JP5561178B2 - Surface defect inspection apparatus, surface defect inspection method, and program - Google Patents

Description

  The present invention relates to a surface defect inspection apparatus, a surface defect inspection method, and a program, and more particularly to a technique suitable for application to surface inspection of a shape steel which is a kind of steel product.

  Conventionally, various shapes of steel (for example, H-shaped steel) are formed by a universal rolling mill or the like installed in a rolling line. At that time, the web portion of the rolled material is rolled with a pair of upper and lower horizontal rolls, and the flange portion is rolled with a pair of left and right heel rolls. During the rolling process, since the web surface of the H-section steel is always conveyed facing the upper surface, foreign objects are likely to enter, and deep dents (crimping flaws) may occur due to the foreign-material pressure bonding, which occurs in the H-shaped steel. About 80% to 90% of the crimped wrinkles are generated on the web surface. Therefore, in order to ensure the reliability of product quality and prevent the outflow of wrinkles, it is necessary to inspect for surface flaws not only during product inspection before product shipment but also in the manufacturing stage.

  Numerous inspection methods, such as electromagnetic and optical methods, have been developed as methods for inspecting sputum. Among them, the optical inspection method is widely used because it can detect surface wrinkles without contact with an inspection object and can easily obtain wrinkle images at high speed.

  For example, in the following Patent Document 1, illumination light is alternately irradiated around a corner portion at a predetermined angle from before and after a square steel material to be conveyed, and an image signal obtained by imaging the irradiated portion with a facing CCD camera is used. Based on this, wrinkles on the steel surface are detected.

  There is also a light-cutting shape measurement method in which a linear laser light source and a delay integration type niria sensor are combined. In this measurement method, the shape of the steel material to be conveyed can be measured closely in the width direction and the longitudinal direction, and the unevenness on the surface of the object to be inspected can be obtained from the light cut image (striped image) obtained from the delay integration type linear sensor. Detect shape surface defects.

  For example, in the optical cutting method optical inspection method disclosed in Patent Document 2 below, the inspection surface is not a relatively flat surface, such as a rail or a shape steel, but both ends are lowered (or increased). This is applied to the inspection object on the surface. In such a method, a shape image that represents the shape of the inspection surface and a luminance image that represents the difference in roughness of the inspection surface from the density of the stripe image are generated from the stripe image, and the luminance image is obtained with respect to the obtained shape image. By performing centering processing and fitting function using even function based on the edge position detected from (1), shape correction processing is performed to reshape the curved surface shape of the inspection surface into a flat surface, and surface defects are detected.

JP 2003-75358 A JP 2008-281493 A

  However, in the technique for detecting wrinkles on the steel surface from the image brightness photographed by the CCD camera as described in Patent Document 1, if there is roughness or dirt on the inspection surface, a slight amount generated on the surface of the minute uneven wrinkles. There has been a problem that it is often difficult to detect luminance changes caused by the difference in diffuse reflection and the angle dependency of the reflectance.

  In addition, the technique disclosed in Patent Document 2 represents a difference between the shape image representing the shape and the roughness of the steel sheet surface even for an inspection object whose inspection surface is a curved surface that is not a relatively flat surface. Since a luminance image can be obtained, it is possible to detect uneven wrinkles and patterned wrinkles. However, when applying to inspection of a web inspection surface of a shape steel such as an H-shaped steel (a surface including a web surface and an R portion located at an end of the web surface), a shape image corresponding to the web inspection surface is obtained. There was a problem that it could not be obtained accurately. Below, the problem at the time of applying the technique described in patent document 2 to the inspection of the web inspection surface of a shape steel is demonstrated concretely.

  FIG. 20A is a diagram illustrating a configuration of an apparatus in the case where the technique described in Patent Document 2 is applied to the inspection of the web inspection surface of the shape steel, and FIG. It is a figure which shows the relationship between the camera imaging area | region LA and the irradiated laser beam LS when the web inspection surface of a shape steel is seen from the camera 905 of a).

  The laser light emitted from the laser light source 901 shown in FIG. 20A is converted into a linear laser light LS by the rod lens 903, and is irradiated onto the shape steel 1 as shown in FIG. 20B. Further, the linear laser light LS irradiated to the section steel 1 is incident obliquely on the web inspection surface of the section steel 1 (incident angle: θ). As shown in FIG. 20A, the camera 905 is configured so that the region irradiated with the linear laser beam LS obliquely incident on the structural steel 1 is directed to the side surface of the structural steel 1 (that is, the direction facing the web surface). )

  Here, as shown in FIGS. 20 (a) and 20 (b), when the web inspection surface is photographed with one camera, the camera field of view (angle of view) also extends in the height direction of the shape steel. For this reason, the laser beam irradiated on the inside of the flange surface is also imaged. Here, as shown in FIG. 20A, the linear laser light is obliquely applied to the steel frame 1, so that the stripes projected on the flange surface deviate from the imaging area LA on the way. . Therefore, the camera 905 can image only the laser beam in the range from the laser tip end portion E1 to the laser line end portion E2 in FIG. 20B, and picks up the entire surface on the side in contact with the web surface via the corner R portion of the flange. I can't do it.

  Further, laser light edges (E1 and E2 in FIG. 20B) captured on the luminance image, and these edges are indicated by the width of the imaging field of view in the conveyance direction (shown by B in FIG. 20A). )) And the imaging position of the camera.) Even if processing is performed as an edge position, the flange portion of the shape steel that is not in contact with the conveyance member such as a roller will roll while being conveyed. The end of the laser beam is blurred and the position cannot be detected accurately. As a result, it was difficult to set the range of the web inspection surface detected from the luminance image.

  On the other hand, installing a plurality of cameras instead of a single camera leads to an increase in cost. A telecentric lens can be applied because it is sufficient to capture an image without an angle of view, but such a lens does not exist because an inspection target is about 1 m in height.

  Even if the flange part is set as a dead zone from the edge position of the section steel detected by another means and it is omitted from the inspection range, there are various standards for the products to be conveyed. It is necessary to set the dead band width. Further, providing edge detection by another means has a problem of increasing the cost.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to accurately set the range of the web inspection surface of the shape steel without increasing the cost. An object of the present invention is to provide a surface defect inspection apparatus, a surface defect inspection method, and a program capable of accurately detecting a surface defect that may exist on the surface of an inspection surface.

In order to solve the above-described problems, according to an aspect of the present invention, the steel is transported on a transport line, has a flange surface and a web surface, and the flange surface and the web surface are corners. A laser light source and a rod lens that irradiates a shaped steel connected via the R portion with a modulated linear laser beam, and the laser beam picked up by imaging the linear laser light reflected by the shaped steel. A shape-steel imaging device having a delay integration type imaging device that generates a light-cut image that is a captured image of light, and a flange illumination device that illuminates an end surface of the flange surface, and the shape-steel imaging device. An arithmetic processing unit that performs image processing on the captured image of the shape steel and determines whether or not a defect exists on the surface of the web surface, and the arithmetic processing device includes the shape steel imaging device. From the generated light section An image generation unit that generates a shape image representing the uneven state of the surface of the shape steel and a luminance image representing a difference in roughness on the surface of the shape steel, using the formed fringe image; Based on a luminance image, an edge position detection unit that detects an edge position of the flange surface, an edge position detected by the edge position detection unit, information on the shape of the shape steel, the shape steel imaging device, and the Using the information regarding the positional relationship with the shape steel, an edge dead zone calculation unit that calculates a portion corresponding to the flange surface in the shape image as a dead zone, and calculated by the edge dead zone calculation unit of the shape image has been a part except the dead zone and the surface defects detected portion, possess the relevant surface defect detected portion, and the defect detection processing unit for detecting surface defects present, to the edge dead band calculation Parts, from the image information on the end surface of the flange surface, the surface defect inspection apparatus for detecting the edge position of the flange surface is provided.

The installation position of the flange illumination device is preferably a position in a region that satisfies all of the following three conditions (1) to (3).
  (1) Of the end of the flange surface on the side where the flange illumination device is located, the other of the end on the side connected to the corner R portion and the other end of the corner R portion connected to the flange surface on the other side On the center side of the shape steel with respect to the straight line connecting the point connected to the flange surface on the side
  (2) Shape steel outer side than a straight line passing through the end of the flange surface and perpendicular to the horizontal plane
  (3) Outside the field of view of the delay integration type imaging device

  The arithmetic processing unit further includes a shape correction processing unit that separates the surface defect detection target portion into the web surface and the corner R portion, and performs correction for flattening the shape image corresponding to the corner R portion. It is preferable to provide.

  The surface defect inspection device includes a movement control device that moves the position of the laser light source and the rod lens, the delay integration type imaging device, and the flange illumination device according to the size of the shape steel to be inspected. Further, it may be provided.

  A plurality of the flange illumination devices are provided at predetermined intervals along the width direction of the flange surface, and the surface defect inspection device has the laser light source and the rod lens according to the size of the shape steel to be inspected. And a movement control device that moves the position of the delay integration type imaging device.

  The movement control device maintains the relative positional relationship between the laser light source and the rod lens of the structural steel imaging device and the delay integration type imaging device, and the laser light source and the rod lens and the delay. It is preferable to move the position of the web surface in the height direction and the position of the flange surface in the width direction with the integral type imaging device.

Moreover, in order to solve the said subject, according to another viewpoint of this invention, it is a shape steel conveyed on a conveyance line, Comprising: It has a flange surface and a web surface, The said flange surface and the said web surface And a laser light source for irradiating a modulated linear laser beam and a rod lens, and imaging the linear laser beam reflected by the shaped steel. The laser beam is picked up by a shape-steel imaging device having a delay integration type imaging device that generates a light-cut image that is a captured image of the laser light, and a flange illumination device that illuminates the end face of the flange surface . A step of generating a light section image that is a captured image, a shape image that represents an uneven state of the surface of the shape steel, using a fringe image composed of the generated light section image, and the surface of the shape steel Luminance image showing the difference in roughness at A step of detecting an edge position of the flange surface based on the generated luminance image, information on the detected edge position, a shape of the shape steel, and the shape steel Using the information on the positional relationship between the imaging device and the shape steel, calculating a portion corresponding to the flange surface in the shape image as a dead zone, and calculating the dead zone calculated from the shape image. a portion except the surface defects detected portion for the surface defects detected portion, and detecting a surface defect present, only including, in the step of calculating the dead zone from the image information on the end surface of the flange surface, A surface defect inspection method for detecting an edge position of the flange surface is provided.

Moreover, in order to solve the said subject, according to another viewpoint of this invention, it is a shape steel conveyed on a conveyance line, Comprising: It has a flange surface and a web surface, The said flange surface and the said web Imaging the linear laser light reflected by the laser light source and the rod lens that irradiates the modulated steel beam with the surface connected via the corner R portion and the modulated linear laser beam. And a computer that can communicate with the structural steel imaging device having a delay integration type imaging device that generates a light-cut image that is a captured image of the laser light, and a flange illumination device that illuminates the end face of the flange surface , By using a fringe image composed of a light section image generated by the shape steel imaging device, a shape image representing an uneven state on the surface of the shape steel and a difference in roughness on the surface of the shape steel are represented. Brightness image and image generation to generate An edge position detection function for detecting an edge position of the flange surface based on the brightness image, an edge position detected by the edge position detection function, information on the shape of the shape steel, and the shape steel An edge dead zone calculation function for calculating a portion corresponding to the flange surface in the shape image as a dead zone using information on a positional relationship between the imaging device and the shape steel, and the edge dead zone in the shape image. A portion excluding the dead zone calculated by the calculation function is a surface defect detection target portion, and for the surface defect detection target portion, a defect detection processing function for detecting an existing surface defect is realized, and the edge dead zone calculation function is A program for detecting an edge position of the flange surface from image information relating to an end surface of the flange surface is provided.

  As described above, according to the present invention, the dead zone is calculated using the edge position of the flange surface, and the web inspection of the shape steel is performed in order to detect surface defects existing on the surface of the shape image except the dead zone. It is possible to accurately detect surface defects that may exist on the surface of the surface.

It is the block diagram which showed the structure of the surface defect inspection apparatus which concerns on the 1st Embodiment of this invention. It is explanatory drawing which showed the shape of H-shaped steel. It is explanatory drawing which showed the structural steel imaging device which concerns on the same embodiment. It is explanatory drawing which showed the structural steel imaging device which concerns on the same embodiment. It is explanatory drawing which showed the structural steel imaging device which concerns on the same embodiment. It is explanatory drawing which showed the structural steel imaging device which concerns on the same embodiment. It is explanatory drawing which showed an example of the fringe image which concerns on the embodiment. It is the block diagram which showed the structure of the image process part which concerns on the same embodiment. It is explanatory drawing for demonstrating the phase continuation process which concerns on the same embodiment. It is explanatory drawing for demonstrating a dead zone calculation process which concerns on the same embodiment. It is explanatory drawing for demonstrating the shape correction process which concerns on the same embodiment. It is explanatory drawing for demonstrating the kind of shape steel. It is the flowchart which showed the flow of the surface defect inspection method which concerns on the same embodiment. It is explanatory drawing for demonstrating the size of the shape steel conveyed. It is the block diagram which showed the structure of the surface defect inspection apparatus which concerns on the 2nd Embodiment of this invention. It is explanatory drawing for demonstrating the movement amount of the structural steel imaging device which concerns on the same embodiment. It is explanatory drawing for demonstrating the movement amount of the flange illuminating device which concerns on the same embodiment. It is explanatory drawing for demonstrating the modification of the flange illuminating device which concerns on the same embodiment. It is the block diagram which showed the hardware constitutions of the surface defect inspection apparatus which concerns on embodiment of this invention. It is explanatory drawing shown about the case where a shape steel is imaged by a prior art.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

  Hereinafter, a surface defect inspection apparatus and a surface defect inspection method according to an embodiment of the present invention will be described in detail with reference to FIGS.

(First embodiment)
<Overall configuration of surface defect inspection apparatus>
First, the overall configuration of the surface defect inspection apparatus 10 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is an explanatory view showing the configuration of the surface defect inspection apparatus according to the present embodiment.

  The surface defect inspection apparatus 10 according to the present embodiment images the shape steel 1 conveyed on a conveyance line composed of a plurality of rollers 2, and performs image processing on the image obtained as a result of the imaging. It is an apparatus for inspecting whether a surface defect exists on the surface.

  As shown in FIG. 1, the surface defect inspection apparatus 10 according to the present embodiment includes a shape steel imaging device 100 that images the shape steel 1 on the conveyance line, and an arithmetic processing device 200.

  The shape steel imaging device 100 is a device that sequentially images the shape steel 1, generates a light section image at each position on the web inspection surface of the shape steel, and outputs it to the arithmetic processing device 200. In this structural steel imaging device 100, the imaging timing of the structural steel is controlled by the arithmetic processing device 200.

  Further, the arithmetic processing device 200 generates a fringe image as described later by using the light section image generated by the structural steel imaging device 100, and performs image processing as described below on the fringe image. Thus, this is a device for detecting surface defects that may be present on the surface of the structural steel 1.

  In the following, a detailed description will be given by taking an H-shaped steel as shown in FIG. 2 as an example of a shaped steel. The H-shaped steel has flange surfaces above and below the web surface, and the web surface and the flange surface are connected via a corner R portion (hereinafter also simply referred to as “R portion”). The surface defect inspection apparatus 10 according to the present embodiment uses an area including a web surface and R portions located at both ends of the web surface as a web inspection surface. Here, the thickness of the web is expressed as t1, the thickness of the flange is expressed as t2, and the radius of the R portion is expressed as r. The height of the web is represented as h, and the width of the flange is represented as w. A surface parallel to the web surface at the end of the flange is referred to as a flange end surface.

[Configuration of Shaped Steel Imaging Device 100]
Then, the structure of the structural steel imaging device 100 which concerns on this embodiment is demonstrated in detail, referring FIGS. 3-6. 3-6 is explanatory drawing which showed the structural steel imaging device 100 which concerns on this embodiment. Here, FIG. 3 is a perspective view showing a positional relationship between the structural steel imaging device 100 and the structural steel 1. 4 is a top view of the structural steel imaging device 100 and the structural steel 1 as viewed from above the structural steel 1, and FIG. FIG. 6 is a side view of the structural steel imaging device 100 and the structural steel 1 as viewed from the side of the structural steel 1.

  As shown in FIGS. 3 to 6, the structural steel imaging device 100 according to this embodiment includes a laser light source 101, a rod lens 103, a delay integration imaging device 105, and a flange illumination device 107.

  The surface defect inspection apparatus according to the present embodiment is an apparatus for inspecting a surface defect of a web surface that is always conveyed facing the upper surface in a rolling process for manufacturing a shape steel. Therefore, as shown in FIGS. 3 to 6, the laser light source 101, the rod lens 103, and the delay integration type imaging device 105 may be installed at least on the surface side facing upward in the rolling process. 3 to 6, the flange illumination device 107 is installed above the flange not in contact with the roller 2, but the flange illumination device 107 is installed below the flange in contact with the roller 2. Alternatively, it may be installed both above the flange not in contact with the roller 2 and below the flange in contact with the roller 2.

  As the laser light source 101, for example, a CW laser light source that continuously performs laser oscillation can be used. The wavelength of light oscillated by the laser light source 101 is preferably a wavelength belonging to the visible light band of about 400 nm to 800 nm, for example. The laser light source 101 oscillates laser light based on an irradiation timing control signal sent from the arithmetic processing unit 200 described later.

  The rod lens 103 is a lens that spreads the laser light emitted from the laser light source 101 in a fan shape along the height direction of the web surface of the shaped steel 1 that is the inspection object. As a result, the laser beam emitted from the laser light source 101 becomes a linear laser beam and is irradiated onto the shaped steel 1. Here, as shown in FIG. 3, it is assumed that the irradiation range of the linear laser light is a range indicated by a thick line (LS) in the drawing. In addition, in the structural steel imaging device 100 according to the present embodiment, a lens other than a rod lens such as a cylindrical lens or a Powell lens may be used as long as the laser beam can be expanded in a fan shape.

  Here, as shown in FIGS. 3 to 6, the laser light source 101 and the rod lens 103 are arranged so that the linear laser light is obliquely incident on the web inspection surface of the shaped steel 1 (incident angle: θ). Has been placed.

  In a portion irradiated with the linear laser beam on the web inspection surface of the shaped steel 1 that is the inspection object, a linear bright portion is formed along the height direction of the web surface of the shaped steel 1. The reflected light (linear reflected image) from the linear bright part propagates to the delay integration type imaging device 105 and is imaged by the delay integration type imaging device 105.

  A delay integration type camera 105 which is an example of a delay integration type (Time Delay Integration: TDI) imaging device captures a linear reflection image (generated by a corresponding laser irradiation device) of the shape steel 1 being conveyed. . The TDI camera 105 includes a two-dimensional light receiving surface on which a large number of photoelectric conversion elements are arranged in a matrix. When the linear reflection image of the section steel 1 enters the photoelectric conversion element with a width corresponding to one column through the lens of the TDI camera 105, each photoelectric conversion element of the TDI camera 105 converts the accumulated electric charge into the photoelectric conversion element. The data is transferred to the photoelectric conversion element located in the same row as the conversion element and located in the next column. The timing of this transfer is the same for all photoelectric conversion elements, and is controlled by a camera shift pulse signal sent from the arithmetic processing unit 200. That is, each time a camera shift pulse signal is input, each photoelectric conversion element transfers the charge one column at a time. When the camera shift pulse signal is input, the photoelectric conversion element located in the last column reads out the accumulated charge and outputs it to the arithmetic processing unit 200. As a result, a light cut image corresponding to the linear reflection image is output to the arithmetic processing device 200.

  Here, since the shape steel 1 moves along the longitudinal direction of the shape steel, the shape light 1 is irradiated with laser light from the laser light source 101, and a linear reflection image of the shape steel 1 using the TDI camera 105. 5 and FIG. 6, a light cut image at each position in the longitudinal direction of the structural steel 1 can be sequentially obtained. By arranging the light cut images obtained in this way in order, an entire image of the area of the shape steel 1 captured by the TDI camera 105 can be obtained.

  In general, in the TDI camera 105, when light is incident on each photoelectric conversion element while charges are being transferred, a charge corresponding to the intensity of the incident light is added. However, in the shape measuring apparatus 10 according to the present embodiment, as described above, a linear reflection image having a width corresponding to one column is incident on the photoelectric conversion elements, so that charges are added to the photoelectric conversion elements during the transfer of charges. Little happens. An optical bandpass filter that transmits only the wavelength of the laser beam may be provided in front of the TDI camera 105.

  Further, since the linear laser light is periodically modulated and the intensity of the linear laser light changes with time, the charges accumulated in the photoelectric conversion elements in the column direction in each row on the light receiving surface of the TDI camera 105. The distribution of the quantity (that is, the received light intensity) also changes periodically. For this reason, an image obtained by sequentially arranging the light cut images output from the TDI camera 105 in the horizontal direction in the vertical direction is the density of each light cut image (that is, the horizontal direction of the image (that is, (Corresponding to intensity) is a fringe image that periodically changes.

  The flange illumination device 107 is a device for illuminating the end (end surface) of the flange. The flange illuminating device 107 illuminates the end of the flange when at least the TDI camera 105 captures an image of the region irradiated with the linear laser light. The flange illuminating device 107 is preferably a divergent light source, but even when a divergent light source is used, the flange is an umbrella, so it does not affect the web inspection surface at all and does not cause disturbance.

  When the flange illuminating device 107 illuminates the end of the flange, the reflected light (scattered light) from the end face of the flange is integrated according to the imaging principle of the TDI camera as described above, and the amount of light is saturated. It will be in the state. Accordingly, in the image captured by the TDI camera 105, the portion corresponding to the end face of the flange is a white image. Therefore, by setting a threshold value corresponding to the brightness of the flange end face in the brightness image profile calculation or the like, The position (edge position) can be easily calculated, and the range of the web inspection surface can be easily set.

  Here, the arrangement of the laser light source 101 (including the rod lens 103), the TDI camera 105, and the flange illumination device 107 will be described with reference to FIGS.

  As shown in FIGS. 4 to 6, the laser light source 101 and the rod lens 103 irradiate the web inspection surface (web surface) with linear laser light from an oblique direction. An angle (incident angle) formed by the optical axis of the linear laser beam and the central axis of the lens of the TDI camera 105 is defined as θ. Moreover, the projection angle ψ of the linear laser light needs to be an angle that can secure an irradiation surface enough to cover at least the web height h of the shaped steel 1 as shown in FIG. 6.

  As shown in FIG. 4, the imaging area LA of the TDI camera 105 has a width B along the conveyance direction, and the height direction is the height direction of the web as shown in FIG. The web height h is obtained by scanning along.

  As shown in FIG. 5, there is a portion where the irradiation region of the linear laser light irradiated from the oblique direction deviates from the imaging region of the TDI camera. Therefore, the inner surface of the flange surface is imaged only within the region q shown in FIG. Here, the region q shown in FIG. 4 corresponds to the point from the surface of the web surface to the intersection of the linear laser light LS irradiated on the inner surface of the flange surface and the boundary line of the imaging region LA of the TDI camera 105. It is an area to do. Such a region of the flange portion can be a portion that prevents accurate inspection of the web inspection surface. Therefore, in the arithmetic processing apparatus 200 according to the present embodiment, the size D of the dead zone shown in FIG. 10 is calculated by a method described later, and the fringe image area corresponding to the flange portion is appropriately masked. This makes it possible to accurately inspect the web inspection surface.

  In addition, the flange illumination device 107 is preferably installed at a position that does not enter the field of view of the TDI camera 105. As shown in FIG. 5, the position is a line L (actually a surface) connecting the end of the flange closest to the flange illumination device 107 and the end of the R portion connected to the flange surface on the other side. It is preferable to be provided on the center side of the shape steel than. By providing the flange illumination device 107 at such a position, it is possible to appropriately illuminate the end of the flange while preventing the illumination from reaching the R portion and the web surface.

  FIG. 7 shows an example of a fringe image generated as described above. However, FIG. 7 is a part of a striped image in which only the upper part is cut out, not the entire height direction of the captured steel, and the shaped steel is conveyed from the bottom to the top on the striped image. Yes. Therefore, the laser beam is irradiated from the lower oblique side on the fringe image. Here, the stripe is a light section image corresponding to one period of density change. In such a stripe image, the longitudinal direction, that is, the direction orthogonal to the stripe corresponds to the longitudinal direction of the shaped steel 1 that is the inspection object, and the lateral direction, that is, the direction parallel to the stripe is the shaped steel that is the inspection object. 1 corresponds to the web height direction. If the ratio of the camera shift frequency of the TDI camera 105 to the modulation frequency of the laser light is M: 1, M light-cut images, that is, M pixels in the horizontal direction form one stripe.

  As is apparent from FIG. 7, since the flange end surface is illuminated by the flange illumination device 107, the light amount of the flange end surface is saturated, and the flange end surface is white. Therefore, the edge position on the outer side of the flange (the position of the upper end of the flange shown in FIG. 2) can be easily detected by setting the brightness threshold value.

  The area a shown in FIG. 7 is an area where the image is blank and is an area corresponding to the flange end face. Further, it can be seen that the region b shown in FIG. 7 is inside the flange surface, and the shade of the image is dark. Moreover, the area | region c shown in FIG. 7 is an area | region corresponding to the R part which connects a flange surface and a web surface, and it turns out that the striped pattern is curving.

  Here, since the linear laser beam is incident on the surface of the structural steel 1 that is an inspection object from an oblique direction (incident angle: θ), for example, when a concave portion exists in the structural steel 1, the reflection point of the linear laser light is It will be shifted upward on the striped image. As a result, the position of the light section image on the photoelectric conversion element of the TDI camera 105 is also shifted rightward, that is, in the column direction. For this reason, in the fringe image, the light cut image corresponding to the linear laser light reflected by the concave portion is output earlier in time than the light cut image corresponding to the linear laser light reflected by the flat portion other than the concave portion. Will be. Therefore, in the two-dimensional image obtained by sequentially arranging the one-dimensional images output from the TDI camera 105, the concave portion present in the shape steel 1 can be recognized as a fringe shift.

  Note that the incident angle θ of the linear laser beam on the shaped steel 1 can be set to an arbitrary value, but is preferably set to, for example, 45 degrees. By setting the incident angle to 45 degrees, the amount of change in the depth of the section steel 1 that is the inspection object becomes equal to the amount of movement of the stripes, and the depth of the recesses that are easily present in the section steel 1 from the amount of movement of the stripes. This is because information can be obtained.

  Below, the specific structure is enumerated about each apparatus which the structural steel imaging device 100 which concerns on this embodiment has. Such a configuration is merely an example, and the structural steel imaging device 100 according to the present invention is not limited to the following specific example.

○ Laser irradiation device Laser light is irradiated at an incident angle θ = 45 degrees and a projection angle ψ = 60 degrees. Distance to section 1 (inspection surface) = 1040 mm, irradiation width of linear laser beam = 1200 mm
○ TDI camera 2048bits × 96bits, camera shooting area LA = 2048mm × 96mm (shooting resolution 1.0mm × 1.0mm)
A fringe image is captured at a constant period where the ratio between the camera shift frequency (= 18.7 kHz) of the TDI camera and the modulation frequency (= 4675 Hz) of the laser light is M: 1 (= 4: 1).

[Overall configuration of arithmetic processing unit]
The configuration of the structural steel imaging device 100 has been described above. Next, returning to FIG. 1 again, the configuration of the arithmetic processing apparatus 200 provided in the surface defect inspection apparatus 10 according to the present embodiment will be described in detail.

  The arithmetic processing apparatus 200 according to the present embodiment mainly includes a timing signal generation unit 201, an image processing unit 203, a display unit 205, and a storage unit 207, for example, as illustrated in FIG.

  The timing signal generation unit 201 is realized by, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a communication device, and the like. The timing signal generator 201 generates a sine waveform signal having a predetermined frequency ω, and sends the generated sine waveform signal to the laser light source 101. Since the laser light source 101 is capable of continuously changing the oscillation intensity by an irradiation timing control signal input from the outside, the sine wave signal is received by receiving the sine waveform signal sent from the timing signal generator 201. It is possible to oscillate laser light whose output changes with the waveform. That is, the timing signal generator 201 can periodically modulate the laser light emitted from the laser light source 101 by sending the generated sine waveform to the laser light source 101.

  In addition, the timing signal generation unit 201 generates a rectangular waveform having a frequency M times the frequency ω as a camera shift pulse signal, and sends the generated camera shift pulse signal to the TDI camera 105.

  As described above, it can be said that the timing signal generation unit 201 is a drive control unit that controls the driving of the laser light source 101 and the TDI camera 105 provided in the structural steel 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 is described below with respect to the fringe image generated using the imaging data acquired from the structural steel imaging device 100 (more specifically, the TDI camera 105 of the structural steel imaging device 100). Image processing is performed to detect defects present on the surface of the structural steel 1 that is the inspection object. When the image processing on the striped image corresponding to the structural steel 1 is completed, the image processing unit 203 transmits information on the obtained inspection result of the structural steel 1 to the display unit 205.

  The image processing unit 203 will be described in detail later again.

  The display unit 205 is realized by, for example, a CPU, a ROM, a RAM, an output device, and the like. The display unit 205 displays the inspection result of the structural steel 1 that is the inspection object transmitted from the image processing unit 203 on an output device such as a display provided in the arithmetic processing device 200. Thereby, the user of the surface defect inspection apparatus 10 can grasp the inspection result regarding the surface defect of the inspection object being conveyed (the web inspection surface of the shaped steel 1) on the spot.

  The storage unit 207 is an example of a storage device included in the arithmetic processing device 200. The storage unit 207 appropriately records various parameters, the progress of processing, or various databases that need to be saved when the arithmetic processing apparatus 200 according to the present embodiment performs some processing. The The storage unit 207 can be freely read and written by the timing signal generation unit 201, the image processing unit 203, the display unit 205, and the like.

[About image processing unit]
Next, the image processing unit 203 included in the arithmetic processing apparatus 200 according to the present embodiment will be described in detail with reference to FIG. FIG. 8 is a block diagram illustrating a configuration of an image processing unit included in the arithmetic processing apparatus according to the present embodiment.

  As shown in FIG. 8, the image processing unit 203 according to the present embodiment includes an image generation unit 209, an edge position detection unit 225, an edge dead zone calculation unit 227, a centering processing unit 229, and a shape correction processing unit 231. And a defect detection processing unit 233.

  The image generation unit 209 is realized by, for example, a CPU, a ROM, a RAM, a communication device, and the like. The image generation unit 209 generates a plurality of shape images representing the uneven state of the surface of the shape steel 1 using a fringe image formed from the light section image generated by the shape steel imaging device 100.

  The image generation unit 209 includes an A / D conversion unit 211, a pre-filter unit 213, an orthogonal sine wave generation unit 215, a low-pass filter unit 217, 219, a phase calculation unit 221, an amplitude calculation unit 223, and a phase continuation processing unit 225. In addition.

  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 performs A / D conversion on each light section image output from the TDI camera 105 and outputs it as digital multivalued image data. Such digital multivalued image data is stored in an image memory provided in the storage unit 207 or the like. By arranging these digital multivalued image data in order, a striped image as shown in FIG. 7 is formed.

  From such a striped image (or digital multi-valued image data), data representing the density distribution of the striped image along the web height direction is generated at each position in the transport direction. Hereinafter, the data representing the density distribution of the stripe image along the web height direction is referred to as “slice stripe image data”. Slice fringe image data at each position in the transport direction is sequentially output from an image memory provided in the storage unit 207 or the like.

  The prefilter unit 213 is realized by, for example, a CPU, a ROM, a RAM, and the like. The pre-filter unit 213 performs predetermined filter processing on each slice stripe image data, thereby removing noise from each slice stripe image data and making the stripe state clear. Note that the filtering process by the prefilter unit 213 is not necessarily performed. For example, the filtering process may be performed only when a lot of fine noise is generated in the striped image.

The pre-filter unit 213 outputs slice fringe image data I _j (k) at each position j (j = 0, 1, 2,...) In the transport direction when the noise removal processing on the slice fringe image data is completed. . Here, k (k = 0, 1, 2,...) Is a parameter representing a position in the web height direction. At this time, it is assumed that the slice fringe image data I _j (k) at the position j in the transport direction changes sinusoidally. That is, I _j (k) is expressed as shown in Equation 101 below.

... (Formula 101)

  Here, in Equation 101 above, A (j, k) represents the amplitude of the slice stripe image data at the pixel position (j, k), and φ (j, k) represents the slice at the pixel position (j, k). This represents the phase shift of the fringe image data.

Here, the influence of the fringe shift generated in the fringe image due to the dent on the surface of the shape steel 1 appears as a phase shift φ. Further, although the amplitude of the linear laser beam is constant, when the surface of the shape steel 1 is dirty or there are pattern-like wrinkles such as scale wrinkles, the amplitude is at the pixel position corresponding to the position. May fluctuate. Therefore, in the above equation 101, the amplitude A is expressed in a form depending on the pixel position (j, k). In the above equation 101, the reason why 1 is added after the cos term is to satisfy the condition that the slice fringe image data (density value) I _j (k) does not become negative. Therefore, the slice fringe image data I _j (k) changes between 0 and 2A.

  The orthogonal sine wave generation unit 215 is realized by, for example, a CPU, a ROM, a RAM, and the like. The orthogonal sine wave generation unit 215 generates two orthogonal reference sine wave data sin (2πk / M) and cos (2πk / M) generated in advance in the storage unit 207 or the like. Hereinafter, the former sine wave data is referred to as reference sin data, and the latter sine wave data is referred to as reference cos data.

These two types of reference sine wave data are respectively multiplied by the slice fringe image data I _j (k) output from the prefilter unit 213. By this multiplication processing, two outputs I _aj (k) and I _bj (k) are generated. The details of I _aj (k) and I _bj (k) are as shown in Equations 102 and 103 below.

... (Formula 102)
... (Formula 103)

Here, the output data I _aj (k) expressed by the equation 102 is input to a low-pass filter unit 217 described later, and the output data I _bj (k) expressed by the equation 103 is input by a low-pass filter unit described later. 219 is input.

The low-pass filter units 217 and 219 are realized by, for example, a CPU, a ROM, a RAM, and the like. The low-pass filter units 217 and 219 perform predetermined filter processing on the outputs I _aj (k) and I _bj (k) obtained by the above-described multiplication processing, thereby removing the fringe frequency component and its harmonic components. . By such processing, it is possible to extract a component including only the phase shift φ from the input data I _aj (k), I _bj (k). Here, the low-pass filter unit 217 is a processing unit that performs a predetermined filter process on the input data I _aj (k), and the low-pass filter unit 219 applies the input data I _bj (k). And a processing unit that performs predetermined filter processing.

_Assuming that the output from the low-pass filter unit 217 is LPF (I _aj (k)) and the output from the low-pass filter unit 219 is LPF (I _bj (k)), these are expressed by the following equations 104 and 105: expressed.

... (Formula 104)
... (Formula 105)

The low pass filter unit 217 outputs the data LPF (I _aj (k)) obtained by the filtering process to a phase calculation unit 221 and an amplitude calculation unit 223 described later. The low-pass filter unit 219 outputs the data LPF (I _bj (k)) obtained by the filtering process to a phase calculation unit 221 and an amplitude calculation unit 223 described later.

The phase calculation unit 221 is realized by, for example, a CPU, a ROM, a RAM, and the like. The phase calculation unit 221 calculates a phase shift φ (j, k) at each pixel position (j, k) based on the results output from the low-pass filter units 217 and 219. The phase shift φ (j, k) can be calculated by the following Expression 107 to Expression 109 according to the values of LPF (I _aj (k)) and LPF (I _bj (k)).

Here, the following expression 107 is an expression used by the phase calculation unit 221 when LPF (I _aj (k)) ≧ 0. Further, the following formula 108 is a formula used by the phase calculation unit 221 when LPF (I _aj (k)) <0 and LPF (I _bj (k)) <0. Further, the following formula 109 is a formula used by the phase calculation unit 221 when LPF (I _aj (k)) <0 and LPF (I _bj (k)) ≧ 0.

... (Formula 107)
... (Formula 108)
... (Formula 109)

The phase calculation unit 221 sets the range of the inverse trigonometric function (arctan) to −π / 2 to + π / 2 in the above formulas 107 to 109, and LPF (I _aj (k)), LPF (I _bj (k )) Is used to obtain the phase shift φ in the range of −π to + π. Here, the phase shift obtained in this range is represented by φ ′ again. In this case, the phase shift φ ′ obtained by the above formulas 107 to 109 has a periodic relationship with the dent (depth) of the surface of the web inspection surface of the structural steel 1 and is a value with the phase shift φ ′. There are multiple depths that take Therefore, if such a phase shift φ ′ is used, accurate information on the surface shape of the web inspection surface of the section steel 1 cannot be obtained. For this reason, it is necessary to obtain the phase shift φ in proportion to the dent (depth) of the surface of the web inspection surface of the structural steel 1 from the phase shift φ ′. The process of obtaining the phase shift φ proportional to the depth is performed by the phase continuation processing unit 225 described later.

  Therefore, the phase calculation unit 221 outputs information on the calculated phase shift φ ′ to the phase continuation processing unit 225 described later. An image can be generated by illustrating the phase shift φ ′ (j, k). An image generated based on such a phase shift φ ′ is hereinafter referred to as a phase image. There are various methods for illustrating the phase shift φ ′ (j, k). For example, the image becomes white when the phase shift φ ′ is + π, and the image is displayed when the phase shift φ ′ is −π. It can be illustrated as a grayscale image that becomes black.

  The amplitude calculation unit 223 is realized by a CPU, a ROM, a RAM, and the like, for example. The amplitude calculation unit 223 calculates the amplitude A (j, k) at each pixel position (j, k) based on the results output from the low-pass filter units 217 and 219. The amplitude calculation unit 223 calculates the amplitude A (j, k) by the following expression 110.

... (Formula 110)

  The amplitude calculation unit 223 outputs information on the amplitude A calculated in this way to the edge position detection unit 227 described later. An image can be generated by illustrating the amplitude A (j, k). Such an image generated based on the amplitude A is hereinafter referred to as an amplitude image. There are various methods for illustrating the amplitude A (j, k). For example, the amplitude A (j, k) can be illustrated as a grayscale image in which the image becomes black as the amplitude A is small.

  In the arithmetic processing apparatus 200 according to the present embodiment, the amplitude image that can be generated in this way is used as a luminance image that is an image representing the difference in roughness on the surface of the shape steel.

  The phase continuation processing unit 225 is realized by a CPU, a ROM, a RAM, and the like, for example. For example, as illustrated in FIG. 9, the phase continuation processing unit 225 detects discontinuous points of the phase shift φ ′ based on the phase image calculated by the phase calculation unit 221, and detects the phase shift φ ′. The phase shift φ ′ is corrected so as to be smoothly connected.

  As described above, since the value range of the phase shift φ ′ calculated by the phase calculator 221 is −π to + π, the phase shift φ ′ is not −π and + π as shown in FIG. It will be continuous. For example, in a phase image represented as a grayscale image, a portion that changes from white (or black) to black (or white) corresponds to a discontinuous point of the phase shift φ ′. If such a phase image is used as it is, it is difficult to recognize the surface shape of the structural steel 1. Accordingly, it is necessary to correct the phase shift φ ′ so that the phase shift φ ′ is smoothly connected at the discontinuous points of the phase shift φ ′. Such correction (phase jump correction) is a process for obtaining a unique phase shift φ proportional to the dent (depth) of the surface of the shape steel 1 from the phase shift φ ′ defined in the range of 2π.

  Specifically, the phase continuation processing unit 225 first detects a discontinuous point of the phase shift φ ′ and corrects the phase shift φ ′ at the discontinuous point. It is difficult to determine whether or not the phase shift φ ′ is discontinuous even if only one pixel is referred to, and it is preferable to determine by referring to adjacent pixels. Therefore, the phase continuation processing unit 225 examines the phase image along the horizontal direction at each position in the vertical direction of the phase image, and compares the phase shift φ ′ between adjacent pixels. When the phase shift φ ′ differs greatly between the adjacent pixels, it is determined that the phase shift φ ′ is discontinuous between the pixels, and the phase shift φ ′ is corrected. Here, since the depth at the surface of the shaped steel 1 does not change abruptly, it is considered that the phase shift φ ′ is largely different because the phase shift φ ′ is changed by ± 2π. Accordingly, the phase continuation processing unit 225 examines pixels in which the phase shift φ ′ is significantly different from the phase shift φ ′ in the adjacent pixels, and smoothly connects these phase shifts φ ′. You can do it.

  For example, when the phase shift φ ′ is close to + π at a certain pixel position and the phase shift φ ′ is close to −π at the pixel position on the right side of the pixel position, the phase continuation processing unit 225 recognizes that the phase shift φ ′ changes by + 2π at the pixel position on the right side. Then, the phase continuation processing unit 225 corrects the phase shift φ ′ by adding + 2π to the phase shift φ ′ at the pixel position on the right side. Further, when the phase shift φ ′ is a value close to −π at a certain pixel position and the phase shift φ ′ is a value close to + π at the pixel position to the right of the pixel position, the phase continuation processing unit 225 recognizes that the phase shift φ ′ is changed by −2π at the pixel position on the right side. Then, the phase continuation processing unit 225 corrects the phase shift φ ′ by adding −2π to the phase shift φ ′ at the pixel position on the right side.

  The phase continuation processing unit 225 examines adjacent pixels along the horizontal direction at each position in the vertical direction by the method described above, corrects the phase shift φ ′, and then performs vertical correction at each position in the horizontal direction. The adjacent pixels along the direction are examined, and the phase shift φ ′ is corrected in the same manner. The phase shift at each pixel position after the correction is a unique phase shift φ proportional to the dent (depth) of the surface of the structural steel 1.

  Next, the phase continuation processing unit 225 newly creates a phase image based on the corrected phase shift φ. This new phase image accurately represents the surface shape of the structural steel 1. This new phase image is hereinafter referred to as a shape image.

  The phase continuation processing unit 225 outputs the shape image in which the phase shift is corrected to the centering processing unit 231 described later.

  The edge position detection unit 227 is realized by a CPU, a ROM, a RAM, and the like, for example. The edge position detection unit 227 detects the edge positions of the left and right flanges (that is, the top and bottom of the H-shaped steel) for each line based on the amplitude image (luminance image) calculated by the amplitude calculation unit 223. More specifically, the edge position detection unit 227 focuses on the luminance value of the luminance image and detects a portion where the luminance value is equal to or greater than a predetermined threshold value. In the surface defect inspection apparatus 10 according to the present embodiment, since the flange end surface is illuminated by the flange illuminating device 107, the exposure of the portion imaged from the flange end surface is always saturated because the exposure is integrated by the TDI camera 105. It has become a state. Therefore, the edge position can be easily detected by such threshold processing. Information about the edge position detected by the edge position detection unit 227 is output to the edge dead zone calculation unit 229 described later.

  The edge dead zone calculation unit 229 is realized by, for example, a CPU, a ROM, a RAM, and the like. The edge dead zone calculating unit 229 uses information on the shape of the shape steel and information on the positional relationship between the shape steel imaging device and the shape steel on the flange surface (particularly on the web surface side of the flange) in the shape image. The corresponding part is calculated as a dead zone.

Hereinafter, the dead zone calculation method will be described in detail with reference to FIG.
In FIG. 10, t1 represents the web thickness, t2 represents the flange thickness, and r represents the radius of the R portion. A represents the width of the flange from the web surface, and is calculated by A = (1/2) × (w−t1). However, w is a flange width. These data are information regarding the shape of the section steel (H-shaped steel). The information regarding these shapes may be a design value of a section steel (H-section steel) or a measurement value obtained by actually measuring a section steel (H-section steel). Information regarding these shapes may be input by a user of the surface defect inspection apparatus 10 or may be acquired from an apparatus other than the surface defect inspection apparatus 10.

  In FIG. 10, the angle α is an angle formed by the intersection of the web surface and the R portion and the image center (horizontal line) of the TDI camera, and B is the height from the camera image center to the flange upper surface. , L is the distance between the web inspection surface and the camera. These data are information relating to the positional relationship between the shape steel 1 and the TDI camera 105.

  The edge dead zone calculation unit 229 calculates the dead zone width D by the following formula 111 using the information on the shape of the shape steel and the information on the positional relationship between the shape steel and the TDI camera. Here, the angle α in the formula 111 is a value calculated from the following formula 112.

... (Formula 111)
... (Formula 112)

  Similarly, the dead zone of the lower flange portion (the flange portion in contact with the roller 2) may be calculated from the height from the center of the camera image to the lower surface of the flange, or the web height h that is information related to the shape. Alternatively, the parameter B may be subtracted from the value.

  The edge dead zone calculation unit 229 uses the information about the edge position detected by the edge position detection unit 227 and the information about the calculated dead zone width D for each line in the shape image for each end of the dead zone (dead zone). The position corresponding to the web surface end) is specified. The edge dead zone calculation unit 229 outputs information regarding the position corresponding to the end of the dead zone to the centering processing unit 231 described later.

  Strictly speaking, when the position corresponding to the end of the dead zone on the image is specified from the calculated dead zone width D, there is a difference between the distance from the camera position to the web inspection surface and the distance to the flange end. It is necessary to make corrections. However, since the distance from the web inspection surface of the structural steel to the camera position is sufficiently larger than the flange width A, it can be ignored in practice compared to the pixel size of the image to be captured.

  The centering processing unit 231 is realized by a CPU, a ROM, a RAM, and the like, for example. The centering processing unit 231 performs centering processing on the shape image output from the phase continuation processing unit 225 based on the information regarding the position corresponding to the end of the dead zone output from the edge dead zone calculation unit 229.

  The centering processing unit 231 calculates the center position of the web inspection surface of the shaped steel 1 that is the inspection object for each line based on the positions of the left and right dead band ends, and the longitudinal direction (conveying direction) of the shaped steel 1 ). By such centering treatment, even if the shape steel 1 rolls while being conveyed, the surface defect detection accuracy can be increased.

  The centering processing unit 231 outputs the shape image after the centering process to the shape correction processing unit 233 described later.

  The shape correction processing unit 233 is realized by a CPU, a ROM, a RAM, and the like, for example. The shape correction processing unit 233 separates the portion of the shape image after the centering processing except the dead zone (that is, the surface defect detection target portion) into the web surface and the R portion, and flattens the shape image corresponding to the R portion. Make corrections.

  As is clear from FIG. 11, the central portion (web surface, region (2) in FIG. 11) is flat, while the R portion is present at the base of the flange surface, so the portion corresponding to the R portion. The brightness levels in the regions (1) and (3) in FIG. 11 are not uniform. Even if a process for determining surface defects is performed on a shape image derived from such a shape, it is difficult to extract surface defects such as dents and wrinkles on the surface of the shape steel. Therefore, the shape correction processing unit 233 performs shape correction processing for re-baking the curved surface shape of the shaped steel 2 that is the inspection object into a flat surface.

  However, even if shape correction processing using an even function or the like is performed on the entire surface of the obtained shape image, although shape correction succeeds for the portion corresponding to the R portion, in the portion corresponding to the flat surface, The shape is corrected to a shape in which the flat portion is recessed by being dragged by the shape of the R portion. Therefore, the shape correction processing unit 233 according to the present embodiment separates a part of the shape image after the centering process except the dead zone into a web surface and an R part, and performs a flattening process only on the shape image corresponding to the R part. I do.

  In the arithmetic processing device 200 according to the present embodiment, it is possible to accurately calculate the positions of the upper flange and the lower flange by the dead zone calculation process, so that the R portion and the web surface can be easily separated. It becomes. Since the R portion is adjacent to the dead zone as illustrated in FIG. 10, the position of the R portion uses information on the shape (information on the size of r) and information on the position of the dead zone end. By doing so, it can be easily identified.

  Further, if the size of the portion corresponding to the R portion in the shape image can be grasped to some extent by prior verification using statistical processing or the like, a fixed value may be determined in advance and the fixed value may be used. . For example, in the case of an H-shaped steel conforming to the standard, it is assumed that the portion corresponding to the R portion is 8 mm to 24 mm. Therefore, if the fixed value is set to 30 mm, the portion corresponding to the R portion can be efficiently identified. It becomes possible to do.

  Specifically, the shape image corresponding to the R part after the centering process is subjected to a fitting process by a predetermined function such as an odd function or a spline function for each line, and the original data (the R part after the centering process is applied). Difference calculation with the corresponding shape image) is performed.

  Subsequently, the shape image of the R part after the fitting process is averaged (accumulated) by a predetermined length in the conveying direction (longitudinal direction) of the shaped steel 1, subjected to low-pass filter processing, and the original data (R after the fitting process) Difference calculation (or division calculation). By this shading correction, it is possible to flatten the shape image corresponding to the R portion while retaining the unevenness information that is the surface defect candidate.

  As described above, the shape correction processing unit 233 performs a two-stage process including a fitting process using a predetermined function and a shading correction as the shape correction process for the shape image corresponding to the R part. By such shape correction processing, the image of the portion excluding the dead zone in the shape image is all flat while retaining the unevenness information, and the surface defect detection processing described later can be easily performed. Hereinafter, the shape image after the shape correction process is referred to as a depth image.

  The shape correction processing unit 233 outputs the depth image that has undergone the shape correction processing to the defect detection processing unit 235 described later.

  The defect detection processing unit 235 is realized by, for example, a CPU, a ROM, a RAM, and the like. The defect detection processing unit 235 is based on the shape image (depth image) after the shape correction process output from the shape correction processing unit 233, and the depth of the dent that exists on the surface of the shaped steel 1 that is the inspection object. d is calculated, and the shape of the inspection object is specified. Thereafter, when the shape of the section steel 1 that is the inspection target is specified, the defect detection processing unit 235 determines whether or not there is a surface defect on the surface of the web inspection surface of the section steel 1.

  Here, when the imaging resolution in the column direction of the photoelectric conversion elements in the TDI camera 105 is s (mm / pixel) and the vertical component incident angle of the linear laser light is θ, the reflection point of the linear laser light is in the longitudinal direction. The shifted distance h = d · tan θ corresponds to h / s pixels in the striped image. When the ratio between the camera shift frequency of the TDI camera 105 and the modulation frequency of the laser beam is M: 1, M pixels in the horizontal direction form one stripe in the stripe image. That is, when the fringes are shifted by M pixels, the phase shift is 2π. Therefore, the phase shift Δφ in the fringe image data when the reflection point of the linear laser beam L is shifted by a distance h in the longitudinal direction is expressed by the following equation 113 from the relationship M / 2π = (h / s) / Δφ. It becomes like this.

  d = {M · s / (2π · tan θ)} · Δφ (Formula 113)

  Therefore, the defect detection processing unit 235 includes the setting value of the shape steel imaging device 100 such as the imaging resolution of the TDI camera 105 and the incident angle θ of the linear laser beam, the frequency ratio M acquired from the timing signal generation unit 201, and the shape. Using the phase φ obtained from the depth image output from the correction processing unit 233 and the above equation 113, the depth d of the dent existing on the surface of the web inspection surface of the inspection object (section steel 1) is calculated. can do.

  Strictly speaking, when a normal lens is used, the imaging resolution s changes according to the depth d, and thus correction is necessary. However, as in the case of measuring the indentation of the shape steel, the lens working distance is set. On the other hand, when the change in depth is very small, such a change in imaging resolution s can be ignored in practice. If a telecentric lens is used, the imaging resolution s can be made constant regardless of the depth d.

  When the calculation of the depth of the dent existing on the surface of the web inspection surface of the structural steel 1 is completed, the defect detection processing unit 235 performs surface defects (疵) existing on the surface of the web inspection surface based on the obtained information. Specify the position of.

  The defect detection processing unit 235 outputs information on the surface defects (wrinkles) thus detected to the display unit 205 or outputs a form.

  As described above, in the image processing unit 203 according to the present embodiment, the surface shape of the shaped steel 1 is accurately and easily grasped by using the shape image (depth image) after the expansion / contraction process. Can do.

  Further, the defect detection processing unit 235 can detect surface defects that may exist on the web inspection surface by the following method instead of the above-described method. That is, the defect detection processing unit 235 first binarizes the depth image obtained by the shape correction processing unit 233. In the binarization process, a threshold value is set, and 0 is applied to a portion within the threshold value, and 1 is applied to a portion exceeding the threshold value.

  Subsequently, the defect detection processing unit 235 performs surface defect determination using the generated binarized image and detects surface defects. Further, the defect detection processing unit 235 performs surface defect determination based on not only the binarized image but also the maximum and minimum depths of the depth image, and the amplitude image (luminance obtained by the amplitude calculation unit 223). The surface defect may be determined based on the maximum brightness, minimum brightness, average brightness, etc. of the image.

  Heretofore, an example of the function of the arithmetic processing apparatus 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. In addition, the CPU or the like may perform all functions of each component. Therefore, it is possible to appropriately change the configuration to be used according to the technical level at the time of carrying out the present embodiment.

  A computer program for realizing each function of the arithmetic processing apparatus according to the present embodiment as described above can be produced and installed in a personal computer or the like. In addition, a computer-readable recording medium storing such a computer program 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. Further, the above computer program may be distributed via a network, for example, without using a recording medium.

  In the above description, the H-shaped steel has been described as an example of the shape steel 1. However, if the shape steel has a shape in which the web surface and the flange surface are connected via the R portion, the shape steel 1 is the same. Processing can be performed.

  The surface defect inspection method according to the present embodiment can be applied to, for example, an I-shaped steel as shown in FIG. 12 (a), and can also be applied to a grooved steel as shown in FIG. 12 (b). It can be applied to various angle steels as shown in FIG. Moreover, the surface defect inspection method according to the present embodiment can be applied not only to these shape steels but also to rails having a shape as shown in FIG. 12 (d), and also to steel sheet piles. Applicable.

<Flow of surface defect inspection method>
Next, the flow of the surface defect inspection method according to the present embodiment will be briefly described with reference to FIG. FIG. 13 is a flowchart showing the flow of the surface defect inspection method according to the present embodiment.

  First, the surface defect inspection apparatus 10 captures the shape steel 1 irradiated with the linear laser light with the TDI camera 105 of the shape steel imaging apparatus 100 to generate a fringe image (step S101). Thereafter, the image processing unit 203 (more specifically, the image generation unit 209) of the arithmetic processing device 200 calculates the amplitude and phase based on the signal of the fringe image (step S103).

  Subsequently, the phase continuation processing unit 225 performs the phase continuation processing on the phase image generated by the phase calculation unit 221 (step S105), and centers the phase image (shape image) after the phase continuation processing is completed. The data is output to the processing unit 231.

  On the other hand, the edge position detection unit 227 performs edge position detection processing based on the amplitude image generated by the amplitude calculation unit 223 (step S107). The edge position detection unit 227 outputs information indicating the detected edge position to the edge dead zone calculation unit 229.

  The edge dead zone calculation unit 229 calculates the width D of the edge dead zone using the information related to the shape of the shape steel 1 and the information related to the positional relationship between the shape steel and the shape steel imaging device (step S109). Thereafter, the edge dead zone calculation unit 229 uses the information related to the shape of the shape steel 1 and the information related to the calculated width D of the edge dead zone to calculate information related to the edge of the edge dead zone and outputs the information to the centering processing unit 231. To do.

  The centering processing unit 231 calculates the center position of the shape image using information regarding the edge of the edge dead zone, and performs centering processing for aligning the shape image with the calculated center position (step S111).

  The centering processing unit 231 outputs the shape image (that is, the depth image) after the centering process to the shape correction processing unit 233.

  The shape correction processing unit 233 divides the depth image excluding the part corresponding to the dead zone into a part corresponding to the web surface and a part corresponding to the R part, and the shape correction processing unit 233 performs shape processing on the depth image corresponding to the R part. Correction processing is performed (step S113). Thereby, the depth image corresponding to the R portion is flattened, and the surface defect can be detected more accurately.

  The shape correction processing unit 233 outputs the depth image for which the shape correction processing has been completed to the defect detection processing unit 235.

  Subsequently, the defect detection processing unit 235 performs a surface defect detection process that may exist on the surface of the web inspection surface by using the depth image for which the shape correction process has been completed (step S115).

  By processing in such a flow, it becomes possible to accurately and easily grasp the surface shape of the shaped steel, and to detect minute uneven shapes and pattern-shaped wrinkles simultaneously with high accuracy and high speed. Can do.

(Second Embodiment)
The type of shape steel conveyed on the conveyance line is not limited to one type. For example, as shown in Table 1 below, when multiple types of shape steel having different sizes are conveyed on the conveyance line. There is.

  In order to stably convey various shape steels as described in Table 1 above on the conveyance line, as shown in FIG. 14, by feeding with the skid S (or guide), the table roll 2 The flange ends (for example, the left ends of the flanges in FIG. 14) of various shape steels as described above overlap the inside from the end by a predetermined distance D (for example, 200 mm).

  For this reason, as shown in FIG. 14, the shape which has a web height lower than the visual field center of a shape steel imaging device in the conveyance line in which the shape steel imaging device is installed according to the web height of the shape steel A When steel (for example, shape steel B in Table 1 above) is conveyed, the flange becomes an umbrella and an area that cannot be photographed is generated.

  In addition, as shown in FIG. 14, when a shape steel having a narrow flange width such as shape steel D is conveyed to the conveyance line in which the shape image pickup device is installed in accordance with the flange width of the shape steel C. In this case, the focus of the shape-steel imaging device becomes out of focus on the web surface, and defocusing occurs.

  In this way, when shape steels having various sizes are conveyed on the conveyance line, the web surface position to be inspected may deviate from the optical conditions of the shape steel imaging device, resulting in the inspection surface. There may be a case where the entire surface is not imaged or a defocusing occurs, so that an accurate inspection cannot be performed.

  Therefore, the surface defect inspection apparatus according to the second embodiment of the present invention described below further includes a movement control device that moves the imaging position of the shape-steel imaging device. While maintaining the arrangement of the optical system with the laser light source, the shape steel imaging device is appropriately moved according to the size of the shape steel. As a result, since the shape steel imaging device can appropriately image the web surface of the shape steel to be inspected, it is accurate even when multiple types of shape steel are conveyed on the conveyance line. It is possible to inspect surface defects.

<Overall configuration of surface defect inspection apparatus>
First, the overall configuration of the surface defect inspection apparatus 10 according to the second embodiment of the present invention will be described with reference to FIG. FIG. 15 is an explanatory diagram showing the configuration of the surface defect inspection apparatus according to the present embodiment.

  The surface defect inspection apparatus 10 according to the present embodiment images the shape steel 1 conveyed on a conveyance line composed of a plurality of rollers 2, and performs image processing on the image obtained as a result of the imaging. It is an apparatus for inspecting whether a surface defect exists on the surface.

  As shown in FIG. 15, the surface defect inspection apparatus 10 according to the present embodiment includes a structural steel imaging device 100 that images the structural steel 1 on the conveyance line, an arithmetic processing device 200, and a movement control device 300. Prepare.

  Here, the structural steel imaging device 100 according to the present embodiment is provided with an arbitrary moving mechanism (not shown) for changing the imaging position. The moving mechanism provided in the structural steel imaging device 100 is controlled by a movement control device 300 described later, in the horizontal direction (flange width direction) and the vertical direction (web height direction), the laser light source 101 and the rod lens 103, The imaging position is moved while maintaining the relative positional relationship with the TDI camera 105.

  In the present embodiment, the laser light source 101 and the rod lens 103 of the structural steel imaging device 100, and the TDI camera 105 are configured such that the optical axes of the structural steel are the reference structural steel (for example, transported on a transport line). The steel having the maximum web height (hereinafter referred to as the shape steel a) is assumed to be pre-arranged so as to lie on a horizontal plane perpendicular to the web surface of the steel. Hereinafter, the positions of the laser light source 101 and the rod lens 103 and the TDI camera 105 according to the reference shape a are referred to as the reference imaging positions of the laser light source 101 and the rod lens 103 and the TDI camera 105. And

  The shape steel imaging device 100 according to the present embodiment has the same configuration as that of the shape steel imaging device 100 according to the first embodiment of the present invention except for the points described above, and has the same effects. Therefore, further detailed description is omitted below.

  In addition, the arithmetic processing device 200 according to the present embodiment has the same configuration as the arithmetic processing device 200 according to the first embodiment of the present invention and has the same effects, and therefore will be described in detail below. Is omitted.

  The movement control device 300 is a device that controls the change of the imaging position of the structural steel imaging device 100 by controlling various moving mechanisms provided in the structural steel imaging device 100. The movement control device 300 may be realized by a computer including a CPU, a ROM, a RAM, a communication device, and the like, and is a dedicated circuit for controlling various movement mechanisms provided in the structural steel imaging device 100. May be. In FIG. 15, the movement control device 300 is illustrated as a device different from the arithmetic processing device 200, but the arithmetic processing device 200 may also have the function of the movement control device 300.

  The movement control device 300 is conveyed on the conveyance line by an input operation by the user of the surface defect inspection apparatus 10 or a control signal output from an apparatus (for example, a manufacturing control computer) that can communicate with the movement control device 300. When notified that the size of the shape steel to be changed is notified, information indicating that the size of the shape steel 1 is changed is notified to the shape steel imaging device 100 and the arithmetic processing device 200.

  The movement control device 300 acquires information about the size of the changed shape steel 1 together with the notification that the size of the shape steel 1 is changed. The information regarding the size of the shape steel after the change is, for example, an input operation by the user of the surface defect inspection apparatus 10, an apparatus (for example, a production control computer) that can communicate with the movement control apparatus 300, or the arithmetic processing apparatus 200. Acquired from various databases stored in

  The movement control device 300 includes information on the size of the reference shape, information on the laser light source 101 and the rod lens 103, and information on the reference imaging position of the TDI camera 105, and information on the acquired size of the changed shape. Based on this, it is determined whether or not the change of the shape steel satisfies a predetermined condition. When the movement control device 300 determines that the change of the shape steel satisfies a predetermined condition, the movement control device 300 determines the movement amount (more specifically, the laser light source 101) of the shape steel imaging device 100 based on the above-described information used for the determination. And the movement amount of the rod lens 103 and the TDI camera 105).

  In the following, referring to FIG. 16, a process for determining whether or not a predetermined condition that the movement control device 300 performs is satisfied, and a process for calculating the movement amount of the laser light source 101, the rod lens 103, and the TDI camera 105. Will be described in detail.

FIG. 16 is an explanatory diagram for explaining the movement amount of the structural steel imaging device 100 (more specifically, the laser light source 101, the rod lens 103, and the TDI camera 105).
16, a shaped steel section steel a is a reference has a maximum web height h _a among the shaped steel is conveyed, the flange width w _a, web thickness t1 a _flange thickness t2 _It shall have a. Further, in such a case, the laser light source 101 and the rod lens 103, and the reference imaging position of the TDI camera 105, as shown in FIG. 16, has a H0 = (1/2) _{h a.}

Further, in FIG. 16, the shape steel b corresponds to the shape steel after the size change, and has a web height h _b , a flange width w _b , a web thickness t1 _b , and a flange thickness t2 _b. .

  In such a case, the movement control device 300 first determines the value represented by (hb−t2b) for the shape steel b (that is, the side of the upper flange connected to the web as shown in FIG. 16). It is determined whether or not the height H1) to the surface is less than a value representing the center of the visual field of the TDI camera 105 (ie, H0).

  When such a condition is satisfied, the flange of the section steel b becomes an umbrella and the entire web inspection surface of the section steel b cannot be imaged. Therefore, the movement control device 300 includes the laser light source 101, the rod lens 103, In addition, the amount of movement of the TDI camera 105 is calculated to control the position change of these devices. Further, when such a condition is not satisfied (that is, when H0 ≦ H1), since the imaging region is not blocked by the flange of the shape steel after the size change, the movement control device 300 includes the laser light source 101 and The rod lens 103 and the TDI camera 105 are not moved.

  The movement control device 300 calculates the horizontal movement amount MX and the vertical movement amount MY of the laser light source 101, the rod lens 103, and the TDI camera 105 when the above-described conditions are satisfied. Here, the horizontal movement amount MX is determined such that the separation distance L between the TDI camera 105 and the web inspection surface is constant. That is, the movement control device 300 calculates the horizontal movement amount MX by the following equation 201. The horizontal movement amount MX represents the separation distance between the web inspection surface of the section steel a and the web inspection surface of the section steel b, as is apparent from the following equation 201. Further, the movement control device 300 calculates the vertical movement amount MY by the following expression 202 as is apparent from FIG.

_{MX = 1/2 (w a} + t1 a) -1/2 (w b + t1 b) ··· ( Formula 201)
MY = H0−H1 = (1/2) h _a − (h _b −t2 _b ) (Formula 202)

  When the movement control device 300 calculates the horizontal direction movement amount MX and the vertical direction movement amount MY, the movement control device 300 determines the movement mechanism provided in the shape steel imaging device 100 (the laser light source 101, the rod lens 103, and the TDI camera 105). , Information indicating these calculated movement amounts is transmitted. As a result, the laser light source 101, the rod lens 103, and the TDI camera 105 move their positions to a position where the entire web inspection surface of the size-changed shape steel (ie, the shape steel b) can be imaged. Can do. When the position change is completed, the shape steel imaging device 100 notifies the arithmetic processing device 200 to that effect. Thereby, the surface defect inspection process with respect to the shaped steel b which is the shaped steel after a size change will be started.

  When the surface defect inspection process for the shaped steel after the size change is completed, the movement control device 300 transmits a control signal instructing to return to the reference imaging position to the shaped steel imaging device 100.

  By performing the position control of the laser light source 101, the rod lens 103, and the TDI camera 105 as described above, the size of the shape steel conveyed on the conveyance line varies, and the conveyance position of the web inspection surface Even if they are different from each other, the optical system arrangement of the structural steel imaging device 100 is moved to an appropriate position. As a result, it is possible to accurately carry out surface defect inspection processing on various sizes of shape steel.

  The movement control processing of the laser light source 101, the rod lens 103, and the TDI camera 105 by the movement control device 300 has been described above with reference to FIG.

  Here, the movement control device 300 according to the present embodiment can perform movement control of the flange illumination device 107 in addition to the laser light source 101, the rod lens 103, and the TDI camera 105.

  Hereinafter, the movement control process of the flange illumination device 107 by the movement control device 300 will be described with reference to FIG. FIG. 17 is an explanatory diagram for explaining the movement amount of the flange illumination device according to the present embodiment.

  In the following description, as shown in FIG. 17, the laser light source 101 and the rod for imaging the shape steel having the maximum web height (section a) among the shape steels conveyed on the conveyance line. A coordinate system (u, v) is used in which the height of the reference imaging position of the lens 103 and the TDI camera 105 is the origin in the height direction. That is, in the coordinate system (u, v) shown in FIG. 17, it corresponds to the right end of the skid S, and the reference imaging of the laser light source 101 and the rod lens 103 and the TDI camera 105 when imaging the shaped steel a. The point corresponding to the height of the position is handled as the origin. The position of the flange illumination device 107 is represented as FS (u, v) using the uv coordinate system.

Here, the shape steel shown in FIG. 17 has a web height h, a flange width w, a web thickness t ₁ , a flange thickness t ₂ , and a radius r of the corner R portion. It shall be arrange | positioned in this position.

  In such a case, the installation position of the flange illuminating device 107 suitable for the shape steel shown in FIG. 17 is a position in an area (area shown by hatching in FIG. 17) that satisfies all the following three conditions.

(1) Shape steel center side of straight line LE connecting flange end M on the flange illumination device 107 side and end N of the R portion connected to the flange surface on the other side (2) Straight line perpendicular to the flange end shaped steel than L0 outward (3) outside the camera field of view (height V _C above the point of intersection between the camera view and the straight line L0 of imaging the structural steel a)

Here, the initial set position coordinate of the flange illumination device 107 based on the shape steel a that satisfies the above three conditions is represented as FS (u ₀ , v ₀ ). At the initial setting position FS (u ₀ , v ₀ ), v ₀ is a value set in advance so as to satisfy v ₀ > V _C.

Consider how the straight line LE and the straight line L0 are formulated in the uv coordinate system under such conditions.
First, regarding the straight line LE, the coordinate M and the coordinate N are expressed as follows in the uv coordinate system.

  Accordingly, the expression in the uv coordinate system representing the straight line LE is as shown in the following expression 251. Here, in the following formula 251, the coefficient a and the coefficient b are values represented by the following formula 252 and formula 253.

... (Formula 251)
... (Formula 252)
... (Formula 253)

  Further, since the straight line L0 is a straight line that passes through the coordinate M and is parallel to the web height direction, it can be expressed as the following Expression 254.

  u = w (Formula 254)

  Therefore, the position of the flange illumination device 107 with respect to the shape steel shown in FIG. 17 can be expressed as a position within a range that satisfies all of the following three conditional expressions.

(1) v> a · (u−w) + b
(2) u> w
(3) v> V _C

  Here, when Equation 251 is transformed and solved for u, Equation 255 below can be obtained.

... (Formula 255)

  Therefore, when the above conditions (1) to (3) are arranged in consideration of the above-described formula 255, the following formulas 256 and 257 can be expressed.

... (Formula 256)
... (Formula 257)

Therefore, the movement control device 300 according to the present embodiment controls various movement mechanisms provided in the flange illumination device 107 in accordance with the size of the shape steel, and from the coordinates FS (u ₀ , v ₀ ) of the initial setting position. The flange illumination device 107 may be moved to a position FS (u, v) that satisfies both the above formulas 256 and 267.

  Here, as the moving method of the flange illumination device 107, the following two types of methods can be mainly considered.

A method of moving the height position of the flange illumination device 107 in conjunction with the laser light source 101, the rod lens 103, and the TDI camera 105 and moving the horizontal position of the flange illumination device 107 in the horizontal direction. A method in which the height position of 107 is constant without being interlocked with the height positions of the laser light source 101, the rod lens 103, and the TDI camera 105, and is moved only in the horizontal direction.

  Below, the case where the movement control apparatus 300 moves the height direction and the horizontal direction of the flange illuminating device 107 first is demonstrated concretely.

When information related to the shape of the shape steel is input to the movement control device 300, the movement control device 300 uses the acquired information related to the shape of the shape steel to make the laser light source 101 and the rod lens 103 as described above. And movement amounts MX and MY of the TDI camera 105 are calculated. Here, when the movement control device 300 moves the laser light source 101, the rod lens 103, and the TDI camera 105 by MY in the negative v-axis direction with respect to the height direction (that is, the v-axis direction), the flange illumination device 107 is moved. Also, in conjunction with the movement of the laser light source 101, the rod lens 103, and the TDI camera 105 in the height direction, the laser beam is moved by MY to the v-axis negative direction side. Therefore, the coordinate v in the height direction of the flange illumination device 107 is moved to v = v ₀ -MY under the control of the movement control device 300.

In addition, the movement control device 300 sets the position of the flange illumination device 107 in the horizontal direction (that is, the u-axis direction) to a position that satisfies the above expression 256, that is, w <u <(1 / a) · (v ₀ −MY. -B) Move to a position u that satisfies + w.

  When the condition represented by Expression 256 is not satisfied, the movement control device 300 determines the horizontal position u of the flange illumination device 107 as the position represented by the Expression 254 and the position represented by the Expression 255. What is necessary is just to move so that it may become an intermediate position. That is, the movement control device 300 sets the horizontal position u of the flange illumination device 107 to a position represented by the following expression 258.

... (Formula 258)

  Therefore, when the condition represented by Expression 256 is not satisfied, the movement control device 300 sets the position of the flange illumination device 107 to the coordinate FS represented below and performs the movement control of the flange illumination device 107. Will be.

  Next, the case where the movement control device 300 moves only the horizontal direction of the flange illumination device 107 will be specifically described.

When information related to the shape of the shape steel is input to the movement control device 300, the movement control device 300 uses the acquired information related to the shape of the shape steel to make the laser light source 101 and the rod lens 103 as described above. And movement amounts MX and MY of the TDI camera 105 are calculated. Here, the movement control device 300 links the height of the flange illumination device 107 (that is, the position in the v-axis direction) with the movement of the laser light source 101, the rod lens 103, and the TDI camera 105 in the height direction. Instead, v ₀ which is the v coordinate of the initial setting position remains constant.

Further, the movement control device 300 sets the position of the flange illumination device 107 in the horizontal direction (that is, the u-axis direction) to a position that satisfies the above-described formula 256, that is, w <u <(1 / a) · (v ₀ −b). ) Move to position u satisfying + w.

  When the condition represented by Expression 256 is not satisfied, the movement control device 300 determines the horizontal position u of the flange illumination device 107 as the position represented by the Expression 254 and the position represented by the Expression 255. What is necessary is just to move so that it may become an intermediate position. That is, the movement control device 300 sets the horizontal position u of the flange illumination device 107 to a position represented by the following expression 259.

... (Formula 259)

  Therefore, when the condition represented by Expression 256 is not satisfied, the movement control device 300 sets the position of the flange illumination device 107 to the coordinate FS represented below and performs the movement control of the flange illumination device 107. Will be.

  In the above description, the case where the structural steel imaging device 100 includes one flange illumination device 107 including a moving mechanism has been described. However, the structural steel imaging device 100 includes a plurality of flange illumination devices 107. You may have. Since the shape steel imaging device 100 includes a plurality of flange illumination devices 107, it is possible to appropriately illuminate the end portion of the flange of the shape steel without performing the movement control processing of the flange illumination device 107 as described above. It becomes.

  Hereinafter, with reference to FIG. 18, the flange end illumination control process in the case where the structural steel imaging device 100 includes a plurality of flange illumination devices 107 will be briefly described. FIG. 18 is an explanatory diagram for describing a modification of the flange illumination device according to the present embodiment.

As shown in FIG. 18, the structural steel imaging device 100 according to the present embodiment includes a plurality of flange illumination devices 107 along the u-axis direction at a height of v = v ₀ that satisfies v> V _C. It may be. As shown in FIG. 18, it is possible to illuminate the flange end portion of the shape steel without performing the movement control as described above by providing the illumination device in an array.

  In such a case, the lighting control of the flange lighting device 107 is performed instead of the movement control of the flange lighting device 107 as described above. The lighting control of the flange illumination device may be performed by the movement control device 300, or the timing at which the movement amounts MX and MY of the laser light source 101 and the rod lens 103 and the TDI camera 105 calculated by the movement control device 300 are acquired. The signal generator 201 may implement this. Hereinafter, a case where the movement control device 300 performs the lighting control of the flange illumination device 107 will be described as an example.

As shown in FIG. 18, it is assumed that m flange illumination devices 107 are provided at equal intervals along the u-axis direction (that is, the direction perpendicular to the conveyance direction of the shape steel). Here, the interval between the adjacent flange illumination devices 107 can be determined based on the size of the shape steel actually conveyed on the conveyance line, for example, calculated based on the size of the shape steel to be conveyed. is the (1 / a) · (v 0 -b) of may be determined so that the minimum value and equal in value. At this time, the arrangement interval of the flange illuminating devices 107 is adjusted so that at least one flange illuminating device is arranged in a region satisfying the above-described formula 256. Further, the number of flange illumination devices to be installed may be set as appropriate in consideration of the size of the shape steel conveyed on the conveyance line. Here, the position coordinate of each flange illumination device is represented as FS _m (u _m , v ₀ ) (m = 1, 2,..., M).

In such a case, when the size of the shape steel to be conveyed is changed, the movement control device 300 uses the acquired information on the shape of the shape steel, and as described above, the laser light source 101 and the rod lens 103, and The movement amounts MX and MY of the TDI camera 105 are calculated. Subsequently, the movement control device 300 specifies the u coordinate value u _m that satisfies the following expression 260.

... (Formula 260)

Thereafter, the movement control device 300 uses the specified u coordinate value u _m to turn on the flange lighting device 107 so as to turn on only the flange lighting device existing at the position coordinates FS _m (u _m , v ₀ ). Implement control.

  The movement control process of the flange illumination device 107 by the movement control device 300 has been described above with reference to FIGS. 17 and 18.

  In the above-described embodiment, attention is paid to whether or not H0> H1 is satisfied as a condition when the movement control device 300 controls the imaging positions of the laser light source 101, the rod lens 103, and the TDI camera 105, and H0. In the case where ≦ H1, the case where the imaging positions of the laser light source 101, the rod lens 103, and the TDI camera 105 are not changed has been described.

  However, the conditions when the movement control device 300 controls the imaging positions of the laser light source 101, the rod lens 103, and the TDI camera 105 are not limited to the above example. For example, the movement control device 300 may determine whether or not to control the imaging position by paying attention to whether or not the center position of the web height changes when the type of the shape steel is switched. In such a case, the movement control device 300 keeps track of the type and size of the currently transferred shape steel, and when the size of the shape steel to be transferred is changed, the center position of the web height is changed. Determine whether it changes. When the movement control device 300 determines that the center position of the web height changes, the laser light source 101, the rod lens 103, and the TDI camera 105 are always set to the center position of the web height of the section steel. Device position control can be performed.

(About hardware configuration)
Next, the hardware configuration of the arithmetic processing apparatus 200 according to the embodiment of the present invention will be described in detail with reference to FIG. FIG. 19 is a block diagram for explaining a hardware configuration of the arithmetic processing device 200 according to the embodiment of the present invention.

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

  The CPU 901 functions as an arithmetic device and a control device, and controls all or a part of the operation in the arithmetic processing device 200 according to various programs recorded in the ROM 903, the RAM 905, the storage device 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 change as appropriate during execution of the programs, and the like. These are connected to each other 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 PCI (Peripheral Component Interconnect / Interface) 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, remote control means (so-called remote control) using infrared rays or other radio waves, or may be an external connection device 923 such as a PDA corresponding to the operation of the arithmetic processing device 200. May be. Furthermore, the input device 909 includes, for example, an input control circuit that generates an input signal based on information input by a user using the operation unit and outputs the input signal to the CPU 901. The user of the arithmetic processing device 200 can input various data and instruct processing operations to the arithmetic processing device 200 by operating the input device 909.

  The output device 911 is configured by a device that can notify the user of the acquired information visually or audibly. Examples of such devices include CRT display devices, liquid crystal display devices, plasma display devices, EL display devices and display devices such as lamps, audio output devices such as speakers and headphones, printer devices, mobile phones, and facsimiles. The output device 911 outputs results obtained by various processes performed by the arithmetic processing device 200, for example. Specifically, the display device displays results obtained by various processes performed by the arithmetic processing device 200 as text or images. 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 the analog signal.

  The storage device 913 is a data storage device configured as an example of a storage unit of the arithmetic processing device 200. The storage device 913 includes, for example, a magnetic storage device such as an HDD (Hard Disk Drive), 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 recording medium reader / writer, and is built in or externally attached to the arithmetic processing unit 200. The drive 915 reads information recorded on a removable recording medium 921 such as a mounted magnetic disk, optical disk, magneto-optical disk, or 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 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 medium, or the like. The removable recording medium 921 may be a CompactFlash (registered trademark) (CompactFlash: 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) on which a non-contact IC chip is mounted, an electronic device, or the like.

  The connection port 917 is a port for directly connecting a device to the arithmetic processing device 200. Examples of the connection port 917 include a USB (Universal Serial Bus) port, an IEEE 1394 port, a SCSI (Small Computer System Interface) port, and an RS-232C port. By connecting the external connection device 923 to the connection port 917, the arithmetic processing apparatus 200 acquires various data directly from the external connection device 923 or provides various data to the external connection device 923.

  The communication device 919 is a communication interface configured with, for example, a communication device for connecting to the communication network 925. The communication device 919 is, for example, a communication card for wired or wireless LAN (Local Area Network), Bluetooth (registered trademark), or WUSB (Wireless USB). The communication device 919 may be a router for optical communication, a router for ADSL (Asymmetric Digital Subscriber Line), or a modem for various communication. 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 and other communication devices. The communication network 925 connected to the communication device 919 is configured by a wired or wireless network, and may be, for example, the Internet, a home LAN, infrared communication, radio wave communication, satellite communication, or the like. .

  Heretofore, an example of the hardware configuration capable of realizing the function of the arithmetic processing device 200 according to the embodiment of the present invention has been shown. Each component 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 at the time of carrying out this embodiment.

  Note that the hardware configuration of the movement control device 300 according to the embodiment of the present invention is the same as the hardware configuration of the arithmetic processing device 200 according to the embodiment of the present invention, and thus detailed description thereof is omitted.

  As described above, in the surface defect inspection apparatus and the surface defect inspection method according to the embodiments of the present invention, the fringe image obtained by sequentially arranging the light section images obtained by the delay integration type imaging apparatus is inspected. It became possible to accurately determine the inspection range of objects. Therefore, even when the inspection object is a long material having a curved line in which both end portions are lowered or raised in the cross-sectional shape like the web surface of H-shaped steel, it is possible to improve the detection accuracy of surface defects including irregularities. it can.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Shape steel 2 Roller 10 Surface defect inspection apparatus 100 Shape steel imaging device 101 Laser light source 103 Rod lens 105 Delay integration type imaging device (TDI camera)
DESCRIPTION OF SYMBOLS 200 Arithmetic processor 201 Timing signal generation part 203 Image processing part 205 Display part 207 Storage part 209 Image generation part 211 A / D conversion part 213 Prefilter part 215 Orthogonal sine wave generation part 217,219 Low-pass filter part 221 Phase calculation part 223 Amplitude calculation unit 225 Phase continuation processing unit 227 Edge position detection unit 229 Edge dead zone calculation unit 231 Centering processing unit 233 Shape correction processing unit 235 Defect detection processing unit 300 Movement control device

Claims (8)

Shaped steel conveyed on a conveying line, which has a flange surface and a web surface, and is modulated into a shape steel in which the flange surface and the web surface are connected via a corner R portion. -Integration type imaging that generates a light-cut image that is a captured image of the laser light by imaging the linear laser light reflected by the shape steel and a laser light source and a rod lens that irradiate a laser beam A structural steel imaging device comprising: a device; and a flange illumination device that illuminates an end surface of the flange surface ;
An arithmetic processing device that performs image processing on a captured image of the shape steel generated by the shape steel imaging device and determines whether or not a defect exists on the surface of the web surface;
With
The arithmetic processing unit includes:
By using a fringe image composed of a light section image generated by the shape steel imaging device, a shape image representing an uneven state on the surface of the shape steel and a difference in roughness on the surface of the shape steel are represented. An image generation unit for generating a luminance image;
An edge position detection unit that detects an edge position of the flange surface based on the luminance image;
Using the edge position detected by the edge position detection unit, information on the shape of the shape steel, and information on the positional relationship between the shape steel imaging device and the shape steel, the flange in the shape image An edge dead zone calculator that calculates a dead zone corresponding to the surface;
Of the shape image, a portion excluding the dead zone calculated by the edge dead zone calculation unit is a surface defect detection target portion, and for the surface defect detection target portion, a defect detection processing unit that detects an existing surface defect;
I have a,
The surface defect inspection apparatus, wherein the edge dead zone calculation unit detects an edge position of the flange surface from image information relating to an end surface of the flange surface . 2. The surface defect inspection apparatus according to claim 1, wherein the installation position of the flange illumination device is a position in an area that satisfies all of the following three conditions (1) to (3).
  (1) Of the end of the flange surface on the side where the flange illumination device is located, the other of the end on the side connected to the corner R portion and the other end of the corner R portion connected to the flange surface on the other side On the center side of the shape steel with respect to the straight line connecting the point connected to the flange surface on the side
  (2) Shape steel outer side than a straight line passing through the end of the flange surface and perpendicular to the horizontal plane
  (3) Outside the field of view of the delay integration type imaging device   The arithmetic processing unit further includes a shape correction processing unit that separates the surface defect detection target portion into the web surface and the corner R portion, and performs correction for flattening the shape image corresponding to the corner R portion. The surface defect inspection apparatus according to claim 1, further comprising a surface defect inspection apparatus. The apparatus further comprises a movement control device that moves the position of the laser light source and the rod lens, the delay integration type imaging device, and the flange illumination device according to the size of the shape steel to be inspected. The surface defect inspection apparatus of any one of Claims 1-3 . A plurality of the flange illumination devices are provided at predetermined intervals along the width direction of the flange surface,
The surface defect inspection device further includes a movement control device for moving the position of the laser light source and the rod lens and the delay integration type imaging device according to the size of the shape steel to be inspected. The surface defect inspection apparatus according to any one of claims 1 to 3 .   The movement control device maintains the relative positional relationship between the laser light source and the rod lens of the structural steel imaging device and the delay integration type imaging device, and the laser light source and the rod lens and the delay. 6. The surface defect inspection apparatus according to claim 4, wherein a position in the height direction of the web surface with respect to the integral imaging device and a position in the width direction of the flange surface are moved. Shaped steel that is conveyed on a conveying line, and has a flange surface and a web surface, and the shaped steel is connected to the flange surface and the web surface via a corner R portion. -Integration type imaging that generates a light-cut image that is a captured image of the laser light by imaging the linear laser light reflected by the shape steel and a laser light source and a rod lens that irradiate a laser beam Imaging a shape-steel imaging device having a device and a flange illuminating device that illuminates an end surface of the flange surface to generate a light section image that is an image captured by the laser beam;
Using a fringe image composed of the generated light section image, a shape image representing the uneven state of the surface of the shape steel, and a luminance image representing a difference in roughness on the surface of the shape steel, Generating step;
Detecting an edge position of the flange surface based on the generated luminance image;
A portion corresponding to the flange surface in the shape image by using the detected edge position, information on the shape of the shape steel, and information on a positional relationship between the shape steel imaging device and the shape steel. Calculating as a dead zone;
Of the shape image, a portion excluding the calculated dead zone is a surface defect detection target portion, and for the surface defect detection target portion, detecting a surface defect existing;
Only including,
In the step of calculating the dead zone, an edge position of the flange surface is detected from image information relating to an end surface of the flange surface . Shaped steel conveyed on a conveying line, which has a flange surface and a web surface, and is modulated into a shape steel in which the flange surface and the web surface are connected via a corner R portion. -Integration type imaging that generates a light-cut image that is a captured image of the laser light by imaging the linear laser light reflected by the shape steel and a laser light source and a rod lens that irradiate a laser beam A computer capable of communicating with a structural steel imaging device having a device and a flange illumination device that illuminates an end surface of the flange surface ;
By using a fringe image composed of a light section image generated by the shape steel imaging device, a shape image representing an uneven state on the surface of the shape steel and a difference in roughness on the surface of the shape steel are represented. An image generation function for generating a luminance image;
An edge position detection function for detecting an edge position of the flange surface based on the luminance image;
Using the edge position detected by the edge position detection function, information on the shape of the shape steel, and information on the positional relationship between the shape steel imaging device and the shape steel, the flange in the shape image Edge dead zone calculation function to calculate the part corresponding to the surface as dead zone,
Of the shape image, a portion excluding the dead zone calculated by the edge dead zone calculation function is a surface defect detection target portion, and for the surface defect detection target portion, a defect detection processing function for detecting an existing surface defect,
To achieve,
The edge dead zone calculation function is a program for detecting an edge position of the flange surface from image information relating to an end surface of the flange surface .