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KR-20260065931-A - Pipe surface inspection device, surface inspection method, manufacturing device, manufacturing method, quality control method, and pipe

KR20260065931AKR 20260065931 AKR20260065931 AKR 20260065931AKR-20260065931-A

Abstract

A surface inspection device for a tube related to the present invention is a surface inspection device for a tube that inspects the inner surface of a tube as an inspection target area, and comprises an imaging element having a field of view on the inner surface and two distinguishable light sources, an imaging unit positioned on the axis of the tube to enclose the imaging element with the two distinguishable light sources, a processing unit that acquires an image by capturing reflected light from each light source, generates a difference image of the two acquired images, and detects surface defects in the inspection target area from the generated difference image, and a scanning unit that scans the imaging unit in the direction of the tube axis, wherein the two distinguishable light sources irradiate illumination light onto the same predetermined inspection target area, and the imaging element captures an image of the predetermined inspection target area.

Inventors

  • 오노 히로아키
  • 구보 류지
  • 가시와바라 유타

Assignees

  • 제이에프이 스틸 가부시키가이샤

Dates

Publication Date
20260511
Application Date
20240805
Priority Date
20231027

Claims (13)

  1. A tube surface inspection device that inspects the inner surface of a tube as the inspection target area, An imaging unit having an imaging element having a field of view on the inner surface and two distinguishable light sources, and positioned on the axis of the tube to enclose the imaging element with the two distinguishable light sources, A processing unit that acquires an image of reflected light from each light source, generates a difference image of the two acquired images, and detects surface defects in the inspection target area from the generated difference image, and The above imaging unit is provided with an injection unit that injects the above imaging unit in the axial direction of the above tube, and The two discriminable light sources above irradiate illumination light onto the same predetermined inspection target area, and The above imaging element is a surface inspection device for a tube that captures an image of the above-mentioned inspection target area.
  2. In Article 1, A surface inspection device for a tube, wherein the imaging pitch of the imaging element in the axial direction of the tube is smaller than the value obtained from the inner radius of the tube, the maximum displacement amount of the imaging element assumed when scanning the imaging unit in the axial direction of the tube, the axial overlap width of two fields of view of the imaging element adjacent in the axial direction of the tube, and the angle of view of the imaging element in the axial direction of the tube.
  3. In Article 1 or Article 2, A surface inspection device for a tube, wherein the above-described imaging element is a full circumference imaging element capable of obtaining an image of the entire area in the circumferential direction of the inner surface of the tube in a single imaging shot.
  4. In any one of paragraphs 1 to 3, A surface inspection device for a tube, wherein the difference in angle between the specular reflection direction of illumination light from an upstream light source positioned upstream of the imaging element in the axial direction of the tube and the imaging direction of the imaging element, and the angle between the specular reflection direction of illumination light from a downstream light source positioned downstream of the imaging element in the axial direction of the tube and the imaging direction of the imaging element is greater than a value obtained from the inner radius of the tube, the maximum displacement amount of the imaging element assumed when scanning the imaging part in the axial direction of the tube, the angle of view of the imaging element in the axial direction of the tube, and the distance from the imaging element to the upstream light source or the downstream light source.
  5. In any one of paragraphs 1 to 4, A tube surface inspection device in which the two aforementioned distinguishable light sources are circular illuminations.
  6. In any one of paragraphs 1 to 5, The above injection unit is a tube surface inspection device that injects the imaging element along the central axis of the tube.
  7. A surface inspection method for a tube in which the inner surface of the tube is inspected as the inspection target area, A processing step comprising: using an imaging unit positioned on the axis of the tube to enclose the imaging element with the two distinguishable light sources, the imaging element having a field of view on the inner surface and two distinguishable light sources, thereby acquiring an image of reflected light from each light source, generating a difference image of the two acquired images, and detecting surface defects in the inspection target area from the generated difference image; It includes a scanning step for scanning the imaging unit in the axial direction of the tube, and A method for inspecting the surface of a tube, wherein the processing step comprises irradiating illumination light onto the same predetermined inspection target area using the two distinguishable light sources and capturing an image of the predetermined inspection target area using the imaging element.
  8. In Article 7, A method for inspecting the surface of a tube, wherein the imaging pitch of the imaging element in the axial direction of the tube is smaller than the value obtained from the inner radius of the tube, the maximum displacement amount of the imaging element assumed when scanning the imaging portion in the axial direction of the tube, the axial overlap width of two fields of view of the imaging element adjacent in the axial direction of the tube, and the angle of view of the imaging element in the axial direction of the tube.
  9. In Article 7 or Article 8, A method for inspecting the surface of a tube, wherein the imaging element is a full circumference imaging element capable of obtaining an image of the entire circumference area of the inner surface of the tube in a single imaging step.
  10. A tube manufacturing apparatus having a tube surface inspection device described in any one of claims 1 to 6.
  11. A method for manufacturing a tube, wherein the inner surface of the tube is inspected using a surface inspection method for a tube described in any one of claims 7 to 9, and the tube is manufactured based on the inspection results.
  12. A quality control method for a tube, wherein the inner surface of the tube is inspected using a surface inspection method for a tube described in any one of claims 7 to 9, and the quality of the tube is controlled based on the inspection results.
  13. A tube whose quality is guaranteed by the surface inspection method of a tube described in any one of paragraphs 7 to 9.

Description

Pipe surface inspection device, surface inspection method, manufacturing device, manufacturing method, quality control method, and pipe The present invention relates to a surface inspection device for a tube, a surface inspection method, a manufacturing device, a manufacturing method, a quality control method, and a tube, wherein the inner surface of the tube is inspected as an inspection target area. In modern society, pipes are used in various applications, such as construction, infrastructure like pipelines, transportation equipment, and industrial machinery, and their quality is critical from a safety perspective. In particular, if there are surface defects in pipes, they can lead to reduced strength or failure originating from those defects, potentially resulting in severe damage such as structural collapse or the leakage of pipeline contents. Among these surface defects, concave defects caused by the indentation of foreign substances during manufacturing processes like rolling directly lead to wall thinning; furthermore, if the defects are caused by foreign substances stuck to rolling rolls, they occur repeatedly and pose a high risk. Therefore, inspecting for such surface defects at the raw material stage to prevent leakage into the product is crucial for preventing serious accidents. For example, in the case of steel pipes made of iron, products are sometimes shipped after undergoing a process in which the presence or absence of surface defects is inspected by visually examining the exterior after forming. At this time, surface defects on the outer surface of the steel pipe can be inspected under conditions where visual observation is easy and defects are easily detected. In contrast, regarding surface defects on the inner surface of the steel pipe, since visual inspection is performed by looking into the inner surface from the outside, it is very difficult to inspect under conditions where surface defects are easily detected because the distance to the surface defect is long or the inner core is observed at a very shallow angle. For this reason, submerged pipe inspection, which involves entering the inside of the steel pipe to inspect, is sometimes performed; however, there are many challenges, such as the fact that it is a dangerous operation and that it cannot be applied to small-diameter steel pipes where submerged pipe inspection is difficult in the first place. Against this backdrop, there is a strong demand for technology that measures the condition of the inner surface of a steel pipe and automatically detects concave surface defects, and various technology developments have been carried out in the past. Specifically, Patent Document 1 describes a method of capturing the inner surface of a steel pipe with a camera and detecting surface defects from the obtained image. FIG. 1 is a schematic diagram showing the overall configuration of a surface inspection device, which is an embodiment of the present invention. FIG. 2 is a schematic diagram showing the configuration of a modified example of the injection part shown in FIG. 1. FIG. 3 is a schematic diagram for explaining the configuration of the imaging unit shown in FIG. 1. FIG. 4 is a diagram showing the configuration of the downstream optical system, an inner image, and a difference image obtained from the inner image. Figure 5 is a schematic diagram showing the configuration of the upstream light source and the downstream light source. Figure 6 is a schematic diagram showing the configuration of the entire perimeter camera. Figure 7 is a schematic diagram showing the configuration of a modified example of a full perimeter camera. Figure 8 is a schematic diagram showing the configuration of a modified example of a full perimeter camera. Figure 9a is a schematic diagram illustrating the configuration of a full perimeter camera. Figure 9b is a schematic diagram illustrating the configuration of the entire perimeter camera. FIG. 10 is a flowchart showing the flow of image processing, which is an embodiment of the present invention. Figure 11 is a diagram illustrating the flow of image processing shown in Figure 10. FIG. 12 is a drawing showing the light and shadow patterns of concave surface defects and convex surface defects, where FIG. 12(a) shows the light and shadow pattern of concave surface defects and FIG. 12(b) shows the light and shadow pattern of convex surface defects. FIG. 13 is a drawing showing an example of a concave-shaped surface defect detected by image processing shown in FIG. 10. Figure 14 is a schematic diagram illustrating the configuration of the injection unit. Figure 15 is a schematic diagram illustrating the configuration of the injection unit. Figure 16 is a diagram showing an example of a defect map. FIG. 17 is a schematic diagram showing an example of the configuration of a marking device. FIG. 18 is a schematic diagram showing an example of the configuration of a marking device. Hereinafter, with reference to the