JP6619715B2 - Imaging device and illumination device - Google Patents

Description

  The present invention relates to a technique for detecting a defect such as a metal can including a tightening portion, and more particularly, to an imaging device and an illumination device that are used for defect inspection using double ring images on both sides of a winding upper end.

  Patent Document 1 discloses a defect inspection apparatus for a mouth portion such as a glass bottle. This Patent Document 1 states that “the annular shed is illuminated by an annular illuminator, the reflected light from the shed is converted into an electrical signal by a photoelectric conversion sensor, and the electrical signal is processed by an electronic processor. In the mouth defect inspection apparatus for inspecting the presence or absence of defects in the mouth portion, the diameter of the annular illuminator is larger than the outer diameter of the mouth portion, the optical axis of the photoelectric conversion sensor, the annular shape While aligning the central axes of the illuminator and the mouth portion with each other, select the position along the axis of the photoelectric conversion sensor, the annular illuminator and the mouth portion, near the outer periphery and the inner periphery of the mouth portion There is a description that only the reflected annular reflected light is introduced into the photoelectric conversion sensor as double annular light, converted into an electrical signal, and the electrical signal is processed by an electronic processor.

  Further, Patent Document 2 describes a method for measuring the winding thickness of the winding portion of the can with high accuracy over the entire circumference. Patent Document 2 states that “a double ring-shaped image on both sides of the upper end of the winding is obtained, and the ring width between the double ring outer end and the ring inner end radiates from the center of the ring image at appropriate intervals. It is measured and when each ring width dimension is outside the preset upper and lower threshold ranges, it is determined that the metal can is defective. "

JP-A-62-69154 JP 2012-159320 A

  Patent Document 1 is a technical idea of taking a double ring image by irradiating light downward on a bottle. There is a problem that a double ring image cannot be obtained when applied to a can tightening portion. In contrast, Patent Document 2 solves the problems of Patent Document 1. So far, the imaging device of Patent Document 2 has been used for inspection of beer cans and beverage cans, but it has been desired to use it for inspection of various cans having different calibers.

  The present invention is an invention for solving the above-described problems, and an object thereof is to provide an imaging device and an illumination device that can be used for inspection of various types of cans having different diameters.

In order to achieve the above object, an imaging apparatus of the present invention is disposed between an imaging unit, a lens unit provided on the optical axis incident optical path side of the imaging unit, and a lens unit and a subject such as a metal can. An annular first rod lens (for example, ring-shaped rod lens 31) having a rod lens with an opening provided in the ring portion, and a first light source disposed radially outside the first rod lens (For example, light source 33), an annular first light guide plate (for example, light guide plate) that is disposed between the first light source and the first rod lens and has reflection surfaces on the imaging unit side and the subject side. 32), and the subject is irradiated with light and the reflected light is imaged. Other aspects of the present invention will be described in the embodiments described later.

  According to the present invention, it can be used for inspection of various types of cans having different diameters.

It is a figure which shows the inspection apparatus containing the illuminating device which concerns on this embodiment, (a) is a structural example of an inspection apparatus, (b) is an example of the captured image which the imaging device imaged. It is a figure which shows the characteristic of a captured image. It is a figure which shows the structure of the illuminating device which concerns on 1st Embodiment, (a) is a side view, (b) is an enlarged view around a light source, (c) is an image figure of a ring-shaped rod lens. It is a figure which shows the structure of an illuminating device, (a) is an example of arrangement | positioning of the light source of a light emission goods part, (b) is an example of arrangement | positioning of the ring-shaped rod lens and light-guide plate of an optical goods part. It is the figure which looked at the illuminating device from the can lid side. It is a figure which shows the structure of an illuminating device, (a) is a perspective view which shows the relationship with an LED drive circuit board etc., (b) is a side view. It is a figure which shows the optical path from the ring-shaped rod lens in 1st Embodiment. It is a figure which shows the characteristic of this embodiment at the time of applying to various cans. It is a figure which shows the example of an imaging | photography when not adjusting as a comparative example, (a) is a case of a beer can, (b) is a case of a drink can. It is a figure which shows the structure of the illuminating device which concerns on 2nd Embodiment, and the optical path from a some ring-shaped rod lens. It is a figure which shows the captured image example of this embodiment, (a) is a captured image example of 1st Embodiment, (b) is a captured image example of 2nd Embodiment. It is a figure which shows the structure of the illuminating device which concerns on 3rd Embodiment, and the optical path from a some ring-shaped rod lens.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
<< first embodiment >>
1A and 1B are diagrams illustrating an inspection apparatus including an illumination device according to the present embodiment. FIG. 1A is a configuration example of the inspection apparatus, and FIG. 1B is an example of a captured image captured by the imaging apparatus. The inspection device shown in FIG. 1A is provided with an illumination device 3 on the upper side in order to inspect the winding tightening portion 20 (can lid) of the can 10 conveyed on the conveyor 2. A lens 4a is mounted and disposed on a camera 4 such as a CCD (Charge-Coupled Device) camera so that the winding part 20 (can lid) of the can 10 can be imaged from above through the center hole 38. The imaging device 40 includes the camera 4, the lens 4a, the illumination device 3, and the like.

  The sensor 5 generates a detection signal at the moment when the can 10 passes almost directly below the illumination device 3 and the camera 4, and this detection signal activates the illumination power source 3 a via the image processing device 6 to emit light from the illumination device 3. Then, the winding part 20 of the can 10 is irradiated. At the same time, the video signal of the camera 4 is input to the image processing device 6 in synchronization with the detection signal. The image processing device 6 performs a predetermined analysis process from the video signal to determine pass / fail, and rejects defective products by the sorting mechanism 7.

  The left side of FIG. 1B is a captured image of the lid portion of the can including the tightening unit 20, and the right side of FIG. 1B is an enlarged captured image of the winding unit 20. The feature of the appearance inspection apparatus of the present embodiment that is different from the conventional appearance inspection apparatus is that the portion of the seaming panel radius 23 and the portion of the seaming wall radius 25 can be captured as a double ring image. In addition, the can lid can be clearly imaged, including the shape of the pull top of the can lid. A double ring image, which is a feature of the present embodiment, will be described in detail with reference to FIG.

  FIG. 2 is a diagram illustrating the characteristics of the captured image. FIG. 2 shows an enlarged sectional view of double winding. The outer shape of the double winding is formed of the counter sink 21, chuck wall 22, seaming panel / radius 23, seaming panel 24, seaming wall / radius 25, and seaming wall 26. Here, the winding thickness T of the can refers to the thickness (T dimension) between the seaming wall 26 and the chuck wall 22. Note that “non-reflective” in the figure means that no reflected light enters the lens 4a even when light from a light source is incident.

  The image of the double ring shown in FIG. 1B is mainly composed of a ring by reflection of the seaming panel radius 23 (inner ring) and a ring by reflection of the seaming wall radius 25 (outside). Ring). A dark portion between the inner ring and the outer ring is a portion of the seaming panel 24. If there is no reflection due to scratches or the like on the seaming panel 24, the illumination device 3 (see FIG. 1) is illuminated so as to capture an image as a dark part.

When calculating the T dimension equivalent value of the winding thickness T of the can from the captured image, the outermost edge coordinate of the seaming wall radius 25 is P1, and the innermost edge coordinate of the seaming panel radius 23 is P2. Then, the imaging edge interval Δd is calculated by the following equation.
Δd = | P1-P2 |

  The T dimension value and the radius part are continuous, and the imaging edge interval Δd, which is a measured value, and the T dimension have a significant correlation and can be handled as equivalent values. In the present embodiment, a value equivalent to the T dimension can be measured by reflecting up to the base of the radius. Further, a coefficient calculation may be performed on the imaging edge interval Δd to approximate the T dimension.

  3A and 3B are diagrams showing the structure of the illumination device according to the first embodiment, wherein FIG. 3A is a side view, FIG. 3B is an enlarged view around the light source, and FIG. 3C is a ring-shaped rod lens. It is an image figure. The camera 4 and the lens 4a, the illumination device 3, and the can 10 are arranged as shown in the figure. The illumination device 3 is disposed below the lens 4a, and a can 10 that is a subject is disposed below the illumination device 3.

  The illuminating device 3 includes a ring-shaped rod lens 31, a light guide plate 32, a light source 33 (LED light emitting element) mounted on a support plate 35a, and an LED drive circuit board 34 in a housing 30. The support plate 35a is disposed on the support plate 35b. The housing 30 has a first opening 38 at the center of the upper surface. The LED drive circuit board 34 and the support plate 35b have a second opening 37 at the center. Further, the housing 30 has a lid 39 on the lower surface and a third opening 36 in the center. The illuminating device 3 is formed of an optical product portion 30a (see FIG. 4) and a light emitting product portion 30b (see FIG. 4) in consideration of maintainability of the illuminating device, and is configured by combining them. The combination will be described later with reference to FIG.

  FIG. 3B is an enlarged view of the ring-shaped rod lens 31, the light guide plate 32, and the light source 33 (LED light emitting element). FIG. 3C is a perspective image view of the ring-shaped rod lens 31. The ring-shaped rod lens 31 is a donut-shaped lens. This is a condensing lens with a rod lens in a ring shape. A plurality of LEDs as the light source 33 may be arranged in the vertical direction in order to ensure brightness. The ring-shaped rod lens 31 can change the irradiation angle by moving the adhesion position with the light guide plate 32 up and down. It is desirable that the setting is such that the light is directed toward the winding part 20.

  Reflecting material 32a is provided on the upper and lower surfaces of light guide plate 32 shown in FIG. 3B, and is formed by painting or double-sided adhesion of the reflecting material. The ring-shaped rod lens 31 and the light guide plate 32 are separately manufactured and assembled by bonding or the like in order to obtain a lens effect. It is desirable to process a perfect circle on the light guide plate 32 side and the tightening portion 20 side of the ring-shaped rod lens 31. The material of the ring-shaped rod lens 31 and the light guide plate 32 may be any material that transmits light and is easy to process, such as polypropylene, acrylic resin, and transparent plastic resin material.

  FIGS. 4A and 4B are diagrams showing the configuration in the illumination device, where FIG. 4A is an example of the arrangement of the light sources in the light emitting part, and FIG. 4B is an example of the arrangement of the ring-shaped rod lens and the light guide plate in the optical part. . 4A shows the light emitting part 30b, and is a view from the bottom of FIG. 3 with the lid 39 opened. FIG. 4B shows the optical part 30a, and the lid 39 is shown. FIG. The light emitting product portion 30b and the optical product portion 30a are formed as a single lighting device 3 by combining the surfaces of the mounting screw holes A, B, C, and D.

  The light emitting product part 30 b includes a light source 33 (LED light emitting element) and an LED drive circuit board 34 (not shown) in the housing 30. In the optical part 30a, a ring-shaped rod lens 31 and a light guide plate 32 are disposed on the lid 39 side. The illuminating device 3 is configured by combining a light emitting product part 30b shown in FIG. 4A and an optical product part 30a shown in FIG. 4B.

  4A has a second opening 37 of the LED driving circuit board 34, and a plurality of LEDs are arranged in an octagonal shape. Although there is a gap at each corner of the octagon, adjacent LEDs can be arranged to supplement the light. If it is a quadrangle, the corner gap becomes large, and it becomes difficult to irradiate the LED light evenly to the ring-shaped rod lens. For example, 11 three stages are arranged on one side. By placing 33 × 8 = 264 LEDs, a clear double ring image can be obtained. FIG. 4B shows an optical product part 30 a having a ring-shaped rod lens 31 and a light guide plate 32. In addition, although the octagon was selected from the ease of the process which adhere | attaches LED, another polygon and a circle may be sufficient.

  FIG. 5 is a view of the lighting device viewed from the can lid side. The reflective material 32a is painted and bonded on both sides, and is white. Light from the light source 33 (LED light emitting element) can be transmitted to the ring-shaped rod lens 31 without leaking.

  6A and 6B are diagrams illustrating the configuration of the illumination device, in which FIG. 6A is a perspective view illustrating a relationship with an LED drive circuit board and the like, and FIG. 6B is a side view. FIG. 6A shows a state seen through the lid 39 shown in FIG. FIG. 6B shows the arrangement configuration in the side surface in the illuminating device 2 with a broken line, and shows a state in which the illuminating device 3 is transposed up and down. The support plate 35b and the LED drive circuit board 34 shown in FIG. 6B are fixed by a mounting portion 36b at a predetermined distance. Further, the support plate 35b is fixed to the housing 30 with a fixture 36a.

  FIG. 7 is a diagram showing an optical path from the ring-shaped rod lens in the first embodiment. Reference is made to FIG. 2 as appropriate. The irradiation to the can 10 from the light source 33 (LED light emitting element) will be described in detail. Irradiation light 31a from the light source 33L on the left side of the drawing is reflected to the outside by the surface of the can 10 to become reflected light 31a20. It does not enter the lens 4a. The same applies to the light incident on the seaming wall 26 (not shown). The irradiation light 31b is reflected by the seaming wall radius 25 to become reflected light 31b20 and enters the lens 4a. The light incident on the seaming panel 24 is reflected to become reflected light and is reflected in the direction of the reflecting material 32aR, and therefore does not enter the lens 4a (not shown). The irradiation light 31c is reflected by the seaming panel radius 23 to become reflected light 31c20.

  The irradiation light 41a from the light source 33R on the right side of the drawing is reflected to the outside by the surface of the can 10 to become reflected light 41a20 and does not enter the upper lens 4a. The same applies to the light incident on the seaming wall 26 (not shown). The irradiation light 41b is reflected by the seaming wall radius 25 to become reflected light 41b20 and enters the lens 4a. The light incident on the seaming panel 24 is reflected and becomes reflected light, and is reflected in the direction of the reflecting material 32aL, and therefore does not enter the lens 4a (not shown). The irradiation light 41c is reflected by the seaming panel radius 23 to become reflected light 41c20.

  FIG. 8 is a diagram showing the characteristics of the present embodiment when applied to various types of cans. FIG. 8 shows the length L1 of the light guide plate in the radial direction, the diameter L3 of the rod lens of the ring-shaped rod lens 31, and the inner diameter L2 of the ring-shaped rod lens 31 as main dimensions. In the present embodiment, the dimensional difference of the subject can be dealt with by changing the radial length L1 of the light guide plate or the inner diameter L2 of the ring-shaped rod lens 31. Specifically, it is possible to deal with dimensional differences such as beer cans, beverage cans, and milk cans.

  By changing the diameter L3 or the inner diameter L2 of the rod lens of the ring-shaped rod lens 31, it is easy to change the illumination angle θ, so that the range in which illumination is desired can be changed.

  Therefore, it is possible to inspect from No. 3 can to No. 7 can with one housing. Further, the No. 1 can and No. 2 can can be inspected by designing the casing large.

  FIGS. 9A and 9B are diagrams showing an example of imaging when no fitting is performed as a comparative example, where FIG. 9A shows a beer can and FIG. 9B shows a beverage can. In FIG. 9, as an inspection system of a comparative example, an imaging example in which fitting is insufficient in a can inspection with different diameters is shown. FIG. 9A is an example of photographing a beer can, and the inner line of the double line of the winding tightening portion 20 is unclear because it is not fitted. FIG. 9B is an example of photographing a beverage can, and the pull tab is unclear because it is not fitted.

  As described above, the inspection system of the comparative example could not cope with various cans. However, by combining the ring-shaped rod lens 31 and the light guide plate 32 according to the present embodiment, it is possible to easily handle multiple cans at a lower cost than using a conventional inspection system.

<< Second Embodiment >>
FIG. 10 is a diagram illustrating a configuration of the illumination device according to the second embodiment and an optical path from a plurality of ring-shaped rod lenses. Reference is made to FIG. 2 as appropriate. The illumination device according to the second embodiment is a case where a plurality of ring-shaped rod lenses are used, and the amount of light is larger than when the one-stage ring-shaped rod lens 31 shown in the first embodiment is used. In particular, a stable image of the seaming panel and radius inside the can can be secured.

  When the ring-shaped rod lens of the first embodiment is a single-stage type, the ring-shaped illumination device condensed by one ring-shaped rod lens 31 causes the seaming wall radius 25 on the outer side of the winding portion 20 and the inner side Since the seaming panel radius 23 is illuminated and the reflected light is imaged, the amount of the reflected light inside tends to be insufficient.

  In addition to the first embodiment, FIG. 10 includes a ring-shaped rod lens 310 (second rod lens), a light guide plate 320 (second light guide plate), and a light source 330. The ring-shaped rod lens 310 is located inside the ring-shaped rod lens 31.

  Only the optical path with the characteristic points will be described. Irradiation light 310c (shown by a broken line) output from the ring-shaped rod lens 310L related to the inner ring, and irradiation light 410c (shown by a broken line) output from the ring-shaped rod lens 310R. The irradiation light 310c, 410c has a shorter optical path than the irradiation light 31c, 41c output from the ring-shaped rod lens 31. When the optical path is shortened, the amount of light that strikes the winding portion (can lid) 20 increases.

  The irradiation lights 31c and 310c are reflected by the seaming panel radius 23 and become a value (31c20 + 310c20) obtained by adding the reflected lights 31c20 and 310c20. Therefore, the light which hits the winding part (can lid) 20 becomes brighter than in the first embodiment. Similarly, the irradiation lights 41c and 410c have a value (41c20 + 410c20) in which the reflected lights 41c20 and 410c20 are added after being reflected by the seaming panel radius 23. Therefore, the light which hits the winding fastening part 20 (can lid | cover) becomes bright compared with 1st Embodiment.

  In the case of the two-stage type, the ring-shaped illuminating device focused by two ring-shaped rod lenses mainly uses the seaming wall radius 25 outside the tightening portion 20 as the first stage and the inner seaming panel radius 23. By mainly illuminating in the second stage, the amount of light of the seaming panel radius (inside) can be secured.

  FIG. 11 is a diagram illustrating an example of a captured image of the present embodiment, where (a) is an example of a captured image of the first embodiment, and (b) is an example of a captured image of the second embodiment. FIG. 11 shows a case where an image is taken with respect to a can having a diameter larger than a beer can (can diameter: 75 mm) as an application example of the multi-purpose can.

  In the case of the one-stage type of the first embodiment shown in FIG. 11A, the double ring image of the tightening portion 20 is clearly captured, but the inner light amount is slightly weakened. On the other hand, in the case of the two-stage type of the second embodiment of FIG. 11 (b), the double ring image of the winding portion 20 is clearly captured, but the inner edge compared to FIG. 11 (a). Is clear.

<< Third Embodiment >>
FIG. 12 is a diagram illustrating a configuration of the illumination device according to the third embodiment and an optical path from a plurality of ring-shaped rod lenses. In the third embodiment, a lens support adjustment unit 3100 is added to bond the ring-shaped rod lens 310 away from the light guide plate 320 in the second embodiment. By adjusting the bonding position between the ring-shaped rod lens 310 and the light guide plate 320, it is possible to obtain an arbitrary light collection angle.

  By changing the bonding position of the ring-shaped rod lens 310 and the light guide plate 320, the light collection angle can be changed arbitrarily, so that it is possible to obtain a constant reflected light regardless of a change in the light amount of the illumination device 3. . The diameters of the ring-shaped rod lenses 31 and 310 are changed according to the degree of light collection. The diameter of the ring-shaped rod lenses 31 and 310 needs to be about twice the opening size of the light guide plates 32 and 320. If installing away from the opening, make it larger. With this configuration, there is an effect that the degree of freedom as the lighting device 3 is increased.

  The illuminating device of this embodiment uses a plastic ring-shaped rod lens 31 and can appropriately irradiate the winding part 20 of the can. Further, a plurality of plastic ring-shaped rod lenses 31 and 310 may be used in order to accurately measure double ring images on both sides of the upper end of the tightening portion 20.

  Using LED as the light source, it is possible to obtain double ring images on both sides of the upper end of the tightening with stable light, and to detect the tightening failure by inspecting the entire circumference of the ring width of the seaming panel image. Can be increased. Moreover, it can respond flexibly to changes in the can size. In addition, the system can be constructed at low cost.

  In addition, this invention is not limited to above-described embodiment, Various modifications are included. For example, the above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to one having all the configurations described. Further, a part of the configuration of an embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of an embodiment. In addition, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

2 Conveyor 3 Illumination device 3a Illumination power supply 4 Camera (imaging part)
4a Lens (lens part)
5 Sensor 6 Image processing device 7 Sorting mechanism 10 Can 20 Tightening part (can lid)
21 Countersink 22 Chuck wall 23 Seaming panel / radius 24 Seaming panel 25 Seaming wall / radius 26 Seaming wall 30 Housing 30a Optical part 30b Light emitting part 31 Ring rod lens (first rod lens)
32 Light guide plate (first light guide plate)
33 Light source (first light source)
34 LED drive circuit board 39 Lid 40 Imaging device 310 Ring rod lens (second rod lens)
320 Light guide plate (second light guide plate)
330 light source (second light source)
3100 Lens support adjustment section

Claims (6)

An imaging unit;
A lens unit provided on the optical axis incident optical path side of the imaging unit;
A ring-shaped first rod lens arranged between the lens unit and a subject such as a metal can and having a ring lens provided with an opening in the center;
A first light source disposed on a radially outer side of the first rod lens;
An annular first light guide plate disposed between the first light source and the first rod lens and having reflection surfaces on the imaging unit side and the subject side surface;
An imaging apparatus, wherein the subject is irradiated with light and the reflected light is imaged. The imaging device further includes:
An annular second rod lens that is disposed between the first rod lens and the lens portion and has a ring shape with a rod lens having an opening at the center;
A second light source disposed on a radially outer side of the second rod lens;
An annular second light guide plate disposed between the second light source and the second rod lens and having a surface opposite to the imaging unit side as a reflection surface is provided. The imaging device according to claim 1. The imaging apparatus according to claim 1, wherein the first light source is an LED (Light Emitting Diode). A ring-shaped first rod lens that is arranged between an imaging unit and a subject such as a metal can photographed by the imaging unit, and in which a rod lens provided with an opening in the center is formed into a ring shape ;
A first light source disposed on a radially outer side of the first rod lens;
An annular first light guide plate disposed between the first light source and the first rod lens and having reflection surfaces on the imaging unit side and the subject side surface;
An illumination device that irradiates the subject with light. The lighting device further includes:
An annular second rod lens disposed between the first rod lens and the imaging unit and having a ring shape with a rod lens provided with an opening at the center;
A second light source disposed on a radially outer side of the second rod lens;
An annular second light guide plate disposed between the second light source and the second rod lens and having a surface opposite to the imaging unit side as a reflection surface is provided. The lighting device according to claim 4. The lighting device according to claim 4, wherein the first light source is an LED (Light Emitting Diode).