical illumination light source for illuminating the conical illumination light, the inner surface irradiated with the annular laser beam and the conical illumination light, an irradiated portion of the annular laser beam, and the conical shape And an area camera for imaging so that the illumination area of the illumination light falls within the same field of view, the area camera being a specular reflection of the conical illumination light from the illumination area of the conical illumination light It is disposed opposite to the annular laser light source and the conical illumination light source so that light is imaged and irregularly reflected light of the annular laser light from the annular laser light irradiation portion is imaged. The arithmetic processing unit calculates an annular beam center calculating unit that calculates a barycentric position and a radius of the irradiation portion of the annular laser light in each of the in-pipe surface images, the calculated barycentric position, and the barycenter location and The coordinate system of the in-pipe surface image is converted based on the distance between the annular laser light irradiation portion and the distance between the center of gravity position and the conical illumination light irradiation area, and A light cutting line image which is a band-like area including a light cutting line which is a line segment in which an irradiation part of an annular laser light is expanded in a circumferential direction of the tubular body, and an irradiation area of each conical illumination light A coordinate transformation unit that generates a plurality of specular reflection developed images, which are band-like regions developed in the circumferential direction of the tubular body, and a light cutting line image frame in which the light cutting line images are arranged in order along the axial direction Based on the depth image calculating unit for calculating a depth image representing the uneven body on the inner surface of the tubular body, and the annular laser on the inner surface of the tubular body based on the light cutting line image frame A diffuse reflection image representing the distribution of light intensity The irregular reflection image calculation unit to be calculated and the regular reflection developed image are arranged in order along the axial direction to generate a regular reflection image representing the distribution of the brightness of the conical illumination light on the inner surface of the tubular body A defect detection apparatus comprising: a regular reflection image generation unit; and a defect detection unit for detecting a defect present in the tubular body based on the calculated depth image, the irregular reflection image, and the regular reflection image. Provided.

  The depth image calculation unit calculates a barycentric position of the light cutting line in the line width direction along the circumferential direction, and the radius is a position in an axial direction previously designated with respect to the light cutting line image. It is preferable to calculate the depth image as a reference position based on a displacement between the reference position and the barycentric position.

  The irregular reflection image calculation unit may set, for each of the light cutting lines, a pixel having a luminance value equal to or greater than a first threshold for specifying a pixel corresponding to the light cutting line at each position in the circumferential direction. Calculating the number of pixels added in the width direction and the total luminance of pixels having luminance values equal to or greater than the first threshold, and calculating the irregular reflection image based on an average value of the total luminance in the line width direction preferable.

  The annular laser light source and the conical illumination light source may be disposed such that the irradiation portion of the annular laser light and the illumination area of the conical illumination light do not overlap with each other.

  The annular laser light source and the conical illumination light source are disposed such that the irradiation portion of the annular laser light and the irradiation region of the conical illumination light overlap each other, and the annular laser light And the conical illumination light are different from each other in wavelength, irradiation timing, or polarization, and the area camera is configured to reflect the reflected light from the portion irradiated with the annular laser beam and the conical illumination light. The reflected light from the irradiation area of may be distinguished from each other and imaged.

  The area camera is a color camera capable of color imaging, and the annular laser light source and the conical illumination light source are combinations of colors of the annular laser light and the conical illumination light (red / blue) The light sources may have different wavelengths so as to be either (blue / green) or (red / green).

  The illumination area of the conical illumination light has a length d in the axial direction on the inner surface of the tubular body, and the illumination area of the conical illumination light has the annular laser beam along the axis It may be imaged only once while advancing in the direction by d.

  The coordinate conversion unit is configured to convert the luminance value of each pixel of the light section image and the luminance value of each pixel of the specular reflection developed image at each position of the corresponding in-pipe surface image when converting the coordinate system. You may calculate by the image interpolation process from the luminance value of a neighboring pixel.

  The defect detection unit determines whether the pixel values of the depth image, the irregular reflection image, and the regular reflection image are equal to or more than a second threshold value for identifying a defect site set for each of the images. The defect site is identified based on the above, the feature quantity information on the form and pixel value of the defect site is extracted for the identified defect site, and the defect site is present on the inner surface of the tubular body based on the extracted feature quantity information It is preferable to identify the defects that occur.

  The tubular body imaging device further includes one or more connecting members that couple and fix the annular laser light source, the conical illumination light source, and the area camera, and the tubular body imaging device is the tubular body The annular laser light and the conical illumination light are blocked by the connecting member when being fed into the interior of the tube and when the tubular body imaging device is delivered from the inside of the tubular body, respectively. And generating an inner surface image of the inner surface of the inner tube at the time of delivery, between the infeed and The tubular body imaging device is rotated so that it does not overlap with the shielded area of the surface image, and the arithmetic processing unit utilizes the light cutting line image at the time of delivery or the light cutting line image at the time of delivery. Light cutting line image and the regular reflection exhibition A shielding area specifying unit for specifying the position of the shielding area in the image; and the shielding area in the depth image, the diffuse reflection image and the specular reflection image generated based on the in-pipe surface image at the time of delivery or delivery; The coordinate conversion unit further includes an image interpolation unit that interpolates using the depth image, the diffuse reflection image, and the regular reflection image generated based on the in-pipe surface image at the time of delivery or at the time of delivery. The coordinate system of the tube surface image at the time of delivery and at the time of delivery is respectively converted using a predetermined position on the inner surface of the tubular body as a reference point, and a plurality of the light cut line images and the specular reflection developed image at the time of delivery And a plurality of the light section line images and the specular reflection developed image at the time of delivery.

  The number of bright line pixels, which is the number obtained by adding, in the line width direction, pixels having a luminance value equal to or more than the first threshold for each position of the circumferential direction with respect to each of the light cutting lines. And the circumferential direction position of the shielding area may be specified by the number of bright line pixels.

  The shielding area specifying unit stores the circumferential position at which the number of bright line pixels has become zero, and counts the number of consecutive states in which the number of bright line pixels becomes zero at a position in the circumferential direction thereafter, When the number of consecutive lines in which the number of bright line pixels becomes zero is equal to or more than the third threshold for determination of the number of consecutive lines, the stored circumferential position is regarded as the start position of the shield area, and the start position of the shield area Is specified and the number of bright line pixels at the circumferential position of interest is not zero, the circumferential position at which the number of bright line pixels is not zero for the subsequent circumferential position is The number of consecutive lines in a state where the number of bright line pixels is not zero is counted, and the number of consecutive lines in a state where the number of bright line pixels is not zero is equal to or greater than a fourth threshold for determining the number of consecutive lines. And the circumferential position may be a position where the new unshielded region has started the shielded region ends.

  The shielding area specifying unit calculates a moving average of the number of bright line pixels for each position of the circumferential direction with respect to each of the light cutting lines, and the moving average is a fifth threshold for moving average determination. The position in the circumferential direction, which is less than, is defined as the start position of the shielding area, the start position of the shielding area is specified, and the position in the circumferential direction in which the moving average is equal to or more than the fifth threshold The end position of the shielding area may be used.

In order to solve the above problems, according to another aspect of the present invention, while moving along the axial direction of the tubular body, an annular laser beam is generated with respect to the entire circumferential direction of the inner surface of the tubular body. And the conical illumination light are respectively irradiated, and the annular laser light and the conical illumination light on the inner surface are imaged by imaging the inner surface irradiated with the annular laser light and the conical illumination light. And an annular laser light source for emitting the annular laser beam to the entire circumferential direction of the inner surface of the tubular body. A conical illumination light source for illuminating the conical illumination light in the entire circumferential direction of the inner surface of the tubular body, and the inner surface illuminated with the annular laser beam and the conical illumination light; An annular laser beam irradiation portion and the conical illumination light And an area camera for imaging so that the irradiation area falls within the same field of view, and the area camera forms an image of specularly reflected light of the conical illumination light from the illumination area of the conical illumination light. And a tubular body disposed opposite to the annular laser light source and the conical illumination light source so that diffuse reflection light of the annular laser light from the annular laser light irradiation portion forms an image An annular beam center for generating a plurality of the tube surface images along the axial direction of the tubular body by an imaging device, and calculating a barycentric position and a radius of the annular laser light irradiated portion in each tube surface image; Calculating step, the calculated position of the center of gravity, the distance between the position of the center of gravity and the portion irradiated with the annular laser light, and the distance between the position of the center of gravity and the irradiation region of the conical illumination light The light cutting which is a band-like region including a light cutting line which is a line segment in which the coordinate system of the tube surface image is converted based on the above and the irradiation part of each annular laser light is expanded in the circumferential direction of the tubular body A coordinate conversion step of generating a plurality of line images and specular reflection developed images which are band-like regions obtained by expanding the irradiation regions of the respective conical illumination light in the circumferential direction of the tubular body; A depth image calculating step of calculating a depth image representing a concavo-convex body on the inner surface of the tubular body based on the light sectioning line image frame in which each is arranged in order along the axial direction; A diffuse reflection image calculating step of calculating a diffuse reflection image representing a distribution of the luminance of the annular laser light on the inner surface of the tubular body based on an image frame; and each of the specular reflection expanded images along the axial direction A specular reflection image generating step of arranging to generate a specular reflection image representing the distribution of the brightness of the conical illumination light on the inner surface of the tubular body, the calculated depth image, the diffuse reflection image and the positive reflection image A defect detection step of detecting a defect present in the tubular body based on a reflection image;
And a defect detection method is provided.

  As described above, according to the present invention, not only uneven wrinkles accompanied by uneven changes that may occur on the inner surface of the tubular body, but harmful wrinkles not accompanied by uneven changes are separated from harmless dirt etc. and accurately detected It is possible to

It is an explanatory view showing an example of composition of a defect detection apparatus concerning an embodiment of the present invention. It is an explanatory view showing typically an example of composition of a tubular body imaging device concerning the embodiment. It is an explanatory view showing typically an example of composition of a tubular body imaging device concerning the embodiment. It is an explanatory view for explaining a tubular body imaging device concerning the embodiment. It is explanatory drawing for demonstrating the in-pipe surface image which concerns on the embodiment. It is the block diagram which showed an example of the structure of the image processing part which the arithmetic processing unit concerning the embodiment has. It is an explanatory view for explaining coordinate conversion processing in an arithmetic processing unit concerning the embodiment. It is an explanatory view for explaining coordinate conversion processing in an arithmetic processing unit concerning the embodiment. It is an explanatory view for explaining coordinate conversion processing in an arithmetic processing unit concerning the embodiment. It is an explanatory view for explaining coordinate conversion processing in an arithmetic processing unit concerning the embodiment. It is an explanatory view for explaining a light sectioning line image frame concerning the embodiment. It is an explanatory view for explaining a light sectioning line image frame concerning the embodiment. It is an explanatory view for explaining a specular reflection image concerning the embodiment. It is an explanatory view showing a two-dimensional arrangement of light sectioning line displacement concerning the embodiment. It is explanatory drawing which showed the two-dimensional arrangement | sequence of the sum total of the brightness | luminance which concerns on the embodiment. It is explanatory drawing which showed the two-dimensional arrangement | sequence of the pixel number of the luminescent line which concerns on the embodiment. It is an explanatory view for explaining shielding field identification processing in the arithmetic processing unit concerning the embodiment. It is an explanatory view for explaining shielding field identification processing in the arithmetic processing unit concerning the embodiment. It is an explanatory view for explaining shielding field identification processing in the arithmetic processing unit concerning the embodiment. It is an explanatory view for explaining shielding field identification processing in the arithmetic processing unit concerning the embodiment. It is an explanatory view for explaining shielding field identification processing in the arithmetic processing unit concerning the embodiment. It is an explanatory view for explaining shielding field identification processing in the arithmetic processing unit concerning the embodiment. It is an explanatory view for explaining shielding field identification processing in the arithmetic processing unit concerning the embodiment. It is explanatory drawing which showed the relationship between the displacement of a light sectioning line, and the height of a defect. It is an explanatory view for explaining approximation correction processing of a light section line concerning the embodiment. It is an explanatory view for explaining occlusion field interpolation processing in the arithmetic processing unit concerning the embodiment. It is the block diagram which showed an example of the structure of the defect detection part with which the image processing part concerning the embodiment is equipped. It is an explanatory view showing an example of a logic table used by defect detection processing concerning the embodiment. It is the flowchart which showed an example of the flow of the defect detection method concerning the embodiment. It is the block diagram which showed an example of the hardware constitutions of the arithmetic processing unit concerning the embodiment. It is the graph which showed an example of the cross-sectional profile of a lidded bite-in type | mold.

  The present invention will now be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. In the present specification and the drawings, components having substantially the same functional configuration will be assigned the same reference numerals and redundant description will be omitted.

(About the entire configuration of the defect detection device)
First, the entire configuration of a defect detection apparatus 10 according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is an explanatory view showing the configuration of a defect detection apparatus 10 according to the present embodiment.

  The defect detection device 10 according to the present embodiment is at least one of the inner surface of the tubular body 1 when the tubular body imaging device is fed into the inside of the tubular body, or when it is delivered from the inside of the tubular body. On the other hand, it is an apparatus for imaging whether or not various surface defects exist on the inner surface of the tubular body 1 by imaging and processing an image obtained as a result of imaging.

  The tubular body 1 according to the present embodiment is not particularly limited as long as it is a tubular body having a hollow portion, but as an example of the tubular body 1, a spiral steel pipe, a seam welded steel pipe, a UO steel pipe, a seam Not only various steel pipes and pipes such as steel pipe (seamless steel pipe), forged welded steel pipe and TIG welded steel pipe but also tubular materials such as a cylinder called a container used in the hot extrusion method can be mentioned.

  As shown in FIG. 1, the defect detection apparatus 10 according to the present embodiment controls the movement of the tubular body imaging device 100 for imaging the inner surface of the tubular body 1 and the tubular body imaging device 100 along the tube axis direction. And an arithmetic processing unit 200 that performs image processing on the inner surface image of the tubular body obtained as a result of imaging.

  The tubular body imaging device 100 is installed in the hollow portion of the tubular body 1. The tubular body imaging device 100 has two types of illumination light sources, and while sequentially changing the position along the axial direction of the tubular body 1, sequentially imaging the inner surface of the tubular body 1 along the axial direction It is an apparatus which outputs the captured image obtained as a result of imaging to the arithmetic processing unit 200. The position in the axial direction of the tubular body imaging device 100 is controlled by the drive control device 150, and as the tubular body imaging device 100 moves, the PLG signal from a PLG (Pulse Logic Generator: pulse type speed detector) or the like It is output to the arithmetic processing unit 200. Further, in the tubular body imaging device 100, the imaging timing and the like of the tubular body 1 are controlled by the arithmetic processing unit 200.

  The specific configuration of the tubular body imaging device 100 will be described in detail later.

  The drive control device 150 is a device such as an actuator that controls movement of the tubular body imaging device 100 in the tube axis direction and rotation of the tubular body circumferential direction with the tube central axis direction as the rotation axis. The drive control device 150 controls operations such as movement of the tubular body imaging device 100 in the axial direction of the tube and rotation of the tubular body in the circumferential direction under the control of the arithmetic processing unit 200.

  Further, the drive control device 150 can also perform the following processing as necessary. That is, when the drive control device 150 sends the tubular body imaging device 100 into the tubular body and the imaging of the inner surface to be inspected by the tubular body imaging device 100 ends, the feeding operation of the tubular body imaging device 100 Stop. Thereafter, the drive control device 150 rotates the tubular body imaging device 100 in the circumferential direction of the tubular body with the central axis of the tubular body imaging device 100 as a rotation axis. Thereafter, the drive control device 150 causes the tubular body imaging device 100 to be delivered from inside the tubular body.

  The arithmetic processing unit 200 generates various image frames as will be described later using a plurality of captured images (in-pipe surface images) generated by the tubular body imaging device 100, and this image frame will be described below. It is an apparatus which detects the various defects which may exist in the inner surface of the tubular body 1 by performing such image processing.

  Under the present circumstances, even if the dead zone resulting from the member which comprises the tubular-body imaging device 100 exists in the pipe | tube surface image mentioned later at the time of sending in or sending out, the arithmetic processing unit 200 which concerns on this embodiment The image generated from the captured image captured at the time of delivery or at the time of delivery can be interpolated using the image generated from the captured image captured. As a result, even if a dead zone is present in the captured image captured at the time of delivery or delivery, the inner surface of the tubular body can be inspected over the entire circumference.

  The detailed configuration of the arithmetic processing unit 200 will be described again below.

  The imaging process of the tubular body surface by the tubular body imaging apparatus 100 and the detection process of the surface defect by the arithmetic processing unit 200 can be performed in real time in accordance with the movement of the tubular body imaging apparatus 100 along the axial direction of the tubular body. It is. The user of the defect detection apparatus 10 pays attention to the inspection result output from the defect detection apparatus 10 (more specifically, the arithmetic processing apparatus 200) to make surface defects present on the inner surface of the tubular body 1 in real time. It becomes possible to grasp.

(About the structure of the tubular body imaging device 100)
First, the configuration of a tubular body imaging device 100 according to the present embodiment will be described in detail with reference to FIGS. 2A to 4.
FIG. 2A and FIG. 2B are explanatory views schematically showing an example of the configuration of the tubular body imaging device according to the present embodiment. FIG. 3 is an explanatory view for explaining a tubular body imaging device according to the present embodiment. FIG. 4 is an explanatory view for explaining an in-pipe surface image according to the present embodiment.

  In the following description, for convenience, the description will be made using a coordinate system as shown in FIG. 2A and FIG. 2B. More specifically, as shown in FIGS. 2A and 2B, the z-axis is taken in the axial direction of the tubular body 1, and the plane orthogonal to the axial direction of the tubular body is an xy plane.

  As shown in FIG. 2A and FIG. 2B, the tubular body imaging device 100 according to the present embodiment includes an annular laser light source 101 for irradiating an annular laser beam (annular laser beam) to the inner surface of the tubular body; A conical illumination light source 107 for illuminating conical illumination light (hereinafter also referred to as "conical illumination light") on the inner surface of the body, an area camera 113 having various known lenses, and an annular laser light source 101 A conical illumination light source 107, a pair of holding members 115 for holding the area camera 113, and a connecting member 117 for connecting the pair of holding members 115 are provided. Further, the annular laser light source 110 and the conical illumination light source 107 connected by the connecting member 117 and the area camera 113 are fixed by known means so that their setting positions do not change during imaging. These members are integrated with each other to function as an imaging probe for imaging the inner surface of the tubular body 1.

  The annular laser light source 101 is an apparatus for irradiating an annular laser beam (hereinafter, also referred to as an “annular beam”) along the circumferential direction of the inner surface of the tubular body 1, as shown in FIGS. 2A and 2B. , A laser light source 103, and a conical optical element 105.

  The laser light source 103 is a light source that oscillates laser light having a predetermined wavelength. As such a laser light source 103, for example, it is possible to use a CW laser light source which continuously performs laser oscillation. The wavelength of light oscillated by the laser light source 103 is preferably a wavelength belonging to a visible light band of about 400 nm to 800 nm, for example. The laser light source 103 oscillates laser light based on an irradiation timing control signal sent from the arithmetic processing unit 200 described later.

  The conical optical element 105 is an optical element provided with a conical mirror or prism, and is disposed such that the apex of the conical portion faces the laser light source 103. The spot-like laser light emitted from the laser light source 103 is reflected by the apex of the conical portion of the optical element 105, and a line beam is generated in a ring shape. Here, when the conical angle of the conical portion is 90 °, as shown in FIGS. 2A and 2B, the annular laser beam is irradiated in the direction perpendicular to the laser incident direction from the laser light source 103. It will be.

  The conical illumination light source 107 radiates conical illumination light having a wavelength belonging to a visible light band of, for example, about 400 nm to 800 nm, while spreading it all around the surface of the tubular body (spread width at the inner surface: d) It is a light source. For example, as shown in FIG. 3, the conical illumination light source 107 includes a light emitting element 111 provided with a lens for controlling the irradiation direction of the illumination light along the circumference of the annular base 109, etc. A plurality of intervals are provided. Conical illumination light is emitted radially from the respective light emitting elements 111 with respect to the center of the annular base 109 (that is, outward in the radial direction of the annular ring).

  The number of light emitting elements 111 provided on the annular base 109 and the installation interval are not particularly limited, and may be determined so that the visual field of the inner surface to be focused has a desired uniform brightness. Further, instead of the plurality of light emitting elements 111 as shown in FIG. 3, a single ring-shaped light emitting element provided with a lens for controlling the irradiation direction of the illumination light may be used.

  The annular laser light source 101 and the conical illumination light source 107 as described above are fixed to the holding member 115 so as to be concentric with each other.

  The area camera 113 mounted with various known lenses is fixed at the center of the other holding member 115 and faces the holding member 115 to which the annular laser light source 101 and the conical illumination light source 107 are fixed. It is provided as. The area camera 113 is mounted with a two-dimensional imaging device such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). As such an area camera 113, a known one can be used.

  Although the focal length and angle of view, etc. of the lens mounted on the area camera 113 are not particularly limited, the reflected light on the inner surface of the annular laser beam irradiated to the inner surface of the tubular body 1, and the cone Each of the reflected light at the inner surface of the illumination light is selected to be within the same field of view. Also, the size and pixel size of the imaging device mounted on the area camera 113 are not particularly limited, but it is preferable to use a large-sized imaging device in consideration of the image quality, image resolution and the like of the generated image. . Further, from the viewpoint of image processing described below, it is preferable to adjust the area camera 113 so that the line width (line width) of the annular laser light is about 1 to 3 pixels on the imaging device.

  The area camera 113 images the reflected light on the inner surface of the annular laser light imaged in the same field of view and the reflected light on the inner surface of the conical illumination light. Thereby, the area camera 113 can specify data indicating the intensity of the reflected light on the inner surface of the annular laser light or the conical illumination light. As a result of performing imaging with the area camera 113 every time the tubular body imaging device 100 travels a fixed distance inside the tubular body 1, the area camera 113 has a circumferential distribution of reflected light on the inner surface of the annular laser light, and a conical shape. The circumferential distribution of the reflected light on the inner surface of the illumination light can be specified.

  Here, as shown in FIGS. 2A and 2B, the irradiation area of the conical illumination light has a spread d. Therefore, if it is assumed that the annular laser light and the reflected light of the conical illumination light are simultaneously imaged at a certain timing, then the imaging of the reflected light of the conical illumination light may be performed while the annular laser light travels by the distance d. You do not have to. This is because the reflected light of the conical illumination light while the annular laser light travels by the distance d can use the reflected light of the conical illumination light imaged simultaneously with the annular laser light. Therefore, in the tubular body imaging device 100 according to the present embodiment, the reflected light of the conical illumination light may be imaged every time the reflected light of the annular laser light is imaged, or the reflected light of the annular laser light may be The reflected light of the conical illumination light may be imaged once during imaging of d lines (while the irradiation portion of the annular laser light advances by d). With the latter configuration, resources can be used more effectively, and processing can be further speeded up.

  Subsequently, the positional relationship between the annular laser light source 101, the conical illumination light source 107, and the area camera 113 will be described. In the tubular body imaging device 100 according to the present embodiment, as schematically shown in FIG. 2A, the irradiation position of the annular laser light on the inner surface of the tubular body 1 and the conical illumination on the inner surface of the tubular body 1 The annular laser light source 101 and the conical illumination light source 107 may be disposed such that the irradiation positions of the light are different from each other in the tube axis direction of the tubular body. Further, as schematically shown in FIG. 2B, the annular laser light source 101 and the conical shape are arranged so that the irradiation position of the annular laser light is included inside the irradiation region of the conical illumination light on the inner surface of the tubular body 1 The illumination light source 107 may be disposed.

In any of the cases shown in FIGS. 2A and 2B, the conical illumination light source 107 is disposed such that the conical illumination light is incident on the inner surface at an incident angle θ ₁ (θ ₁ <90 °). The area camera 113 is disposed so that specular reflection light of conical illumination light forms an image. That is, the area camera 113, the angle between the optical axis in the normal direction and the area camera 113 of the inner surface are disposed so as to be substantially equal to theta _1. At this time, the length in the tube axis direction of the inner surface irradiated with the conical illumination light is represented by d.

Here, the tubular body imaging apparatus 100, when a configuration as shown in FIG. 2A, the conical illumination light source 107, in addition to the above conditions, the incident angle theta ₁ is than the reflection angle theta ₂ of the annular laser beam Are also increased (ie, θ ₁ > θ ₂ is satisfied). Further, it is preferable that the irradiation portion of the annular laser light and the irradiation region of the conical illumination light be separated as much as possible in a range in which these irradiation regions are located within the same field of view of the area camera 113. By separating the irradiation portion of the annular laser light from the irradiation region of the conical illumination light, it is possible to suppress the decrease in S / N of the annular laser light that is caused by the conical illumination light becoming background light.

Further, when the tubular body imaging device 100 adopts the configuration as shown in FIG. 2B, in addition to the above conditions, the conical illumination light source 107 and the area camera 113 are arranged such that θ ₁ θθ ₂ holds. It will be set up.

  The wavelength of each illumination light emitted from the annular laser light source 101 and the conical illumination light source 107 is the wavelength of the annular laser light when the tubular imaging device 100 has the configuration as shown in FIG. 2A. The wavelength of the conical illumination light is not particularly limited, and the wavelength of the annular laser light may be equal to the wavelength of the conical illumination light. Because the irradiation position of the annular laser light and the irradiation position of the conical illumination light are set to be different in the field of view of the area camera 113, the imaging results of the reflected light of the two are easily distinguished. Is possible. In this case, although a color camera capable of color imaging may be used as the area camera 113, it is easier to use a monochrome camera.

  On the other hand, when the tubular body imaging device 100 adopts the configuration as shown in FIG. 2B, the annular laser light and the conical illumination light are imaged while being distinguished from each other by the area camera 113, and the respective reflected light intensities are In order to be separately identifiable, for example, the wavelength, the irradiation timing, or the polarization needs to be different from one another.

  When the wavelengths of the annular laser light and the conical illumination light are different, it is possible to separately measure the intensity of the annular laser light and the intensity of the conical illumination light by color filters having different transmission bands. Further, when the irradiation timings of the annular laser light and the conical illumination light are different, the timing when the respective illumination light irradiates the surface of the tubular body is divided in time, and one illumination light is irradiated on the inner surface. In this case, the other illumination light is not irradiated to the inner surface. Therefore, the intensity of the annular laser beam and the intensity of the conical illumination light can be calculated by separately treating the image captured at the timing of the annular laser beam irradiation and the image captured at the timing of the conical illumination light irradiation. It can be measured separately. Further, in order to make the polarizations of the annular laser light and the conical illumination light different from each other, polarizers orthogonal to each other in the polarization direction may be disposed on the optical axis of each light source. By arranging the analyzers orthogonal to each other also in the area camera 113, it is possible to separately measure the intensity of the annular laser light and the intensity of the conical illumination light.

  Moreover, when using visible light from which a wavelength mutually differs as annular laser beam and conical illumination light, the combination of the hue of annular laser beam and conical illumination light is (red, blue), (blue, green) It is preferable to combine a visible light source so as to be either (red or green). In addition, when using the light source which has a continuous spectrum as a visible light source, it is preferable to select the light source which the overlap of the light emission wavelength decreases. In this case, it is convenient and preferable to use a known color camera as the area camera 113. This makes it possible to simultaneously and independently measure the magnitudes of the red component, the green component, and the blue component contained in the reflected light of the annular laser light and the reflected light of the conical illumination light.

  In addition, red refers to the light of wavelength 600-700 nm, green refers to the light of wavelength 500-560 nm, and blue refers to the light of wavelength 430 nm-500 nm.

  FIG. 4 schematically shows an example of an inner surface image of a tube taken. The tube inner surface image generated by the tubular body imaging device 100 according to the present embodiment is a circular captured image as schematically shown in FIG. 4. Among these, in the central part of the image, there is a region where a part of the imaging device or the like is captured, and in the further outside of this region, the irradiation portion of the annular laser light and the irradiation region of the conical illumination light (z There is a region where the inner surface of the tubular body 1 is imaged, including an axial size d). Data of a region corresponding to the inner surface of the tubular body is used in the image processing apparatus 200 described later.

  The material of the connecting member 117 may be appropriately selected according to the strength required for the tubular imaging device 100 and the like. The number of connecting members 117 may be appropriately set according to the strength required for the tubular imaging device 100, and may be one or more.

  Depending on the thickness of the connecting member 117 (for example, the diameter of the tube in the case of a cylindrical connecting member 117), two types of illumination light and imaging field of view may be blocked by the connecting member 117. Therefore, the thickness of the connecting member 117 is such that the irradiation area in the circumferential direction of the illumination light is smaller than the area in the circumferential direction in which the illumination light and the imaging field of view are blocked by the connecting member 117 (hereinafter also referred to as a shielding area). Set to be wider.

  Here, in the case of providing a plurality of connecting members 117, for example, as shown in FIG. 3, they are arranged at equal intervals along the circumferential direction of the base 109 with respect to the inner edge portion of the annular base 109. Is preferred. Further, in the case where a plurality of connecting members 117 are installed, it is preferable to determine the number so that the shielding area is as narrow as possible.

  In addition, when the number of connection members 117 is one, for example, the connection members 117 may be installed at any one position among four connection members illustrated in FIG. 3.

  The tubular body imaging device 100 having such a configuration is preferably moved along the inner surface of the tubular body 1 while being axially moved by the drive control device 150 so as to substantially coincide with the central axis of the tubular body 1. And scan both at the time of delivery. Here, the arithmetic processing unit 200 described later outputs a trigger signal for imaging to the area camera 113 each time the tubular body imaging device 100 moves a predetermined distance in the axial direction. The movement distance in the axial direction of the annular laser light source 101, the conical illumination light source 107, and the area camera 113 can be set as appropriate, but for example, the imaging pixel size of the area camera 113 is preferably the same. By matching the movement interval in the axial direction with the imaging pixel size, it is possible to match the vertical resolution of the captured image with the horizontal resolution.

  In the case where the imaging processing is performed by the tubular body imaging device 100 both at the time of delivery and at the time of delivery, the drive control device 150 is configured to connect the connecting members when imaging of the tubular body surface at the time of delivery is completed by the tubular body imaging device 100 The tubular body imaging device 100 is rotated in the circumferential direction according to the number 117. The size of this rotation angle is such that, when considered on the basis of a reference line virtually set on the inner surface of the tubular body, the shielded area generated by the arrangement of the connecting member 117 is at different positions at the time of delivery and delivery. (In other words, the shielding area at the time of delivery and the shielding area at the time of delivery do not overlap). Specifically, when the number of connection members 117 is one, the drive control device 150 rotates the tubular body imaging device 100 by, for example, 180 degrees in the circumferential direction. Further, in the case where two connection members 117 are installed at equal intervals, the drive control device 150 rotates the tubular body imaging device 100 by, for example, 90 degrees in the circumferential direction, and three are installed at equal intervals. For example, it is rotated by 60 degrees in the circumferential direction. Further, as shown in FIG. 3, in the case where four connection members 117 are installed at equal intervals, the drive control device 150 rotates the tubular body imaging device 100 by, for example, 45 degrees in the circumferential direction.

  The specific configuration, setting values, and the like of the respective devices included in the tubular body imaging device 100 according to the present embodiment will be listed below. The configuration, setting values, and the like are merely examples, and the tubular imaging device 100 according to the present invention is not limited to the following specific examples.

場合 When the tubular body of interest is a steel pipe with an inner diameter of 100 mm to 500 mm and a length of 10 m to 20 m. ○ An annular laser light source A red laser diode (LD) light source and a mirror with a conical angle of 90 °. When a 100 mW red LD light source module is used, the intensity of the line beam functioning as the annular laser light is about 50 mW at the position of the inner surface.
○ Conical illumination light source An LED with a red or blue lens is circumferentially disposed, and has an outer diameter of 60 mm and an inner diameter of 40 mm. In addition, 20 LEDs were installed at an interval of 18 degrees.
○ Lens: focal length 1.81mm, horizontal angle of view 180 °
○ Area camera: Equipped with a CCD of 1024 bits × 1024 bits as an imaging device. The frame rate is 90 fps.
The inner surface of the tubular body is imaged once each time the tubular body imaging device 100 axially travels by 0.5 mm in length.

  In the above, the tubular body imaging device 100 according to the present embodiment has been described in detail with reference to FIGS. 2A to 4.

(About the whole configuration of the arithmetic processing unit 200)
Subsequently, referring back to FIG. 1 again, the overall configuration of the arithmetic processing unit 200 according to the present embodiment will be described.

  The arithmetic processing apparatus 200 according to the present embodiment mainly includes an imaging control unit 201, an image processing unit 203, a display control unit 205, and a storage unit 207, as shown in FIG. 1, for example.

  The imaging control unit 201 is realized by a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), a communication device, and the like. The imaging control unit 201 performs imaging control of the inspection object by the tubular body imaging device 100 according to the present embodiment. More specifically, when imaging of the tubular body 1 is started, the imaging control unit 201 transmits a control signal for the annular laser light source 101 and the conical illumination light source 107 of the tubular body imaging device 100 to emit illumination light. At the same time, the imaging start position is sent to the image processing unit 203.

  In addition, when the tubular body imaging device 100 starts imaging the tubular body 1, the PLG signal from the tubular body imaging device 100 is periodically (for example, one pulse of PLG signal every 0.5 mm of movement of the tubular body imaging device 100). However, the imaging control unit 201 transmits a trigger signal for starting imaging to the area camera 113 each time the PLG signal is acquired.

  Furthermore, the imaging control unit 201 further transmits a control signal for causing the drive control device 150 to move or rotate the tubular imaging device 100.

  The image processing unit 203 is realized by, for example, a CPU, a ROM, a RAM, a communication device, and the like. The image processing unit 203 generates two types of image frames to be described later, using imaging data acquired from the tubular body imaging device 100 (more specifically, the area camera 113 of the tubular body imaging device 100). Thereafter, image processing as described below is performed on the generated two types of image frames to detect defects that may exist on the inner surface of the tubular body that is the measurement object. When the defect detection process for the inner surface of the tubular body 1 is completed, the image processing unit 203 transmits information on the obtained detection result to the display control unit 205.

  Moreover, the shielding area | region resulting from the connection member 117 may exist as mentioned above in the image which the tubular body imaging device 100 which concerns on this embodiment imaged. Therefore, the image processing unit 203 according to the present embodiment interpolates the image generated from the inner surface image taken at the time of delivery using the image generated from the inner surface image taken at the time of delivery, and there is no shielded area. After generating the image, the defects present on the inner surface are detected.

  The detailed configuration of the image processing unit 203 and the image processing performed by the image processing unit 203 will be described again in detail below.

  The display control unit 205 is realized by, for example, a CPU, a ROM, a RAM, an output device, and the like. The display control unit 205 is provided outside the arithmetic processing unit 200 or an output device such as a display provided in the arithmetic processing unit 200 and the defect detection result of the tubular body 1 which is an inspection object transmitted from the image processing unit 203. Control the display when displaying on the output device etc. Thereby, the user of the defect detection apparatus 10 can grasp the detection results regarding various defects present on the inner surface of the inspection object (tubular body 1) on the spot.

  The storage unit 207 is realized by, for example, a RAM, a storage device, or the like included in the arithmetic processing unit 200 according to the present embodiment. In the storage unit 207, various parameters that need to be stored when the arithmetic processing unit 200 according to the present embodiment performs some processing, progress of processing, etc., various databases, programs, etc. It is recorded. In the storage unit 207, the imaging control unit 201, the image processing unit 203, the display control unit 205, and the like can freely read and write.

<About the image processing unit>
Subsequently, the image processing unit 203 provided in the arithmetic processing unit 200 according to the present embodiment will be described in detail with reference to FIGS.
FIG. 5 is a block diagram showing an example of the configuration of an image processing unit included in the arithmetic processing unit according to the present embodiment. 6A to 7B are explanatory diagrams for describing coordinate conversion processing in the arithmetic processing unit according to the present embodiment. FIGS. 8A and 8B are explanatory diagrams for describing a light-cut line image frame according to the present embodiment, and FIG. 8C is an explanatory diagram for describing a specular reflection image according to the present embodiment. FIG. 9A is an explanatory view showing a two-dimensional array of light cutting line displacements according to the embodiment, and FIG. 9B is an explanatory view showing a two-dimensional array of sums of luminances according to the embodiment; These are explanatory drawings showing a two-dimensional array of the number of pixels of the bright line according to the present embodiment. FIG. 10 to FIG. 16 are explanatory diagrams for describing a shielding area identification process in the arithmetic processing unit according to the present embodiment. FIG. 17 is an explanatory view showing the relationship between the displacement of the light sectioning line and the height of the defect, and FIG. 18 is an explanatory view for explaining the approximate correction process of the light sectioning line according to the present embodiment. FIG. 19 is an explanatory diagram for describing a shielded area interpolation process in the arithmetic processing unit according to the present embodiment. FIG. 20 is a block diagram showing an example of the configuration of a defect detection unit provided in the image processing unit according to the present embodiment. FIG. 21 is an explanatory view showing an example of a logic table used in the defect detection process according to the present embodiment.

  As shown in FIG. 5, the image processing unit 203 according to the present embodiment includes an A / D conversion unit 211, an annular beam center calculation unit 213, a coordinate conversion unit 215, and a light-cut image frame generation unit 217. The light section processing unit 219, the depth image calculation unit 221, the irregular reflection image calculation unit 223, the regular reflection image generation unit 225, the image interpolation unit 227, the defect detection unit 229, and the result output unit 231. Prepare mainly.

  The A / D conversion unit 211 is realized by, for example, a CPU, a ROM, a RAM, and the like. The A / D conversion unit 211 A / D converts the captured image output from the area camera 113, and outputs it as digital multilevel image data (that is, an inner surface image in the tube) as shown in FIG. The digital multilevel image data is stored in an image memory provided in the storage unit 207 or the like. By sequentially using these digital multilevel image data along the axial direction of the tubular body, a light cut image frame and a regular reflection image frame as described later are formed.

  As shown in FIG. 4, at a position along the axial direction of the inner surface of the tubular body 1, the surface image of the inside of the tube reflects the reflected light of the annular laser light and the conical illumination light applied to the inner surface of the tubular body It is an image. The tube surface image is such that the portion irradiated with the annular beam and the conical illumination light is displayed, for example, in white and the other portions are displayed in black, by appropriately setting the camera gain and the lens aperture in advance. It becomes a gray scale image.

  When the A / D conversion unit 211 generates an in-pipe surface image as schematically shown in FIG. 4 based on the captured image output from the area camera 113, data corresponding to the generated in-pipe surface image will be described later. Output to the annular beam center calculator 213.

  The annular beam center calculation unit 213 is realized by, for example, a CPU, a ROM, a RAM, and the like. The annular beam center calculation unit 213 calculates, for each of the in-pipe surface images output from the A / D conversion unit 211, the barycentric position and the radius of the ring corresponding to the annular beam.

  The method of calculating the center of gravity position and radius of the ring is not particularly limited, and any known method can be used. As a specific example of the method of calculating the barycentric position and radius of the ring, for example, when the shape of the annular beam in the in-pipe surface image is close to a perfect circle, the following two methods can be mentioned.

Extract arbitrary three points on the annular beam in the binarized tube surface image, and calculate the center of gravity of these three position coordinates. The distance between the obtained barycentric position and any one of the three points is the radius of the ring.
Perform circle extraction by Hough transform, and calculate the center of gravity and radius of the circle (that is, annular beam).

  After calculating the barycentric position and radius of the ring for each tube surface image, the annular beam center calculation unit 213 generates information on the barycentric position and radius of the ring and outputs the information to the coordinate conversion unit 215 described later.

  In addition, in this embodiment, although the case where the cross-sectional shape of the inner surface of the tubular body 1 is close to a perfect circle is described, the present invention is applicable to any cross-sectional shape. It may be rectangular or the like. The center of gravity in such a case can be determined from the shape of the annular beam, and by using the average value of the maximum value and the minimum value of the distances to the determined center of gravity as the radius, the coordinate transformation described later is performed in the same procedure. It can be implemented.

  The coordinate conversion unit 215 is realized by, for example, a CPU, a ROM, a RAM, and the like. The coordinate conversion unit 215 converts the coordinate system of the in-pipe surface image based on the calculated barycentric position and the separation distance between the barycentric position and the irradiation portion of the annular beam. Thereafter, the coordinate conversion unit 215 generates a light-cut image representing the irradiation portion of the annular beam as a line segment developed in the circumferential direction of the tubular body, and develops the irradiation region of the conical illumination light in the circumferential direction of the tubular body. Generate a regular reflection image.

  By calculating the barycentric position of the annular beam, the existing position of the pixel corresponding to the irradiation position of the annular beam can be represented by polar coordinates (r, θ) with the barycentric position as the origin. As shown in FIGS. 6A and 6B, the coordinate conversion unit 215 provides a predetermined margin in the radial direction with respect to the radius r calculated by the annular beam center calculation unit 213, and then 0 ° ≦ Ψ ≦≦. Coordinate transformation to Cartesian coordinates (r cos Ψ, r sin Ψ) is performed as 360 °.

At this time, when the tubular body imaging device 100 has a structure as shown in FIG. 2A, the irradiation position of the annular laser light and the conical illumination light in the inner surface image of the tube is the barycentric position (radius r With respect to the corresponding position), the positional relationship as shown in FIG. 6A is obtained. Therefore, as shown in FIG. 7A, the coordinate conversion unit 215 provides a margin of ± Δr in the radial direction with respect to the radius r calculated by the annular beam center calculation unit 213, and Coordinate transformation is performed in the range of r−Δr to r + Δr + d, 0 ° ≦ Ψ ≦ 360 °. At this time, the value of the margin Δr may be different between the plus direction and the minus direction within the range including the irradiation portion of the annular beam. In such a case, for example, the range in which coordinate conversion is performed can be expressed as r−Δr _{1 to} r + Δr ₂ or the like. However, in the present embodiment, the following description will be made on the case where the same value Δr is used in the positive direction and the negative direction.

  By performing such coordinate conversion, as shown on the right side of FIG. 7A, the annular laser light irradiated portion has a height of 2Δr around the radius r in the radial direction, and in the angular direction A strip-shaped image having a length of 360 ° is extracted, and for the conical illumination light irradiation area, a strip having a height of d in the radial direction and a length of 360 ° in the angular direction Images are extracted. As is apparent from the above description, the strip-like image extracted from the annular laser beam irradiation portion is a line segment in which the annular laser beam irradiation portion is expanded in the circumferential direction of the tubular body (hereinafter also referred to as light cutting line). Will be included. Also, by extracting the range of 2Δr around the radius r in the radial direction, even if the unevenness is present around the annular beam, it is possible to extract the circumference of the annular beam including the unevenness without loss. It becomes. The band-shaped image thus obtained is hereinafter referred to as a light cut image.

  Further, a strip-like image extracted from the conical illumination light irradiation area is an image regarding the reflected light of the conical illumination light formed on the area camera 113 so as to satisfy the regular reflection condition, and the specular reflection of the conical illumination light It is an image in which the luminance distribution of light is expanded in the circumferential direction of the tubular body. The strip-shaped image thus obtained is hereinafter referred to as a regular reflection developed image.

  In the case where the tubular body imaging device 100 has a structure as shown in FIG. 2A, the conical illumination light irradiation area and the annular laser light irradiation portion are separated in advance by the separation amount b + Δr. The light cut image frame generation unit 217 and the specular reflection image calculation unit 219 can easily separate the light cut image and the specular reflection developed image.

  In addition, the magnitude of Δr is roughly calculated in advance based on the past operation data and the like, in order to satisfy the separation amount b> 0, based on the past operation data and the like. It is possible to decide.

  On the other hand, when the tubular body imaging apparatus 100 has a structure as shown in FIG. 2B, the irradiation position of the annular laser light and the conical illumination light in the in-pipe surface image is shown in FIG. It has a positional relationship as shown in 6B. Therefore, as shown in FIG. 7B, the coordinate conversion unit 215 sets a margin of ± d / 2 in the radial direction with respect to the radius r calculated by the annular beam center calculation unit 213, and Coordinate transformation is carried out with 0 ° ≦ Ψ ≦ 360 ° in the range of r−d / 2 to r + d / 2 in the direction.

  By performing such coordinate conversion, as shown on the right side of FIG. 7B, a strip having a height d around the radius r in the radial direction and a length of 360 ° in the angular direction Images are extracted.

  When the tubular body imaging device 100 has a structure as shown in FIG. 2B, the conical illumination light irradiation area and the annular laser light irradiation portion overlap each other. However, in the case where the tubular body imaging device 100 has a structure as shown in FIG. 2B, the conical illumination light and the annular laser light are selected to be distinguishable from each other, and hence the light cutting described later The image frame generation unit 217 and the specular reflection image calculation unit 219 can easily separate the light section image and the specular reflection developed image.

  The in-pipe surface image imaged by the tubular-body imaging device 100 as described above will include a ring having a radius r corresponding to about 300 pixels. Therefore, if a light-cut image is extracted within the range of 0 ° ≦ Ψ ≦ 360 ° with r = 300 pixels and Δr = 25 pixels, a light-cut image of 2041 horizontal pixels × 50 pixels high is generated. Become. Further, assuming that d = 25 pixels, a specular reflection developed image of horizontal 2041 pixels × height 50 pixels is generated. The pixel size at this time is 0.5 mm wide × 0.5 mm long.

  As described above, the tubular-body imaging device 100 according to the present embodiment captures the irradiation area of the conical illumination light every time the reflected light of the annular laser beam is imaged (that is, the conical illumination light). Each time the annular laser light travels by d), the imaging area of the conical illumination light is imaged only once (ie, the conical illumination light is It may be made to irradiate only once) while advancing. Therefore, when performing the irradiation control of the conical illumination light source such as the latter, there is no irradiation region of the conical illumination light in the in-pipe surface image when the conical illumination light is not irradiated. Become. In that case, the coordinate conversion unit 215 may perform the above-described coordinate conversion process only on the irradiation portion of the annular laser light to generate a light-cut image.

  In addition, even when the conical illumination light is emitted each time, the above-described operation is performed only to 1 degree while the annular laser light travels by d only for both the illumination portion of the annular laser light and the illumination region of the conical illumination light. While performing the coordinate conversion process as described above, in other cases, the coordinate conversion process as described above may be performed only on the portion irradiated with the annular laser light.

  In addition, the coordinate conversion unit 215 uses the coordinates (r, Ψ) of each pixel in the extracted light section image and regular reflection expanded image to calculate the coordinates of the pixels included in the light section image and regular reflection expanded image. Convert to Cartesian coordinates (r cos Ψ, r sin Ψ). Here, since conversion of coordinate values performed by the coordinate conversion unit 215 is conversion from a polar coordinate system to an orthogonal coordinate system, grid points in the polar coordinate system (that is, center positions of pixels) must always be grids in the orthogonal coordinate system. Not only corresponding points but also corresponding non-lattice points exist. Therefore, in order to interpolate the density (pixel value) of the non-grid point in the orthogonal coordinate system, the coordinate conversion unit 215 interpolates based on the density of another grid point located in the vicinity of the point of interest. It is preferable to carry out the image interpolation method together.

  Such an image interpolation method is not particularly limited, and for example, it is possible to use a known image interpolation method described in “Shokyodo Image Processing Handbook” or the like. Examples of such an image interpolation method may include the nearest neighbor method, bi-linear interpolation method, bi-cubic convolution method, and the like. Among these methods, the former is faster and the latter is higher in quality. Therefore, the coordinate conversion unit 215 may appropriately determine the type of image interpolation method to be used according to the amount of resources that can be used for processing, the processing time, and the like.

  When the coordinate conversion unit 215 completes the coordinate conversion processing and the image interpolation processing as described above, the image data corresponding to the obtained light section image and the specular reflection developed image is stored in the image memory provided in the storage unit 207 or the like. , Sequentially store along the axial direction of the tubular body.

  The light-cut image frame generation unit 217 is realized by, for example, a CPU, a ROM, a RAM, and the like. The light-cut image frame generation unit 217 sequentially obtains light-cut images stored along the axial direction of the tubular body from an image memory provided in the storage unit 207 or the like. Thereafter, the light-cut image frame generation unit 217 sequentially arranges each of the obtained light-cut images along the axial direction of the tubular body to generate a light-cut image frame as schematically shown in FIG. 8A.

  The number of light sectioned images constituting one light sectioned image frame may be set as appropriate, but for example, one light sectioned image frame may be configured by 256 light sectioned images. Each light section image exists at every imaging interval (for example, 0.5 mm interval) of the annular beam image as described above. Therefore, one light-cut image frame consisting of 256 light-cut images, based on the in-pipe surface image taken at intervals of 0.5 mm, is 128 mm (== axially along the entire circumference of the inner surface of the tubular body). This corresponds to the result of imaging in the range of 256 × 0.5 mm).

  When the light-cut image frame generation unit 217 generates a light-cut image frame, the light-cut image frame generation unit 217 outputs the generated light-cut image frame to a light-cut line processing unit 221 described later. In addition, the light-cut image frame generation unit 217 associates the data corresponding to the generated light-cut image frame with time information on the date and time when the light-cut image frame is generated, and stores it in the storage unit 207 as history information. May be

  The light cutting line processing unit 219 is realized by, for example, a CPU, a ROM, a RAM, and the like. The light cutting line processing unit 219 calculates a light cutting line feature amount including the displacement amount of the light cutting line (the degree of bending of the bright line) for each light cutting line included in the light cutting image frame. Hereinafter, the processing performed by the light cutting line processing unit 221 and the light cutting line feature quantity calculated by the light cutting line processing unit 221 will be described in detail with reference to FIGS. 8A and 8B.

  In FIG. 8A, N light sectioning lines exist in one light sectioning image frame, and the horizontal length of the light sectioning image frame is M pixels. In addition, one light section image including one light section line is configured of vertical 2Δr pixels × horizontal M pixels.

Here, for convenience of explanation, the light cutting is performed by taking the X axis in the circumferential direction (horizontal direction in FIG. 8A) of the light cutting image frame and the Y axis in the axial direction (longitudinal direction in FIG. 8A) of the light cutting image frame. The position of the pixel in the image frame is represented by XY coordinates. In the following description, the position of the m-th pixel (1 ≦ m ≦ M) from the left side of the j (1 ≦ j ≦ N) light cutting line present in the light cutting image frame (ie, X _{j, m} Focus on the

When the light cutting line processing unit 219 first selects the X coordinate position (position represented by X _{j, m} in this description) to be focused on of the light section line to be focused on (hereinafter, also simply referred to as a line). As shown in FIG. 8B, the distribution of the pixel values (that is, the luminance values of the annular beam) associated with the pixels at the focused X coordinate position of the focused line is referred to. At this time, the light sectioning line processing unit 219 does not execute the processing described below for all the pixels at the X coordinate position in the light sectioned image, and the reference position Y _s of the Y coordinate in the light sectioned image. The process described below is performed on pixels belonging to the range of W before and after W (that is, pixels belonging to the range of Y _s −W to Y _s + W).

Here, the reference position Y _s of the Y coordinate is a position in the axial direction specified in advance with respect to the light-cut image of the j-th line of the light-cut image frame, for example, the center in the axial direction of the light-cut image For example, in the case where the same margin value Δr is used in the plus direction and the minus direction as described above, the radius r (that is, the position of the light cutting line) calculated by the annular beam center calculation unit 213 is equal. Further, the parameter W defining the processing range is the range of heights of the concavities and convexities that may exist in the tubular body 1 based on the past operation data etc., before and after W at the reference position Y _s of the Y coordinate in the light cut image. The range may be roughly calculated in advance so as to fall within the light cut image, and may be determined appropriately. If the value of the parameter W can be reduced, the processing load of the light cutting line processing unit 219 can be reduced.

Light section line unit 219, first, from among the pixels included in the range of Y _s -W~Y _s + _W, the first threshold value for specifying the pixels corresponding to the light section line given as an example A pixel having a pixel value equal to or greater than a threshold Th is identified. In the example shown in FIG. _{8B, Y j, k, Y} j, k + 1, Y j, k + 3 single pixel represented by _2, each threshold value Th or more pixel values _{I j, k, I j,} k + 1, I j _{, K + 2} . Therefore, the light section processing unit 219 sets the number p _{j, m} = 3 in which pixels having pixel values equal to or larger than the predetermined threshold Th are added in the line width direction. The number p _{j, m} obtained by adding pixels having pixel values equal to or more than the predetermined threshold value Th in the line width direction is a value corresponding to the number of pixels of the bright line at the position (j, m). one of. In addition, the light section processing unit 219 performs information (Y _{j, k 1} , I _{j, k} ), (Y _{j, k + 1} , I _{j, k + 1} ), (Y _{j, k + 2} ) on the extracted pixels in the following processing. , I _{j, k +2} (hereinafter, may be simply abbreviated as (Y, I)) to calculate further light-cut line feature quantities.

In addition, the light section line processing unit 219 calculates the total sum K _{j, m} of the luminance of the extracted pixel using the parameter p _{j, m} and the information (Y, I) on the extracted pixel. In the case of the example shown in FIG. 8B, the sum of the luminances calculated by the light cutting line processing unit 219 is K _{j, m} = I _{j, k} + I _{j, k + 1} + I _{j, k + 2} . The total sum K _{j, m of the} luminance is also one of the light cutting line feature quantities.

Furthermore, the light section line processing unit 219 uses the information (Y, I) on the extracted pixel and the reference position Y _{s of the} Y coordinate to set the barycentric position Y _C (j, of the extracted pixel in the Y direction). calculates a m), and calculates the center of gravity position _Y C (j, the amount of displacement from the reference position _{Y s} of _{m) Δd j, m = Y} s -Y C (j, m) the.

Here, assuming that the set of extracted pixels is represented by A, the barycentric position Y _C (j, m) has a value represented by the following Expression 101. Thus, in the example shown in FIG. 8B, the center of gravity position _Y C (j, m) is a value represented by the following formula 101a.

Here, the position in the axial direction corresponding to the pixel is a value quantized by the movement width (for example, 0.5 mm) of the tubular imaging device 100. On the other hand, since the barycentric position Y _C (j, m) calculated by the calculation as shown in the above equation 101 is a value calculated by using a numerical operation of division, the movement of the tubular body imaging device 100 It can be smaller than the width (in other words, the quantization unit). Therefore, the displacement amount Δd _{j, m} calculated using the barycentric position Y _C (j, m) is also a value that can have a value smaller than the movement width. The displacement amount Δd _{j, m} calculated in this manner is also one of the light cutting line feature amounts.

  The light sectioning line processing unit 219 calculates the three types of feature amounts as described above with respect to the M elements included in each sectioning line. As a result, as shown in FIGS. 9A to 9C, a two-dimensional array of M columns × N rows is generated with respect to the displacement amount Δd of the light sectioning line, the sum K of luminance, and the pixel number p of the bright line.

  Here, as shown in FIG. 2A and FIG. 2B, in the tubular body imaging device 100 according to the present embodiment, the pair of holding members 115 are connected to each other using the connecting members 117, so As schematically shown in FIG. 10, in the actual in-pipe surface image to be imaged, there may be a shielded area which is a dead zone in which reflected light of annular laser light and conical illumination light is shielded by the connecting member 117. There is sex. In addition, when the tubular body imaging device 100 is rotated by a predetermined angle in the circumferential direction of the tubular body (in FIG. 11, the tubular body imaging device 100 is rotated 45 degrees clockwise), the tubular body surface is switched. Focusing on a certain reference point, the position of the shielded area will be different at the time of delivery and at the time of delivery.

  Here, the coordinate conversion unit 215 described above is virtually set on the surface of the tubular body when performing conversion of the coordinate system in order to simplify the process of specifying the shielding area as described in detail below. It is preferable to perform conversion processing on the basis of the set reference point. The position of the reference point to be set on the surface of the tubular body is not particularly limited, and can be set to any position. For example, in the example shown in FIG. 11, the reference point K is set in the 3 o'clock direction when the tubular body surface is viewed in the delivery direction. The reference points K are selected so as to be at the same position among the in-pipe surface images captured at each position in the tube axis direction.

  When the coordinates of the reference point K are specified on the inside surface image of the pipe at the time of delivery, the position of the reference point K in the inside surface image of the pipe at the delivery rotates the coordinates of the reference point K at the time of delivery by a predetermined angle. It can be identified by That is, when the tubular body imaging device 100 is rotated by + X degrees when the clockwise direction is set as the positive direction at the time of delivery, the position of the reference point K at the time of delivery is rotated by -X degrees. It is possible to specify the position of the reference point K at.

  FIG. 12 schematically shows an inner surface image of a tube taken by the tubular body imaging device 100 at the time of delivery and at the time of delivery. In the case of the example shown in FIG. 12, the tubular body imaging device 100 is rotated by 45 degrees in the clockwise direction, and then the in-pipe surface image at the time of delivery is generated. Here, since the annular laser light source 101, the conical illumination light source 107, and the area camera 113 of the tubular body imaging device 100 are integrally formed, the area camera 113 also rotates according to the rotation of the tubular body imaging device 100. Become. Therefore, in the in-pipe surface image shown in FIG. 12, the reference point K rotates 45 degrees in the counterclockwise direction.

  For such a shielded area, it is preferable that the light cutting line processing unit 219 according to the present embodiment performs a process for specifying the shielded area described in detail below, in addition to the process described above. Hereinafter, the shielding area identification process performed by the light cutting line processing unit 219 will be described in detail with reference to FIGS. 13 to 16. That is, the light cutting line processing unit 219 according to the present embodiment also has a function as a shielding area specifying unit.

  As shown in FIGS. 13 and 14, the number of connecting members 117 provided in the tubular imaging device 100 in the light-cut image frames generated by the light-cut image frame generation unit 217 at the time of delivery and at the time of delivery. Depending on the situation, there will be a shielded area. Further, since the coordinate transformation is carried out with respect to the origin in the circumferential direction of each light-cut image frame with reference point K shared by coordinate transformation unit 215 as the origin, as shown in FIG. 13 and FIG. It becomes point K.

Here, since the reflected light of the annular laser light and the conical illumination light is not imaged by the area camera 113 in the shielded area by the connecting member 117, as schematically shown in FIG. 15, the luminance is higher than the predetermined threshold Th. There is no big bright line. Therefore, in the process of calculating the light cutting line feature amount, the light cutting line feature amount p _{j, m} for the number of pixels of the bright line becomes zero in the shielding region.

Therefore, the light cutting line processing unit 219 according to the present embodiment identifies circumferential direction coordinates (X coordinates) indicating the range of the shielding area, focusing on the number of pixels of the bright line at each circumferential direction (X direction) position. . In the following, the optical section image frame image, taking the case of calculating the starting position X _S1S and the end position X _S1e shielding region present in the first from the left, it will be referred to.

The light cutting line processing unit 219 sets the position X _{s1 js of the} X coordinate at which the shielding area starts and the X coordinate at which the shielding area ends for each of the N light cutting lines constituting the light cutting image frame at the time of transmission. The position X _s1je (j = 1 to N) is identified. Then, in consideration of the case where the start position and the end position of the shielding area are shifted due to the influence of the vibration generated in the tubular body imaging device 100, etc., among the N shielding area starting positions _{Xs1js specified} the minimum value with the _{X S1S} of the maximum value of the shielded area end position _{X S1je} and _{X S1e.}

The start position X _{s1 js} and the end position X _{s1 je} of the first shielding region from the left in the j-th line can be specified as follows. Hereinafter, a method of specifying the start position X _{s1 js} and the end position X _{s1 je} of the shielding area will be specifically described with reference to FIG.

The light cutting line processing unit 219 focuses on the number of pixels p _{j, m} (m = 1 to M) of the bright line at each X coordinate of the light cutting line at the j-th line. Then, the light cutting line processing unit 219 determines whether an X position where p _{j, m} = 0 appears for the number p _{j, m} of pixels of the bright line at each X position. When there is an X position where p _{j, m} = 0, the light cutting line processing unit 261 stores the coordinate X _m and continues the state in which p _{j, m} = 0 for the subsequent X coordinate Count the numbers. Here, as schematically shown in FIG. 16, when the number of consecutive states in which p _{j, m} = 0 becomes equal to or more than a predetermined threshold TH _s (for example, TH _s = 10 etc.), the light cutting is performed. The line processing unit 219 specifies the stored X coordinate X _m as the start position X _{s1 js} of the first shielding area from the left in the j-th line.

Further, it is _assumed that, while searching for the number of pixels of the bright line in the X direction, an X coordinate X _{n such} that p _{j, m}遮蔽 0 appears in a state where the start position X _{s1 js} of the shielding area is specified. . In this case, the light cutting line processing unit 219 stores the coordinate X _n and counts the number of consecutive states in which p _{j, m} ≠ 0 with respect to the subsequent X coordinate. Here, as schematically shown in FIG. 23, when the number of consecutive states in which p _{j, m} ≠ 0 becomes equal to or more than a predetermined threshold value TH _s (for example, TH _s = 10 etc.), the light cutting is performed. The line processing unit 219 specifies the X position one position before the stored X coordinate X _n as the end position X _{s1 je} of the first shielding area from the left in the j-th line. Here, the threshold value TH _s is an example of a third threshold value for determining the number of continuous lines and an example of a fourth threshold value for determining the number of continuous lines, and the third threshold value and the fourth threshold value are the same value. It corresponds to a case. In the above description has shown the case with the threshold value TH _s used to identify the start position of the shielding region, and the threshold value TH _s used to identify an end position of the shielding region is the same value These two thresholds may be different from each other.

It may also be as follows Another way to determine the starting position X _S1S and the end position X _S1e shielding region.
In each X coordinate of the light cutting line of the j-th line, while moving the coordinate position, k pieces (for example, k = 3 etc.) of predetermined left and right pixels of the number p _{j, m} (m = 1 to M) of pixels of the bright line The average value q _{j, m} (m = 1 to M) of the above is sequentially obtained (moving average processing). Next, an X-coordinate position at which the calculated average value q _{j, m} is less than a preset threshold A (for example, A = 0.5 or the like) is set as the start position _Xs1s of the shielding area. Further, an X coordinate position at which the start position X _{s1 s} of the shielding area is specified and the calculated average value q _{j, m} is equal to or _larger than the preset threshold A is taken as the end position X _{s1 e} of the shielding area. The threshold A is an example of a fifth threshold for moving average determination.

By performing the aforementioned processing for each light section lines j = 1 to N, the light section line processor 219, the starting position X _S1S and the end position X _S1e of the first shielding area from the left It can be decided. Moreover, the start position and the end position of the shielding area can be determined by performing the same processing for the second and subsequent shielding areas from the left.

Note that the light cutting line processing unit 219 sets the light cutting line feature amount Δd _{j, m} for the displacement amount of the light cutting line in the shielding region and the light cutting line feature amount K _{j, m} for the sum of the luminance in the shielding region. Each is treated as zero.

Therefore, for example, for the first shielding region from the left _, a two-dimensional array of the number p _{j, m} of pixels of the bright line _, a two-dimensional array of the sum K _{j, m} of luminance of the bright line, and a displacement amount Δd _{j, m} of the bright line Each two-dimensional array is as follows.

p _{j, m} = 0 (j = 1 to N, m = X _{s1 s} ,..., X _{s1 e} )
K _{j, m} = 0 (j = 1 to N, m = X _s1s ,..., X _s1e )
Δd _{j, m} = 0 (j = 1 to N, m = X _{s1 s} ,..., X _{s1 e} )

  The light cutting line processing unit 219 performs the above-described processing on the light-cut image frame at the time of feeding in which the four connection members 117 are captured, as illustrated in FIG. 13, for example. The start position and the end position of each of the four shielding areas can be identified.

The light cutting line processing unit 219 also calculates the light cutting line feature amount for the light cutting image frame at the time of delivery illustrated in FIG. 14. However, for the light-cut image frame at the time of delivery, the start position and the end position of the shielding area may not be specified. Here, when the X position where the pixel number p _{j, m} = 0 of the bright line appears in the light-cut image frame at the time of transmission, the light section processing unit 219 calculates the total sum K _{j, m} of the luminance at the corresponding X position, And, the displacement amount Δd _{j, m} of the bright line is treated as zero.

The light cutting line processing unit 219 outputs, to the depth image calculating unit 221 to be described later, a feature amount related to the displacement amount Δd of the light cutting line among the light cutting line feature amounts calculated as described above. Further, the light cutting line processing unit 219 outputs the sum K of the luminance and the feature amount related to the number p of pixels of the bright line among the calculated light cutting line feature amounts to the diffuse reflection image calculating unit 223 described later. Furthermore, the light sectioning line processing unit 219 may use information (for example, information representing _Xs1s to _Xs4e in FIG. 13) indicating the start position and the end position of each shielding area present in the light section image frame at the time of transmission. , And output to an image interpolation unit 227 described later.

  The depth image calculation unit 221 is realized by, for example, a CPU, a ROM, a RAM, and the like. The depth image calculation unit 221 is configured to generate the light cutting line feature amount (in particular, the feature amount related to the displacement amount Δd) at the time of delivery and at the time of delivery, which the light cutting line processing unit 219 generates. Two types of depth images representing the uneven state are respectively calculated.

Specifically, the depth image calculator 221 calculates the feature amount (two-dimensional array) related to the displacement amount Δd as shown in FIG. 9A and the vertical component incident angle of the annular beam (angle θ ₂ in FIGS. 2A and 2B). And) to calculate the depth image.

  First, with reference to FIG. 17, the relationship between the height of the unevenness present on the inner surface of the tubular body and the displacement amount Δd of the light cutting line will be described.

In FIG. 17, the case where a dent exists in the inner surface of the tubular body 1 is shown typically. Here, the difference between the height of the surface position when there is no dent on the inner surface and the height of the bottom of the dent is represented as Δh. Focusing on the case where the annular laser light vertically incident is surface-reflected, when there is no dent in the inner surface, the reflected light propagates like the light ray A in FIG. 17, but there is a dent in the inner surface. If it exists, the reflected light propagates as shown by a ray B in FIG. The deviation between the light ray A and the light ray B is observed as the displacement amount Δd of the light cutting line in the present embodiment. Here, as it is clear from the geometric positional relationship between the depth Delta] h of the recess and the displacement amount [Delta] d of the optical cutting line, the relationship of Δd = Δh · sinθ ₂ is established.

  Although FIG. 17 describes the case where the recess is present on the inner surface of the tubular body, the same relationship holds even if the protrusion is present on the inner surface of the tubular body.

  The depth image calculation unit 221 uses the above-described relationship to generate a tubular shape based on the feature amount related to the displacement amount Δd of the light cutting line at the time of delivery and at the time of delivery calculated by the light cutting line processing unit 219. The amount Δh of unevenness on the inner surface of the body is calculated.

  Here, the displacement amount Δd of the light cutting line used to calculate the depth image is calculated based on the barycentric position of the light cutting line as described above, and has a value smaller than the movement width. It is a possible value. Therefore, the depth image calculated by the depth image calculation unit 221 is an image in which the unevenness is reproduced with a resolution smaller than the pixel size of the imaging device.

Assuming that the light-cut image frame shown in the present embodiment is, for example, the displacement of light-cut lines imaged at a shooting pitch of 0.5 mm, if the respective displacement amounts Δd are converted to Δh, the width 0. A depth image of 5 mm × 0.5 mm in height is to be calculated. Further, assuming that the angle θ ₂ = 45 °, the relationship of Δd = (1/2 ^0.5 ) · Δh is established.

  Note that, as shown in FIG. 18, distortion such as bending occurs in the light cutting line due to the change of the shape of the inner surface of the tubular body which is the inspection object and the camera scanning direction axis shifting from the center of the tubular body. There is a case. On the other hand, in the defect detection method according to the present embodiment, the concavities and convexities overlapping the light cutting line are information on the cross-sectional shape of the inner surface of the tubular body and the surface defect present on the inner surface. Therefore, when calculating the depth image based on the displacement amount Δd of the light cutting line, the depth image calculation unit 221 performs distortion correction processing for each light cutting line, and the unevenness is superimposed on the light cutting line. You may extract only information about By carrying out such distortion correction processing, the camera scanning direction axis exists on the inner surface even if it does not exactly coincide with the central axis of the tubular body or the shape of the inner surface is not a circle. It becomes possible to obtain only the information on the uneven surface.

  As a specific example of the distortion correction process, (i) a process of performing a fitting process using a multidimensional function or various non-linear functions, and performing a difference operation of the obtained fitting curve and the observed light section line, ii) Using the fact that the information on unevenness is a high frequency component, it is possible to cite a process of applying a low pass filter such as a floating filter or a median filter. By carrying out such distortion correction processing, it becomes possible to achieve the flattening of the light sectioning line while holding the information of the unevenness wrinkles present on the inner surface.

  The depth image calculation unit 221 outputs the information on the depth image at the time of transmission and at the time of transmission, calculated as described above, to the image interpolation unit 227 described later. Also, the depth image calculation unit 221 stores the calculated information on the depth image at the time of transmission and at the time of transmission as history information in the storage unit 207 etc. May be Furthermore, the depth image calculation unit 221 may output information on the calculated depth image at the time of transmission and at the time of transmission to the display control unit 205, and may cause the display unit (not shown) to output the information.

  The diffuse reflection image calculation unit 223 is realized by, for example, a CPU, a ROM, a RAM, and the like. The irregular reflection image calculation unit 223 generates a tubular shape based on the light cutting line feature quantities (in particular, the total quantity of luminance K and the feature quantity related to the number p of pixels of bright lines) generated by the light cutting line processing unit 219 at the time of delivery and at delivery. A luminance image is calculated that represents the distribution of the luminance of the annular beam on the inner surface of the body. As apparent from FIGS. 2A and 2B, in the tubular body imaging device 100 according to the present embodiment, the diffusely reflected light of the annular laser light forms an image on the area camera 113. Therefore, the luminance image calculated as described above is hereinafter also referred to as a diffuse reflection image.

Specifically, the diffuse reflection image calculation unit 223 is configured to include the feature amount (two-dimensional array) related to the total sum K of luminance at the time of transmission and at the time of transmission as shown in FIG. 9B, and as shown in FIG. The average luminance K _AVE (average value of the line width direction of the total luminance at the time of transmission and at the time of transmission) using the feature quantities (two-dimensional array) regarding the number p of pixels of the bright line at the time of j, m) = _{Kj, m} / _{pj, m} (1 <j <N, 1 <m <M) are calculated. Thereafter, the diffuse reflection image calculation unit 225 sets two types of data arrays composed of the calculated average luminance K _AVE (j, m) as diffuse reflection images at the time of delivery and delivery of the tubular body in question.

  The irregular reflection image calculation unit 223 outputs the information on the irregular reflection image at the time of transmission and reception calculated as described above to the image interpolation unit 227 described later. In addition, the diffuse reflection image calculation unit 223 may store the calculated information on the diffuse reflection image at the time of transmission and at the time of transmission as the history information in the storage unit 207 or the like in association with the time information on the date and time etc. Good. Furthermore, the diffuse reflection image calculation unit 223 may output the calculated information on the diffuse reflection image at the time of transmission and reception to the display control unit 205 and output the information to the display unit (not shown).

  The specular reflection image generation unit 225 is realized by, for example, a CPU, a ROM, a RAM, and the like. The specular reflection image calculation unit 225 sequentially acquires specular reflection developed images stored along the axial direction of the tubular body from an image memory provided in the storage unit 207 or the like. At this time, the regular reflection developed image corresponding to the d-line arrangement of the light-cut image by the light-cut image frame generation unit 217 is a positive-cut image taken simultaneously with the light-cut image of the first line as mentioned earlier. It is possible to cope with one reflection developed image. Therefore, the specular reflection image calculation unit 225 acquires a specular reflection developed image for each d line, arranges each acquired specular reflection developed image in order along the axial direction of the tubular body, and is schematically shown in FIG. 8C. A regular specular image is generated for each of the infeed and outfeed.

  After generating the regular reflection image as described above, the regular reflection image generation unit 225 outputs the generated regular reflection image to an image interpolation unit 227 described later. In addition, the regular reflection image generation unit 225 may store the data corresponding to the generated regular reflection image in the storage unit 207 or the like as history information by associating time information regarding the date and time when the regular reflection image is generated. .

  The image interpolation unit 227 is realized by, for example, a CPU, a ROM, a RAM, and the like. The image complementation unit 227 performs interpolation processing of a portion corresponding to the shielding area in the depth image using the depth image at the time of transmission and reception calculated by the depth image calculation unit 221. Further, the image interpolation unit 227 performs interpolation processing of a portion corresponding to the shielding area in the diffuse reflection image by using the diffuse reflection images at the time of transmission and reception calculated by the diffuse reflection image calculation unit 223. Furthermore, the image interpolation unit 227 performs interpolation processing of a portion corresponding to the shielding area in the regular reflection image, using the regular reflection images at the time of transmission and at the time of transmission calculated by the regular reflection image generation unit 225.

  In the images at the time of transmission and at the time of transmission calculated by the depth image calculation unit 221, the irregular reflection image generation unit 223, and the regular reflection image generation unit 225, changes in pixel value occur in the portions corresponding to the shielded area by the connection member 117. It is a part that does not exist, and it is not possible to obtain an accurate knowledge of the state of the inner surface of the tubular body from this part. Therefore, the image interpolation unit 227 performs processing of interpolating the depth information and the luminance information corresponding to the shielded area by using the images at the time of transmission and the time of transmission.

  Hereinafter, with reference to FIG. 19, the interpolation processing of a portion corresponding to the shielding region which is present first from the left in the image at the time of transmission (depth image at transmission and irregular reflection image at transmission) will be concretely described. Explain to.

  In the tubular body imaging device 100 according to the present embodiment, the entire tubular body imaging device 100 is a predetermined one when switching from a state in which the in-pipe surface image at delivery is taken to a state in which the in-pipe surface image at delivery is picked up. Rotate by an angle. Further, in the tubular body imaging device 100, the thickness and the arrangement position of the connecting member 117 are determined such that the irradiation area of each illumination light is wider than the shielding area.

  For the setting as described above, in the defect detection apparatus 10 according to the present embodiment, as shown in the light-cut image frame of FIG. 13 and FIG. The position of will change. Further, as is clear from FIG. 14, since the irradiation area of each illumination light is wider than the shielding area, the shielding area in one light cut image frame (for example, the light cut image frame at the time of delivery) is the other light cut. It will be included in the unshielded area in the image frame (e.g. light cut image frame at the time of delivery).

  Therefore, as shown in, for example, FIG. 19, the image interpolation unit 227 according to the present embodiment interpolates the shielded area of the image at the time of transmission using the image at the time of transmission, and a portion corresponding to the shielded area Generate non-existent images (depth image, diffuse image and specular image).

FIG. 19 schematically illustrates the process of interpolating the first shielding area present from the left.
Feeding start position X _S1S and the end position X _S1e of the shielding area in an image of Nyutoki is identified by the light section line unit 219 is notified to the image interpolation unit 227. Therefore, the image interpolation unit 227 refers to the image at the time of delivery, and acquires information (depth information and luminance information) of a portion (X _{s1 s to} X _{s1 e} ) corresponding to the shielded area of the image at the time of delivery. The acquired information is substituted for the part corresponding to the shielded area of the image at the time of delivery.

  Here, as is clear from the operation of the tubular body imaging device 100, the Nth light cutting line in the light cutting image frame at the time of delivery and the first light cutting line in the light cutting image frame at the time of delivery are , Corresponds to the same tube axial position. Therefore, when interpolating the information corresponding to the first line of the image at the time of transmission, the image interpolation unit 227 performs the interpolation process using the image corresponding to the Nth line of the image at the time of transmission. . Similarly, when interpolating the information corresponding to the j-th line of the image at the time of transmission, the image interpolation unit 227 performs interpolation using the image corresponding to the (N + 1-j) -th line of the image at the time of transmission. Perform the process.

  The image interpolation unit 227 performs such interpolation processing on portions corresponding to the first line to the Nth line of the depth image and the diffuse reflection image, thereby making the first image from the left in the image at the time of transmission. It is possible to interpolate the information of the existing shielding area.

  In addition, the image interpolation unit 227 applies the same complementing process to the part corresponding to the shielding area existing from the left onwards to correspond to all the shielding areas existing in the image at the time of transmission. It is possible to interpolate part information.

  When the image interpolation unit 227 interpolates the information of the portion corresponding to the shielded area by the interpolation processing as described above, the image interpolation unit 227 outputs information on the depth image and the irregular reflection image after interpolation to the defect detection unit 229 described later.

  In addition, as for the regular reflection image, a shielding area similar to the depth image and the diffuse reflection image exists. On the other hand, the position of the shielding area in the specular reflection image is considered to be the same as the position of the shielding area in the depth image or the diffuse reflection image. Therefore, the image interpolation unit 227 outputs information indicating the start position and the end position of each shielding area present in the light-cut image frame at the time of transmission output from the light-cut line processing unit 219, and at the time of generated transmission And, using the regular reflection image at the time of transmission, interpolation processing of the regular reflection image is performed in the same manner as the depth image and the diffuse image.

  When the image interpolation unit 227 interpolates the luminance information of the portion corresponding to the shielded area by such interpolation processing, the image interpolation unit 227 outputs information on the regular reflection image after interpolation to the defect detection unit 229 described later.

  Further, the image interpolation unit 227 stores the information on the depth image after interpolation, the irregular reflection image, and the regular reflection image in the storage unit 207 or the like as history information in association with time information on the date and time when the information is calculated. It is also good. Furthermore, the image interpolation unit 227 may output information on the depth image after interpolation, the irregular reflection image, and the regular reflection image to the display control unit 205 and output the information to the display unit (not shown).

The defect detection unit 229 is realized by, for example, a CPU, a ROM, a RAM, and the like. The defect detection unit 229 detects the uneven wrinkles and the uneven wrinkles existing on the inner surface of the tubular body from the harmless dirt and the like based on the regular reflection image, the irregular reflection image and the depth image after the interpolation process, Do.
Hereinafter, the configuration of the defect detection unit 229 will be briefly described with reference to FIG.

  The defect detection unit 229 according to the present embodiment includes a binarization unit 241, a labeling unit 243, a feature quantity extraction unit 245, and a determination unit 247 as shown in FIG.

  The binarizing unit 241 is realized by a CPU, a ROM, a RAM, and the like. The binarization unit 241 refers to the generated regular reflection image, the irregular reflection image, and the depth image, and sets these data groups based on the predetermined threshold (binarization threshold) set for each image. And binarize. The binarization threshold value used for the binarization process is not particularly limited, and can be appropriately determined by analyzing past operation data and the like.

  When the binarization unit 241 generates binarized data of the above-described three types of image data groups, the binarization unit 241 outputs the generated binarized data to the labeling unit 243 described later.

  The labeling unit 243 is realized by, for example, a CPU, a ROM, a RAM, and the like. The labeling unit 243 refers to each of the three types of binarized data output from the binarization unit 241, and uses a well-known image processing technique to select surface defect candidate regions for each of the three types of binarized data. Extract from The candidate region of the surface defect corresponds to a portion of the binarized data output from the binarizing unit 241, in which the pixel value (data value) is "1". The labeling unit 243 can also combine known image processing techniques such as filter processing, edge extraction, edge tracking and the like when extracting candidate regions of surface defects.

  Next, the labeling unit 243 assigns label numbers which are the same as label numbers in the area and do not overlap other areas with respect to each of the areas in which the portion where the pixel value is “1” is continuous. We will give in order. As a result, identification information for identifying these candidate areas is provided to the extracted candidate area of surface defect.

  The feature amount extraction unit 245 is realized by, for example, a CPU, a ROM, a RAM, and the like. The feature amount extraction unit 245 determines the width, length, area (size), circularity, straightness, rectangularity, brightness, and the like of each candidate region in the three types of binarized images extracted by the labeling unit 243. It extracts known feature quantities that characterize surface defects, such as contrast and edge strength. When the feature amount extraction unit 245 extracts the feature amount for each candidate region in the three types of binarized images extracted by the labeling unit 243, the feature amount extraction unit 245 determines the extracted feature amount after associating it with the label number of the candidate region. Output to the unit 247.

  The determination unit 247 is realized by, for example, a CPU, a ROM, a RAM, and the like. The determination unit 247 refers to a database or the like as shown in FIG. 21 in which the correspondence relationship between the type of surface defect and the feature amount is stored in advance in the storage unit 207, and the candidate region of the surface defect is a surface defect. Determine if applicable. At this time, the determination unit 247 performs determination by focusing on the degree of coincidence between the feature amount stored in the database or the like and the feature amount extracted by the feature amount extraction unit 245. If the calculated matching degree is equal to or higher than a predetermined threshold value, the determining unit 247 determines that there is a type of surface defect whose matching degree is equal to or higher than the predetermined threshold value in the surface defect candidate area of interest. . Further, when the candidate region of the surface defect of interest does not correspond to any type of surface defect, it is determined that the candidate region of the surface defect of interest is not a surface defect.

  Here, in regular reflection illumination using conical illumination light according to the present embodiment, when the surface roughness is small (when it is close to a mirror surface), the specular reflection component is increased and the brightness is increased, and the ring according to the present embodiment In diffuse reflection illumination using a laser beam, when the surface roughness is large, the scattered component increases and the luminance becomes high. In the case of the treading rod without unevenness according to the present embodiment, since the surface of the treaded part is leveled and the roughness is small, the luminance is observed high (white light) in the regular reflection image. On the other hand, if the diffuse reflection image is merely obtained as in the prior art, such a stomp is only imaged a little black, so it can not be distinguished from the over-detection factor that is imaged black such as dirt. Therefore, by combining and using both the specular reflection image and the diffuse reflection image in a complementary manner, it becomes possible to sort and detect three types of surface properties as follows.

Stump marks: observed white in regular reflection image, black observed or not changed in irregular reflection image Stain / pattern: observed black or not observed in regular reflection image. It is observed black in the diffuse reflection image.

  As a result, it is possible to detect the flailing treads of the lid from the depth image, and the lidded treads without unevenness can be detected from the combination of the regular reflection image and the diffuse reflectance image. Further, fine rubs and the like hardly causing a change in luminance in the diffuse reflection image can also be similarly detected because the edge portion of the rub is linearly lightened and imaged in the regular reflection image.

  Here, the format of the database as shown in FIG. 21 showing the correspondence between the type of surface defect and the feature amount is not particularly limited. For example, the type of the surface defect and the feature amount are items It is also possible to use a logic table or the like in the form of a look-up table in which the discrimination condition formula is described in each cell of the table defined by the type of defect and the feature amount. Such a logic table is a known method using a database constructed by a learning process in which teacher data is used to identify past operation data and the type and severity of defects identified by the inspector based on the operation data. It is possible to generate.

  By performing such processing, the determination unit 247 can detect various surface defects present on the inner surface of the tubular body, and can specify the degree of harmfulness of each detected surface defect.

  In the above description, the case of determining the type and the harmfulness of the defect using the matching degree of the feature amount and the logic table has been described, but the method of judging the type and the harmfulness of the defect is limited to the above example It does not mean that For example, a classifier such as a neural network or a support vector machine (SVM) is generated by learning processing using teacher data as past operation data and identification results of defect types and harmfulness by a tester based on the operation data. Such a discriminator may be used to determine the type of defect or the degree of harmfulness.

  When the determination unit 247 detects various surface defects present on the inner surface of the tubular body as described above, the determination unit 247 outputs the obtained detection result to the result output unit 231.

  The result output unit 231 is realized by, for example, a CPU, a ROM, a RAM, and the like. The result output unit 231 outputs the information on the detection result of the surface defect output from the determination unit 247 to the display control unit 205. As a result, information on surface defects present on the inner surface of the tubular body is output to the display unit (not shown). In addition, the result output unit 231 may output the obtained detection result to an external device such as a manufacturing control procon, or the defect report of the product may be created using the obtained detection result. Good. In addition, the result output unit 231 may store information on the detection result of the surface defect in the storage unit 207 or the like as history information in association with time information on the date and time when the information is calculated.

  Heretofore, the configuration of the image processing unit 203 included in the arithmetic processing device 200 according to the present embodiment has been described in detail.

  Heretofore, an example of the function of the arithmetic processing unit 200 according to the present embodiment has been shown. Each component described above may be configured using a general-purpose member or circuit, or may be configured by hardware specialized for the function of each component. Further, all functions of each component may be performed by a CPU or the like. Therefore, it is possible to change the configuration to be used as appropriate according to the technical level at which the present embodiment is implemented.

  In addition, it is possible to create a computer program for realizing each function of the arithmetic processing unit according to the present embodiment as described above, and to install it on a personal computer or the like. In addition, a computer readable recording medium in which such a computer program is stored can be provided. The recording medium is, for example, a magnetic disk, an optical disk, a magneto-optical disk, a flash memory or the like. In addition, the above computer program may be distributed via, for example, a network without using a recording medium.

(About the defect detection method)
Subsequently, the flow of the defect detection method according to the present embodiment will be briefly described with reference to FIG. FIG. 22 is a flow chart showing an example of the flow of a defect detection method according to this embodiment.

  First, the tubular body imaging device 100 of the defect detection device 10 transmits and receives a probe using the annular laser light emitted from the annular laser light source 101 and the conical illumination light emitted from the conical illumination light source 107. The inner surface of the tubular body is imaged at the time of delivery, and two types of captured images (in-tube surface image) at the time of probe delivery and at the time of probe delivery are generated. Output. The A / D conversion unit 211 of the image processing unit 203 included in the arithmetic processing unit 200 performs A / D conversion processing on the acquired two types of captured images, and the tube surface image at the time of delivery and the tube surface at the time of delivery Images are generated respectively (step S101).

  Next, the annular beam center calculation unit 213 calculates the barycentric position and radius of each tube inner surface image using the tube inner surface images generated by the A / D converter 211 at the time of delivery and at the time of delivery (step S103). ), And outputs the obtained calculation result to the coordinate conversion unit 215.

  Subsequently, the coordinate conversion unit 215 performs coordinate conversion of the in-pipe surface image at the time of delivery and the in-pipe surface image at the time of delivery using the calculated barycentric position and radius, etc. Are generated (step S105). At this time, the coordinate conversion unit 215 performs coordinate conversion processing on the basis of the reference point K. This unifies the origin of the position coordinate of the circumferential direction of each light cutting line in the light cutting line image frame and the regular reflection image generated at the post stage and at the time of transmission and generates the light cutting image and the regular reflection development. It becomes possible to unify the origin of the position coordinate in the circumferential direction with the image. The generated light section image and the specular reflection developed image are sequentially stored in an image memory provided in the storage unit 207 or the like along the axial direction of the tubular body.

  Thereafter, the light-cut image frame generation unit 217 sequentially arranges the generated light-cut images along the axial direction of the tubular body to generate light-cut image frames at the time of delivery and at the time of delivery (step S107). . The light-cut image frame generation unit 217 outputs the generated light-cut image frames at the time of delivery and at the time of delivery to the light-cutting line processing unit 219.

  On the other hand, the regular reflection image generation unit 225 arranges the generated regular reflection development images in order along the axial direction of the tubular body, and generates regular reflection images at the time of delivery and at the time of delivery (step S109). The regular reflection image generation unit 225 outputs the generated regular reflection images at the time of transmission and at the time of transmission to the image interpolation unit 227.

  The light cutting line processing unit 219 uses the generated light cutting image frames at the time of transmission and at the time of transmission, and for each light cutting line, the number of pixels having a luminance equal to or greater than a threshold, the sum of the luminances of the pixels, The displacement amount of the light cutting line is calculated (step S111). These calculation results are used as light cutting line feature quantities. The calculated light section line feature amount is output to the depth image calculating unit 221 and the diffuse reflection image calculating unit 223, respectively.

  In addition, the light cutting line processing unit 219 specifies the position of the shielding area (that is, the start position and the end position of the shielding area) of the light sectioning image frame at the time of delivery, in addition to the calculation of the light cutting line feature amount. (Step S113). Thereafter, the light cutting line processing unit 219 outputs information on the position of the identified shielding area to the image interpolation unit 227.

  The depth image calculation unit 221 uses the calculated light section line feature amount (in particular, the feature amount related to the displacement amount of the light section line) to respectively transmit the depth image at the time of delivery and the depth image at the time of delivery. In addition to the calculation, the diffuse reflection image calculation unit 223 uses the calculated light cutting line feature amount (in particular, the feature amount related to the number of pixels of the pixels having the luminance equal to or higher than the threshold and the feature amount related to the sum of the luminance). The irregular reflection image at the time of transmission and the irregular reflection image at the time of transmission are calculated (step S115). The depth image calculation unit 221 outputs the calculated depth image at the time of transmission and the calculated depth image at the time of transmission to the image interpolation unit 227. Further, the diffuse reflection image calculation unit 265 outputs the calculated diffuse reflection image at the time of transmission and the diffuse reflection image at the time of transmission to the image interpolation unit 227.

  Next, the image interpolation unit 227 generates the information on the position of the shielded area notified from the light cutting line processing unit 219 and the depth image calculation unit 221, the irregular reflection image calculation unit 223, and the regular reflection image generation unit 225. Interpolation processing of each image at the time of transmission is performed using each image at the time of transmission (step S117). Thereafter, the image interpolation unit 227 outputs each image after complementation to the defect detection unit 229.

  Subsequently, the defect detection unit 229 detects a defect site existing on the inner surface of the tubular body using the depth image, the regular reflection image and the irregular reflection image after complementation, and the type of defect of the detected defect site, The harmfulness level is identified (step S119). By the flow as described above, a defect present on the inner surface of the tubular body is detected.

Hereinabove, the defect detection apparatus and the defect detection method according to the embodiment of the present invention have been described in detail.
According to the defect detection apparatus and the defect detection method according to the embodiment of the present invention, in the simple apparatus configuration, the inner surface of the tubular body extends in the circumferential direction all around the entire length and in addition to the wrinkles of the minute uneven shape It can be detected with high accuracy and at the same time while distinguishing wrinkles and fine abrasions with different surface roughness, from over-inspection factors such as background pattern and dirt, and accurately grasp the occurrence position of wrinkles be able to. Furthermore, since the inspection can be easily and quickly carried out during the process of manufacturing the tubular body, it can greatly contribute to the productivity of the manufacturing of the tubular body, the improvement of the yield, and the quality assurance of the tubular body.

(About hardware configuration)
Next, the hardware configuration of the arithmetic processing unit 200 according to the embodiment of the present invention will be described in detail with reference to FIG. FIG. 23 is a block diagram for explaining the hardware configuration of the arithmetic processing unit 200 according to the embodiment of the present invention.

  The arithmetic processing unit 200 mainly includes a CPU 901, a ROM 903 and a RAM 905. The arithmetic processing unit 200 further includes a bus 907, an input unit 909, an output unit 911, a storage unit 913, a drive 915, a connection port 917, and a communication unit 919.

  The CPU 901 functions as an arithmetic processing unit and a control unit, and controls all or part of the operation in the arithmetic processing unit 200 in accordance with various programs recorded in the ROM 903, the RAM 905, the storage unit 913, or the removable recording medium 921. The ROM 903 stores programs used by the CPU 901, calculation parameters, and the like. The RAM 905 primarily stores programs used by the CPU 901, parameters that appropriately change in the execution of the programs, and the like. These are mutually connected by a bus 907 constituted by an internal bus such as a CPU bus.

  The bus 907 is connected to an external bus such as a peripheral component interconnect / interface (PCI) bus via a bridge.

  The input device 909 is an operation unit operated by the user, such as a mouse, a keyboard, a touch panel, a button, a switch, and a lever. The input device 909 may be, for example, a remote control unit (so-called remote control) using infrared rays or other radio waves, or an external connection device 923 such as a PDA corresponding to the operation of the processing unit 200. May be Furthermore, the input device 909 is configured of, for example, an input control circuit that generates an input signal based on the information input by the user using the above-described operation means, and outputs the generated input signal to the CPU 901. By operating the input device 909, the user of the defect detection apparatus 10 can input various data to the arithmetic processing unit 200 and instruct processing operations.

  The output device 911 is configured of a device capable of visually or aurally notifying the user of the acquired information. Such devices include display devices such as CRT display devices, liquid crystal display devices, plasma display devices, EL display devices and lamps, audio output devices such as speakers and headphones, printer devices, mobile phones, facsimiles and the like. The output device 911 outputs, for example, results obtained by various processes performed by the arithmetic processing device 200. Specifically, the display device displays the results obtained by the various processes performed by the arithmetic processing device 200 as text or an image. On the other hand, the audio output device converts an audio signal composed of reproduced audio data, acoustic data and the like into an analog signal and outputs it.

  The storage device 913 is a device for data storage configured as an example of a storage unit of the arithmetic processing unit 200. The storage device 913 includes, for example, a magnetic storage unit device such as a hard disk drive (HDD), a semiconductor storage device, an optical storage device, or a magneto-optical storage device. The storage device 913 stores programs executed by the CPU 901, various data, various data acquired from the outside, and the like.

  The drive 915 is a reader / writer for a recording medium, and is built in or externally attached to the arithmetic processing unit 200. The drive 915 reads out information recorded in a removable recording medium 921 such as a mounted magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory, and outputs the information to the RAM 905. The drive 915 can also write a record on a removable recording medium 921 such as a mounted magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory. The removable recording medium 921 is, for example, a CD medium, a DVD medium, a Blu-ray (registered trademark) medium, or the like. Further, the removable recording medium 921 may be Compact Flash (registered trademark) (Compact Flash: CF), a flash memory, an SD memory card (Secure Digital memory card), or the like. Further, the removable recording medium 921 may be, for example, an IC card (Integrated Circuit card) equipped with a noncontact IC chip, an electronic device, or the like.

  The connection port 917 is a port for directly connecting a device to the arithmetic processing unit 200. Examples of the connection port 917 include a universal serial bus (USB) port, an IEEE 1394 port, a small computer system interface (SCSI) port, and an RS-232C port. By connecting the external connection device 923 to the connection port 917, the arithmetic processing unit 200 directly acquires various data from the external connection device 923 or provides various data to the external connection device 923.

  The communication device 919 is, for example, a communication interface configured of a communication device or the like for connecting to the communication network 925. The communication device 919 is, for example, a communication card for wired or wireless Local Area Network (LAN), Bluetooth (registered trademark), or WUSB (Wireless USB). In addition, the communication device 919 may be a router for optical communication, a router for asymmetric digital subscriber line (ADSL), a modem for various types of communication, or the like. The communication device 919 can transmit and receive signals and the like according to a predetermined protocol such as TCP / IP, for example, with the Internet or another communication device. The communication network 925 connected to the communication device 919 is configured by a network or the like connected by wire or wireless, and is, for example, the Internet, a home LAN, an in-house LAN, infrared communication, radio wave communication or satellite communication. May be

  Heretofore, an example of the hardware configuration capable of realizing the function of the arithmetic processing unit 200 according to the embodiment of the present invention has been shown. Each of the components described above may be configured using a general-purpose member, or may be configured by hardware specialized for the function of each component. Therefore, it is possible to change the hardware configuration to be used as appropriate according to the technical level of the time of carrying out the present embodiment.

  Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited to such examples. It is obvious that those skilled in the art to which the present invention belongs can conceive of various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also fall within the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 10 Defect detection apparatus 100 Tubular body imaging device 101 Annular laser light source 103 Laser light source 105 Conical optical element 107 Conical illumination light source 109 Base 111 Light emitting element 113 Area camera 115 Holding member 117 Connection member 150 Drive control device 200 Arithmetic processing device 201 imaging control unit 203 image processing unit 205 display control unit 209 storage unit 211 A / D conversion unit 213 annular beam center calculation unit 215 coordinate conversion unit 217 light-cut image frame generation unit 219 light-cut line processing unit 221 depth image calculation unit 223 irregular reflection image calculation unit 225 regular reflection image generation unit 227 image interpolation unit 229 defect detection unit 231 result output unit

Claims (14)

While moving along the axial direction of the tubular body, annular laser light and conical illumination light are respectively irradiated to the entire circumferential direction of the inner surface of the tubular body, and the annular laser light and conical light By imaging the inner surface irradiated with illumination light, a plurality of tube inner surface images, which are captured images of the annular laser light and conical illumination light on the inner surface, are generated along the axial direction of the tubular body A tubular body imaging device
An arithmetic processing unit that performs image processing on the in-pipe surface image generated by the tubular body imaging device to determine whether a defect is present on the inner surface of the tubular body;
Equipped with
The tubular body imaging device is
An annular laser light source that irradiates the annular laser beam in the entire circumferential direction of the inner surface of the tubular body;
A conical illumination light source for illuminating the conical illumination light in the circumferential direction of the inner surface of the tubular body;
The inner surface irradiated with the annular laser light and the conical illumination light is imaged such that the irradiation portion of the annular laser light and the irradiation area of the conical illumination light fall within the same field of view Area camera,
Have
In the area camera, specular reflection light of the conical illumination light from the conical illumination light irradiation area forms an image, and irregular reflection of the annular laser light from the annular laser light irradiation portion It is disposed opposite to the annular laser light source and the conical illumination light source so that light is imaged.
The arithmetic processing unit
An annular beam center calculation unit configured to calculate the position of the center of gravity and the radius of the portion irradiated with the annular laser beam in each of the in-pipe surface images;
The inside of the tube based on the calculated barycentric position, the separation amount between the barycentric position and the portion irradiated with the annular laser light, and the separation amount between the barycentric position and the irradiation region of the conical illumination light. A light sectioning line image which is a band-like area including a light sectioning line which is a line segment in which a coordinate system of a surface image is transformed and a portion irradiated with each of the annular laser light is expanded in a circumferential direction of the tubular body A coordinate conversion unit that generates a plurality of specular reflection developed images, which are band-like regions obtained by expanding the irradiation region of the conical illumination light in the circumferential direction of the tubular body;
And a depth image calculation unit for calculating a depth image representing a concavo-convex body on the inner surface of the tubular body based on the light section line image frame in which the light section line images are sequentially arranged along the axial direction; ,
A diffuse reflection image calculating unit that calculates a diffuse reflection image representing a distribution of luminance of the annular laser light on the inner surface of the tubular body based on the light cutting line image frame;
A specular reflection image generation unit that arranges the specular reflection developed images in order along the axial direction to generate a specular reflection image representing the distribution of the luminance of the conical illumination light on the inner surface of the tubular body;
A defect detection unit that detects a defect present in the tubular body based on the calculated depth image, the diffuse reflection image, and the regular reflection image;
And a defect detection device.   The depth image calculation unit calculates a barycentric position of the light cutting line in the line width direction along the circumferential direction, and the radius is a position in an axial direction previously designated with respect to the light cutting line image. The defect detection apparatus according to claim 1, wherein the depth image is calculated based on a displacement amount between the reference position and the barycentric position as the reference position.   The irregular reflection image calculation unit may set, for each of the light cutting lines, a pixel having a luminance value equal to or greater than a first threshold for specifying a pixel corresponding to the light cutting line at each position in the circumferential direction. The irregular reflection image is calculated based on the number of pixels added in the width direction and the total luminance of pixels having luminance values equal to or greater than the first threshold, and the average value of the total luminance in the line width direction. The defect detection apparatus according to claim 1 or 2.   The said annular laser light source and the said conical illumination light source are arrange | positioned so that the irradiation part of the said annular laser beam and the irradiation area | region of the said conical illumination light may not mutually overlap. The defect detection device according to any one of the above. The annular laser light source and the conical illumination light source are disposed such that the irradiation portion of the annular laser light and the illumination area of the conical illumination light overlap each other.
The annular laser light and the conical illumination light have different wavelengths, irradiation timings, or polarizations from each other.
The area camera according to any one of claims 1 to 3, wherein the reflected light from the portion irradiated with the annular laser light and the reflected light from the irradiated region of the conical illumination light are distinguished from each other and imaged. The defect detection apparatus as described in a term. The area camera is a color camera capable of color imaging,
In the annular laser light source and the conical illumination light source, a combination of the annular laser light and the conical illumination light is (red / blue), (blue / green) or (red / green) The defect detection device according to claim 5, wherein the light sources are different from each other in wavelength. The illumination area of the conical illumination light has a length d in the axial direction on the inner surface of the tubular body,
The defect detection device according to any one of claims 1 to 6, wherein the conical illumination light irradiation area is imaged only once while the annular laser light travels in the axial direction by d.   The coordinate conversion unit is configured to convert the luminance value of each pixel of the light section image and the luminance value of each pixel of the specular reflection developed image at each position of the corresponding in-pipe surface image when converting the coordinate system. The defect detection device according to any one of claims 1 to 7, which is calculated by image interpolation processing from the luminance value of the neighboring pixel. The defect detection unit
The defect area is determined based on whether the pixel values of the depth image, the diffuse reflection image and the regular reflection image are equal to or greater than a second threshold for defect area identification set for each of the images. Identify
Extracting feature amount information on the form and pixel value of the defect site for the identified defect site;
The defect detection device according to any one of claims 1 to 8, wherein a defect present on the inner surface of the tubular body is determined based on the extracted feature amount information. The tubular body imaging device is
The annular laser light source, the conical illumination light source, and the area camera are further provided with one or more connecting members that connect and fix the light source.
When the tubular body imaging device is fed into the interior of the tubular body and when the tubular body imaging device is delivered from the inside of the tubular body, the annular laser light and The in-tube surface image at the time of delivery is generated between the delivery and the delivery of the tubular body imaging device, while generating the in-tube surface image including a shielded area generated by blocking the conical illumination light. Rotating the tubular body imaging device so that the shielded area of the tube and the shielded area of the tube surface image at the time of delivery do not overlap;
The arithmetic processing unit
A shielded area specifying unit which specifies the position of the shielded area in the light sectioned line image and the regular reflection developed image using the light sectioned line image at the time of delivery or the light sectioned line image at the time of delivery;
The shielded area in the depth image, the diffuse reflection image and the regular reflection image generated based on the in-pipe surface image at the time of delivery or at the time of delivery is generated based on the in-pipe surface image at the time of delivery or at the time of delivery An image interpolation unit that interpolates using the depth image, the diffuse reflection image, and the regular reflection image;
And have
The coordinate conversion unit respectively converts the coordinate system of the tube surface image at the time of delivery and at the time of delivery using a predetermined position on the inner surface of the tubular body as a reference point, and a plurality of the light cutting line images at the time of delivery The defect detection device according to any one of claims 1 to 9, wherein the specular reflection developed image, and a plurality of the light section line images and the specular reflection developed image at the time of delivery are generated. The shielding area specifying unit
For each of the light cutting lines, the number of bright line pixels, which is the number obtained by adding in the line width direction pixels having luminance values equal to or more than the first threshold value, is specified for each circumferential position.
The defect detection device according to claim 10, wherein a circumferential position of the shielding area is specified by the number of bright line pixels. The shielding area specifying unit
The position in the circumferential direction in which the number of bright line pixels becomes zero is stored, and the number of consecutive bright line pixels in the state in which the number of bright line pixels becomes zero is counted at subsequent positions in the circumferential direction, and the number of bright line pixels becomes zero. When the number of consecutive states becomes equal to or more than a third threshold for determining the number of consecutive states, the stored position in the circumferential direction is set as the start position of the shielding area,
When the start position of the shielding area is specified and the number of bright line pixels at the focused circumferential position is not zero, the number of bright line pixels at the subsequent circumferential position is not zero The position in the circumferential direction is stored, and the number of consecutive lines in which the number of bright line pixels is not zero is counted, and the number of consecutive lines in which the number of bright line pixels is not zero is equal to or greater than a fourth threshold for determining the number of consecutive lines. 12. The defect detection device according to claim 11, wherein, when having become, the stored position in the circumferential direction is a position where the shielding area ends and a non-shielding area starts anew. The shielding area specifying unit
A moving average of the number of bright line pixels is calculated for each of the light cutting lines at each position in the circumferential direction,
The circumferential position at which the moving average is less than a fifth threshold for moving average determination is set as the start position of the shielding area,
The defect detection according to claim 11, wherein the circumferential position at which the start position of the shielding area is specified and the moving average is equal to or more than the fifth threshold is the end position of the shielding area. apparatus. While moving along the axial direction of the tubular body, annular laser light and conical illumination light are respectively irradiated to the entire circumferential direction of the inner surface of the tubular body, and the annular laser light and conical light By imaging the inner surface irradiated with illumination light, a plurality of tube inner surface images, which are captured images of the annular laser light and conical illumination light on the inner surface, are generated along the axial direction of the tubular body An annular laser light source for emitting the annular laser beam to the entire circumferential direction of the inner surface of the tubular body, and the conical illumination light to the entire circumferential direction of the inner surface of the tubular body A cone-shaped illumination light source for irradiating the inner surface, the inner surface irradiated with the annular laser light and the conical illumination light, an irradiation portion of the annular laser light, and an irradiation area of the conical illumination light; Area camera that captures images within the same field of view , And the area camera focuses the specularly reflected light of the conical illumination light from the conical illumination light illumination area, and the annular light from the annular laser light illumination portion The tube surface image is arranged along the axial direction of the tubular body by a tubular body imaging device disposed opposite to the annular laser light source and the conical illumination light source so that the diffusely reflected light of the laser light forms an image. Step to generate multiple
An annular beam center calculating step of calculating the position of the center of gravity and the radius of the portion irradiated with the annular laser light in each of the in-pipe surface images;
The inside of the tube based on the calculated barycentric position, the separation amount between the barycentric position and the portion irradiated with the annular laser light, and the separation amount between the barycentric position and the irradiation region of the conical illumination light. A light sectioning line image which is a band-like area including a light sectioning line which is a line segment in which a coordinate system of a surface image is transformed and a portion irradiated with each of the annular laser light is expanded in a circumferential direction of the tubular body A coordinate conversion step of generating a plurality of specular reflection developed images which are band-like regions in which the irradiation region of the conical illumination light is developed in the circumferential direction of the tubular body;
A depth image calculating step of calculating a depth image representing a concavo-convex body on the inner surface of the tubular body based on a light sectioning line image frame in which the light sectioning line images are sequentially arranged along the axial direction; ,
A diffuse reflection image calculating step of calculating a diffuse reflection image representing a distribution of luminance of the annular laser light on the inner surface of the tubular body based on the light cutting line image frame;
Regular reflection image generation step of arranging the respective regular reflection developed images in order along the axial direction to generate a regular reflection image representing the distribution of the brightness of the conical illumination light on the inner surface of the tubular body;
A defect detection step of detecting a defect present in the tubular body based on the calculated depth image, the diffuse reflection image and the regular reflection image;
Defect detection methods, including:

Images