JP2006337074A - Visual inspection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a visual examination device capable of enhancing the inspection accuracy of the inner peripheral surface of an inspection target, using a simple configuration. <P>SOLUTION: The visual inspection device 1 is equipped with the camera 4, arranged in the opening direction of the opening 100a of an O-ring 100, the mirror part 2 arranged between the O-ring 100 and the camera 4 on the outer peripheral side of the opening 100a, as seen from the camera 4 to photograph the mirror image of the inner peripheral surface 100b of the opening 100a and a processing part 5 for discriminating the flaws in the O-ring 100, based on the mirror image taken by the camera 4. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an appearance inspection apparatus for inspecting the appearance of an inner peripheral surface of a product having an opening such as an O-ring.

  Japanese Patent Application Laid-Open No. 2004-133260 discloses a technique for capturing an inner peripheral surface of an O-ring with a camera arranged in a direction in which the opening of the O-ring opens and detecting a defect based on the captured image.

  In Patent Document 2, a conical mirror is inserted into a through hole of a cylindrical inspection target portion, a mirror image projected on the mirror is captured by a camera provided in the axial direction of the through hole, and based on the captured image. A technique for detecting defects is disclosed.

Although the inner peripheral surface of the inspection object is not inspected, a reflection mechanism is disposed on the outer periphery side of the cylindrical inspection object, and a plurality of mirror images projected on the reflection mechanism are captured as one image. Accordingly, there is a technique that enables appearance inspection from a plurality of viewpoints using images from a single viewpoint (Patent Document 3).
Japanese Patent Laid-Open No. 03-207169 JP 2004-205218 A Japanese Patent Laid-Open No. 11-51620

  The O-ring is an annular member having a substantially circular cross section, and the inner peripheral surface has a reduced diameter on the center side in the opening direction. Therefore, in imaging from one viewpoint set in the opening direction as in the technique of Patent Document 1. As a result, it is impossible to obtain a sufficient image necessary for the inspection on the back side of the inner peripheral surface as viewed from the camera. That is, sufficient inspection accuracy cannot be obtained.

  However, if an image from a plurality of viewpoints is captured while changing the relative position between the O-ring and the camera, or a plurality of cameras are arranged for one O-ring to capture an image from a plurality of viewpoints. This causes inconveniences such as a complicated configuration, an increase in cost, and a decrease in inspection speed.

  The technique of Patent Document 2 substantially captures an image of the inner peripheral surface from the inside of the through hole by capturing a mirror image projected on a conical mirror, and capturing from one viewpoint set in the opening direction. In addition, the field of view of 360 degrees is realized. However, the mirror has a conical shape with a smaller diameter than the opening, and the mirror image is projected smaller than the actual inner peripheral surface. Therefore, the inspection accuracy is reduced by the amount of the mirror image. Further, since the mirror is taken in and out of the opening, a drive mechanism for that purpose is necessary, and there is a possibility of contact between the mirror and the inspection object.

  An object of the present invention is to provide an appearance inspection apparatus capable of improving the inspection accuracy of the inner peripheral surface of an inspection object with a simple configuration.

  An appearance inspection apparatus according to the present invention includes an imaging unit disposed in an opening direction of an opening of an inspection object, and an outer peripheral side of the opening as viewed from the imaging unit between the inspection object and the imaging unit. And a discriminating unit that projects a mirror image of the inner peripheral surface of the opening, and a discriminating unit that discriminates whether there is a defect in the inspection object based on the image of the mirror image captured by the imaging unit. .

  Preferably, the inner peripheral surface has a reduced diameter on the center side in the opening direction.

  Preferably, the mirror unit includes a plurality of plane mirrors that are arranged so as to surround the opening as viewed from the imaging unit and project a mirror image of the inner peripheral surface.

  Preferably, between the inspection object and the imaging means, between the first illumination means for irradiating light to the inspection object side, between the first illumination means and the inspection object, A second illuminating means for irradiating light toward the first illuminating means; and provided between the first illuminating means and the second illuminating means, and the light from the first illuminating means is Diffusion means for diffusing and transmitting to the inspection object side, and reflecting light from the second illumination means to the inspection object side.

  Preferably, the first illumination unit and the second illumination unit are ring illumination units that irradiate light from a position surrounding the opening as viewed from the imaging unit.

  Preferably, the determination unit determines that a defect has occurred in the inspection object when an area whose luminance is lower than a predetermined luminance threshold is larger than a predetermined area threshold in the mirror image.

  Preferably, there is further provided conveying means provided behind the inspection object as viewed from the imaging means, and carrying the inspection object into and out of a position where the mirror image can be captured by the imaging means. Prepare.

  According to the present invention, it is possible to improve the inspection accuracy of the inner peripheral surface of the inspection object with a simple configuration.

  FIG. 1 is a schematic diagram showing an overall configuration of an inspection apparatus 1 according to an embodiment of the present invention. The inspection apparatus 1 is configured as an apparatus for inspecting the appearance of the inner peripheral surface 100b of the O-ring 100 as an inspection target. The O-ring 100 is an annular packing having a substantially circular (O-shaped) cross section for sealing a fluid or the like, and is formed of, for example, rubber. FIG. 1 shows a state in which the O-ring 100 is disposed at the imaging position P for inspection.

  The inspection apparatus 1 includes a mirror unit 2 that displays a mirror image of the O-ring 100, an illumination unit 3 that illuminates the O-ring 100, a camera 4 that captures a mirror image of the O-ring 100 that is displayed on the mirror unit 2, A processing unit 5 that performs various processes such as detection of defects in the O-ring 100 based on the captured image, and a transport unit 6 that transports the O-ring 100 are provided.

  The camera 4 includes, for example, a camera body 11 and a C-mount type lens 12 attached to the camera body 11, and in the opening direction (up and down direction on the paper surface) of the opening 100 a of the O-ring 100 at the imaging position P, The optical axis direction of the lens 12 is aligned with the opening direction, and the center of the opening 100a of the O-ring 100 is positioned at the center of the visual field (optical axis LL of the lens 12).

  The camera body 11 includes, for example, a CCD (imaging device) 13 that outputs an electrical signal corresponding to received light. The lens 12 forms an optical image on the CCD 13, and the CCD 13 outputs an electrical signal corresponding to the formed optical image. An electrical signal from the CCD 13 is output to the processing unit 5 as image data through an image processing unit (not shown) built in the camera body 11. The camera 4 includes a control unit (not shown), for example, and the control unit controls the operation of the CCD 13 in accordance with an instruction from the processing unit 5.

  The processing unit 5 is constituted by a personal computer, for example, and includes a main body unit 15, a monitor (display unit) 16, and a keyboard (input unit) 17.

  The main body unit 15 includes, for example, a CPU, a ROM, a RAM, and the like (not shown). When the CPU reads and executes a program recorded in the ROM or the like, the operation of the camera 4 is performed on the main body unit 15. Based on a camera control unit (not shown) that controls the image data, an image processing unit (not shown) that processes image data output from the camera 4, image data output from the camera 4, or data obtained by image processing of the image data. Various means such as a determination unit (not shown) that determines the presence or absence of a defect in the ring 100 and a transfer control unit (not shown) that controls the operation of the transfer unit 6 are constructed.

  The monitor 16 is constituted by a CRT, for example, and displays an image in accordance with an instruction from the main body unit 15. For example, when a defect occurs in the O-ring 100 by the main body unit 15, an image for notifying the user of the occurrence of the defect is displayed. In addition, the keyboard 17 accepts a user input operation and outputs an electrical signal corresponding to the input operation to the main body unit 15. For example, an operation for changing a criterion for determining the presence / absence of a defect, correcting an exposure amount of the camera 4, etc. is received and output to the main body unit 15.

  The transport unit 6 includes, for example, a feed mechanism 21, a motor 22 for driving the feed mechanism 21, and a motor drive unit 23 for controlling the operation of the motor 22.

  The feed mechanism 21 includes, for example, a transfer table 26 on which the O-ring 100 is placed. The transfer table 26 is disposed behind the mirror unit 2 and the illumination unit 3 when viewed from the camera 4 and moves in a direction orthogonal to the shooting direction of the camera 4. The transfer table 26 is moved by, for example, a movable arm (not shown) that holds the transfer table 26 or a plurality of rollers that are arranged under the transfer table 26 and are rotatable. As the transport table 26 moves, the O-ring 100 is carried into a range where a mirror image is projected on the mirror unit 2 when viewed from the camera 4 and is carried out from the range.

  The transport table 26 is made of, for example, metal, and the surface of the transport table 26 on the camera 4 side is formed so as to have higher brightness than the O-ring 100. A plurality of transfer tables 26 may be provided along the transfer path, or one transfer table 26 may be provided. In addition, a plurality of O-rings 100 may be arranged on the one conveyance table 26 along the conveyance direction, or one O-ring 100 may be arranged on the one conveyance table 26.

  The motor 22 is composed of, for example, a servo motor or a stepping motor, and rotates the output shaft (not shown) by an appropriate rotation amount at an appropriate speed in accordance with an instruction from the motor drive unit 23 to move the transport table 26. The motor drive unit 23 controls the operation of the motor 22 based on instructions from the processing unit 5.

  2 is a perspective view showing the appearance of the mirror part 2. FIG. 3 (a) is a top view of the mirror part 2, and FIG. 3 (b) is a cross-section in the direction of arrows IIIb-IIIb in FIG. 3 (a). FIG. 2 and 3, the feeding mechanism 21 on which the O-ring 100 is placed is shown in a simplified manner.

  The mirror unit 2 includes an annular mirror base 31 and a plurality of mirror units 32 arranged on the mirror base 31.

  The mirror base 31 is made of, for example, metal, and is open so that the O-ring 100 is exposed when viewed from the camera 4. Specifically, the inner diameter of the opening of the mirror base 31 is larger than the outer diameter of the O-ring 100 and wider than the field of view of the camera 4. Further, the photographing position P of the O-ring 100 is, for example, the center of the opening of the mirror base 31 when viewed from the camera 4.

  For example, eight mirror units 32 are provided so as to surround the O-ring 100 when viewed from the camera 4. Each mirror unit 32 includes a mirror 34 that reflects a mirror image of the O-ring 100, a holding block 35 that holds the mirror 34, a holding plate 36, and a screw 37.

  The mirror 34 is constituted by, for example, a plane mirror having a reflective surface formed in a plane. The planar shape of the mirror 34 is, for example, a rectangle. The mirror 34 is disposed between the O-ring 100 at the imaging position P and the camera 4 so as to surround the outer periphery of the O-ring 100 when viewed from the camera 4. As shown in FIG. 3B, at least a part of the mirror 34 is located in the field of view of the camera 4 so that the reflecting surface 34a is inclined with respect to the optical axis LL and the reflecting surface 34a faces the camera 4 side. Has been placed. Accordingly, the camera 4 can capture a mirror image of the inner peripheral surface 100b of the O-ring 100 projected on the mirror 34.

  As shown in FIG. 1, the inclination angle θ1 of the reflecting surface 34a is required with respect to the relative position between the O-ring 100 and the camera 4, the viewing angle of the camera 4, the size of the O-ring 100, and the inner peripheral surface 100b. It is appropriately set according to various conditions such as an imaging angle. For example, in FIG. 1, the case where the inclination angle θ1 of the reflecting surface 34a is set so that the image of the inner peripheral surface 100b viewed at an angle θ2 with respect to the mounting surface is reflected in a direction substantially parallel to the optical axis LL. For example, when θ2 = 40 degrees, θ1 = 25 degrees. In this case, the width W is, for example, 30 mm.

  As shown in FIGS. 2 and 3A, the mirrors 34 are arranged so that the O-ring 100 side is dense. On the camera 4 side of the mirror 34, a gap is generated between the mirrors 34 as much as the mirror 34 is inclined toward the outer peripheral side. The planar shape of the mirror 34 may be a trapezoid in which the end on the O-ring 100 side is wider than the end on the camera 4 side, and the gap between the mirrors 34 on the camera 4 side may be eliminated.

  As shown in FIG. 3B, the holding block 35 is made of, for example, metal, and has a cross-sectional shape that is substantially L-shaped as a whole. The holding block 35 includes an attachment part 35 a attached to the mirror base 31 and a holding part 35 b that holds the mirror 34. The attachment portion 35a constitutes one side of the L shape, and the holding portion 35b constitutes the other side of the L shape.

  The attachment portion 35a is formed, for example, in a substantially rectangular parallelepiped shape, and is placed on the mirror base 31. Fastening means such as a screw 38 inserted in a through hole (not shown) provided in the attachment portion 35a is used for the mirror. The mirror 31 is fixed to the mirror base 31 by being screwed into a screw hole (not shown) provided in the base 31.

  The holding portion 35b has a substantially trapezoidal cross section and has an inclined surface 35c on which the mirror 34 is disposed. The width of the inclined surface 35c (the depth direction in the drawing of FIG. 3B) is the same size as the width of the mirror 34, and the length of the inclined surface 35c in the height direction (the vertical direction of the drawing in FIG. 3B). Is slightly shorter than the length of the mirror 34 in the height direction.

  The holding plate 36 and the screw 37 are provided on the optical end surface of the holding block 35 on the camera 4 side and the O-ring 100 side. The holding plate 36 includes a flat plate portion 36a and a curved portion 36b that curves to form a ridge portion.

  The flat plate portion 36a is disposed along the end surface of the holding block 35 on the camera 4 side or the O-ring 100 side. A screw 37 is inserted into a through hole (not shown) provided in the flat plate portion 36 a, and the screw 37 is screwed into a screw hole (not shown) provided in the holding block 35, whereby the holding plate 36 is attached to the holding block 35. Fixed.

  The curved portion 36 b is convex outward of the mirror 34. Specifically, the holding plate 36 on the camera 4 side of the holding block 35 has the bending portion 36b on the holding plate 36 on the O-ring 100 side of the holding block 35 so that the bending portion 36b protrudes toward the camera 4 side. It arrange | positions so that it may become convex at the O-ring 100 side.

  The end of the mirror 34 protruding from the inclined surface 35c of the holding block 35 is inserted into the concave portion of the curved portion 36b. The curved portion 36b contacts the end of the mirror 34 and supports the mirror 34 in the vertical direction. Further, the end of the mirror 34 is inserted in a state where the bending portion 36b is distorted in a direction in which the bending portion 36b extends in a flat plate shape, and a direction perpendicular to the optical axis LL due to elastic force (FIG. 3B). The mirror 34 is also supported in the left and right direction of the sheet.

  As shown in FIG. 3B, the mirror base 31 is fixed to a support base 55 fixed to the camera 4 and the transport unit 6 by fastening means such as screws. The support base 55 is configured by combining, for example, a plurality of columns 55a and beams 55b. Each column 55a and the beam 55b are fixed to each other by, for example, welding or fastening means, and the relative position of the mirror base 31 with respect to the camera 4 and the transport unit 6 can be adjusted by changing the fastening position by the fastening means. Has been. The support base 55 is made of, for example, metal.

  As shown in FIGS. 1 and 3B, the illumination unit 3 includes an illumination base 41, a first ring illumination 42 and a second ring illumination 43 for illuminating the O-ring 100, and these illumination units 42, And a diffusion plate 44 for diffusing the light from 43.

  The illumination base 41 is made of, for example, metal, and is configured as an annular member having a size substantially equal to that of the mirror base 31 so that the O-ring 100 is exposed when viewed from the camera 4. The mirror base 31 and the illumination base 41 are fixed to each other by fastening means (not shown), for example. The mirror base 31 and the illumination base 41 may be integrally formed.

  As shown in FIG. 1, the first ring illumination 42 is configured, for example, by arranging point light sources 47 in a ring shape on a substrate 46. The substrate 46 is formed in an annular shape, and the size of the opening is substantially the same as the size of the opening formed by the end of the mirror 34 on the O-ring 100 side. The board | substrate 46 is being fixed to the camera 4 side of the base 41 for illumination by the fastening means, for example. The point light source 47 is composed of, for example, a white LED, and is arranged on the O-ring 100 side of the substrate 46.

  The second ring illumination 43 has the same configuration as the first ring illumination 42 and includes a substrate 48 and a point light source 49. However, the substrate 48 is disposed on the O-ring 100 side of the illumination base 41, and the point light source 49 is arranged on the camera 4 side of the substrate 48. In other words, the first ring illumination 43 and the second ring illumination 43 are arranged to face each other at a predetermined interval. The operations of the point light sources 47 and 49 are controlled by the processing unit 5 through the light source driving unit 51.

  FIG. 4 is an enlarged view showing the diffusion plate 44. The diffusion plate 44 is made of, for example, milky white resin. The diffuser plate 44 is disposed between the point light source 47 of the first ring illumination 42 and the point light source 49 of the second ring illumination 43 and is disposed so as to be inclined by θ5 with respect to the optical axis LL. . Accordingly, the diffusion plate 44 diffuses the light from the first ring illumination 42 and transmits it to the O-ring 100, and reflects the light from the second ring illumination 43 toward the O-ring 100. The diffusing plate 44 may have a shape obtained by cutting a conical body, or may be configured by arranging a flat diffusing plate so as to surround the O-ring 100 like the mirror 34.

  FIG. 5 is a flowchart showing the procedure of the inspection process executed by the processing unit 5 of the inspection apparatus 1. When the inspection apparatus 1 is turned on and an operation for instructing the start of a predetermined inspection is performed on the keyboard 17, the processing unit 5 performs an initial operation (step S1). For example, the processing unit 5 turns on the first ring illumination 42 and the second ring illumination 43 via the light source driving unit 51. Further, the position of the feed mechanism 21 is detected by a detection sensor (not shown) or the like.

  In step S <b> 2, the processing unit 5 drives the transport unit 6. That is, an instruction signal is output to the motor drive unit 23 to rotate the motor 22, and the O-ring 100 is conveyed by the feed mechanism 21. For example, when a plurality of O-rings 100 are sequentially supplied from an unillustrated O-ring manufacturing apparatus to the feeding mechanism 21, the plurality of O-rings 100 are moved along the moving direction of the transport table 26 at regular intervals. Are arranged.

  When the O-ring 100 reaches the imaging position P, the processing unit 5 stops the transport unit 6 (step S3). Specifically, for example, the processing unit 5 determines whether or not the O-ring 100 is positioned substantially at the center of the opening of the mirror unit 2 and the illumination unit 3 based on the image data output from the camera 4 every moment. The transport unit 6 is stopped when it is determined that it is located in the center. Alternatively, the conveyance unit 6 is stopped when the motor 22 is rotated by a predetermined amount from the initial position.

  In step S <b> 4, a mirror image of the O-ring 100 at the imaging position P projected on the mirror unit 2 by the camera 4 is captured. When the position of the O-ring 100 is detected by the camera 4 as described above and the transport unit 6 is controlled based on the detection result, the image quality level in the case of position detection is lower than the image quality level in step S4. However, the burden on the camera 4 and the processing unit 5 may be reduced.

  In step S5, the processing unit 5 determines the presence / absence of a defect in the O-ring 100 based on the image data obtained in step S4. If it is determined that there is no defect, the process returns to step S2. If it is determined that there is a defect, a predetermined defect occurrence process is executed (step S6), and the process returns to step S2.

  In the processing at the time of defect occurrence, for example, information for identifying the O-ring 100 in which the defect has occurred is collected in order to separate and collect the O-ring 100 determined to have a defect from the other O-rings 100. Recorded in the RAM. The information for specifying the O-ring 100 is, for example, the rotational position of the motor 22 when the O-ring 100 in which a defect has occurred is at the imaging position P. After that, when the defective O-ring 100 is transported to a predetermined position by the transport unit 6, the defective O-ring 100 is recovered by the defective product recovery device provided at the transport destination of the transport unit 6.

  Note that the presence or absence of a defect may be determined based on an image obtained by capturing the O-ring 100 being transported without stopping the transport unit 6 in step S3.

  6A is a diagram showing an image captured by the camera 4 in step S4, FIG. 6B is a partially enlarged view of FIG. 6A, and FIG. 6C and FIG. FIG. 6B is a diagram showing an image in the same range as FIG. 6B when the first ring illumination 42 or the second ring illumination 43 is used to illuminate and take an image.

  As shown in FIG. 6A, the center of the image G1 includes an image obtained by imaging reflected light from the O-ring 100, that is, a direct image G2 obtained by directly imaging the O-ring 100. In addition, a mirror image G3 obtained by capturing a mirror image of the O-ring 100 projected on the mirror 34 is included in the periphery. The mirror image G3 includes eight partial mirror image images G3a corresponding to the eight mirrors 34. Since the surface of the transport table 26 on the camera 4 side is set to have a relatively high reflectance, the partial mirror image G3a has a lower luminance than the image G5 of the surface of the transport table 26.

  The processing unit 5 performs various image processes on the image G1 to determine the presence / absence of a defect. For example, first, the contour of each partial mirror image G3a is specified by edge processing. Then, the luminance in each partial mirror image G3a is specified, and it is determined that a defect has occurred when the number of pixels whose luminance is lower than a predetermined luminance threshold exceeds a predetermined pixel number threshold. FIG. 6B illustrates a case where a concave defect is generated in the area A5 and a shadow is generated in the area A5. The determination as to whether or not the number of pixels whose luminance is lower than the luminance threshold exceeds the pixel number threshold is a determination of whether or not the area where the luminance is lower than the luminance threshold is greater than a predetermined area threshold. It is an example.

  The presence or absence of a defect may be determined based on both the direct image G2 and the mirror image G3. For example, when the presence / absence of a defect is determined based on the direct image G2 as in the conventional case, and the presence / absence of a defect is determined based on the mirror image G3 as described above. You may make it finally determine that there is no defect.

  When determining the presence / absence of a defect using an image obtained by directly capturing the O-ring 100, an image obtained by directly capturing the O-ring 100 and a mirror image may be acquired as one image or different from each other. You may acquire as an image. In the case where the images are acquired as separate images, the illumination method may be switched between direct imaging of the O-ring and when mirror images are captured, and illumination conditions suitable for the respective imaging may be set.

  As shown in FIG. 6C, when the O-ring 100 is illuminated only by the first ring illumination 42, it becomes darker as a whole than in FIG. The shadow of the generated area A5 ′ is small.

  As shown in FIG. 6D, when the O-ring 100 is illuminated only by the second ring illumination 43, it becomes darker as a whole compared to FIG. 6B. Moreover, it is dark as a whole compared with FIG.6 (c). However, an area A7 of the O-ring 100 on the camera 4 side (upper side in the drawing of FIG. 6D) is brighter in a wider range than FIG. 6C. Further, since the light reflected by the diffusion plate 44 is closer to the direct light than the light transmitted through the diffusion plate 44, the shadow of the region A5 ″ is larger than that of FIG. 6C.

  FIG. 4 shows a state in which the portion on the camera 4 side of the O-ring 100 that could not be illuminated by the first ring illumination 42 is illuminated by the second ring illumination 43. The light emitted from the first illumination ring 42 in the direction parallel to the optical axis LL as indicated by the arrow y1 in FIG. 4 is applied to the O-ring 100 while diffusing from the diffusion plate 44 as indicated by the arrow y2. The angle between the center of the diffused light indicated by the arrow y3 and the diffuser plate 44 is θ5. On the other hand, the light emitted from the second ring illumination 43 in the direction parallel to the optical axis LL as indicated by the arrow y4 is reflected by the diffusion plate 44 and applied to the O-ring 100 as indicated by the arrow y5. The angle between the arrow y5 and the diffusion plate 44 is θ6. Since θ6> θ5 in general, the second ring illumination 43 can illuminate a portion of the O-ring 100 on the camera 4 side (above the paper surface) that cannot be sufficiently illuminated by the first illumination ring 42.

  According to the above embodiment, the mirror 34 disposed on the outer peripheral side of the O-ring 100 projects the mirror image of the inner peripheral surface 100b, and the presence or absence of a defect is determined based on the image obtained by capturing the mirror image. An image of the inner peripheral surface 100b can be sufficiently obtained without taking in and out the mirror, and the inspection accuracy of the inner peripheral surface of the inspection object can be improved with a simple configuration.

  In particular, when the object to be inspected is an O-ring having a reduced diameter on the center side of the inner peripheral surface, it is difficult to obtain an image of a wide range of the inner peripheral surface from a camera arranged in the opening direction. Therefore, the inspection apparatus 1 according to the present embodiment is effective.

  Since the mirror unit 2 is configured by arranging a plurality of mirrors 34 as plane mirrors so as to surround the O-ring 100, the entire circumference inspection of the inner peripheral surface 100b is performed by a highly versatile mirror, that is, an inexpensive mirror. Can be realized.

  The first ring illumination 42 and the second ring illumination 43 are opposed to each other, the light from the first ring illumination 42 is transmitted while diffusing to the O ring 100 side, and the light from the second ring illumination 43 is transmitted to the O ring 100 side. Since the diffuser plate 44 that reflects toward the surface is provided, the inner peripheral surface 100b of the O-ring 100 can be illuminated uniformly and over a wide range by the compact illumination unit 3 as a whole.

  Since the mirror unit 2 is disposed between the camera 4 and the O-ring 100, the feed mechanism 21 provided on the back side of the O-ring 100 when viewed from the camera 4 has a high degree of freedom in design. That is, the influence of the mirror unit 2 on the degree of freedom in designing the feeding mechanism 21 is small.

  The present invention is not limited to the above embodiment, and may be implemented in various aspects.

  For example, the inspection object only needs to have an opening, and is not limited to an O-ring. The opening member may be a seal member having a constant diameter in the opening direction, or may be a product having a through hole into which another member is inserted, such as a bearing member.

  The mirror part is not limited as long as it is arranged on the outer peripheral side of the opening of the inspection object and can project a mirror image of the inner peripheral surface of the opening to the imaging means, and a plurality of plane mirrors are arranged concentrically with the opening. It is not limited to what is comprised. For example, a single plane mirror may be arranged to inspect only a specific part of the inner periphery, or an annular mirror surrounding the opening may be arranged.

  The defect determined by the processing unit is not limited to the unevenness (contour) on the inner peripheral surface as long as it relates to the appearance of the inspection object. For example, discoloration of the inner peripheral surface may be detected.

  The ring illumination only needs to be able to irradiate light from the position surrounding the opening of the inspection object, and is not limited to the one in which the point light source is arranged in an annular shape. For example, light is emitted from the position surrounding the opening by an optical fiber. May be.

It is the schematic which shows the inspection apparatus of embodiment of this invention. It is a perspective view of the mirror part of the inspection apparatus of FIG. It is the top view and sectional drawing of the mirror part of the inspection apparatus of FIG. It is a partial expanded sectional view of the illumination part of the inspection apparatus of FIG. It is a flowchart which shows the procedure of the inspection process which the process part of the inspection apparatus of FIG. 1 performs. It is a figure which shows the image imaged with the camera of the inspection apparatus of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... O-ring (inspection object), 100a ... Inner peripheral surface, 4 ... Camera (imaging means), 2 ... Mirror part, 5 ... Processing part (discriminating means).

Claims (7)

Imaging means (4) arranged in the opening direction of the opening (100a) of the inspection object (100);
A mirror unit (2) disposed between the inspection object and the imaging unit on the outer peripheral side of the opening as viewed from the imaging unit and displaying a mirror image of the inner peripheral surface (100b) of the opening;
Discriminating means (5) for discriminating the presence or absence of defects of the inspection object based on the mirror image (G3) imaged by the imaging means;
Appearance inspection apparatus (1) provided with. The appearance inspection apparatus according to claim 1, wherein the inner peripheral surface has a reduced diameter on the center side in the opening direction. 3. The appearance inspection apparatus according to claim 1, wherein the mirror unit includes a plurality of plane mirrors (34) arranged so as to surround the opening as viewed from the imaging unit and projecting a mirror image of the inner peripheral surface. . A first illumination means (42) for irradiating light to the inspection object side between the inspection object and the imaging means;
A second illuminating means (43) for irradiating light to the first illuminating means side between the first illuminating means and the inspection object;
Provided between the first illuminating means and the second illuminating means, allowing the light from the first illuminating means to transmit while diffusing to the inspection object side, and from the second illuminating means. Diffusing means (44) for reflecting light to the inspection object side;
The visual inspection apparatus according to claim 1, further comprising: The visual inspection apparatus according to claim 4, wherein the first illuminating unit and the second illuminating unit are ring illuminating units that irradiate light from a position surrounding the opening as viewed from the imaging unit. The determination unit determines that a defect has occurred in the inspection object when an area whose luminance is lower than a predetermined luminance threshold is larger than a predetermined area threshold in the mirror image. The visual inspection apparatus according to any one of the above. Further provided is a conveying means (26) provided behind the inspection object as viewed from the imaging means and for carrying the inspection object into and out of a position where the mirror image can be taken by the imaging means. The appearance inspection apparatus according to any one of claims 1 to 6.

Images