JP2726808B2 - Appearance inspection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a visual inspection apparatus for capturing an image of an inspection object and inspecting a defect or the like existing on the surface of the inspection object, and more particularly, to an optimal light for capturing an image on the inspection object. The present invention relates to an appearance inspection apparatus capable of inspecting the appearance by irradiating light.

[0002]

2. Description of the Related Art A visual inspection apparatus captures an image of the surface of an object to be inspected and recognizes the state of colors and patterns on the surface. 2. Description of the Related Art A visual inspection apparatus is used to inspect the surface of a cylindrical electrolytic capacitor. The electrolytic capacitor body has a cylindrical shape made of aluminum, and its surface is covered with vinyl for insulation. If a hole of about 0.5 mm is present in the vinyl coating, the insulation property deteriorates and poses a problem. FIG. 7 is a conceptual diagram of an image capturing unit of a conventional visual inspection device. In this arrangement, a light 52 is arranged as a lighting means in parallel with the electrolytic capacitor 51, and an imaging camera 55 is provided so as to be paired with the electrolytic capacitor 51 with the light 52 interposed therebetween. In the conventional example of FIG. 7, a circline fluorescent lamp is used as the light 52. Here, the electrolytic capacitor 51 is formed with a concave portion 72 for caulking and fixing the aluminum cylindrical portion and for sealing.

As described above, in the conventional appearance inspection apparatus in which the imaging camera 55 is provided with the light 52 interposed between the electrolytic capacitor 51 to be inspected, the electrolytic capacitor 51 is illuminated by the light 52 and reflected on the surface thereof. Light is captured by the imaging camera 55, and an inspection process of the electrolytic capacitor 51 is performed based on the captured optical data. However, with such a visual inspection device, only a part of the side surface of the electrolytic capacitor 51 can be inspected at a time. Therefore, in order to inspect the entire circumference, it is necessary to rotate the electrolytic capacitor 51 with respect to the imaging camera 55 and the light 52. was there. Therefore, it takes time to inspect one electrolytic capacitor 51, and the efficiency is low.

On the other hand, as an appearance inspection device for instantaneously and efficiently inspecting the entire circumference of a cylindrical product, Japanese Patent Publication No.
No. 79327 proposes a cigarette inspection apparatus. FIG. 8 shows a main part of the apparatus. The feature of this device is that a circular mirror 59 is provided with a conical mirror 56 provided at the apex of a hole 61 into which a cigarette 57 is inserted, and captures a ring-shaped image projected on the conical mirror 56 against the mirror surface 60 of the conical mirror 56. Is attached. Further, the entire periphery of the cigarette 57 is simultaneously irradiated with light by the circular light source 58 via the mirror surface 60. This allows
It is stated that the three-dimensional surface of the cigarette can be instantaneously captured as a two-dimensional image.

[0005]

However, such a conventional visual inspection apparatus has the following problems. When the electrolytic capacitor 51 is inspected by the appearance inspection device of Japanese Patent Publication No. 6-79327, there is a problem that a pinhole generated in the concave portion 72 of the electrolytic capacitor 51 cannot be detected. That is, as shown in FIG. 9, the irradiation light emitted from the circular light source 58 is irradiated by the mirror surface 60 of the conical mirror 56 as incident light N perpendicular to the entire circumference of the electrolytic condenser 51. When the pinhole P exists on the side surface other than the concave portion 72, as shown in FIG. 10, the reflected light R that has passed through the pinhole P and reflected on the aluminum surface also follows the same route as the incident light N. . However, when the pinhole P exists in the concave portion 72 serving as the caulked portion, the incident light N passes through the pinhole P and is reflected on the aluminum surface as shown in FIG.
It goes in the direction of the reflected light R. Therefore, the light cannot be reflected by the mirror surface 60 and cannot be detected by the circular camera 58.

Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide an appearance inspection apparatus capable of accurately inspecting the surface of an uneven portion when the object has an uneven surface. I do.

[0007]

The appearance inspection apparatus of the present invention has the following configuration. (1) Illuminating means for illuminating a side surface of a cylindrical inspection object, image capturing means for capturing an image of the inspection object illuminated by the illumination means, and inspection object captured by the image capturing means A visual inspection apparatus having inspection processing means for performing a predetermined inspection processing based on the image data of the inspection object, wherein the illumination means irradiates a side surface of the inspection object from an upper direction; A second irradiating unit that irradiates the side surface of the object from below, and the image capturing unit is a conical mirror having the inspection object on the center line. (2) In the apparatus described in (1), specularly reflected light emitted from the first illumination unit and the second illumination unit and reflected from the inspection object is converted into image data via the image capturing unit. The first lighting means and the second lighting means are arranged so as to be taken in.

(3) In the apparatus described in (1) or (2), the conical mirror is a half mirror that reflects a part of incident light and passes the remaining light. (4) The device according to (1) or (2), wherein the first lighting unit and the second lighting unit are ring-shaped lighting units. (5) In the device described in (1), the illumination unit includes one ring-shaped illumination unit and a mirror that reflects light from the ring-shaped illumination unit and irradiates the side surface of the inspection object from the opposite direction. It is characterized by having.

Next, the operation of the appearance inspection apparatus of the present invention will be described. The first illumination means of the visual inspection device irradiates the side surface of the cylindrical inspection object from above. The second illumination means irradiates the side surface of the cylindrical inspection object from below. The irradiated light is reflected on the side surface of the inspection object, and is condensed on the imaging camera by the conical mirror. The inspection processing means performs an inspection process based on the image data captured by the imaging camera. When there is a recess on the side surface of the inspection object, the lower half of the surface of the recess can be illuminated by the first lighting means. Further, the upper half of the surface of the concave portion can be irradiated by the second lighting means. Thus, even if a defect exists on the surface of the concave portion, the defect can be accurately recognized by the imaging camera.

[0010] Here, the specularly reflected light emitted from the second illumination means and reflected from the inspection object is captured as image data via the image capturing means. Further, since the image capturing means is a conical mirror having the inspection object on the center line, the reflected light from the inspection object can be simultaneously captured. Further, since the conical mirror is a half mirror, a part of the light incident on the inspection object from the illumination means is passed.
Further, when a ring-shaped illumination unit is used as the first illumination unit and the second illumination unit, it is possible to simultaneously and uniformly illuminate the entire peripheral side surface of the cylindrical inspection object. Also,
When one ring-shaped illumination means and a mirror are used as the illumination means, the ring-shaped illumination irradiates the inspection object from one side, and the reflected light from the mirror illuminates the inspection object from the opposite side. Can be.

[0011]

Next, an embodiment of the appearance inspection apparatus according to the present invention will be described. FIG. 1 shows a conceptual diagram of a lighting unit, which is a characteristic part of the visual inspection device of the present embodiment. In the present embodiment, the case where the inspection object is the electrolytic capacitor 51 will be described.
In the appearance inspection device of the present embodiment, an insertion hole 61 is formed at a vertex of a conical shape, and a conical mirror 5 having a mirror surface 60 is provided.
6 is fixed. Here, the conical mirror 56 uses a half mirror that reflects half of the incident light and passes the remaining light. The electrolytic condenser 51 is inserted from the insertion hole 61 of the conical mirror 56 onto the central axis of the conical mirror 56, and is held at the position shown in FIG. Above the conical mirror 56, an upper ring light 11, which is a first illumination means, is attached. In addition, below the conical mirror 56, a lower ring light 12, which is a second illumination means, is attached. Further, the CCD camera 13 and the lens 14 are fixedly provided slightly above the conical mirror 56. As the upper ring light 11 and the lower ring light 12, circline fluorescent lamps are used.

Next, the configuration of the control unit of the visual inspection apparatus according to the present embodiment will be described. FIG. 6 is a block diagram showing the inspection processing means of the visual inspection device. Image processing means 10
Is a CCD camera 13 arranged at the above position.
It is connected to the. An A / D converter 21 for converting an analog signal into a digital signal is directly connected to the CCD camera 13 in the image processing means 10. The A / D converter 21 has a CCD camera 13
An image memory 22 for storing the image data fetched by the above, a video mixer 23 for mixing and outputting given signals, and a calculation logic 26 for calculating the appearance from the image data by a predetermined calculation method are connected to each other. Further, the image memory 22 and the calculation logic 26 are connected to the control logic 15 that specifies each operation.

On the other hand, the image memory 22, the calculation logic 26, and the CPU 16 for performing the arithmetic processing and the control processing of the image processing means 10 are connected bidirectionally. The CPU 16 is connected to a ROM 17 for storing a control program and the like, and a RAM 18 for temporarily storing data and the like. Further, an input / output device 19 is connected to the CPU 16, and the input / output device 19 is provided with a start unit for driving the appearance inspection device and an inspection display unit for inspecting whether the electrolytic capacitor 51 is normal. (Not shown), and a keyboard 20 is connected as external input means. The display monitor 25 that displays the captured image is connected to the video mixer 23 so that the appearance of the electrolytic capacitor 51 can be processed and recognized by human eyes.

The appearance inspection apparatus of the present embodiment having the above-described configuration operates as follows. As shown in the conventional example, the electrolytic capacitor 51 is provided with two electrodes 51a and 51b as shown in FIG. This electrode 51
The electrolytic capacitors 51 are inserted one by one from the insertion holes 61 while holding the a and 51b. Here, a case will be described in which a pinhole existing in the concave portion 72 is detected by the illumination means, which is a main part of the present invention. If a pinhole P occurs in the vinyl coating of the electrolytic capacitor 51, the pinhole P
The part is in a state where aluminum is raised. This pinhole P
When inspecting the occurrence of pinholes P by irradiating light, it is important that the irradiating light and the reflected light captured by the imaging system have a regular reflection relationship.

The reason is that the surface of aluminum makes specular reflection as strong as a mirror, but the surface of vinyl has a stronger diffuse reflection component than aluminum, so that the specular reflection light becomes weaker than aluminum. Because there is. Therefore, if the relationship between the irradiation light and the light captured by the imaging system is maintained as a regular reflection, the electrolytic capacitor 51 without the pinhole P becomes a dark image, and the defective electrolytic capacitor 51 with the pinhole P becomes
Only the pinhole P portion has a locally bright image, and it is possible to easily distinguish non-defective products from defective products. As shown in FIG. 12, the irradiation light emitted from the lower ring light 12 irradiates the upper half of the concave portion 72 as shown by N1 in the figure because half of the light passes as it is because the conical mirror 56 is a half mirror. Thus, the reflected light can be returned to the mirror surface 60. The reflected light that has returned to the mirror surface 60 is further specularly reflected by the mirror surface 60, and enters the lens 14 and the CCD camera 13 directly as shown by N1a in the drawing.

On the other hand, the light emitted from the upper ring light 11 can irradiate the lower half of the concave portion 72 and return the reflected light to the mirror surface 60 as indicated by N2 in the figure. The reflected light returning to the mirror surface 60 is further specularly reflected by the mirror surface 60,
As shown by N2a in the figure, the lens 14, the CCD camera 13
The light goes straight on. Further, the irradiation light that has exited the upper ring light 11 also irradiates the side surface flat portion of the electrolytic capacitor 51 as indicated by N3 in the figure, and the reflected light is returned to the mirror surface 60, is further reflected, and is reflected by N3a in the figure Lens 1
4. Light enters the CCD camera 13 directly.

In order to simultaneously irradiate the concave portion 72 and the side surface flat portion of the electrolytic capacitor 51, the upper ring light 1 is used.
It is necessary that 1 has a certain width. For that purpose, as shown in FIG.
The upper ring light 11 and the second upper ring light 24 may be used. Further, instead of the second upper ring light 24, a conical diffusion plate 27 for diffusing light may be used as shown in FIG. The shape of the diffusion plate is shown in FIG.
5, a donut-shaped flat plate may be used. Since the illumination device of the present embodiment includes the upper ring light 11 and the lower ring light 12, the light reflected from the pinhole P existing in the concave portion 72 can be reliably captured by the CCD camera 13.

The light radiated by the upper ring light 11 and the lower ring light 12 is specularly or irregularly reflected on the surface of the electrolytic capacitor 51, is reflected again on the mirror surface 60, and enters the CCD camera 13. The light reflected on the surface of the electrolytic condenser 51 is the lens 14 of the CCD camera 13.
, The side surface of the electrolytic capacitor 51 is imaged simultaneously by a number of image pickup devices constituting the CCD camera 13 all around the circumference, and further converted into digital data to capture the image data. That is, the image captured by the CCD camera 13 is input to the A / D converter 21 of the inspection processing unit 10 as image data for each image sensor. Then, the image data, which is an analog signal, is converted into digital data by the A / D converter 21 and input to the image memory 22, the video mixer 23, and the calculation logic 26. Then, the presence or absence of the pinhole P or the like is confirmed by the calculation logic 26.

As the processing of the calculation logic 26, the presence or absence of the pinhole P can be confirmed by utilizing the fact that the pinhole P is brighter than the portion other than the pinhole P. As a processing method of the calculation logic 26, for example, after binarizing a pixel such that a pixel above a certain brightness threshold is set to 1 and a pixel below the threshold is set to 0, the pixel is set to 1 The CPU 16 reads this count result, and if the count number is 1 or more, it is determined that at least one or more pinholes P are present, and the input / output device 19 indicates that the pinhole P is defective. There is a way to display. if,
When the number of pinholes P present in the electrolytic capacitor 51 is plural and it is necessary to count the number,
What is necessary is just to set it as the structure which performs a connectivity analysis process. Further, as a method other than the binarization, various processing methods such as differentiating in a multi-valued image space and capturing a change from a dark portion to a bright portion can be considered. Since this kind of technology is well known, a detailed description is omitted.

As described above, according to the appearance inspection apparatus of the present embodiment, the upper ring light 11 and the lower ring light 12 irradiate the side surface of the cylindrical inspection object. Even if a defect such as a pinhole P exists in the concave portion 72 formed in the above, the defect can be accurately recognized.

Next, a second embodiment of the present invention will be described. The only difference between the second embodiment and the first embodiment is the illumination means, and only that will be described. FIG. 2 shows the illumination means of the visual inspection device according to the second embodiment. The insertion hole 61 of the conical mirror 56 is formed large, and the irradiation light of the lower ring light 12 is reflected on the mirror surface 60.
Is irradiated directly on the upper half of the concave portion 72 without passing through the surface of the concave portion 72. According to this, the conical mirror 56 becomes large,
Since a normal mirror can be used as the conical mirror 56, and a half mirror does not need to be used, the cost can be reduced.

Next, a third embodiment of the present invention will be described. The third embodiment differs from the first embodiment only in the illumination means, and only that will be described. FIG. 3 shows a lighting unit of the visual inspection device according to the third embodiment. In the third embodiment, the lower ring light 1
There is no 2 and the ring illumination is only the upper ring light 11. A half mirror is used as the conical mirror 56. A normal mirror 62 is provided below the conical mirror 56.
Is attached. In this embodiment, a conical mirror is used as the mirror 62, but a plane mirror may be used according to the angle of the optical path. According to this,
Of the irradiation light that has exited the upper ring light 11, the light indicated by N 4 in the figure is directly applied to the lower half of the recess 72. Also,
Half of the light that has entered the conical mirror 56 passes through the mirror surface 60, enters the mirror 62, is reflected and passes again through the conical mirror 56, which is a half mirror, and is applied to the upper half of the concave portion 72. According to the third embodiment, although the amount of light irradiated to the upper half of the concave portion 72 decreases, the lower ring light 1
Since the device 2 is not used, the device can be made compact.

Next, a fourth embodiment of the present invention will be described. The fourth embodiment differs from the first embodiment only in the illumination means, and only that will be described. FIG. 4 shows the illumination means of the visual inspection device according to the fourth embodiment. In the fourth embodiment, the lower ring light 1
There is no 2 and the ring illumination is only the upper ring light 11. Normally, a mirror is used as the conical mirror 56. The insertion hole 61 of the conical mirror 56 is formed large, and a normal mirror 62 is attached below the insertion hole 61. The mirror 62 has a conical shape, and an insertion hole 63 is formed at the center thereof. According to this, of the irradiation light that has exited the upper ring light 11, the light indicated by N 4 in the figure is directly applied to the lower half of the recess 72. The irradiation light N5 incident on the mirror 62 is reflected by the mirror 62 and is applied to the upper half of the concave portion 72. According to the fourth embodiment, the size of the conical mirror 56 is increased, but the amount of light applied to the upper half of the concave portion 72 can be increased as compared with the third embodiment. In this embodiment, a conical mirror is used as the mirror 62, but a plane mirror may be used according to the angle of the optical path.

Next, a fifth embodiment of the present invention will be described. The fifth embodiment differs from the first embodiment only in the illumination means, and only that will be described. FIG. 5 shows the illumination means of the visual inspection apparatus according to the fifth embodiment. In the fifth embodiment, the upper ring light 1
There is no 1 and the ring illumination is only the lower ring light 12. Normally, a mirror is used as the conical mirror 56. The insertion hole 61 of the conical mirror 56 is formed large, and a normal mirror 62 is attached above the insertion hole 61. The mirror 62 has a conical shape, and an insertion hole 63 is formed at the center thereof. According to this, of the irradiation light that has exited the lower ring light 12, the irradiation light indicated by N 6 in the figure is directly applied to the upper half of the recess 72. The irradiation light N7 incident on the mirror 62 is reflected by the mirror 62 and is applied to the lower half of the concave portion 72. According to the fifth embodiment, the size of the conical mirror 56 is increased, but the amount of light applied to the lower half of the concave portion 72 can be increased as compared with the third embodiment. In this embodiment, a conical mirror is used as the mirror 62, but a plane mirror may be used according to the angle of the optical path.

Although some embodiments of the present invention have been described, the present invention is not limited to these embodiments, and various modifications can be made without departing from the gist of the present invention. For example, as the lighting means to be used, generally available means such as a household circline fluorescent lamp and a halogen ring light for irradiating light from an optical fiber in a ring shape from a circular light guide may be used. In the above embodiment, the inspection object is described as an electrolytic capacitor. However, any inspection object having a cylindrical shape and a concave portion formed on a side surface can be used for the appearance inspection of various objects. Of course.

[0026]

According to the present invention, there is provided a visual inspection apparatus which illuminates a side surface of a cylindrical inspection object, an image capturing means for capturing an image of the inspection object illuminated by the illumination means, An appearance inspection apparatus having an inspection processing unit that performs a predetermined inspection process based on image data of an inspection object captured by a capturing unit, wherein the illumination unit includes:
Since it has the first illuminating means for irradiating the side surface of the inspection object from above and the second irradiating means for irradiating the side surface of the inspection object from below, the side surface of the electrolytic capacitor 51 Even if a defect such as a pinhole P exists in the concave portion 72 formed in the above, the defect can be accurately recognized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a main configuration of a visual inspection device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a main configuration of a visual inspection device according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a main configuration of a visual inspection device according to a third embodiment of the present invention.

FIG. 4 is a sectional view showing a main configuration of a visual inspection device according to a fourth embodiment of the present invention.

FIG. 5 is a sectional view showing a main configuration of a visual inspection device according to a fifth embodiment of the present invention.

FIG. 6 is a block diagram illustrating a configuration of a control device of the visual inspection device.

FIG. 7 is a perspective view showing a lighting device of a conventional visual inspection device.

FIG. 8 is a cross-sectional view showing a main configuration of a conventional visual inspection device.

FIG. 9 is a view showing a light path in FIG. 8;

FIG. 10 is a view showing a path of reflected light when irradiation light hits a vertical portion on a side surface of the electrolytic capacitor 51.

FIG. 11 is a drawing showing a path of reflected light when the irradiation light hits a concave portion 72 on the side surface of the electrolytic capacitor 51.

FIG. 12 is a view showing paths of irradiation light and reflected light that strike a side surface of the electrolytic capacitor 51.

FIG. 13 is a drawing showing another configuration of the irradiation means.

FIG. 14 is a drawing showing another configuration of the irradiation means.

FIG. 15 is a drawing showing another configuration of the irradiation means.

[Explanation of symbols]

 11 Upper Ring Light 12 Lower Ring Light 13 CCD Camera 14 Lens 24 Second Upper Ring Light 51 Electrolytic Condenser 56 Conical Mirror 60 Mirror Surface 61 Insertion Hole 72 Recess

Claims (5)

(57) [Claims] An illumination unit for irradiating a side surface of a cylindrical inspection object, an image capturing unit for capturing an image of the inspection object illuminated by the illumination unit, and an inspection captured by the image capturing unit An appearance inspection apparatus having an inspection processing unit that performs a predetermined inspection process based on image data of an object, wherein the illumination unit irradiates a side surface of the inspection object from above in a first illumination unit, A second irradiating unit for irradiating the side surface of the inspection object from below, and an image inspection unit, wherein the image capturing unit is a conical mirror having the inspection object on a center line. apparatus. 2. The appearance inspection apparatus according to claim 1, wherein the specularly reflected light emitted from the first illumination unit and the second illumination unit and reflected from the inspection object passes through the image capturing unit. To be captured as image data,
An appearance inspection apparatus, wherein the first lighting unit and the second lighting unit are arranged. 3. The appearance inspection apparatus according to claim 1, wherein the conical mirror is a half mirror that reflects a part of incident light and passes the remaining light. apparatus. 4. The visual inspection device according to claim 1, wherein the first lighting means and the second lighting means are ring-shaped lighting means. 5. The appearance inspection device according to claim 1, wherein the illumination unit reflects the light from the ring-shaped illumination unit, and reflects the light from the ring-shaped illumination unit from the opposite direction. An appearance inspection device having a mirror for irradiating a side surface.