Inspection system

Abstract

To provide an inspection system capable of improving inspection accuracy of a hole formed in a bottle-shaped container.SOLUTION: An inspection system 1 for inspecting a bottle 3 includes a lighting device 10 for irradiating the inside of the bottle 3 with ultraviolet light, a camera 20 for photographing the bottle 3 irradiated with the ultraviolet light by the lighting device 10 from the outside of the bottle 3, and a control device 30 for determining a hole of the bottle 3 using an image photographed by the camera 20. The bottle 3 has a characteristic of transmitting visible light but not transmitting light having a wavelength equal to or shorter than that of the ultraviolet light emitted by the lighting device 10.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an inspection system that uses images to inspect an object. [Background technology]

[0002] In the field of FA (Factory Automation), it is known to photograph an object such as a part or a finished product while irradiating it with light, and then use the photographed image to inspect the appearance of the object. For example, Patent Document 1 listed below discloses an inspection device that irradiates the surface of a blister pack with ultraviolet light, and uses an image of the light that passes through the blister pack to inspect for molding defects in the blister pack.

[0003] The inspection device described in Patent Document 1 inspects for molding defects in press-through pack (PTP) sheets used to package tablets, capsules, etc., in blister packs. In this inspection device, an illumination device located below the PTP sheet irradiates the PTP sheet with ultraviolet light, and a camera located above the PTP sheet captures an image of the ultraviolet light that has passed through the PTP sheet. The transmitted image captured by the camera is then used to inspect the flange and pocket portions of the PTP sheet. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-160774 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, bottle-shaped containers such as PET bottles are not sheet-shaped but have a three-dimensional shape with a cavity formed inside the container. If such a bottle-shaped container is placed between a lighting device and a camera, as in Patent Document 1, and ultraviolet light is irradiated from one side of the container and the container is photographed from the other side, much of the ultraviolet light will be blocked by the bottle-shaped container. In this case, it will be difficult to distinguish holes even if they exist in the container, resulting in a decrease in the accuracy of the hole inspection.

[0006] Therefore, the present invention provides an inspection system that can improve the accuracy of inspecting bottle-shaped containers for holes. [Means for solving the problem]

[0007] An inspection system according to one aspect of the present disclosure is an inspection system for inspecting bottle-shaped containers, and includes an illumination unit that irradiates the container with ultraviolet light, an imaging unit that photographs the container being irradiated with ultraviolet light by the illumination unit from the opposite side of the ultraviolet light-irradiated surface of the container, and a control unit that determines whether the container has a hole using the image photographed by the imaging unit, and the container has the property of transmitting visible light but being considered to not transmit light of wavelengths below the ultraviolet light irradiated by the illumination unit.

[0008] According to this aspect, ultraviolet light is irradiated onto a bottle-shaped container that has the property of transmitting visible light but not transmitting light with wavelengths below the ultraviolet light irradiated by the lighting unit, and the container being irradiated with the ultraviolet light is photographed from the opposite side of the ultraviolet light irradiated surface of the container, and the captured image can be used to determine whether the container has a hole.

[0009] This allows the bottle-shaped container to be in a state where almost no ultraviolet light is transmitted through it, and if there is a hole in the bottle-shaped container, it allows ultraviolet light to be emitted from the hole to the outside. Therefore, by photographing the ultraviolet light emitted from the hole to the outside, it becomes possible to determine whether there is a hole in the bottle-shaped container.

[0010] In the above aspect, the imaging unit may be sensitive to ultraviolet light.

[0011] According to this aspect, the ultraviolet light emitted to the outside from the hole can be photographed by the photographing section that is sensitive to ultraviolet light.

[0012] In the above aspect, the device may further include a filter unit that blocks fluorescence excited inside the container by ultraviolet light irradiated by the lighting unit, the filter unit being positioned between the container and the photographing unit, and the photographing unit photographing the container through the filter unit.

[0013] According to this aspect, when photographing the ultraviolet light emitted to the outside from the hole, the fluorescence can be removed and the image can be photographed using an imaging section that is sensitive to ultraviolet light.

[0014] In the above aspect, the device may further include a fluorescent screen that absorbs ultraviolet light irradiated by the lighting unit and emits visible light, the fluorescent screen being positioned between the container and the photographing unit, the photographing unit having sensitivity to visible light, and photographing the container through the fluorescent screen.

[0015] According to this aspect, the ultraviolet light emitted to the outside from the hole can be converted into visible light by the fluorescent screen and photographed by a photographing section that is sensitive to visible light. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide an inspection system that can improve the accuracy of inspecting bottle-shaped containers for holes. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a schematic diagram illustrating the configuration of an inspection system according to an embodiment of the present invention. [Figure 2] 1 is a graph showing the transmittance of PET. [Figure 3A] 1 is a diagram illustrating an example of an image of the bottom surface of a bottle with visible light irradiated inside, captured by a camera sensitive to visible light. [Figure 3B] 10 is a diagram illustrating an example of an image of the bottom surface of a bottle with ultraviolet light irradiated inside, taken with a camera sensitive to ultraviolet light. FIG. [Figure 4] 10 is a graph illustrating that the wavelength of the fluorescence excited inside the bottle is longer than the wavelength of the excitation light irradiated therewith. [Figure 5] FIG. 1 is a diagram illustrating an example of a hardware configuration of an inspection system. [Figure 6] FIG. 1 is a schematic diagram for explaining an example of a situation in which the present invention is applied. [Figure 7] FIG. 7 is a cross-sectional view of the main star wheel shown in FIG. 6 taken along line Aa. [Figure 8] FIG. 7 is a cross-sectional view of the outlet star wheel shown in FIG. 6 taken along line Bb. [Figure 9] FIG. 10 is a schematic diagram illustrating the configuration of an inspection system according to a first modified example. [Figure 10] FIG. 10 is a schematic diagram illustrating the configuration of an inspection system according to a second modified example. [Figure 11] FIG. 10 is a schematic diagram illustrating the configuration of an inspection system according to a third modified example. [Figure 12] 1 is a graph showing the transmittance of PE. DETAILED DESCRIPTION OF THE INVENTION

[0018] The present invention will be described with reference to the accompanying drawings. In each drawing, components with the same reference numerals have the same or similar configurations. Furthermore, since the drawings are schematic, the dimensions and proportions of each component may differ from those of the actual components.

[0019] 1 is a schematic diagram illustrating the configuration of an inspection system 1 according to an embodiment of the present invention. The inspection system 1 includes, for example, an illumination device (illumination unit) 10, a camera (photographing unit) 20, a control device 30, and a filter unit 40. Details of each unit will be described later.

[0020] The inspection system 1 in this embodiment, for example, inspects for holes in a bottle 3, which is an object to be inspected. The bottle 3 preferably has light transmission characteristics that allow it to transmit visible light but not transmit light of wavelengths equal to or shorter than the ultraviolet light irradiated by the lighting device 10. An example of a bottle 3 having such characteristics is a plastic bottle made from polyethylene terephthalate (PET).

[0021] In this embodiment, a case will be described in which a PET bottle is used as the bottle 3, but the bottle 3 is not limited to a PET bottle. In addition to polyethylene terephthalate, bottle-shaped containers made from materials such as polyethylene (PE), polypropylene (PP), and glass can also be used as the bottle 3. In particular, transparent or translucent containers are preferred, so that when a bottle irradiated with visible light is photographed with a camera sensitive to visible light, it is difficult to distinguish between the hole in the bottle and the bottle itself.

[0022] Figure 2 is a graph showing the transmittance of PET. The horizontal axis of the graph represents wavelength [nm], and the vertical axis of the graph represents transmittance [%]. As shown in Figure 2, in the visible light range, where wavelengths are 380 [nm] or more, the transmittance remains at approximately 90 [%]. In other words, the transmittance of visible light is high, and most of the light passes through PET.

[0023] On the other hand, as the wavelength shifts to the ultraviolet region, which is the region of wavelengths less than 380 nm, the transmittance begins to gradually decrease, then drops sharply between wavelengths of around 330 nm and 310 nm, and once the wavelength becomes shorter than around 310 nm, the transmittance remains at almost 0%. In other words, the transmittance in the ultraviolet region, around 200 to 380 nm, is lower than the transmittance in the visible light region. In particular, there is almost no transmittance in the wavelength region of around 200 to 310 nm.

[0024] Returning to the explanation of Figure 1, the lighting device 10 irradiates ultraviolet light onto the inside of the bottle 3. The wavelength of the ultraviolet light irradiated by the lighting device 10 is preferably about 200 to 330 [nm], and more preferably about 200 to 310 [nm], which is in the deep ultraviolet region.

[0025] By irradiating the inside of the PET bottle 3 with ultraviolet light, it is possible to make it so that the ultraviolet light is almost not transmitted to the outside of the bottle 3. On the other hand, if the bottle 3 has a hole, the ultraviolet light will be emitted from the hole to the outside. Therefore, by capturing an image of the ultraviolet light emitted from the hole to the outside with the camera 20, it becomes possible to determine whether or not a hole has occurred in the bottle 3.

[0026] The camera 20 photographs the bottle 3 from the outside, with ultraviolet light being irradiated from the opening to the inside by the lighting device 10. When inspecting the bottle 3 for holes, the entire periphery of the bottle 3 is inspected. Therefore, in FIG. 1, for example, two cameras 20 are arranged one above the other, facing the side of the bottle 3, and one camera 20 is arranged facing the bottom of the bottle 3. In this state, for example, by rotating the bottle 3 around the longitudinal axis of the bottle 3, it becomes possible to photograph the entire side of the bottle 3 with the two cameras 20.

[0027] The camera 20 in this embodiment has an image sensor that is sensitive to the wavelength region of ultraviolet light, which makes it possible to capture an image of the ultraviolet light emitted from the hole formed in the bottle 3. This will be specifically described with reference to Figures 3A and 3B.

[0028] Figure 3A is an image of the bottom surface of bottle 3, the interior of which is irradiated with visible light, captured by a camera having an image sensor sensitive to the wavelength range of visible light. Figure 3B is an image of the bottom surface of bottle 3, the interior of which is irradiated with ultraviolet light, captured by a camera having an image sensor sensitive to the wavelength range of ultraviolet light.

[0029] In the image of Figure 3A, it is difficult to distinguish the hole Ha on the bottom surface of the bottle 3 from the bottom surface of the bottle 3. This is because the bottle 3 has a high visible light transmittance, making it difficult to distinguish between the bottle 3 portion and the hole Ha portion based on the brightness value of the captured image. In addition, fluctuations in brightness due to the unevenness formed on the bottle 3 also make it difficult to distinguish from the hole Ha.

[0030] In the image of Figure 3B, the bottom of the bottle 3 appears black, and only the hole Hb on the bottom of the bottle 3 appears white, making it easy to determine that the bottle 3 has a hole Hb. This is because the UV light transmittance of the bottle 3 is nearly 0%, so the brightness value of the bottle 3 portion is low, while the brightness value of the hole Hb portion of the bottle 3 that emits UV light is high.

[0031] Returning to the explanation of Figure 1, a filter unit 40 is disposed between the bottle 3 and the camera 20. The filter unit 40 is an optical filter that passes the wavelength of the ultraviolet light irradiated by the illumination device 10 and wavelengths shorter than that wavelength. In other words, the filter unit 40 is an optical filter that blocks wavelengths longer than the wavelength of the ultraviolet light irradiated by the illumination device 10.

[0032] By disposing the filter unit 40, it is possible to block fluorescence excited inside the bottle 3 by the ultraviolet light irradiated by the lighting device 10. The fluorescence excited inside the bottle 3 has a longer wavelength than the ultraviolet light irradiated by the lighting device 10, and therefore there is a possibility that the excited fluorescence will pass through the bottle 3. When the fluorescence passes through the bottle 3, the luminance value of the bottle 3 portion increases, and the difference with the luminance value of the hole Hb portion decreases. Therefore, by disposing the filter unit 40 to block the fluorescence, the difference in luminance value between the bottle 3 portion and the hole Hb portion increases, making it possible to more easily and reliably detect the hole Hb portion.

[0033] Referring to FIG. 4, the fact that the wavelength of the excited fluorescence inside the bottle 3 is longer than the wavelength of the irradiated ultraviolet light will be described. The horizontal axis of the graph represents the wavelength of the fluorescence [nm], and the vertical axis of the graph represents the wavelength of the excitation light [nm]. As shown in FIG. 4, in the region where the wavelength of the irradiated excitation light is shorter than 400 [nm], the wavelength of the excited fluorescence is longer than the wavelength of the excitation light. In other words, when irradiating with excitation light having a wavelength of less than 380 [nm] that constitutes ultraviolet light, the wavelength of the excited fluorescence inside the bottle 3 will be longer than the wavelength of the irradiated ultraviolet light. For example, when the wavelength of the irradiated excitation light is 300 [nm], fluorescence with a wavelength of approximately 300 to 400 [nm] will be excited.

[0034] Returning to the explanation of Fig. 1, the control device 30 controls the lighting device 10 and the camera 20 included in the inspection system 1, and also executes various processes related to perforation inspection. An example of the hardware configuration of the inspection system 1 including the control device 30 will be described with reference to Fig. 5.

[0035] The control device 30 includes, for example, a CPU (Central Processing Unit) 31 corresponding to a calculation device, a RAM (Random Access Memory) 32 and a ROM (Read Only Memory) 33 which are examples of storage units, a communication unit 34, an input unit 35, and a display unit 36. These components are connected via a bus so as to be able to send and receive data to and from each other.

[0036] The communication unit 34 is a communication interface for wired or wireless communication with the lighting device 10, the camera 20, and external devices. The input unit 35 is a reception unit that receives data input from a user and includes, for example, a keyboard, a mouse, and a touch panel. The display unit 36 ​​visually displays the results of calculations performed by the CPU 31 and can be, for example, an LCD (Liquid Crystal Display).

[0037] The CPU 31 executes programs stored in the RAM 32 or the ROM 33 and functions as a control unit 31a that performs calculations, processing, etc. of data. The control unit 31a receives various input data from the input unit 35 and the communication unit 34, displays the calculation results on the display unit 36, and stores the calculation results in the RAM 32 or the ROM 33.

[0038] The control unit 31a in this embodiment controls, for example, the lighting device 10 and the camera 20, and also executes various processes related to the hole inspection of the bottle 3. This will be specifically described below.

[0039] The control unit 31a controls the lighting device 10 to irradiate ultraviolet light onto the inside of the bottle 3. The control unit 31a controls the camera 20 to take an image of the bottle 3 irradiated with ultraviolet light by the lighting device 10.

[0040] The control unit 31a determines whether or not the bottle 3 has a hole using an image captured by the camera 20. For example, if there are a predetermined number or more pixels in the captured image that have a brightness value higher than a predetermined value, it may be determined that the bottle 3 has a hole. Alternatively, a model may be trained on images of the bottle 3 that have a hole, and the learned model may be used to determine whether or not the bottle 3 has a hole based on the output results for the captured images input into the trained model.

[0041] An example of a situation in which the present invention is applied will be described with reference to Fig. 6. Fig. 6 is a schematic diagram of a case in which the inspection system 1 is used as a system for in-line inspection on a production line for bottles 3.

[0042] The inspection system 1 inspects bottles 3 conveyed from the entrance of the conveying line for holes while transporting them sequentially on the entrance star wheel 91, main star wheel 92, and exit star wheel 93, and sorts the bottles 3 into either good or defective products.

[0043] The inspection system 1 inspects the side surfaces of the bottles 3 for holes while the bottles 3 are being transported by the main star wheel 92. Then, it inspects the bottom surfaces of the bottles 3 for holes while the bottles 3 are being transported by the outlet star wheel 93. Each type of hole inspection will be described in detail with reference to FIGS. 7 and 8.

[0044] Fig. 7 is a cross-sectional view of the main star wheel 92 taken along line Aa in Fig. 6. Fig. 8 is a cross-sectional view of the outlet star wheel 93 taken along line Bb in Fig. 6.

[0045] As shown in Figure 7, the bottle 3 being transported by the main star wheel 92 is placed on the spin mechanism 96, and the neck of the bottle 3 is supported by a neck holder 95. The spin drive of the spin mechanism 96 causes the bottle 3 to rotate around its longitudinal axis.

[0046] Two cameras 20 are arranged one above the other facing the side of the bottle 3, and filter units 40 are placed between the bottle 3 and the two cameras 20. An illumination device 10 is placed above the mouth of the bottle 3, and irradiates the inside of the bottle 3 with ultraviolet light.

[0047] The two cameras 20 capture the entire side of the bottle 3 rotating on the spin mechanism 96 through the filter unit 40.

[0048] The control unit 31a inspects the bottle 3 for holes based on the images captured by the two cameras 20. For example, if the captured image is completely black, it is determined that there is no hole on the side of the bottle 3, and if there is a white part in the captured image as shown in Figure 3B, it is determined that there is a hole on the side of the bottle 3. Whether the captured image is completely black or has a white part can be determined, for example, using the brightness value of the pixels in the captured image.

[0049] As shown in FIG. 8, the bottles 3 transported by the outlet star wheel 93 have their bodies supported by a pressure belt 97 .

[0050] A camera 20 is placed below the bottle 3 facing the bottom surface, and a filter unit 40 is placed between the bottle 3 and the camera 20. An illumination device 10 is placed above the mouth of the bottle 3, and irradiates the inside of the bottle 3 with ultraviolet light.

[0051] The camera 20 captures an image of the entire bottom surface of the bottle 3 through the filter portion 40.

[0052] The control unit 31a inspects the bottle 3 for holes based on the image captured by the camera 20. For example, if the captured image is completely black, it determines that there is no hole in the bottom surface of the bottle 3, and if there is a white area in the captured image as shown in Figure 3B, it determines that there is a hole in the bottom surface of the bottle 3.

[0053] If the control unit 31a determines that there is a hole in either the hole inspection on the side surface of the bottle 3 or the hole inspection on the bottom surface of the bottle 3, it sends the bottle 3 to the defective product line. On the other hand, if the control unit 31a determines that there is no hole in both the hole inspection on the side surface of the bottle 3 and the hole inspection on the bottom surface of the bottle 3, it sends the bottle 3 to the non-defective product line.

[0054] As described above, according to the inspection system 1 of the embodiment, ultraviolet light is irradiated onto the inside of a bottle 3 that has the property of transmitting visible light but not transmitting light with wavelengths below the ultraviolet light irradiated by the lighting device 10, and the bottle 3 that is being irradiated with the ultraviolet light is photographed from the outside of the bottle 3 using a camera 20 that is sensitive to ultraviolet light, and the captured image can be used to determine whether the bottle 3 has a hole.

[0055] This makes it possible to make the bottle 3 almost completely impermeable to ultraviolet light, but to make the bottle 3 emit ultraviolet light from the hole to the outside if there is a hole in the bottle 3. Therefore, by photographing the ultraviolet light emitted from the hole to the outside, it is possible to determine whether the bottle 3 has a hole.

[0056] Furthermore, by placing a filter unit 40 between the bottle 3 and the camera 20, when photographing the ultraviolet light emitted to the outside from the hole, it is possible to photograph the ultraviolet light while removing the fluorescence excited within the bottle 3.

[0057] Therefore, according to the inspection system 1 according to the embodiment, the accuracy of inspecting the bottle 3 for holes can be improved.

[0058] [Variations] The above-described embodiments are merely examples of the present invention in all respects. It goes without saying that various improvements and modifications can be made without departing from the scope of the present invention. In other words, specific configurations according to the embodiments may be appropriately adopted when implementing the present invention. Furthermore, the above-described embodiments are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The elements included in the embodiments, as well as their arrangement, materials, conditions, shapes, sizes, etc., are not limited to those exemplified and may be modified as appropriate.

[0059] [First Modification] In the above-described embodiment, the lighting device 10 is disposed above the mouth of the bottle 3, and the camera 20 is disposed on the side and bottom of the bottle 3. However, the positions at which the lighting device 10 and the camera 20 are disposed are not limited to this. For example, as shown in Fig. 9, the camera 20 may be disposed above the mouth of the bottle 3, and the lighting device 10 may be disposed on the side and bottom of the bottle 3. In this case, it is preferable to dispose a filter unit 40 between the camera 20 and the bottle 3.

[0060] In the first modified example, the camera 20 photographs the inside of the bottle 3, from the mouth toward the bottom, with ultraviolet light being irradiated from the outside by the lighting device 10 toward the side and bottom.

[0061] In the first modification, ultraviolet light is irradiated onto the bottle 3 from the outside, so that the ultraviolet light is hardly transmitted into the interior of the bottle 3. On the other hand, if the bottle 3 has a hole, ultraviolet light will be emitted from the hole into the interior. Therefore, by capturing an image of the ultraviolet light emitted from the hole into the interior with the camera 20, it is possible to determine whether a hole has been formed in the bottle 3.

[0062] [Second Modification] Furthermore, although the above-described embodiment uses the camera 20 having an image sensor sensitive to the wavelength region of ultraviolet light, a camera having an image sensor sensitive to the wavelength region of visible light may also be used. Fig. 10 illustrates the configuration of a second modified example. The inspection system 1a according to the second modified example differs from the inspection system 1 according to the embodiment in that it uses a camera 20a sensitive to visible light instead of the camera 20 sensitive to ultraviolet light in the embodiment, and it uses a fluorescent screen 50 instead of the filter unit 40 in the embodiment.

[0063] The fluorescent screen 50 is a plate that absorbs the ultraviolet light irradiated by the lighting device 10 and emits visible light. This makes it possible to convert the ultraviolet light emitted from the hole in the bottle 3 into visible light, which can then be photographed by the camera 20a.

[0064] In the second modified example, by irradiating the inside of the bottle 3 with ultraviolet light, the ultraviolet light is hardly transmitted to the outside of the bottle 3. On the other hand, if the bottle 3 has a hole, the ultraviolet light will be emitted to the outside from the hole. Therefore, by converting the ultraviolet light emitted to the outside from the hole into visible light using the fluorescent screen 50 and capturing the visible light with the camera 20, it is possible to determine whether the bottle 3 has a hole.

[0065] [Third Modification] Furthermore, in the above-described embodiment, the lighting device 10 is disposed above the mouth of the bottle 3, and in the above-described first modified example, the lighting device 10 is disposed on the side and bottom of the bottle 3, but the position at which the lighting device 10 is disposed is not limited to this. Fig. 11 illustrates the configuration of a third modified example. The inspection system 1b according to the third modified example differs from the embodiment in which the lighting device 10 is disposed above the mouth of the bottle 3 and from the first modified example in which the lighting device 10 is disposed on the side and bottom of the bottle 3, in that the lighting device 10b is inserted into the bottle 3 from the mouth.

[0066] By disposing the lighting device 10b inside the bottle 3, it is possible to irradiate the entire inner surface, including the side and bottom surfaces of the bottle 3, with ultraviolet light from inside the bottle 3. This makes it possible to improve the accuracy of the hole inspection on the side surfaces of the bottle 3 compared to when ultraviolet light is irradiated from above the mouth.

[0067] Here, because ultraviolet light is highly directional, when ultraviolet light is irradiated from above the mouth of bottle 3, the degree of illumination to the sides tends to be lower than to the bottom surface in front of lighting device 10. Therefore, by inserting lighting device 10b inside bottle 3 and irradiating the entire inner surface of bottle 3 with ultraviolet light, it is possible to improve the accuracy of inspection for holes, particularly on the side surfaces of bottle 3.

[0068] The configuration of the third modified example requires additional steps of inserting the lighting device 10b into the bottle 3 and removing the lighting device 10b, which takes more time in terms of work speed, but it can improve inspection accuracy.

[0069] [Fourth Modification] In addition, in the above-described embodiment, the transmittance of PET in FIG. 2 has been used as an example for explanation, but the present invention can also be applied to other materials that have a lower transmittance in the ultraviolet light region than in the visible light region, such as PE, PP, and glass.

[0070] As an example, a graph showing the transmittance of PE in Fig. 12 will be used for explanation. The horizontal axis of the graph represents wavelength [nm], and the vertical axis of the graph represents transmittance [%]. As shown in Fig. 12, in the visible light region with a wavelength of 380 [nm] or more, the transmittance varies from about 65 to 80 [%], whereas in the ultraviolet light region with a wavelength of less than 380 [nm], the transmittance varies from about 25 to 65 [%]. In particular, in the deep ultraviolet region with a wavelength of less than 310 [nm], the transmittance varies less than 50 [%].

[0071] Here, the transmittance of PE in the ultraviolet region does not decrease to nearly 0% like the transmittance of PET. However, it is possible to determine that the transmittance of PE in the ultraviolet region is lower than the transmittance in the visible region. Therefore, when ultraviolet light is irradiated onto the inside of a PE bottle, a discernible difference occurs between the luminance values ​​of pixels due to the transmitted light that passes through the bottle and the luminance values ​​of pixels due to the ultraviolet light emitted from the holes in the bottle. Therefore, for example, by performing a binarization process on the image captured by camera 20 and setting a threshold value for classification as black and white between the luminance values ​​of pixels due to the transmitted light and the luminance values ​​of pixels due to the ultraviolet light, it is possible to obtain an image similar to the image in FIG. 3B.

[0072] Such a PE bottle can be said to have light transmission characteristics that allow it to transmit visible light but not transmit light with wavelengths shorter than the ultraviolet light emitted by the lighting device 10. The same is true for PP bottles and glass bottles.

[0073] [Note] Aspects of this embodiment include the following disclosure.

[0074] (Appendix 1) An inspection system (1) for inspecting bottle-shaped containers (3), comprising: an illumination unit (10) that irradiates the container (3) with ultraviolet light; an imaging unit (20) that images the container (3) irradiated with the ultraviolet light by the illumination unit (10) from the opposite side of the ultraviolet light irradiated surface of the container (3); a control unit (30) that determines whether or not the container (3) has a hole using the image captured by the imaging unit (20); Equipped with The container (3) has a property that it transmits visible light but does not transmit light having a wavelength equal to or shorter than the ultraviolet light irradiated by the illumination unit (10). Inspection system (1).

[0075] (Appendix 2) The photographing unit (20) has sensitivity to the ultraviolet light. 1. The inspection system (1) described in Appendix 1.

[0076] (Appendix 3) The device further includes a filter unit (40) that blocks fluorescence excited inside the container (3) by the ultraviolet light irradiated by the illumination unit (10), the filter unit (40) is disposed between the container (3) and the photographing unit (20); The photographing unit (20) photographs the container (3) through the filter unit (40). The inspection system (1) described in Appendix 2.

[0077] (Appendix 4) The device further includes a fluorescent screen (50) that absorbs the ultraviolet light irradiated by the illumination unit (10) and emits visible light, The fluorescent screen (50) is disposed between the container (3) and the photographing unit (20), The photographing unit (20) is sensitive to the visible light and photographs the container (3) through the fluorescent screen (50). 1. The inspection system (1) described in Appendix 1.

[0078] (Appendix 5) The wavelength of the ultraviolet light irradiated by the illumination unit (10) is 200 to 310 nm. 4. An inspection system (1) according to any one of appendices 1 to 3.

[0079] (Appendix 6) The container (3) is made of polyethylene terephthalate. 5. An inspection system (1) according to any one of appendices 1 to 4. [Explanation of symbols]

[0080] 1, 1a, 1b...inspection system, 3...bottle, 10, 10b...illumination device, 20, 20a...camera, 30...control device, 31a...control unit, 32...RAM, 33...ROM, 34...communication unit, 35...input unit, 36...display unit, 40...filter unit, 50...fluorescent screen, 91...inlet star wheel, 92...main star wheel, 93...outlet star wheel, 95...neck holder, 96...spin mechanism, 97...holding belt, Ha...hole, Hb...hole

Claims

1. 1. An inspection system for inspecting bottle-shaped containers, comprising: an illumination unit that irradiates the container with ultraviolet light; an imaging unit that images the container irradiated with the ultraviolet light by the illumination unit from the opposite side of the ultraviolet light irradiated surface of the container; a control unit that determines whether the container has a hole using the image captured by the imaging unit; Equipped with The container has a property that it transmits visible light but does not transmit light having a wavelength equal to or shorter than the ultraviolet light irradiated by the illumination unit. Inspection system.

2. The imaging unit has sensitivity to the ultraviolet light. The inspection system of claim 1 .

3. a filter unit that blocks fluorescence excited inside the container by the ultraviolet light irradiated by the illumination unit, the filter unit is disposed between the container and the imaging unit, The photographing unit photographs the container through the filter unit. The inspection system of claim 2 .

4. further comprising a fluorescent screen that absorbs the ultraviolet light irradiated by the illumination unit and emits visible light; the fluorescent screen is disposed between the container and the imaging unit, the photographing unit is sensitive to the visible light and photographs the container through the fluorescent screen; The inspection system of claim 1 .

5. The wavelength of the ultraviolet light irradiated by the illumination unit is 200 to 310 nm. The inspection system of claim 1 .

6. The container is made of polyethylene terephthalate. The inspection system of claim 1 .

Images