JP2025036862A - Apparatus and method for determining defects on outer peripheral surface of pipe - Google Patents

Abstract

To provide a defect determination device which can precisely determine a defect in the outer circumferential surface of a pipe.SOLUTION: A defect determination device 1 determines a defect in an outer circumferential surface Wa of a pipe W, which is glossy on the outer circumferential surface. The defect determination device 1 includes: a pair of light source parts 12a, 12b arranged so that light is radiated to the same part of the outer circumferential surface Wa of the pipe W without causing an optical axis L to intersect with the outer circumferential surface Wa; an image acquisition unit 11 for acquiring an image of the part to which light is radiated from the pair of light source parts 12a, 12b of the outer circumferential surface Wa; and a defect determination unit 30 for determining a defect in the outer circumferential surface Wa of the pipe W by using the image acquired by the image acquisition unit 11.SELECTED DRAWING: Figure 1

Description

The present invention relates to a defect determination device and a defect determination method for determining defects that occur on the outer surface of a tube having a glossy outer surface.

There is a known device that detects defects on the outer surface of a tube that has a glossy outer surface. For example, Patent Document 1 discloses an appearance inspection device that can properly detect geometric appearance defects such as uneven or dented shapes formed on the outer surface of a tube.

The visual inspection device of Patent Document 1 includes an illumination device that irradiates the outer peripheral surface of the tube with uniform diffused light, and a camera that captures a grayscale image of the shadow formed on the outer peripheral surface of the tube by irradiating the diffused light.

The optical axis of the camera is disposed at an angle to the axis of the tube. The diffused light is obtained by diffusing light irradiated from an LED by a reflective surface formed on the hemispherical inner surface of the dome. The diffused light is of uniform intensity and is irradiated onto the outer peripheral surface of the tube in a direction oblique to the axis of the tube. When the outer peripheral surface of the tube is irradiated with uniform diffused light, uneven and concave shadows are created on the irradiated surface. When the outer peripheral surface of the tube is imaged with a camera, a clear image of the shades of the shadows formed by the irradiation of diffused light is obtained.

JP 2011-106909 A

The visual inspection device disclosed in the above-mentioned Patent Document 1 can properly detect geometrical visual defects such as uneven or concave shapes formed on the outer peripheral surface of a pipe.

However, defects other than geometrical appearance defects may occur on the outer surface of the tube. For example, defects on the outer surface of the tube include foreign matter contamination, segregation or whitening, waviness, uneven color, etc. These defects appear as color changes on the outer surface of the tube.

Therefore, if diffuse light is irradiated onto the outer surface of the tube so that the optical axis is oblique to the axis of the tube, as in the appearance inspection device disclosed in Patent Document 1, and a camera is positioned so that the optical axis is oblique to the axis of the tube, the light is reflected by the outer surface of the tube, and a clear image including the defect cannot be obtained. As a result, defects other than geometric appearance defects cannot be detected with high accuracy.

The object of the present invention is to provide a defect determination device that can accurately determine defects on the outer peripheral surface of a pipe.

A defect determination device for a pipe outer circumferential surface according to one embodiment of the present invention determines defects in the outer circumferential surface of a tube having a glossy outer circumferential surface. This defect determination device has a pair of light source units arranged so that light is irradiated to the same portion of the outer circumferential surface of the tube without intersecting the optical axis of the outer circumferential surface of the tube, an image acquisition unit that acquires an image of the portion of the outer circumferential surface of the tube that is irradiated with the light emitted from the pair of light source units, and a defect determination unit that uses the image acquired by the image acquisition unit to determine defects in the outer circumferential surface of the tube (first configuration).

This allows the light emitted from each of a pair of light source units to illuminate the same portion of the outer surface of the tube, without directly irradiating the outer surface of the tube with light whose optical axis intersects with the outer surface of the tube. Therefore, the pair of light source units can illuminate the outer surface of the tube more brightly, and reflected light caused by the light emitted from the pair of light source units being reflected by the outer surface of the tube can be prevented from being captured in the image acquired by the image acquisition unit. Therefore, the image acquired by the image acquisition unit can be used to accurately determine defects in the outer surface of the tube.

In the first configuration, the pair of light source units are arranged opposite each other so that the optical axes are parallel to each other and the light is irradiated onto the same portion of the outer circumferential surface of the tube (second configuration).

This makes it possible to suppress variations in brightness on the outer peripheral surface of the tube irradiated with light emitted from a pair of light source units arranged opposite each other. Therefore, the image acquisition unit can acquire an image in which defects on the outer peripheral surface of the tube are more clearly displayed. Therefore, the image acquired by the image acquisition unit can be used to accurately determine defects on the outer peripheral surface of the tube.

In the second configuration, the optical axes of the pair of light source units are located at the same radial position of the tube relative to the axis when viewed from the side in a direction perpendicular to the axis (third configuration).

The optical axes of the pair of light source units are positioned at the same position in the radial direction of the tube relative to the axis when viewed from the side in a direction perpendicular to the axis of the tube, so that the outer peripheral surface of the tube can be evenly illuminated by the light emitted from the pair of light source units. This makes it possible to prevent light and dark areas from appearing on the outer peripheral surface of the tube, as occurs when the optical axes of the pair of light source units are misaligned in the radial direction.

This allows the image acquisition unit to acquire an image in which defects are more clearly displayed. Therefore, the image acquired by the image acquisition unit can be used to accurately determine defects on the outer peripheral surface of the pipe.

In the first configuration, the image acquisition unit is disposed at a position radially away from the tube than the pair of light source units (fourth configuration).

By positioning the image acquisition unit at a position radially away from the tube relative to the pair of light source units, it is possible to prevent the shadow of the image acquisition unit from being cast on the image acquired by the image acquisition unit. This allows the image acquisition unit to acquire an image in which defects on the outer peripheral surface of the tube are more clearly displayed. Therefore, the image acquired by the image acquisition unit can be used to accurately determine defects on the outer peripheral surface of the tube.

In the second configuration, the defect determination device has multiple pairs of the light source units. The multiple pairs of light source units are arranged in a line in the circumferential direction of the tube. The image acquisition units are arranged in multiple numbers in the circumferential direction of the tube so as to acquire images of the outer circumferential surface of the tube illuminated by the light emitted from the pair of light source units (fifth configuration).

The outer peripheral surface of the tube is irradiated with light emitted from multiple pairs of light source units arranged in the circumferential direction of the tube. This makes it possible to further suppress variations in brightness on the outer peripheral surface of the tube. This allows the image acquisition unit to acquire an image in which defects on the outer peripheral surface of the tube are more clearly displayed. Therefore, the image acquired by the image acquisition unit can be used to accurately determine defects on the outer peripheral surface of the tube.

In addition, the multiple image acquisition units can efficiently acquire images of the outer surface of the pipe. Therefore, the defect determination device having the above-mentioned configuration can efficiently determine defects on the outer surface of the pipe.

In the first configuration, the image acquisition unit acquires an image of the portion of the outer surface of the tube that is irradiated with the light emitted from the pair of light source units, viewed from a direction perpendicular to the axis of the tube (sixth configuration).

This allows the image acquisition unit to acquire an image in which defects are more clearly displayed. Therefore, the image acquired by the image acquisition unit can be used to accurately determine defects on the outer peripheral surface of the pipe.

In the first configuration, the defect determination device further includes a shielding member that covers a portion of the outer circumferential surface of the tube so as to block light other than the light emitted from the pair of light source units. The pair of light source units are arranged to irradiate light onto the portion of the outer circumferential surface of the tube that is covered by the shielding member. The image acquisition unit is arranged to acquire an image of the portion of the portion covered by the shielding member that is irradiated with the light emitted from the pair of light source units (seventh configuration).

In this way, by covering a portion of the outer surface of the tube with a shielding member so as to block light other than that emitted from the pair of light source units, it is possible to prevent light other than that emitted from the pair of light source units from appearing in the image acquired by the image acquisition unit. Therefore, defects in the outer surface of the tube can be accurately determined using the image acquired by the image acquisition unit.

In the first configuration, the defect determination device further includes a defective pipe sorting unit that sorts defective pipes having defects determined by the defect determination unit (eighth configuration). This makes it possible to sort and exclude defective pipes having defects.

In the first configuration, the defect determination device further includes a defect position identification unit that identifies the position of the defect in the pipe determined by the defect determination unit, and a defective pipe identification unit that identifies a defective pipe product having the defect from among multiple pipe products obtained by cutting the pipe in the axial direction based on the position of the defect identified by the defect position identification unit (ninth configuration).

As a result, the defective pipe identification unit can identify defective pipe products from among the multiple pipe products obtained by cutting the pipe in the axial direction. Therefore, defective pipe products can be selected from the multiple pipe products.

In the ninth configuration, the defect determination device further includes a defective pipe sorting unit that sorts the defective pipe products identified by the defective pipe identification unit (tenth configuration).

This makes it possible to separate defective pipe products that have defects from among a plurality of pipe products. Therefore, defective pipe products that have defects can be excluded from among a plurality of pipe products.

A method for determining defects in the outer peripheral surface of a tube according to one embodiment of the present invention is a method for determining defects in the outer peripheral surface of a tube having a glossy outer peripheral surface. This defect determination method includes an image acquisition step of acquiring an image of a portion of the outer peripheral surface of the tube that is irradiated with light emitted from a pair of light source units that are arranged so that the light is irradiated to the same portion of the outer peripheral surface of the tube without intersecting the optical axis of the outer peripheral surface of the tube, and a defect determination step of determining defects in the outer peripheral surface of the tube using the image acquired in the image acquisition step (first method).

This allows the light emitted from each of the pair of light source units to illuminate the same portion of the outer surface of the tube, without directly irradiating the outer surface of the tube with light so that the optical axis intersects with the outer surface of the tube. Therefore, the pair of light source units can illuminate the outer surface of the tube more brightly, and reflected light caused by the light emitted from the pair of light source units being reflected by the outer surface of the tube can be prevented from being captured in the image acquired in the image acquisition step. Therefore, the image acquired in the image acquisition step can be used to accurately determine defects in the outer surface of the tube.

In the first method, the defect determination method further includes a defective pipe sorting step of sorting defective pipes having defects determined by the defect determination step (second method). This makes it possible to sort and exclude defective pipes having defects.

In the first method, the defect determination method further includes a defect position identification step of identifying the position of the defect determined in the defect determination step in the pipe, a defective pipe identification step of identifying defective pipe products having the defect from among multiple pipe products obtained by cutting the pipe in the axial direction based on the position of the defect identified in the defect position identification step, and a defective pipe sorting step of sorting the defective pipe products identified in the defective pipe identification step (third method).

This makes it possible to separate defective pipe products that have defects from among a plurality of pipe products. Therefore, defective pipe products that have defects can be excluded from among a plurality of pipe products.

A defect determination device for a tube outer peripheral surface according to one embodiment of the present invention includes a pair of light source units arranged so that light is irradiated onto the same portion of the outer peripheral surface of the tube without intersecting the optical axis of the outer peripheral surface of the tube, an image acquisition unit that acquires an image of the portion of the outer peripheral surface of the tube that is irradiated with the light emitted from the light source units, and a defect determination unit that uses the image acquired by the image acquisition unit to determine defects in the outer peripheral surface of the tube.

This allows the light emitted from each of a pair of light source units to illuminate the same portion of the outer surface of the tube, without directly irradiating the outer surface of the tube with light whose optical axis intersects with the outer surface of the tube. Therefore, the pair of light source units can illuminate the outer surface of the tube more brightly, and reflected light caused by the light emitted from the light source units being reflected by the outer surface of the tube can be prevented from being captured in the image acquired by the image acquisition unit. Therefore, the image acquired by the image acquisition unit can be used to accurately determine defects in the outer surface of the tube.

FIG. 1 is a diagram showing a schematic configuration of a defect determination device according to the first embodiment. FIG. 2 is a diagram showing an example of a defect on the outer peripheral surface of a pipe. FIG. 3 is a functional block diagram showing a schematic configuration of the defect determination unit. FIG. 4 is a flowchart showing a defect determination method executed by the defect determination device according to the first embodiment. FIG. 5 is a diagram showing a schematic configuration of a defect determination device according to the second embodiment when viewed from the side in a direction perpendicular to the axis of the pipe. FIG. 6 is a diagram showing a schematic configuration of a defect determination device according to the second embodiment when viewed in the axial direction of a pipe. FIG. 7 is a diagram showing a schematic configuration of a defect determination device according to the third embodiment. FIG. 8 is a diagram showing a schematic configuration of a pipe manufacturing apparatus including a defect determination device according to the fourth embodiment. FIG. 9 is a flow chart illustrating a tube making method performed by the tube making machine. FIG. 10 is a flowchart showing a defect determination method executed by the defect determination device according to the fourth embodiment.

Each embodiment will be described below with reference to the drawings. In each drawing, the same parts are given the same reference numerals, and the description of the same parts will not be repeated. Note that the dimensions of the components in each drawing do not faithfully represent the actual dimensions of the components or the dimensional ratios of each component.

In the following description, the vertical direction refers to the vertical direction relative to the pipe W on which the defect determination device 1, 100, 200, 300 performs defect determination when the pipe W is positioned so that its axis P extends horizontally. The axial direction refers to the direction in which the axis P of the pipe W extends. The radial direction refers to the direction perpendicular to the axis P of the pipe W, i.e., the radial direction of the pipe W.

[Embodiment 1]
(Overall composition)
1 is a diagram showing a schematic configuration of a defect determination device 1 according to a first embodiment of the present invention. The defect determination device 1 determines the presence or absence of a defect on an outer peripheral surface Wa of a pipe W. The defect determination device 1 may determine not only the presence or absence of a defect on the outer peripheral surface Wa of the pipe W but also the type of the defect, or may determine only the type of the defect.

The pipe W is made of, for example, resin. The outer peripheral surface Wa of the pipe W has a glossy surface. In other words, the outer peripheral surface Wa of the pipe W has a smoothness that reflects incident light. The pipe W may be made of a material other than resin, so long as the material can provide a surface that is smooth enough to reflect incident light. The outer peripheral surface Wa of the pipe W may have any color, such as gray, black, orange, or white.

As shown in FIG. 1, the defect determination device 1 has an image acquisition unit 11, a pair of light source units 12a and 12b, and a defect determination unit 30.

The image acquisition unit 11 acquires an image of the outer peripheral surface Wa of the tube W. The image acquisition unit 11 includes an imaging device such as a CCD camera. The image acquired by the image acquisition unit 11 is output to the defect determination unit 30 as image data. Note that the image acquisition unit 11 may be an imaging device other than a CCD camera.

The image acquisition unit 11 is positioned relative to the outer peripheral surface Wa of the pipe W in a direction perpendicular to the axis P of the pipe W. In this embodiment, the image acquisition unit 11 is positioned above the pipe W, which is arranged so that its axis P extends horizontally. The image acquisition unit 11 acquires an image of the outer peripheral surface Wa of the pipe W from a direction perpendicular to the axis P of the pipe W (the radial direction of the pipe W).

The pair of light source units 12a, 12b irradiate light onto a portion of the outer surface Wa of the tube W, the image of which is acquired by the image acquisition unit 11. The pair of light source units 12a, 12b include, for example, an LED lighting device.

The pair of light source units 12a, 12b are arranged so as to be aligned in the axial direction of the tube W when viewed radially of the tube W. The pair of light source units 12a, 12b are also arranged so as to sandwich the image acquisition unit 11 in the axial direction of the tube W when viewed radially of the tube W. The pair of light source units 12a, 12b are arranged so that the optical axis L is parallel to the axis P of the tube W with respect to the outer peripheral surface Wa of the tube W. As a result, the outer peripheral surface Wa of the tube W is irradiated with light emitted from the pair of light source units 12a, 12b.

The pair of light source units 12a, 12b are arranged opposite each other so that their optical axes L are parallel to each other and the light is irradiated onto the same portion of the outer circumferential surface Wa of the tube W. In other words, the pair of light source units 12a, 12b are arranged opposite each other so that they illuminate each other. The pair of light source units 12a, 12b are positioned so that they overlap when viewed in the axial direction of the tube W. With the above configuration, the outer circumferential surface Wa of the tube W is illuminated more brightly and more uniformly by the light emitted from the pair of light source units 12a, 12b.

The pair of light source units 12a, 12b are positioned in a direction perpendicular to the axis P of the tube W relative to the outer peripheral surface Wa of the tube W. In this embodiment, the image acquisition unit 11 is positioned above the tube W, which is arranged so that the axis P extends horizontally. The image acquisition unit 11 is positioned at a position radially away from the outer peripheral surface Wa of the tube W than the pair of light source units 12a, 12b. This allows the image acquisition unit 11 to acquire an image of the outer peripheral surface Wa of the tube W irradiated with light by the pair of light source units 12a, 12b without the shadow of the image acquisition unit 11 being captured.

In this embodiment, the direction in which the image acquisition unit 11 acquires an image of the outer peripheral surface Wa of the tube W is perpendicular to the optical axis L of the pair of light source units 12a and 12b. In other words, the image acquisition unit 11 acquires an image of the outer peripheral surface Wa of the tube W viewed from a direction perpendicular to the optical axis L of the pair of light source units 12a and 12b.

In the case of a tube W with a glossy outer peripheral surface Wa, when light is irradiated so that the optical axis L intersects with the outer peripheral surface Wa, reflected light is generated by the outer peripheral surface Wa. As a result, defects that appear as color changes on the outer peripheral surface Wa are difficult to identify. In contrast, by arranging a pair of light source units 12a, 12b so that the optical axis L does not intersect with the outer peripheral surface Wa as described above, it is possible to irradiate light onto the outer peripheral surface Wa without light being reflected by the outer peripheral surface Wa. Therefore, the image acquisition unit 11 can acquire an image in which defects that appear as color changes on the outer peripheral surface Wa can be identified.

The defect determination unit 30 uses the image of the outer peripheral surface Wa of the pipe W acquired by the image acquisition unit 11 to determine the presence or absence of defects on the outer peripheral surface Wa of the pipe W. The defect determination unit 30 detects defects on the outer peripheral surface Wa of the pipe W, for example, by acquiring data that serves as a reference for determining defects on the outer peripheral surface Wa of the pipe W as judgment reference data. The defect determination unit 30 may detect defects on the outer peripheral surface Wa of the pipe W and may also determine the type of the defect. The defect determination unit 30 may have a learning function that learns defects by machine learning.

2 is a diagram showing an example of the types of defects that occur on the outer surface Wa of the pipe W. As shown in FIG. 2, the defects include foreign matter D1, color unevenness D2, chip winding D3, segregation D4, etc. The foreign matter D1 occurs due to the inclusion of a foreign matter in the resin of the pipe W or a malfunction in melting the resin material. The color unevenness D2 occurs due to the inclusion of a foreign matter in the resin of the pipe W or a malfunction in melting the resin material. The color of the part where the foreign matter D1 and color unevenness D2 occur is different from the color of the resin material that constitutes the pipe W. The chip winding D3 occurs due to the wrapping of chips generated when cutting the pipe W. The chip winding D3 is a friction that occurs on the outer surface Wa of the pipe W. The segregation D4 occurs due to the inclusion of a foreign matter in the resin of the pipe W or a malfunction in melting the resin material. The color of the part where the foreign matter D1, color unevenness D2, and segregation D4 occur is different from the color of the resin material that constitutes the pipe W.

In addition to the above defects, the defects also include waviness due to insufficient cooling, poor inner and outer surface texture due to adhesions to the mold or insufficient degassing when the resin material melts, and sweating due to insufficient cooling.

Figure 3 is a functional block diagram showing the schematic configuration of the defect determination unit 30. As shown in Figure 3, the defect determination unit 30 has a determination criterion data acquisition unit 31, a determination execution unit 32, and a determination result output unit 33.

The judgment criteria data acquisition unit 31 acquires judgment criteria data including data that serves as a criterion for judging defects on the outer peripheral surface Wa of the pipe W. The judgment criteria data may be, for example, image data of a non-defective product with no defects on the outer peripheral surface Wa of the pipe W, or image data showing an example of a defect occurring on the outer peripheral surface Wa of the pipe W. Note that the image data showing an example of the defect may include image data relating to only one type of defect, or may include image data relating to multiple types of defects.

The criteria data may be acquired by the image acquisition unit 11, may be acquired by another image acquisition device, or may be image data stored in a storage device, a network, etc.

The judgment execution unit 32 judges the presence or absence of defects on the outer peripheral surface Wa of the pipe W using the judgment criterion data acquired by the judgment criterion data acquisition unit 31 and image data of the outer peripheral surface Wa of the pipe W acquired by the image acquisition unit 11. Specifically, the judgment execution unit 32 compares the image data of the outer peripheral surface Wa of the pipe W acquired by the image acquisition unit 11 with, for example, an image of a non-defective product in the judgment criterion data to judge whether or not a defect exists. The judgment result of the judgment execution unit 32 is output to the judgment result output unit 33.

The judgment execution unit 32 may, for example, perform binarization processing on the image data and judge the presence or absence of a defect according to the area that is equal to or greater than the gradation threshold or less than the threshold. The judgment execution unit 32 may compare the image data with image data of a non-defective product included in the judgment reference data, calculate the difference as the degree of abnormality, and judge the presence or absence of a defect according to the degree of abnormality. The judgment execution unit 32 may compare the image data with image data related to defects in the judgment reference data and image data of a non-defective product, and judge the presence or absence of a defect according to which image data has a higher degree of match.

As described above, when comparing image data with image data included in the judgment reference data, the judgment execution unit 32 uses the brightness, chromaticity, and saturation of pixels in the image data and position information of the pixels. Note that the judgment execution unit 32 may compare the image data with the image data included in the judgment reference data using information other than the brightness, chromaticity, saturation, and position information of pixels in the image data.

The judgment result output unit 33 outputs the judgment result of the judgment execution unit 32 to a display or the like as output data including, for example, at least one of text information and image information. The judgment result output unit 33 may output the reliability of the judgment made by the judgment execution unit 32. The judgment result output unit 33 may output the output data to another device, or may output the judgment result of the judgment execution unit 32 by printing it on paper or the like.

As described above, the pipe outer peripheral surface defect determination device 1 according to this embodiment determines defects in the outer peripheral surface Wa of a pipe W having a glossy outer peripheral surface Wa. This defect determination device 1 has a pair of light source units 12a, 12b arranged so that light is irradiated to the same portion of the outer peripheral surface Wa of the pipe W without the optical axis L intersecting the outer peripheral surface Wa of the pipe W, an image acquisition unit 11 that acquires an image of the portion of the outer peripheral surface Wa of the pipe W that is irradiated with the light emitted from the pair of light source units 12a, 12b, and a defect determination unit 30 that uses the image acquired by the image acquisition unit 11 to determine defects in the outer peripheral surface Wa of the pipe W.

This allows the same portion of the outer peripheral surface Wa of the tube W to be illuminated by the light emitted from each of the pair of light source units 12a and 12b, without directly irradiating the outer peripheral surface Wa of the tube W with light so that the optical axis L intersects. Therefore, the pair of light source units 12a and 12b can illuminate the outer peripheral surface Wa of the tube W more brightly, and the outer peripheral surface Wa of the tube W can be illuminated by the light emitted from the pair of light source units 12a and 12b, without directly irradiating the outer peripheral surface Wa of the tube W with light so that the optical axis L intersects. Therefore, it is possible to suppress reflected light caused by the light emitted from the pair of light source units 12a and 12b being reflected by the outer peripheral surface Wa of the tube W from being reflected in the image acquired by the image acquisition unit 11. Therefore, the image acquired by the image acquisition unit 11 can be used to accurately determine defects in the outer peripheral surface Wa of the tube W.

In this embodiment, the pair of light source units 12a, 12b are arranged opposite each other so that their optical axes L are parallel to each other and light is irradiated onto the same portion of the outer circumferential surface Wa of the tube W.

This makes it possible to suppress variations in brightness of the outer peripheral surface Wa irradiated with light emitted from a pair of light sources 12a, 12b arranged opposite each other. Therefore, the image acquisition unit 11 can acquire an image in which defects on the outer peripheral surface Wa of the tube W are more clearly displayed. Therefore, the image acquired by the image acquisition unit 11 can be used to accurately determine defects on the outer peripheral surface Wa of the tube W.

In this embodiment, the optical axes L of the pair of light source units 12a, 12b are located at the same radial position of the tube W relative to the axis P when viewed from the side in a direction perpendicular to the axis P.

The optical axes L of the pair of light sources 12a, 12b are positioned at the same position in the radial direction of the tube W relative to the axis P when viewed from the side in a direction perpendicular to the axis P, so that the outer peripheral surface Wa of the tube W can be evenly illuminated by the light emitted from the pair of light sources 12a, 12b. This makes it possible to prevent the occurrence of light and dark on the outer peripheral surface Wa of the tube W, as occurs when the optical axes L of the pair of light sources 12a, 12b are misaligned in the radial direction.

This allows the image acquisition unit 11 to acquire an image in which defects are more clearly displayed. Therefore, the image acquired by the image acquisition unit 11 can be used to accurately determine defects on the outer peripheral surface Wa of the pipe W.

In this embodiment, the image acquisition unit 11 is positioned radially away from the tube W than the pair of light source units 12a, 12b.

By positioning the image acquisition unit 11 at a position farther away from the tube W in the radial direction of the tube W than the pair of light sources 12a, 12b, it is possible to prevent the shadow of the image acquisition unit 11 from being reflected in the image acquired by the image acquisition unit 11. This allows the image acquisition unit 11 to acquire an image in which defects on the outer peripheral surface Wa of the tube W are more clearly displayed. Therefore, the image acquired by the image acquisition unit 11 can be used to accurately determine defects on the outer peripheral surface Wa of the tube W. Note that the image acquisition unit may be positioned closer to the tube W in the radial direction than the pair of light sources 12a, 12b, or may be positioned in the same position as the pair of light sources 12a, 12b in the radial direction of the tube W.

In this embodiment, the image acquisition unit 11 acquires an image of the portion of the outer surface Wa of the tube W that is irradiated with light emitted from a pair of light source units 12a, 12b, viewed from a direction perpendicular to the axis P of the tube W.

This allows the image acquisition unit 11 to acquire an image in which defects are more clearly displayed. Therefore, the image acquired by the image acquisition unit 11 can be used to accurately determine defects on the outer peripheral surface Wa of the tube W. Note that the image acquisition unit may acquire an image of the portion of the outer peripheral surface Wa of the tube W irradiated with light emitted from the pair of light source units 12a, 12b, viewed from a direction other than a direction perpendicular to the axis P of the tube W.

(Defect Judgment Method)
The defect determination apparatus 1 having the above-mentioned configuration executes the following defect determination method. The defect determination method executed by the defect determination apparatus 1 will be described with reference to FIG.

As shown in FIG. 4, when the flow of the defect determination method starts (START), the image acquisition unit 11 of the defect determination device 1 acquires an image of a portion of the outer surface Wa of the tube W that is irradiated with light emitted from a pair of light source units 12a, 12b that are positioned so that the light is irradiated onto the outer surface Wa of the tube W without intersecting the optical axis L with respect to the outer surface Wa of the tube W (step SA1).

Then, the defect determination unit 30 of the defect determination device 1 uses the image acquired by the image acquisition unit 11 to determine whether or not there is a defect on the outer peripheral surface Wa of the pipe W (step SA2). Note that the defect determination unit 30 determines the defect by the method already described.

Then, the flow of the defect determination method shown in Figure 4 is terminated (END).

Here, step SA1 corresponds to the image acquisition step, and step SA2 corresponds to the defect determination step.

The method for determining defects in the outer peripheral surface of a pipe according to this embodiment is a method for determining defects in the outer peripheral surface Wa of a pipe W having a glossy outer peripheral surface Wa. This defect determination method includes an image acquisition step SA1 for acquiring an image of a portion of the outer peripheral surface Wa of the pipe W that is irradiated with light emitted from a pair of light source units 12a, 12b arranged so that the light is irradiated to the same portion of the outer peripheral surface Wa of the pipe W without intersecting the optical axis L with respect to the outer peripheral surface Wa of the pipe W, and a defect determination step SA2 for determining defects in the outer peripheral surface Wa of the pipe W using the image acquired in the image acquisition step SA1.

This allows the light emitted from the pair of light sources 12a, 12b to illuminate the same portion of the outer peripheral surface Wa of the tube W without directly irradiating the outer peripheral surface Wa of the tube W with light so that the optical axis L intersects with the outer peripheral surface Wa of the tube W. Therefore, the pair of light sources 12a, 12b can illuminate the outer peripheral surface Wa of the tube W more brightly, and reflected light caused by the light emitted from the pair of light sources 12a, 12b being reflected by the outer peripheral surface Wa of the tube W can be suppressed from being reflected in the image acquired in the image acquisition step SA1. Therefore, the image acquired in the image acquisition step SA1 can be used to accurately determine defects in the outer peripheral surface Wa of the tube W.

[Embodiment 2]
5 and 6 show a schematic configuration of a defect determination device 100 according to embodiment 2. Fig. 5 is a diagram showing a schematic configuration of the defect determination device 100 when viewed from the side in a direction perpendicular to the axis P of the pipe W. Fig. 6 is a diagram showing a schematic configuration of the defect determination device 100 when viewed in the axial direction of the pipe W.

The defect determination device 100 of this embodiment has multiple pairs of light source units 12a, 12b, and multiple image acquisition units 11. In the following description, the same components as those in embodiment 1 are given the same reference numerals and the description is omitted, and only the parts that differ from the configuration of embodiment 1 are described.

The defect determination device 100 has multiple image acquisition units 11, multiple pairs of light source units 12a, 12b, and a defect determination unit 30. As in the first embodiment, each pair of light source units 12a, 12b is aligned along the axis P of the tube W. The arrangement of each pair of light source units 12a, 12b is the same as in the first embodiment, so a detailed description is omitted.

The multiple pairs of light source units 12a, 12b are arranged in a line in the circumferential direction so as to surround the tube W. That is, the multiple pairs of light source units 12a, 12b are arranged in a line around the axis P of the tube W so as to follow the outer peripheral surface Wa of the tube W. In this embodiment, four pairs of light source units 12a, 12b are arranged in a line in the circumferential direction so as to surround the tube W.

This allows light to be irradiated all around the outer circumferential surface Wa of the tube W. Moreover, because a pair of light source units 12a, 12b adjacent to each other in the circumferential direction of the tube W irradiates light to the same location on the outer circumferential surface Wa of the tube W, the same location can be illuminated more uniformly and brightly.

The multiple image acquisition units 11 are arranged corresponding to the multiple pairs of light source units 12a, 12b. That is, each image acquisition unit 11 is provided for each pair of light source units 12a, 12b. In this embodiment, an image acquisition unit 11 is arranged for each of the four pairs of light source units 12a, 12b arranged in the circumferential direction so as to surround the tube W.

This allows the multiple image acquisition units 11 to acquire images of the outer peripheral surface Wa of the pipe W from multiple directions. Therefore, images of the outer peripheral surface Wa of the pipe W can be acquired efficiently.

In addition, the configuration of this embodiment makes it possible to acquire images of the outer peripheral surface Wa of the pipe W around the entire circumferential direction of the outer peripheral surface Wa without moving the image acquisition unit 11 or rotating the pipe W.

In this embodiment, the pair of light source units 12a, 12b are aligned along the axis P of the tube W. The light source unit 12 has multiple pairs of light source units 12a, 12b aligned in the circumferential direction of the tube W. Multiple image acquisition units 11 are arranged in the circumferential direction of the tube W to acquire images of the outer peripheral surface Wa of the tube W illuminated by the light emitted from the light source units 12.

The outer peripheral surface Wa of the tube W is irradiated with light emitted from multiple pairs of light source units 12a, 12b arranged in the circumferential direction of the tube W. This makes it possible to further suppress the variation in brightness on the outer peripheral surface Wa of the tube W. This allows the image acquisition unit 11 to acquire an image in which defects are more clearly displayed. Therefore, the image acquired by the image acquisition unit 11 can be used to accurately determine defects on the outer peripheral surface Wa of the tube W.

Moreover, the multiple image acquisition units 11 can efficiently acquire images of the outer peripheral surface Wa of the pipe W. Therefore, the defect determination device 100 having the above-described configuration can efficiently determine defects in the outer peripheral surface Wa of the pipe W.

[Embodiment 3]
7 shows a schematic configuration of a defect determination device 200 according to embodiment 3. The defect determination device 200 of this embodiment has an image acquisition unit 11, a pair of light source units 12a, 12b, and a shielding member 240 that covers a portion of the outer circumferential surface Wa of the tube W that is irradiated with light by the pair of light source units 12a, 12b. In the following description, the same components as those in embodiment 1 are denoted by the same reference numerals and description thereof is omitted, and only the components different from the configuration of embodiment 1 will be described.

The defect determination device 200 has an image acquisition unit 11, a pair of light source units 12a and 12b, and a shielding member 240. The configurations of the image acquisition unit 11 and the pair of light source units 12a and 12b are the same as those of the embodiment.

The shielding member 240 covers the image acquisition unit 11, the pair of light source units 12a, 12b, and the portion of the outer peripheral surface Wa of the tube W that is irradiated with light by the pair of light source units 12a, 12b. The shielding member 240 is made of a material capable of blocking external light. The shielding member 240 may be, for example, box-shaped or cloth-shaped, so long as it is capable of blocking external light. The shielding member 240 may be made of, for example, cloth, wood, resin, or metal.

The shielding member 240 does not have to cover the image acquisition unit 11 and the pair of light sources 12a, 12b as long as it covers the portion of the outer surface Wa of the tube W that is irradiated with light by the pair of light sources 12a, 12b.

The shielding member 240 has a through hole for the pipe W to pass through. The shielding member 240 also has through holes for the cables and the like connected to the image acquisition unit 11 and the pair of light source units 12a, 12b, respectively.

In this embodiment, the defect determination device 200 further includes a shielding member 240 that covers a portion of the outer peripheral surface Wa of the tube W so as to block light other than the light emitted from the pair of light source units 12a, 12b. The pair of light source units 12a, 12b are arranged to irradiate light onto the portion of the outer peripheral surface Wa of the tube W that is covered by the shielding member 240. The image acquisition unit 11 is arranged to acquire an image of the portion of the portion covered by the shielding member 240 that is irradiated with the light emitted from the pair of light source units 12a, 12b.

In this way, by covering a portion of the outer peripheral surface Wa of the pipe W with the shielding member 240 so as to block light other than the light emitted from the pair of light sources 12a, 12b, it is possible to prevent light other than the light emitted from the pair of light sources 12a, 12b from appearing in the image acquired by the image acquisition unit 11. Therefore, defects in the outer peripheral surface Wa of the pipe W can be accurately determined using the image acquired by the image acquisition unit 11.

[Embodiment 4]
8 shows a schematic configuration of a pipe manufacturing apparatus X equipped with a defect determination device 300 according to embodiment 4. The defect determination device 300 according to this embodiment has an image acquisition unit 11, a pair of light sources 12a, 12b, a defect determination unit 30, a defect position identification unit 50, a defective pipe identification unit 60, and a defective pipe sorting unit 70. In the following description, the same components as those in embodiment 1 are denoted by the same reference numerals and description thereof will be omitted, and only the parts different from the configuration of embodiment 1 will be described.

The pipe manufacturing device X is a device for manufacturing pipes W. The pipe manufacturing device X uses molten resin to manufacture resin pipes W having a glossy outer circumferential surface Wa. Specifically, the pipe manufacturing device X has an extruder 2, a mold 3, a cooling tank 4, a cutting machine 5, and a defect determination device 300. Although not specifically shown, the pipe manufacturing device X also has a take-up machine for transporting the manufactured pipe W in its axial direction. The take-up machine is located, for example, between the cooling tank 4 and the cutting machine 5. In FIG. 8, the hatched arrow indicates the transport direction of the pipe W.

The extruder 2 is a device that melts the supplied resin material and extrudes the molten resin (hereinafter, molten resin) into the die 3. The die 3 is located at the outlet of the molten resin in the extruder 2. The die 3 forms the molten resin extruded from the extruder 2 into a cylindrical tube W.

The cooling tank 4 cools the tube W formed by the mold 3. The cutter 5 cuts the tube W cooled by the cooling tank 4 to a predetermined length M. This results in tube products W1 and W2 having the predetermined length M.

The defect determination device 300 determines the presence or absence of defects on the outer peripheral surface Wa of the pipe W cooled by the cooling tank 4. Specifically, the defect determination device 300 has an image acquisition unit 11, a pair of light source units 12a, 12b, a defect determination unit 30, a defect position identification unit 50, a defective pipe identification unit 60, and a defective pipe sorting unit 70. The configurations of the image acquisition unit 11, the pair of light source units 12a, 12b, and the defect determination unit 30 are the same as those of the first embodiment.

The defect position identification unit 50 identifies the position of defect D when the defect determination unit 30 determines that there is a defect D on the outer peripheral surface Wa of the pipe W. Specifically, the defect position identification unit 50 identifies the position of defect D in the axial direction of the pipe W according to the determination result of the defect determination unit 30. The defect position identification unit 50 determines the axial position of defect D on the pipe W from the cutting position T by the cutting machine 5 based on the axial position of defect D on the outer peripheral surface Wa of the pipe W. This makes it possible to identify the axial position of defect D on the pipe W.

The defective pipe identification unit 60 identifies which pipe product contains defect D when pipe W is cut by the cutting machine 5 to obtain pipe products W1 and W2, based on the axial position of defect D in the pipe W identified by the defect position identification unit 50. The defective pipe identification unit 60 uses the axial position of defect D and the axial length of the pipe product to identify, among the pipe products cut from the pipe W by the cutting machine 5, the pipe product that contains defect D determined by the defect determination unit 30 as a defective pipe product.

The cutter 5 cuts the pipe W while feeding the pipe W a predetermined length M in the axial direction relative to the cut position T. This results in pipe products W1 and W2 having the predetermined axial length M. The defect position identification unit 50 identifies the pipe product containing the defect D determined by the defect determination unit 30 based on whether the sum (β + α) of the axial movement amount β of the pipe W relative to the cut position T and the distance α from the position where the image is acquired by the image acquisition unit 11 on the outer surface Wa of the pipe W to the cut position T is smaller or larger than the predetermined length M. Specifically, if the sum (β + α) is smaller than the predetermined length M, the defect position identification unit 50 identifies the pipe product W3 to be cut next as having defect D. On the other hand, if the sum (β + α) is larger than the predetermined length M as shown in FIG. 8, the defect position identification unit 50 identifies the pipe product to be cut next to the pipe product W3 as having defect D.

The defective pipe sorting unit 70 sorts out the defective pipe products (e.g., pipe product W1 in the example shown in FIG. 8) identified by the defective pipe identification unit 60. Specifically, the defective pipe sorting unit 70 removes the defective pipe products from the production line of the pipe manufacturing device X (white arrow shown in FIG. 8) and stores them in a defective pipe product storage area (not shown).

The defective pipe sorting unit 70 may have a gripping unit that lifts the pipe product W1, or may have a moving mechanism that moves the pipe product W1 in a direction perpendicular to the conveying direction of other pipe products. In other words, the defective pipe sorting unit 70 may have any configuration as long as it is capable of sorting pipe products for the production line.

In this embodiment, the defect determination device 300 further includes a defect position identification unit 50 that identifies the position of the defect D in the pipe W determined by the defect determination unit 30, and a defective pipe identification unit 60 that identifies a pipe product W1 (defective pipe product) having a defect D from among multiple pipe products W1, W2 obtained by cutting the pipe W in the axial direction based on the position of the defect D identified by the defect position identification unit 50.

As a result, the defective pipe identification unit 60 can identify the pipe product W1 having the defect D among the multiple pipe products W1, W2 obtained by cutting the pipe W in the axial direction. Therefore, the pipe product W1 having the defect D can be selected from the multiple pipe products W1, W2.

In addition, in this embodiment, the defect determination device 300 further includes a defective pipe sorting unit 70 that sorts the defective pipe products identified by the defective pipe identification unit 60.

This allows defective pipe products having defect D to be sorted out from among the multiple pipe products W1 and W2. Therefore, defective pipe products having defect D can be excluded from the multiple pipe products W1 and W2. Note that the defect determination device 300 does not need to have a defective pipe sorting unit.

(Tube manufacturing method)
The pipe manufacturing apparatus X having the above-mentioned configuration executes the following pipe manufacturing method. The pipe manufacturing method executed by the pipe manufacturing apparatus X will be described with reference to FIG.

As shown in FIG. 10, when the flow of the pipe manufacturing method starts (START), the extruder 2 of the pipe manufacturing device X melts the resin material that is the material of the pipe W and extrudes it into the die 3 (step SB1). In the die 3, the molten resin is molded into a pipe having a predetermined shape (step SB2). The molded pipe is cooled in the cooling tank 4 (step SB3).

In the next step SB4, the defect determination device 300 determines whether or not there is a defect on the outer peripheral surface Wa of the pipe W. The defect determination method by the defect determination device 300 will be described later. In step SB5, the pipe W is cut to a predetermined axial length (predetermined length M) by the cutter 5 to form pipe products W1 and W2. As will be described in detail later, the defect position identification unit 50 and the defective pipe identification unit 60 of the defect determination device 300 identify the pipe product W1 containing the defect D among the pipe products W1 and W2. In step SB6, the identified pipe product W1 is sorted as a defective pipe product. This makes it possible to separate the defective pipe products from the non-defective pipe products. Thereafter, the flow of the pipe manufacturing method shown in FIG. 9 is terminated (END).

The above pipe manufacturing method makes it possible to easily manufacture multiple pipe products, and to identify and sort defective pipe products from among the multiple pipe products. This improves the production efficiency of pipe products.

(Defect Judgment Method)
Next, a defect determination method executed by the defect determination apparatus 300 having the above-described configuration will be described with reference to FIG.

As shown in FIG. 10, when the flow of the defect determination method starts (START), the image acquisition unit 11 of the defect determination device 300 acquires an image of the outer peripheral surface Wa of the pipe W (step SC1). Next, the defect determination unit 30 of the defect determination device 300 uses the image acquired by the image acquisition unit 11 to determine whether or not there is a defect on the outer peripheral surface Wa of the pipe W (step SC2). Note that the operation of the defect determination device 300 in steps SC1 and SC2 is similar to the operation of the defect determination device 1 in steps SA1 and SA2 of embodiment 1. Therefore, a detailed description of steps SC1 and SC2 will be omitted.

In step SC3, the defect position identification unit 50 of the defect determination device 300 identifies the axial position of the defect D identified by the defect determination unit 30 on the outer peripheral surface Wa of the pipe W. In the following step SC4, the defective pipe identification unit 60 of the defect determination device 300 identifies a pipe product containing defect D (defective pipe product) based on the axial position of defect D identified by the defect position identification unit 50.

Then, in step SC5, the defective pipe sorting unit 70 of the defect determination device 300 sorts out the defective pipe products. Specifically, the defective pipe sorting unit 70 sorts out the defective pipe products identified by the defective pipe identification unit 60 so that they are removed from the production line. This makes it possible to identify and sort out defective pipe products having defect D from among multiple pipe products.

Then, the flow of the defect determination method shown in Figure 10 ends (END).

Here, step SC1 corresponds to the image acquisition step, step SC2 corresponds to the defect determination step, step SC3 corresponds to the defect location identification step, step SC4 corresponds to the defective pipe identification step, and step SC5 corresponds to the defective pipe sorting step.

In this embodiment, the method for determining defects on the outer circumferential surface of a pipe further includes a defect position identification step (step SC3) for identifying the position of the defect D determined in the defect determination step (step SC2) in the pipe W, a defective pipe identification step (step SC4) for identifying defective pipe products having the defect D from among multiple pipe products W1, W2 obtained by cutting the pipe W in the axial direction based on the position of the defect D identified in the defect position identification step, and a defective pipe sorting step (step SC5) for sorting the defective pipe products identified in the defective pipe identification step.

This makes it possible to sort out defective pipe products having defect D from among the multiple pipe products W1 and W2. Therefore, it is possible to exclude defective pipe products having defect D from the multiple pipe products W1 and W2.

(Modification of the fourth embodiment)
The defect determination device 300 according to the fourth embodiment has an image acquisition unit 11, a pair of light sources 12a, 12b, a defect determination unit 30, a defect position identification unit 50, a defective pipe identification unit 60, and a defective pipe sorting unit 70. However, the defect determination device does not have to have the defect position identification unit 50 and the defective pipe identification unit 60. In other words, when a pipe W is to be made into a pipe product without being cut by a cutting machine 5 of a pipe manufacturing apparatus X, a pipe W determined to have a defect by the defect determination unit 30 may be sorted by the defective pipe sorting unit 70. In this case, the pipe manufacturing apparatus X does not have to have a cutting machine 5.

In addition, pipe products in which the pipe W is not cut by the cutting machine 5 of the pipe manufacturing device X include, in addition to straight pipes, pipe products that are formed into a final shape by a mold, such as T-shaped pipes, L-shaped pipes, and joints.

In this modified example, the defect determination device 300 further includes a defective pipe sorting unit 70 that sorts defective pipes having defects determined by the defect determination unit 30. This makes it possible to sort and exclude defective pipes having defects.

As for the method of determining defects on the outer circumferential surface of a pipe, it is possible to determine defects in pipe products in which the pipe W is not cut by the cutting machine 5 of the pipe manufacturing device X, and to sort out pipe products that have defects. That is, in this modified example, the defect determination method further includes a defective pipe sorting step of sorting out defective pipes that have defects determined by the defect determination step. This makes it possible to sort out and eliminate defective pipes that have defects.

[Other embodiments]
Although the embodiment of the present invention has been described above, the above-mentioned embodiment is merely an example for carrying out the present invention. Therefore, the present invention is not limited to the above-mentioned embodiment, and it is possible to carry out the above-mentioned embodiment by appropriately modifying it within the scope of the gist of the present invention.

In the first embodiment, the image acquisition unit 11 and the pair of light source units 12a, 12b are located above the tube W. However, the image acquisition unit and the light source unit may be located to the side or below the tube. Also, the image acquisition unit and the light source unit may be disposed at an angle to the tube when viewed in the axial direction of the tube.

In the second embodiment, the defect determination device 100 has four pairs of light source units 12a, 12b arranged in a circumferential direction to surround the tube W. However, the defect determination device may have three or fewer pairs of light source units arranged in a circumferential direction to surround the tube W, or may have five or more pairs of light source units.

In the second embodiment, the image acquisition units 11 of the defect determination device 100 are arranged corresponding to the multiple pairs of light source units 12a, 12b. However, the image acquisition units may be arranged corresponding to some of the multiple pairs of light source units. The defect determination device may have one image acquisition unit and move the image acquisition unit or the tube.

In the third embodiment, the shielding member 240 covers the image acquisition unit 11, the pair of light source units 12a, 12b, and the portion of the outer surface Wa of the tube W that is irradiated with light by the pair of light source units 12a, 12b. However, the shielding member may cover the entire tube, or may cover the defect determination unit of the defect determination device.

In the fourth embodiment, the defective pipe identification unit 60 of the defect determination device 300 identifies which of the pipe products W1 and W2 obtained by cutting the pipe W to a predetermined length contains a defect, based on the axial position of the defect in the pipe W identified by the defect position identification unit 50. Then, the defective pipe sorting unit 70 of the defect determination device 300 sorts the pipe product W1 identified as a defective pipe product by the defective pipe identification unit 60.

However, the defect determination device may cut the tube in a range that includes the defect and at a length that is shorter than the predetermined length, depending on the location of the defect in the tube. In other words, if there is another defect within a range that is less than the predetermined length from the location of the defect, the defect determination device may cut the tube in a range that includes the other defect and is also shorter than the predetermined length. This makes it possible to shorten the length of defective tube products compared to cutting tubes uniformly at the predetermined length.

The defect determination device may also cut the tube in a range that includes the defect and is shorter than the predetermined length. For example, the defect determination device may identify the location of the defect in the axial direction of the tube and determine the distance to move the tube in the axial direction based on the location of the defect. Specifically, the defect determination device may determine the distance to move the tube in the axial direction relative to the cutting position of a cutting machine so as to cut the range of the tube that includes the defect. Then, after cutting the tube to less than the predetermined length by the cutting machine, the cut portions may be sorted. This makes it easy to remove only the portion of the tube that includes the defect. This configuration also makes it possible to shorten the length of defective tube products compared to cutting tubes uniformly at the predetermined length.

In each of the above embodiments, the pair of light source units 12a, 12b are arranged opposite each other so that their optical axes are parallel to each other and light is irradiated onto the same portion of the outer circumferential surface of the tube. However, the pair of light source units do not have to be arranged opposite each other so that their optical axes are parallel to each other and light is irradiated onto the same portion of the outer circumferential surface of the tube.

In each of the above embodiments, the pair of light source units 12a, 12b are aligned in the axial direction of the tube W. However, the pair of light source units may be aligned in the circumferential direction of the tube. In this case, the pair of light source units irradiate light in the circumferential direction onto the outer peripheral surface of the tube without the optical axis intersecting the outer peripheral surface of the tube. Note that even in this case, the image acquisition unit is positioned to acquire an image of the portion of the outer peripheral surface of the tube that is irradiated with light by the pair of light source units.

In each of the above embodiments, the image acquisition unit 11 and the pair of light source units 12a, 12b are aligned in the axial direction of the tube W. However, the position of the image acquisition unit and the position of the light source unit may be offset in the circumferential direction of the tube. In addition, the pair of light source units may be positioned at positions offset in the circumferential direction of the tube.

In each of the above embodiments, the defect determination unit 30 has a judgment criterion data acquisition unit 31. However, the defect determination unit does not have to have a judgment criterion data acquisition unit. In this case, the defect determination unit may determine whether or not a defect exists in the image acquired by the image acquisition unit based on a judgment criterion set in advance.

In each of the above embodiments, the image acquisition unit 11 acquires an image of the portion of the outer peripheral surface Wa of the tube W irradiated with the light emitted from the pair of light source units 12a, 12b, viewed from a direction perpendicular to the axis P of the tube W. However, the image acquisition unit may acquire an image of the portion of the outer peripheral surface of the tube irradiated with the light emitted from the pair of light source units, viewed from a direction other than perpendicular to the axis of the tube.

In each of the above embodiments, the pair of light source units may each be ring-shaped or arc-shaped. This allows light to be irradiated over a wide area of the outer circumferential surface of the tube.

In each of the above embodiments, the defect determination devices 1, 100, 200, and 300 may have a rotation mechanism that rotates the pipe W around its axis P. The rotation mechanism may have, for example, a rotating part that supports and rotates the pipe W.

In each of the above embodiments, the defect determination device 1, 100, 200, 300 may have a movement mechanism that can move relative to the pipe W. The defect determination device may have a movement mechanism that moves the pipe relative to the defect determination device.

The present invention can be used in a defect detection device that detects defects on the outer surface of a pipe.

1, 100, 200, 300 Defect judgment device 2 Extruder 3 Mold 4 Cooling tank 5 Cutting machine 11 Image acquisition section 12a, 12b Light source section 30 Defect judgment section 31 Judgment reference data acquisition section 32 Judgment execution section 33 Judgment result output section 50 Defect position identification section 60 Defective pipe identification section 70 Defective pipe sorting section 240 Shielding member X Pipe manufacturing device W Pipe Wa Outer circumferential surface W1, W2 Pipe product P Axis L Optical axis D Defect D1 Foreign matter D2 Color unevenness D3 Chip wrapping D4 Segregation

Claims (13)

A defect determination device for determining defects on an outer peripheral surface of a tube having a glossy outer peripheral surface, comprising:
A pair of light source units arranged such that light is irradiated onto the same portion of the outer peripheral surface of the tube without intersecting the optical axis of the pair of light source units;
an image acquisition unit that acquires an image of a portion of an outer peripheral surface of the tube that is irradiated with light emitted from the pair of light source units;
a defect determination unit that determines a defect on an outer peripheral surface of the pipe by using the image acquired by the image acquisition unit;
having
A device for detecting defects on the outer surface of a pipe. 2. The apparatus for determining defects on an outer peripheral surface of a pipe according to claim 1,
The pair of light source units include
The optical axes are arranged opposite each other so that the optical axes are parallel to each other and the same portion of the outer circumferential surface of the tube is irradiated with light.
A device for detecting defects on the outer surface of a pipe. 3. The apparatus for determining defects on an outer peripheral surface of a pipe according to claim 2,
The optical axes of the pair of light source units are located at the same position in the radial direction of the tube with respect to the axis when viewed from the side in a direction perpendicular to the axis of the tube.
A device for detecting defects on the outer surface of a pipe. 2. The apparatus for determining defects on an outer peripheral surface of a pipe according to claim 1,
The image acquisition unit includes:
The light source unit is disposed at a position farther from the tube in a radial direction than the pair of light source units.
A device for detecting defects on the outer surface of a pipe. 3. The apparatus for determining defects on an outer peripheral surface of a pipe according to claim 2,
The light source unit includes a plurality of pairs of light sources,
The plurality of pairs of light source units are arranged in a circumferential direction of the tube,
The image acquisition unit is arranged in a circumferential direction of the tube so as to acquire an image of the outer circumferential surface of the tube illuminated by the light emitted from the pair of light source units.
A device for detecting defects on the outer surface of a pipe. 2. The apparatus for determining defects on an outer peripheral surface of a pipe according to claim 1,
The image acquisition unit includes:
acquiring an image of a portion of the outer peripheral surface of the tube that is irradiated with the light emitted from the pair of light source units, viewed from a direction perpendicular to the axis of the tube;
A device for detecting defects on the outer surface of a pipe. 2. The apparatus for determining defects on an outer peripheral surface of a pipe according to claim 1,
The light source further includes a shielding member that covers a part of an outer circumferential surface of the tube so as to block light other than the light emitted from the pair of light source units,
The pair of light source units are arranged to irradiate light onto a portion of the outer circumferential surface of the tube that is covered by the shielding member,
The image acquisition unit is disposed to acquire an image of a portion of the portion covered by the shielding member that is irradiated with the light emitted from the pair of light source units.
A device for detecting defects on the outer surface of a pipe. 2. The apparatus for determining defects on an outer peripheral surface of a pipe according to claim 1,
The pipe sorting unit further comprises a defective pipe sorting unit for sorting defective pipes having defects determined by the defect determination unit.
A device for detecting defects on the outer surface of a pipe. 2. The apparatus for determining defects on an outer peripheral surface of a pipe according to claim 1,
a defect position identifying unit that identifies a position of a defect in the pipe determined by the defect determining unit;
a defective pipe identifying unit that identifies a defective pipe product having the defect from among a plurality of pipe products obtained by cutting the pipe in the axial direction based on the position of the defect identified by the defect position identifying unit; and
Further comprising
A device for detecting defects on the outer surface of a pipe. 10. The apparatus for determining defects on an outer peripheral surface of a pipe according to claim 9,
The production line further includes a defective pipe sorting unit that sorts the defective pipe products identified by the defective pipe identifying unit.
A device for detecting defects on the outer surface of a pipe. 1. A method for determining defects on an outer peripheral surface of a tube having a glossy outer peripheral surface, comprising the steps of:
an image acquisition step of acquiring an image of a portion of the outer peripheral surface of the tube that is irradiated with light emitted from a pair of light source units arranged such that the light is irradiated to the same portion of the outer peripheral surface of the tube without an optical axis intersecting the outer peripheral surface of the tube;
a defect determination step of determining a defect on the outer peripheral surface of the pipe using the image acquired in the image acquisition step;
having
A method for determining defects on the outer periphery of a pipe. The method for determining defects on an outer peripheral surface of a pipe according to claim 11,
The method further comprises a defective pipe sorting step of sorting defective pipes having defects determined by the defect determination step.
A method for determining defects on the outer periphery of a pipe. The method for determining defects on an outer peripheral surface of a pipe according to claim 11,
a defect location identifying step of identifying a location of the defect determined in the defect determining step in the pipe;
a defective pipe identifying step of identifying a defective pipe product having the defect from among a plurality of pipe products obtained by cutting the pipe in the axial direction based on the position of the defect identified in the defect position identifying step;
a defective pipe sorting step of sorting the defective pipe products identified by the defective pipe identifying step;
Further comprising
A method for determining defects on the outer periphery of a pipe.

Images