JP7028467B2 - Container inspection equipment and inspection method - Google Patents

Description

The present invention relates to an inspection device and an inspection method for inspecting the mouth of a container such as a PET bottle for holding a liquid, and in particular, an inspection for generating an image of the container and inspecting a defect in the mouth of the container based on the image. Regarding equipment and inspection methods.

A container such as a PET bottle for holding a liquid such as a beverage inside usually has a removable lid (cap) for closing the mouth portion. If the mouth of the container is deformed or there is a foreign object or scratch on the top of the mouth, the lid will not be able to adhere to the mouth of the container, especially the top of the mouth, and liquid will spill out of the container. It may end up.

Therefore, it has been conventionally practiced to optically inspect the mouth of a container using an inspection device. This type of inspection device irradiates the mouth of the container before filling with liquid with light from above the container, generates an image of the container from the light reflected by the container, and analyzes the image to make a defect in the mouth. It is configured to check for the presence of. Since the foreign matter or scratch appears as a black shadow on the image, the inspection device can inspect the presence or absence of the foreign matter or scratch based on the image. Further, the inspection device can measure the inner diameter of the mouth portion from the image and determine the deformation of the mouth portion, particularly the roundness of the mouth portion, based on the measured value.

Japanese Unexamined Patent Publication No. 2012-237632

However, the light emitted to the container at the time of imaging of the container travels to the inside of the container through the mouth of the container and is diffusely reflected at the bottom and inner peripheral surfaces of the container. As a result, as shown in FIG. 5, uneven shadows appear in the image of the container. Such shadows interfere with a stable examination of the mouth. In addition, the light reflected from the bottom of the container is scattered on the inner peripheral surface of the mouth, forming an uneven shadow on the inside of the mouth. As a result, the inner diameter of the mouth could not be measured accurately, and the deformation of the mouth could not be correctly determined.

Therefore, the present invention provides an inspection device and an inspection method capable of accurately inspecting defects in the mouth of a transparent container such as a PET bottle for holding a liquid.

In one aspect, it is an inspection device for inspecting a defect in the mouth of a container having light transmission, and is a first method of irradiating the mouth of the container with a first light from above the container that does not hold liquid . The illuminator, the second illuminator that irradiates the bottom of the container with a second light from under the container that does not hold the liquid, the first light reflected by the mouth, and the bottom are transmitted. The first illuminator and the said The second illuminators are arranged in a straight line so as to face each other, and are arranged so as to guide the first light and the second light to the container along the same optical axis. The illuminator is provided with an inspection device configured to emit the second light with a light amount lower than the amount of the first light emitted from the first illuminator .

In one aspect, the second illuminator has a second light source that emits the second light having the same wavelength as the first light.
In one aspect, the first illuminator has a first light source that emits the first light consisting of blue light.
In one aspect, the first light source has a blue light emitting diode.
In one aspect, the second illuminator is configured such that the amount of light transmitted through the bottom of the container is higher than the amount of light reflected by the bottom of the container. It is .
In one aspect, the first illuminator has a half mirror arranged obliquely with respect to the optical axis and a first light source that emits the first light toward the half mirror. The mirror is arranged on the optical axis, and the half mirror reflects the first light emitted from the first light source, guides it to the mouth of the container, and reflects it at the mouth of the container. The first light is transmitted and guided to the image pickup device, and the second light is transmitted and guided to the image pickup device.

In one aspect, it is an inspection method for inspecting a defect in the mouth of a light-transmitting container, in which a first light is emitted from the top of the container that does not hold a liquid to the mouth of the container. When the first light is irradiated to the mouth portion, the second light is irradiated from under the container that does not hold the liquid to the bottom of the container by the second illuminator. The first illuminator and the second illuminator are arranged in a straight line so as to face each other, and are arranged so as to guide the first light and the second light to the container along the same optical axis. The amount of the second light emitted from the second illuminator is lower than the amount of the first light emitted from the first illuminator, and the light reflected by the mouth is the first. It is an inspection method in which one image of the container is generated from both the light of 1 and the second light transmitted through the bottom, and the defect of the mouth is inspected based on the image.

In one aspect, the second light has the same wavelength as the first light.
In one aspect, the first light is blue light.
In one aspect, the amount of light transmitted through the bottom of the container is higher than the amount of light reflected by the bottom of the container .
In one aspect, the first illuminator has a half mirror arranged obliquely with respect to the optical axis and a first light source that emits the first light toward the half mirror. The mirror is arranged on the optical axis, and the half mirror reflects the first light emitted from the first light source, guides it to the mouth of the container, and reflects it at the mouth of the container. It is arranged so as to transmit the first light and guide it to an image pickup device for generating the image, and to transmit the second light and guide it to the image pickup device.

A part of the first light is reflected on the top surface of the mouth, while the other part of the first light enters the container through the mouth and is diffusely reflected in the container. The second light passes through the bottom of the container and further passes through the inside of the mouth to reach the image pickup device. This second light can be superimposed on the first light in the container to make the overall brightness of the bottom of the container uniform. As a result, the shadows caused by the diffuse reflection of the first light disappear from the image, and the top surface of the mouth appears clearly on the image. Therefore, the image analysis unit can accurately inspect the defect of the mouth portion based on the image of the container.

It is sectional drawing of the container to be inspected. It is a schematic diagram which shows one Embodiment of an inspection apparatus. It is a figure explaining the way of traveling of the 1st light and the 2nd light. It is a figure which shows the image generated from the 1st light and the 2nd light shown in FIG. It is a figure which shows the image of the container obtained by the conventional inspection apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 (a) is a cross-sectional view of a container to be inspected, and FIG. 1 (b) is a top view of the container shown in FIG. 1 (a). The container 1 to be inspected is an empty container in which a liquid such as a beverage is filled. The container 1 has a mouth portion 2 on which a screw 2a is formed, a body 3 connected to the mouth portion 2, and a support ring 5 formed on the upper portion of the body 3. The support ring 5 is located below the mouth 2.

The mouth portion 2 is sealed by a lid (not shown) after the liquid is filled in the container 1. The lid is screwed into the screw 2a of the mouth portion 2, and the upper wall of the lid is brought into close contact with the top surface 2b of the mouth portion 2, so that the mouth portion 2 can be sealed. As shown in FIG. 1 (b), the top surface 2b of the mouth portion 2 is an annular surface. The bottom portion 4 of the container 1 has an upwardly recessed shape in order to reinforce the strength.

The container 1 is a transparent container having light transmission. The container 1 may be colored as long as it allows light to pass through. Specific examples of the container 1 include PET bottles and bottles. The container 1 shown in FIG. 1 is a PET bottle. The type of liquid filled in the container 1 is not particularly limited, and examples thereof include beverages.

FIG. 2 is a schematic view showing an embodiment of an inspection device for inspecting a defect in the mouth portion 2 of the container 1 shown in FIG. As shown in FIG. 2, the inspection apparatus includes a first illuminator 11 that irradiates the mouth 2 of the container 1 with the first light L1 from above the container 1, and a bottom 4 of the container 1 from below the container 1. A second illuminator 12 that irradiates the second light L2 is provided. The container 1 is transported to the inspection position shown in FIG. 2 by the transport device 15 in an empty state (that is, in a state where the liquid is not held).

The transport device 15 is a star wheel having a chuck 15a for holding an upper portion of a fuselage 3 located below a support ring 5 of a container 1. However, the type of the transport device 15 is not particularly limited. The star wheel is a transfer device that continuously conveys a plurality of containers 1 along an arc trajectory, but a transfer device that continuously conveys a plurality of containers 1 along a straight track may be adopted.

The first illuminator 11 is arranged above the container 1 at the inspection position shown in FIG. 2, and the second illuminator 12 is arranged below the container 1 at the inspection position. The first illuminator 11 and the second illuminator 12 are arranged in a straight line so as to face each other, and are arranged so as to guide the first light L1 and the second light L2 to the container 1 along the same optical axis. Has been done. More specifically, the first illuminator 11 radiates the first light L1 downward toward the top surface 2b of the mouth portion 2 of the container 1, and the second illuminator 12 emits the second light L2. Is radiated upward toward the bottom 4 of the container 1. When the container 1 is in the inspection position shown in FIG. 2, the first illuminator 11, the container 1, and the second illuminator 12 are aligned in a straight line.

The inspection device is an image pickup device 20 that generates one image of the container 1 from both the first light L1 reflected by the mouth 2 of the container 1 and the second light L2 transmitted through the bottom 4 of the container 1. Further, an image analysis unit 25 for inspecting a defect of the mouth portion 2 based on an image is further provided. The image pickup apparatus 20 is composed of a monochrome camera or a color camera having an image sensor 20a that generates an image from the first light L1 and the second light L2. Examples of the image sensor 20a include a CCD, CMOS, and the like. The image pickup apparatus 20 is arranged above the first illuminator 11 and simultaneously receives the first light L1 and the second light L2 that have passed through the first illuminator 11, and the first light L1 and the second light L1 and the second light L2. One image is generated from both of the light L2. The generated image data is sent to the image analysis unit 25.

The image analysis unit 25 analyzes the image of the container 1 and executes an operation according to a storage device 25a in which a program for determining whether or not the mouth portion 2 is defective is stored and an instruction included in the program. It is provided with a processing device 25b. The storage device 25a includes a main storage device 25a such as a RAM, and an auxiliary storage device 25a such as a hard disk drive (HDD) and a solid state drive (SSD). Examples of the processing device 25b include a CPU (central processing unit) and a GPU (graphic processing unit). The image analysis unit 25 is composed of at least one computer.

The first illuminator 11 is a coaxial epi-illumination type illuminator. The first illuminator 11 is configured to transmit the first light L1 reflected from the container 1 and the second light L2 transmitted through the container 1. That is, the first illuminator 11 has a half mirror 31 arranged obliquely with respect to the optical axis, and a first light source 32 that emits the first light L1 toward the half mirror 31. The first light L1 emitted from the first light source 32 is reflected by the half mirror 31 and changes its traveling direction toward the mouth 2 of the container 1. The first light L1 reflected by the mouth 2 of the container 1 passes through the half mirror 31 and heads toward the image pickup apparatus 20. Further, the second light L2 transmitted through the container 1 passes through the half mirror 31 and heads toward the image pickup apparatus 20.

In this embodiment, the first light source 32 is composed of a light emitting diode. More specifically, the first light source 32 is composed of a blue light emitting diode that emits blue light. The first light L1 emitted from the first illuminator 11 is short-wavelength blue light having a wavelength in the range of 450 nm to 500 nm. In one example, the first light L1 is blue light having a wavelength of 470 nm.

The reason why the first light L1 is blue light is as follows. Blue light with a short wavelength has the property of being more easily scattered than light with a long wavelength. When a recess such as a scratch or a chip is present on the top surface 2b of the mouth portion 2 of the container 1, when short-wavelength blue light is incident on the recess of the top surface 2b, the light is scattered in multiple directions at the recess and reflected at the recess. It is difficult for the emitted light to reach the image pickup apparatus 20. As a result, the recesses (scratches or chips) on the top surface 2b appear darker in the image than the surroundings, and the recesses appear clearly on the image. That is, by using blue light for the first light L1, a high-contrast image in which the recesses clearly appear can be obtained. Therefore, the image analysis unit 25 can accurately detect the recesses such as scratches or chips existing on the top surface 2b based on the high-contrast image.

The second illuminator 12 has a second light source 35 that emits the second light L2, and a dimming device 36 that adjusts the amount of light of the second light L2 emitted from the second light source 35. The second light source 35 is configured to emit a second light L2 having the same wavelength as the first light L1. The second light L2 is preferably blue light, which is the same as the first light L1. In the present embodiment, the second light source 35 is composed of a blue light emitting diode that emits blue light having the same wavelength as the first light L1.

As described above, the first light L1 and the second light L2 are preferably blue light, but are light of other wavelengths as long as the recesses such as scratches or chips existing on the top surface 2b can be detected. There may be. Even in this case, it is preferable that the first light L1 and the second light L2 have the same wavelength.

The amount of light of the second light L2 emitted from the second illuminator 12 is lower than the amount of light of the first light L1 emitted from the first illuminator 11. This is because the influence of the first light L1 diffusely reflected inside the container 1 on the image is erased by the second light L2, and the inner edge of the top surface 2b of the mouth portion 2 is clearly projected on the image. be. In particular, the mouth portion 2 is configured so that the inner edge of the top surface 2b of the mouth portion 2 is clearly projected on the image and the concave portion (scratch or chip) of the top surface 2b is clearly displayed on the image. The amount of light of the second light L2 is set low so that the second light L2 hardly passes through the material. The amount of light is expressed in units [lm · s] and is also called luminosity energy. If the amount of light of the second light L2 is too high, the inner edge of the top surface 2b may not appear clearly on the image. Therefore, the amount of light of the second light L2 emitted from the second illuminator 12 is adjusted by the dimming device 36 so that the inner edge of the top surface 2b clearly appears on the image.

On the other hand, if the amount of light of the second light L2 is too low, the influence of diffused reflection of the first light L1 in the container 1 cannot be eliminated. Therefore, the second illuminator 12 is emitted so that the amount of light of the second light L2 transmitted through the bottom 4 of the container 1 is higher than the amount of light of the first light L1 reflected by the bottom 4 of the container 1. The amount of light of the light L2 of 2 is adjusted. In this way, the second light L2 can eliminate the uneven shadow caused by the diffused reflection of the first light L1 and clearly show the inner edge of the mouth portion 2 on the image.

The image pickup apparatus 20, the first illuminator 11, and the second illuminator 12 are arranged in a straight line. The first illuminator 11 of the present embodiment is a coaxial epi-illumination type illuminator having a half mirror 31, but in one embodiment, the first illuminator 11 is a first light L1 and a second light L2. It may be a ring-shaped illuminator that allows passage. Halogen lamps may be used as the first light source 32 and / or the second light source 35. However, it is preferable to use a light emitting diode having a long life.

The inspection device further includes an operation control unit 40 that controls the operation of the first illuminator 11, the second illuminator 12, and the image pickup device 20. The motion control unit 40 is electrically connected to the first illuminator 11, the second illuminator 12, and the image pickup device 20. When the transport device 15 transports the container 1 to the inspection position shown in FIG. 2, the motion control unit 40 issues a command to the image pickup device 20 to execute the image pickup operation, while the first illuminator 11 and the second illuminator 11 and the second A command is issued to the illuminator 12, and the first light L1 and the second light L2 are simultaneously emitted to the first illuminator 11 and the second illuminator 12 for a predetermined time. The first light L1 reflected from the container 1 and the second light L2 transmitted through the container 1 are incident on the image pickup apparatus 20, and the image sensor 20a of the image pickup apparatus 20 receives the first light L1 and the second light L2. Generate one image of container 1 from both of the above.

The image data is transmitted from the image pickup apparatus 20 to the image analysis unit 25, and the image analysis unit 25 analyzes the image and inspects the defect of the mouth 2 of the container 1 based on the image. Since a known technique is used as a technique for inspecting a defect of the mouth portion 2 based on an image, a detailed description thereof will be omitted.

FIG. 3 is a diagram illustrating how the first light L1 and the second light L2 travel. A part of the first light L1 is reflected by the top surface 2b of the mouth portion 2 and is incident on the image pickup apparatus 20. The other portion of the first light L1 passes through the inside of the mouth portion 2 and travels inside the container 1. The first light L1 is diffusely reflected on the bottom surface of the container 1, and is incident on the image pickup apparatus 20 while being repeatedly reflected on the inner surface of the container 1. The second light L2 vertically enters the bottom 4 of the container 1 from below, passes through the bottom 4, and further passes inside the mouth 2 to enter the image pickup apparatus 20. The second light L2 transmitted through the bottom 4 of the container 1 can be superimposed on the first light L1 diffusely reflected by the bottom 4 of the container 1 to make the overall brightness of the bottom 4 of the container 1 uniform.

The image pickup apparatus 20 simultaneously receives the first light L1 reflected from the container 1 and the second light L2 transmitted through the container 1 to generate one image of the container 1. FIG. 4 is a diagram showing an image generated from the first light L1 and the second light L2. The container on the image shown in FIG. 4 is the same as the container on the image shown in FIG. As shown in FIG. 4, since the amount of light (luminous energy) of the second light L2 is lower than that of the first light L1, the image of the top surface 2b of the mouth portion 2 is substantially the first light L1. Generated from. The second light L2 can make the brightness of the bottom portion 4 of the container 1 uniform, and can eliminate the shadow caused by the diffused reflection of the first light L1 in the container 1 from the image. As a result, the top surface 2b of the mouth portion 2 appears clearly on the image, and the image analysis unit 25 can accurately inspect the presence or absence of defects in the mouth portion 2 based on the image of the container 1.

Reference numeral 50 shown in FIG. 4 is a concave portion (scratch or chip) existing in the mouth portion 2. Although the recesses appear at the same positions in the image of FIG. 5, it can be seen that the recesses 50 shown in FIG. 4 appear more clearly in the image than in FIG. Further, as can be seen from the comparison between FIGS. 4 and 5, the inner edge of the top surface 2b on the image shown in FIG. 4 is clear, and no uneven shadow appears inside the top surface 2b. Therefore, the image analysis unit 25 can accurately determine the position of the top surface 2b in the image. In particular, since the inner edge of the top surface 2b appears clearly in the image, the image analysis unit 25 accurately identifies the region of the mouth portion 2 to be inspected based on the position of the inner edge of the top surface 2b. , Highly accurate defect inspection can be performed.

The above-described embodiments have been described for the purpose of allowing a person having ordinary knowledge in the technical field to which the present invention belongs to carry out the present invention. Various modifications of the above embodiment can be naturally made by those skilled in the art, and the technical idea of the present invention can be applied to other embodiments. Accordingly, the invention is not limited to the described embodiments, but is to be construed in the broadest range in accordance with the technical ideas defined by the claims.

1 Container 2 Mouth 2a Screw 2b Top 3 Body 4 Bottom 5 Support ring 11 1st illuminator 12 2nd illuminator 15 Conveyor device 20 Image sensor 20a Image sensor 25 Image analysis unit 25a Storage device 25b Processing device 31 Half mirror 32 1st light source 35 2nd light source 36 Dimming device 40 Operation control unit

Claims (11)

An inspection device that inspects defects in the mouth of light-transmitting containers.
A first illuminator that irradiates the mouth of the container with the first light from above the container that does not hold the liquid .
A second illuminator that irradiates the bottom of the container with a second light from under the container that does not hold the liquid .
An image pickup device that generates a single image of the container from both the first light reflected by the mouth and the second light transmitted through the bottom.
An image analysis unit for inspecting a defect in the mouth based on the image is provided .
The first illuminator and the second illuminator are arranged in a straight line so as to face each other, and are arranged so as to guide the first light and the second light to the container along the same optical axis. Has been
The second illuminator is an inspection device configured to emit the second light having a light amount lower than the light amount of the first light emitted from the first illuminator . The inspection device according to claim 1, wherein the second illuminator has a second light source that emits the second light having the same wavelength as the first light. The inspection device according to claim 1 or 2, wherein the first illuminator has a first light source that emits the first light composed of blue light. The inspection device according to claim 3, wherein the first light source has a blue light emitting diode. The second illuminator is configured such that the amount of light transmitted through the bottom of the container is higher than the amount of light reflected by the bottom of the container. The inspection device according to any one of Items 1 to 4. The first illuminator has a half mirror arranged obliquely with respect to the optical axis and a first light source that emits the first light toward the half mirror.
The half mirror is arranged on the optical axis, and the half mirror is arranged on the optical axis.
The half mirror reflects the first light emitted from the first light source, guides the first light to the mouth of the container, and transmits the first light reflected by the mouth of the container. The inspection device according to any one of claims 1 to 5, which is arranged so as to guide the image pickup device and transmit the second light to the image pickup device. It is an inspection method for inspecting defects in the mouth of a light-transmitting container.
The first light is applied to the mouth of the container from above the container that does not hold the liquid by the first illuminator.
When the first light is shining on the mouth, the second light is radiated from under the container that does not hold the liquid to the bottom of the container by the second illuminator, and the first lighting is performed. The vessel and the second illuminator are arranged in a straight line so as to face each other, and are arranged so as to guide the first light and the second light to the container along the same optical axis. The amount of the second light emitted from the second illuminator is lower than the amount of the first light emitted from the first illuminator.
An image of the container was generated from both the first light reflected by the mouth and the second light transmitted through the bottom.
An inspection method for inspecting a defect in the mouth based on the image. The inspection method according to claim 7 , wherein the second light has the same wavelength as the first light. The inspection method according to claim 7 or 8 , wherein the first light is blue light. The inspection according to any one of claims 7 to 9, wherein the amount of light of the second light transmitted through the bottom of the container is higher than the amount of light of the first light reflected by the bottom of the container. Method. The first illuminator has a half mirror arranged obliquely with respect to the optical axis and a first light source that emits the first light toward the half mirror.
The half mirror is arranged on the optical axis, and the half mirror is arranged on the optical axis.
The half mirror reflects the first light emitted from the first light source, guides the first light to the mouth of the container, and transmits the first light reflected by the mouth of the container. The inspection method according to any one of claims 7 to 10, wherein the inspection method is arranged so as to guide the image pickup device for generating an image and transmit the second light to the image pickup device.

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