JP2005195332A - Visual inspection apparatus of circular article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inspect a half of a circular article or more with one imaging device and to detect a defect present at a distance in an outer circumferential direction or in an inner circumferential direction from a location on the optical axis of the imaging device without dead angles. <P>SOLUTION: This visual inspection apparatus is provided with a receiving base 2 for supporting the circular article 1; an illuminating device 5 for illuminating the circular article 1; a CCD camera 6 for photographing light from the circular article 1; and an image processing device 7 for determining the presence or absence of a defect by processing images acquired by the CCD camera 6. The receiving base 2 comprises both a conical inner circumferential side reflecting surface 3 for reflecting light from the inner circumferential side of the ring-like article 1 and making the light entering into the CCD camera 6 and an inverted conical outer circumferential side reflecting surface 4 for reflecting light from the outer circumferential side of the circular article 1 and making the light entering into the CCD camera 6. The CCD camera 6 photographs light directly entering into the CCD camera 6 from the circular article 1; light entering into the CCD camera 6 from the inner circumferential side reflecting surface 3; and light entering into the CCD camera 6 from the outer circumferential side reflecting surface 4. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an appearance inspection apparatus for an annular article, and more particularly to an appearance inspection apparatus for an annular article for optically inspecting defects such as scratches, dents and burrs on the surface of an annular article such as an O-ring. .

  In various apparatuses, various annular articles having an annular and substantially circular cross section are used. For example, a rubber O-ring or metal metal ring used as a kind of packing (or gasket) has an annular and substantially circular cross section. If there are defects such as scratches, dents, burrs, etc. on the surface of the packing (or gasket) such as an O-ring or a metal ring, a sealing failure (seal failure) will occur, and an appearance inspection must be performed. As an apparatus for automatically performing this appearance inspection, an annular article such as an O-ring is photographed by an imaging device such as a CCD camera, and the obtained image is processed by an image processing device to detect defects such as scratches and dents on the surface. There is something to detect.

  FIG. 9 is a schematic view showing an example of a conventional inspection apparatus. As shown in FIG. 9, the inspection apparatus includes a rotating table 52 that holds and rotates an annular article 51 such as an O-ring having a circular cross section, an illumination 53 disposed above the annular article 51, and an annular shape. A CCD camera 54 disposed obliquely above the annular article 51 on the outer peripheral side of the article 51 and a CCD camera 55 disposed obliquely above the annular article 51 on the inner peripheral side of the annular article 51 are provided. . The CCD cameras 54 and 55 are connected to image processing devices 56 and 57, respectively.

  In the conventional inspection apparatus shown in FIG. 9, the upper half of the annular article 51 is photographed by the CCD cameras 54 and 55 while rotating the annular article 51 around the rotation axis 52a by the turntable 52, and a large number of images are taken. obtain. In this case, when the annular article 51 is illuminated by the illumination 53, the reflected light reflected by the surface of the annular article 51 enters the CCD cameras 54 and 55 and is photographed. Images obtained by the CCD cameras 54 and 55 are processed by the image processing devices 56 and 57, and defects such as scratches and burrs are detected.

As described above, after the upper half of the annular article 51 is imaged and inspected, the annular article 51 is inverted and the lower half of the annular article 51 is imaged and inspected.
On the other hand, in order to inspect the upper half and the lower half of the annular article 51 without inverting the annular article 51, the rotary table 52 is made transparent, and the illumination and two lights are also provided below the annular article 51. A CCD camera is arranged, and while the annular article 51 is rotated by the turntable 52, the upper half and the lower half of the annular article 51 are simultaneously imaged and inspected by two upper and lower CCD cameras.

  As described above, in order to inspect an annular article having a circular cross section in a conventional inspection apparatus, two cameras having an inspection range of approximately 90 ° are arranged, and the upper half of the annular article is formed by two cameras. After taking an image of the ring, the annular article is reversed and the lower half of the annular article is imaged, or two cameras with an inspection range of approximately 90 ° are arranged up and down for a total of four cameras. The upper half and the lower half of the annular article are imaged simultaneously. That is, in order to inspect the entire surface of the annular article with a conventional inspection apparatus, it is necessary to provide at least two cameras and a reversing device, or to provide at least four cameras.

  If an annular article having a circular cross section is to be inspected with a single camera within an inspection range of a predetermined angle (for example, 90 °), defects on the optical axis of the camera are reflected on the camera as they are. As the distance from the position on the shaft increases in the outer peripheral direction or the inner peripheral direction, the defect deforms and becomes smaller and is reflected in the camera. For example, a circular defect will be described as an example. If there is a defect on the optical axis of the camera, the defect appears as a circle, but the defect appears as it moves away from the position on the optical axis of the camera in the outer circumferential direction or the inner circumferential direction. Has a problem that it becomes difficult to detect a defect because it becomes smaller from a circle to an ellipse and further to a line.

  The present invention has been made in view of the above-described circumstances, and more than half of an annular article having a substantially circular cross section can be inspected with one imaging device, and the outer periphery from the position on the optical axis of the imaging device. An object of the present invention is to provide an appearance inspection apparatus for an annular article that can detect a defect at a position separated in a direction or an inner circumferential direction without blind spots.

  In order to achieve the above-described object, an apparatus for inspecting the appearance of an annular article according to the present invention is an apparatus for inspecting defects on the surface of an annular article. And an imaging device that captures light from the annular article, and an image processing device that processes the image obtained by the imaging device and determines the presence or absence of a defect, wherein the cradle is an inner periphery of the annular article A conical inner peripheral reflecting surface that reflects light from the side and enters the imaging device, and an inverted conical outer reflecting surface that reflects light from the outer peripheral side of the annular article and enters the imaging device; The imaging device includes light that is directly incident on the imaging device from the annular article, light that is incident on the imaging device from the inner reflection surface, and light that is incident on the imaging device from the outer reflection surface. It is characterized by shooting.

  According to the present invention, the light from the illumination is incident on the annular article supported by the cradle and is reflected by the annular article. The light reflected on the side facing the illumination of the annular article is directly incident on the imaging device and photographed, and the light from the inner peripheral side of the annular article is reflected by the conical inner peripheral reflection surface and then the imaging device The light from the outer peripheral side of the annular article is reflected by the inverted conical outer peripheral reflecting surface and then enters the imaging device. Therefore, the imaging device captures light that is directly incident on the imaging device from the annular article, light that is incident on the imaging device from the inner reflection surface, and light that is incident on the imaging device from the outer reflection surface. The surface facing the illumination of the annular article and the inner and outer peripheral surfaces are apparently planar, and the defects of the annular article can be faithfully reproduced without deformation, and defects in the inner and outer circumferential directions can be reproduced. It can be detected reliably.

According to an aspect of the present invention, the cradle can rotate while supporting an annular article. According to the present invention, a large number of images can be taken with an imaging device while rotating an annular article with a cradle, and an inspection of 360 ° or more can be performed in the circumferential direction of the annular article.
According to an aspect of the present invention, the annular article has a circular cross section, and the optical axis of the imaging device is substantially coincident with the center of the circular cross section.

According to one aspect of the present invention, the optical axis of the imaging device is substantially coincident with the center of the annular article. According to the present invention, substantially half of an annular article can be inspected by one imaging.
According to one aspect of the present invention, the inner and outer reflection surfaces are configured by half mirrors, and at least one illumination and imaging device on the opposite side of the illumination and the imaging device across an annular article. And is provided. According to the present invention, since the upper half and the lower half of the annular article can be imaged simultaneously, there is no need to invert the annular article.

  According to the present invention, more than half of an annular article having a substantially circular cross section can be inspected by photographing with a single imaging device. Further, when photographing with the imaging device, the inner and outer peripheral surfaces of the annular article having a substantially circular cross section are apparently planar, and defects in the annular article can be detected without blind spots.

Hereinafter, an embodiment of an appearance inspection apparatus for an annular article according to the present invention will be described with reference to FIGS.
FIG. 1 is a schematic diagram showing a basic configuration of an appearance inspection apparatus for an annular article according to the present invention, and FIG. 2 is a view taken along arrow II in FIG. 1 and 2, reference numeral 1 denotes an annular article such as an O-ring that is an inspection object. The annular article 1 has an annular shape (ring shape) as a whole and has a circular cross section or a substantially circular cross section. doing. The annular article 1 is held by a cradle 2. The cradle 2 is positioned on the inner peripheral side of the annular article 1 and has an inner peripheral reflection surface 3 having a conical shape, and an outer periphery positioned on the outer peripheral side of the annular article 1 and having an inverted conical shape. And a side reflection surface 4. The conical inner peripheral reflecting surface 3 and the inverted conical outer peripheral reflecting surface 4 form a W-shaped cross section. The apex angle (θ ₁ ) of the inner peripheral reflecting surface 3 is set in a range of 30 ° to 60 °, and an example of 50 ° is shown in the embodiment. The apex angle (θ ₂ ) of the outer reflection surface 4 is set in the range of 90 ° to 110 °, and an example of 100 ° is shown in the embodiment.

  In the diameter direction of the annular article 1, the distance L between the intersections of the inner peripheral reflection surface 3 and the outer peripheral reflection surface 4 substantially matches the diameter d of the annular article 1. The apex angles of the inner peripheral reflecting surface 3 and the outer peripheral reflecting surface 4, and the distance L between the intersections of the inner peripheral reflecting surface 3 and the outer peripheral reflecting surface 4 are matched to the dimensions of the annular article 1 such as an O-ring. It is supposed to change. The cradle 2 can be rotated around the rotation shaft 2a by a rotating means (not shown) such as a motor. Above the cradle 2, a pair of substantially rectangular illuminations 5, 5 made of white LEDs are arranged. The angle of the right illumination 5 is set to 27 ° with respect to the horizontal plane, and the angle of the left illumination 5 is set to 40 ° with respect to the horizontal plane. A single CCD camera 6 is disposed above the pair of lights 5 and 5.

  The CCD camera 6 constitutes an image pickup device, and the optical axis 6 a of the CCD camera 6 passes between the pair of illuminations 5 and 5 and is substantially the same as the center O of the circular section of the annular article 1 on the cradle 2. I'm doing it. The CCD camera 6 is connected to an image processing device 7, and the image photographed by the CCD camera 6 is processed by the image processing device 7 to determine the presence or absence of defects on the surface of the annular article 1.

  The operation of the annular article visual inspection apparatus configured as described above will be described with reference to FIGS. FIG. 3 is an enlarged view of a main part of the appearance inspection apparatus for the annular article, and FIG. 4 shows a state in which the reflected light reflected from the annular article 1 is reflected by the outer reflection surface 4 and proceeds toward the CCD camera 6. FIG. 5 is a diagram schematically showing a photographed image of the annular article 1.

As shown in FIG. 3, the illumination light from the illuminations 5 and 5 is incident on the surface of the annular article 1. In this case, the illumination light is incident on the entire surface above the portion where the annular article 1 is in contact with the inner peripheral reflecting surface 3 and the outer peripheral reflecting surface 4.
Light from the pair of illuminations 5 and 5 is reflected by the surface of the annular article 1. The light reflected on the side of the annular article 1 facing the illumination 5 is directly incident on the CCD camera 6 and photographed, and the light from the inner peripheral side of the annular article 1 is reflected on the conical inner peripheral reflecting surface 3. After reflection, the light enters the CCD camera 6 and is photographed, and light from the outer peripheral side of the annular article 1 is reflected by the outer conical reflecting surface 4 having an inverted conical shape and then enters the CCD camera 6. Therefore, the CCD camera 6 is incident on the CCD camera 6 directly from the annular article 1, incident on the CCD camera 6 from the inner reflection surface 3, and incident on the CCD camera 6 from the outer reflection surface 4. The surface facing the illumination 5 and the inner and outer peripheral surfaces of the annular article 1 are apparently planar.

  FIG. 4 illustrates light that is reflected by the surface of the annular article 1 and further reflected by the outer peripheral reflecting surface 4 and incident on the CCD camera 6. As shown in FIG. 4, the light reflected by a of the annular article 1 is reflected by a ′ of the outer peripheral reflection surface 4 and travels in the a ″ direction. Similarly, the light reflected by b of the annular article 1 is reflected by b ′ of the outer peripheral reflection surface 4 and travels in the b ″ direction. The light reflected by c, d, e, f, g, h, i of the annular article 1 is c ′, d ′, e ′, f ′, g ′, h ′, i of the outer peripheral reflecting surface 4. Reflected by 'and proceed in the direction of c ″, d ″, e ″, f ″, g ″, h ″, i ″, respectively.

  In addition, the inner reflection surface 3 also has the same light reflecting action as that of the outer reflection surface 4. As a result, the upper surface side, outer periphery side, and inner periphery side of the annular article 1 having a circular cross section are 1. Images can be taken with a single CCD camera 6. Further, a single CCD camera 6 can pick up an image of 180 ° or more (about 220 ° in the example shown in FIG. 4) in a circular cross section. As shown in FIGS. 5A to 5D, the image of the annular article 1 obtained in this way is a circular arc shape in the center portion due to light directly incident on the CCD camera 6 from the annular article 1. The image 10a, the arc-shaped image 10b by the light incident on the CCD camera 6 from the inner reflection surface 3, and the arc-shaped image 10c by the light incident on the CCD camera 6 from the outer reflection surface 4 are one screen. It will be reflected in. In addition, the bright part inside the image 10b is an image of the inner peripheral reflection surface 3, and the bright part outside the image 10c is an image of the outer peripheral reflection surface 4.

  By comparing the brightness of each pixel from the obtained images 10a, 10b, and 10c with the image processing device 7, defects such as scratches, dents, and burrs on the surface of the annular article 1 can be detected. 5 (a) to 5 (d), FIG. 5 (a) shows a normal image without defects, FIG. 5 (b) shows an image with defects in the flow 11, and FIG. FIG. 5D shows an image with a defect of deburring 13. FIG.

  As described above, the annular article 1 is imaged and inspected, and the cradle 2 is rotated around the rotation axis 2a by 360 ° or more, and during this rotation, the entire circumference of the annular article 1 is rotated. After imaging and inspecting the upper half of the annular article 1 (more precisely, the upper half or more), the annular article 1 is inverted to remove the lower half (more precisely, the lower half or more) of the annular article 1 An image is taken and an inspection is performed as described above.

  According to the appearance inspection apparatus for an annular article of the present invention shown in FIGS. 1 to 5, the inner and outer circumferences of the annular article 1 are constituted by a conical inner peripheral reflecting surface 3 and an inverted conical outer reflecting surface 4. The surface can be developed on a conical surface, the inner and outer peripheral surfaces of the annular article 1 are apparently planar, and the defects on the surface of the annular article 1 can be faithfully reproduced without deforming the image. It is possible to reliably detect defects in the inner and outer peripheral directions of the annular article 1.

  6 and 7 are views showing another embodiment of the appearance inspection apparatus for an annular article according to the present invention. FIG. 6 is a schematic view showing the overall configuration of the appearance inspection apparatus for annular articles, and FIG. 7 is a view showing an image obtained by the inspection apparatus shown in FIG. In the present embodiment, since the inspection of the upper half (precisely, the upper half or more) of the annular article 1 can be performed by one imaging, the cradle 2 does not need to rotate and remains stationary. Yes. The cradle 2 includes the inner peripheral reflecting surface 3 and the outer peripheral reflecting surface 4 as in the embodiment shown in FIG. Moreover, the illumination 5 is comprised from the ring-shaped illumination which consists of white LED, and can light the whole annular article 1 from upper direction. The CCD camera 6 is arranged so that its optical axis 6 a coincides with the center of the annular article 1.

  In the above configuration, the illumination light from the ring-shaped illumination 5 is incident on the entire circumference of the annular article 1 and reflected by the annular article 1. The light reflected on the side of the annular article 1 facing the illumination 5 is directly incident on the CCD camera 6 and photographed, and the light from the inner peripheral side of the annular article 1 is reflected on the conical inner peripheral reflecting surface 3. After reflection, the light enters the CCD camera 6 and is photographed, and light from the outer peripheral side of the annular article 1 is reflected by the outer conical reflecting surface 4 having an inverted conical shape and then enters the CCD camera 6. Therefore, the CCD camera 6 is incident on the CCD camera 6 directly from the annular article 1, incident on the CCD camera 6 from the inner reflection surface 3, and incident on the CCD camera 6 from the outer reflection surface 4. The surface facing the illumination 5 and the inner and outer peripheral surfaces of the annular article 1 are apparently planar. In this way, imaging of the entire circumference of the annular article 1 in the circumferential direction is performed.

FIG. 7 is a diagram schematically showing an image of the annular article 1 obtained by the CCD camera 6. As shown in FIG. 7, a ring-shaped image 10 a in the center portion by light directly incident on the CCD camera 6 from the annular article 1 and an inner ring by light incident on the CCD camera 6 from the inner peripheral reflection surface 3. A ring-shaped image 10b and a ring-shaped image 10c by light incident on the CCD camera 6 from the outer peripheral reflection surface 4 are displayed on one screen. In addition, the bright part inside the image 10b is an image of the inner peripheral reflection surface 3, and the bright part outside the image 10c is an image of the outer peripheral reflection surface 4. The image processing device 7 compares the brightness of each pixel from the obtained images 10a, 10b, and 10c to detect defects such as scratches, dents, and burrs on the surface of the annular article 1.
According to the embodiment shown in FIG. 6 and FIG. 7, the upper half (precisely, the upper half or more) of the annular article 1 can be imaged at one time by one imaging.

FIG. 8 is a view showing still another embodiment of the appearance inspection apparatus for annular articles according to the present invention.
In the embodiment shown in FIG. 8, the configuration of the cradle 2 is changed with respect to the embodiment shown in FIG. 1, and one illumination 15 and two CCD cameras 16 and 16 are added below the cradle 2. Yes. That is, the inner periphery side reflection surface 3 and the outer periphery side reflection surface 4 of the cradle 2 are configured by a half mirror, and the lower part of the inner periphery side reflection surface 3 and the outer periphery side reflection surface 4 of the cradle 2 is configured by a transparent member. ing. The two CCD cameras 16 and 16 are arranged so as to take an image of the lower surface side of the annular article 1 from diagonally below the left and right sides of the annular article 1. The two CCD cameras 16 and 16 reflect the light from the illumination 15 on the lower surface of the annular article 1 and capture the light that has passed through the inner and outer reflecting surfaces 3 and 4 formed of a half mirror. It is configured.

  According to the embodiment shown in FIG. 8, since the CCD camera 6 on the upper side of the annular article 1 can inspect 180 ° or more of the circular cross section, the two CCD cameras 16 and 16 each have 90 °. The inspection range is less than or equal to 60 ° (for example, 60 ° to 70 °), and even if the annular article 1 is directly imaged without using a mirror, the dead angle can be reduced and defects can be reliably detected. As described above, according to the appearance inspection apparatus for an annular article according to this embodiment, the entire surface of the annular article can be inspected with the minimum number of cameras (for example, three) without inverting the annular article.

It is the schematic which shows the basic composition of the external appearance inspection apparatus of the annular | circular shaped article of this invention. FIG. 2 is a view taken in the direction of arrow II in FIG. 1. It is a principal part enlarged view of the external appearance inspection apparatus of an annular | circular shaped article. It is a schematic diagram which shows the state which the reflected light reflected from the annular | circular shaped object reflects on the outer peripheral side reflective surface, and advances toward a CCD camera. It is a figure which represents typically the image of the image | photographed annular | circular shaped goods. It is the schematic which shows the whole structure of the external appearance inspection apparatus of an annular | circular shaped article. It is a figure which shows the image obtained with the inspection apparatus shown in FIG. It is a figure which shows other embodiment of the external appearance inspection apparatus of the annular | circular shaped article which concerns on this invention. It is the schematic which shows an example of the conventional inspection apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Circular article 2 Receiving base 2a Rotating shaft 3 Inner peripheral side reflective surface 4 Outer peripheral side reflective surface 5 Illumination 6 CCD camera 6a Optical axis 7 Image processing apparatus 10a Image 10b Image 10c Image 15 Illumination 16 CCD camera

Claims (5)

In an apparatus for inspecting defects on the surface of an annular article,
A cradle for supporting an annular article;
Lighting to illuminate the annular article;
An imaging device that captures light from the annular article;
An image processing device that processes an image obtained by the imaging device and determines the presence or absence of a defect,
The cradle reflects the light from the inner peripheral side of the annular article to be incident on the imaging device, and reflects the light from the outer peripheral side of the annular article to the imaging device. Having an inverted conical outer peripheral reflecting surface to be incident,
The imaging device shoots light that is directly incident on the imaging device from the annular article, light that is incident on the imaging device from the inner reflection surface, and light that is incident on the imaging device from the outer reflection surface. A device for inspecting the appearance of an annular article.   The appearance inspection apparatus for an annular article according to claim 1, wherein the cradle is rotatable while supporting the annular article.   The appearance inspection apparatus for an annular article according to claim 2, wherein the annular article has a circular cross section, and an optical axis of the imaging device substantially coincides with a center of the circular cross section.   2. An apparatus for inspecting the appearance of an annular article according to claim 1, wherein an optical axis of the imaging device substantially coincides with a center of the annular article. The inner reflection surface and the outer reflection surface are constituted by half mirrors, and at least one illumination and an imaging device are provided on the opposite side of the illumination and the imaging device with an annular article interposed therebetween. The appearance inspection apparatus for an annular article according to any one of claims 1 to 3.

Images