Glass bottle bottom inspection device

Abstract

To provide a device 1 for inspecting a bottom portion of a glass bottle 10, enabling determination to be made whether there is a defect even if the glass bottle 10 has a concavo-convex engraving on the bottom portion 15 of the glass bottle 10.SOLUTION: A device 1 for inspecting a bottom portion of a glass bottle 10 includes: an illumination device 2 which applies light to the bottom portion of the glass bottle; a camera 4 which is placed facing the illumination device 2 with the glass bottle 10 interposed between the camera 4 and the illumination device 2 and photographs an image of a bottom portion 15; a first circularly polarized film 35; and a second circularly polarized film 36. The illumination device 2 comprises: a first illumination unit 21 which applies directional infrared light to the bottom portion 15; and a second illumination unit 31 which is placed between the first illumination unit 21 and the bottom portion 15, and applies diffusible visible light to the bottom portion 15. The camera 4 comprises: a first light receiving unit 41 which detects only infrared light; and a second light receiving unit 42 which detects only visible light. The first circularly polarized film 35 and the second circularly polarized film 36 have the same polarization direction.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a bottom inspection device for glass bottles.

Background Art

[0002] An appearance inspection device for inspecting defects at the bottom of a transparent bottle such as a PET bottle has been proposed (for example, Patent Document 1). This appearance inspection device irradiates diffused blue light (450 nm to 490 nm) and parallel red light (620 nm to 750 nm) toward the outer bottom surface of a transparent PET bottle, captures two types of images with a camera arranged on the mouth side, and compares them to determine the presence or absence of defects.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Generally, many concave and convex engravings such as company logos and control numbers are provided on the bottom of glass bottles. Therefore, for example, even if the technology of Patent Document 1 is applied to glass bottles, it is difficult to distinguish between the patterns caused by the engravings and defects in the image, and the inspection accuracy is lowered so as not to misrecognize the patterns as defects, or different inspections are performed with other inspection devices.

[0005] Therefore, the present invention provides a bottom inspection device for a glass bottle that can accurately determine the presence or absence of defects even in a glass bottle having concave and convex engravings on the bottom.

Means for Solving the Problems

[0006] The present invention has been made to solve at least a part of the above problems and can be realized as the following aspects or application examples.

[0007] In the following explanation, "engraving" refers to the shape change caused by the irregularities on the surface of the glass bottle, and "pattern" refers to the change in brightness and darkness caused by the "engraving" that appears in the image obtained by photographing the glass bottle.

[0008] [1] One embodiment of the glass bottle bottom inspection device according to the present invention is: A lighting device that shines light towards the bottom of a glass bottle, A camera is positioned with respect to the aforementioned lighting device, sandwiching the glass bottle, and capturing an image of the bottom of the bottle. A first circular polarizing film is disposed between the lighting device and the bottom, A second circular polarizing film is placed between the mouth of the glass bottle and the camera, A determination unit that determines whether or not there are defects based on the aforementioned image, Equipped with, The illumination device comprises a first illumination unit that irradiates directional infrared light toward the bottom, and a second illumination unit positioned between the first illumination unit and the bottom, which irradiates diffusive visible light toward the bottom. The camera comprises a first light-receiving unit that detects only infrared light and a second light-receiving unit that detects only visible light. The first circular polarizing film and the second circular polarizing film have the same polarization direction, The first illumination unit comprises a first light source that emits diffusive infrared light, and a louver film having a plurality of louvers that limit the angle through which the infrared light incident from the first light source is transmitted. The louver film has the plurality of louvers extending in a direction perpendicular to the central axis of the glass bottle, The louver film is positioned so as to overlap the entire first light source when viewed from the bottom side. The louver film is arranged in alternating sections: a plurality of plate-shaped louvers with excellent light-blocking properties, and sections between adjacent louvers with excellent light-transmitting properties. By stacking two of the aforementioned louver films vertically, the louvers, which extend in different directions vertically, are configured to form a grid when viewed from the central axis.、 The bottom portion has a carving, The determination unit detects a pattern originating from the engraving from the first image captured by the first light-receiving unit, and uses the second image captured by the second light-receiving unit to determine whether or not there is a defect in the area without the pattern. It is characterized by the following.

[0009] [2] In one aspect of the bottom inspection device for the glass bottle, The camera can be equipped with a beam splitter that splits infrared light and visible light.

[0011] 3 In one aspect of the bottom inspection device for the glass bottle, The louver film can be set so that the viewing angle on the central axis is 15 degrees to 45 degrees. [4] In one embodiment of the glass bottle bottom inspection device, The determination unit can detect dark shadows other than the pattern in the first image as detection objects.

Effect of the Invention

[0012] According to one aspect of the bottom inspection device for the glass bottle according to the present invention, even for a glass bottle with uneven engraving on the bottom, a pattern can be detected from the image of the first light receiving part, so it is easy to determine the presence or absence of defects in the area without a pattern using the image of the second light receiving part.

Brief Description of the Drawings

[0013] [Figure 1] It is a front view schematically showing one aspect of the bottom inspection device. [Figure 2] It is a partially enlarged view schematically showing the louver film. [Figure 3] It is a flowchart of an inspection method using the bottom inspection device. [Figure 4] It is an example of the first image. [Figure 5] It is an example of the second image. [Figure 6] It is a diagram for explaining the inspection area setting process. [Figure 7] It is an example of the third image. [Figure 8] They are the first image and the second image taken by the bottom inspection device of Example 1. [Figure 9] These are the first and second images taken with the bottom inspection device of Comparative Example 1. [Modes for carrying out the invention]

[0014] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. The embodiments described below are not intended to unduly limit the scope of the present invention as described in the claims. Furthermore, not all of the configurations described below are necessarily essential components of the present invention.

[0015] One embodiment of the glass bottle bottom inspection device according to this embodiment comprises: an illumination device that irradiates light toward the bottom of a glass bottle; a camera positioned with the glass bottle in between relative to the illumination device and capturing an image of the bottom; a first circular polarizing film positioned between the illumination device and the bottom; and a second circular polarizing film positioned between the mouth of the glass bottle and the camera, wherein the illumination device comprises: a first illumination unit that irradiates directional infrared light toward the bottom; and a second illumination unit positioned between the first illumination unit and the bottom and irradiates diffusive visible light toward the bottom; wherein the camera comprises: a first light receiving unit that detects only infrared light; and a second light receiving unit that detects only visible light; and the first circular polarizing film and the second circular polarizing film are characterized in that they have the same polarization direction.

[0016] 1. Bottom inspection device The bottom inspection device 1 for glass bottles 10 according to this embodiment will be described in detail with reference to Figures 1 and 2. Figure 1 is a schematic front view showing one aspect of the bottom inspection device 1, and Figure 2 is a schematic enlarged view of a louver film 24.

[0017] As shown in Figure 1, the bottom inspection device 1 for glass bottles 10 comprises a lighting device 2, a camera 4, a first circular polarizing film 35, and a second circular polarizing film 36. The bottom inspection device 1 may be incorporated as part of a glass bottle production line or an inspection line comprising multiple inspection devices, in which case it may further include means for loading and unloading glass bottles 10 into and out of the bottom inspection device 1. The bottom inspection device 1 may further include a control unit 50.

[0018] The glass bottle 10 has a mouth 13, a body 14, and a bottom 15 that extend downward along the central axis 12 of the glass bottle 10. The glass bottle 10 to be inspected is placed in a predetermined position on the mounting table 60 of the bottom inspection device 1. The central axis 12 is a virtual line passing through the center of the mouth 13 and the center of the bottom 15. The mounting table 60 is a platform on which the glass bottle 10 is placed, and at least the area on which the bottom 15 is placed is made of a flat plate that transmits visible light and infrared light, such as a distortion-free transparent acrylic resin plate or a glass plate. Alternatively, the mounting table 60 may be removed and the glass bottle 10 may be suspended in mid-air while imaging is performed. The glass bottle 10 is made of glass and is a transparent or translucent container, and may be colored. Translucency means a degree of transparency that allows defects in the bottom 15 to be determined by light from the illumination device 2 that has passed through the glass bottle 10. The mouth portion 13 is open, and a lid is attached after the contents are filled. The body portion 14 has a circular outer shape in cross-section, but it may have other shapes, such as a roughly rectangular shape. The bottom portion 15 comprises a periphery that touches the ground and a bottom portion consisting of the inside of the periphery, and has an engraving on its outer surface. The engraving is a raised or recessed character or symbol formed on the surface of the glass bottle 10, and is formed, for example, by the raised and recessed areas engraved on the surface of the mold during molding. The engraving is, for example, a company logo representing the manufacturer, or a model number representing a management number such as a mold number. Since the engraving is formed in a predetermined position on the bottom portion 15 corresponding to the raised and recessed areas of the mold, the pattern derived from the engraving can be used for positioning the glass bottle 10 around the central axis 12 or for positioning images captured by the camera 4.

[0019] The lighting device 2 shines light towards the bottom 15 of the glass bottle 10. The lighting device 2, camera 4, and glass bottle 10 are arranged so that the light emitted from the lighting device 2 passes through the bottom 15, through the body 14, and then through the opening of the mouth 13 for the camera 4 to receive the light. In this embodiment, the lighting device 2, glass bottle 10, and camera 4 are arranged in order along the central axis 12, but other arrangements are also acceptable as long as the camera 4 can receive the light that has passed through the bottom 15.

[0020] The illumination device 2 comprises a first illumination unit 21 that irradiates directional infrared light toward the bottom 15, and a second illumination unit 31 positioned between the first illumination unit 21 and the bottom 15 that irradiates diffusive visible light toward the bottom 15. In the example shown in Figure 1, the first illumination unit 21, the second illumination unit 31, the first circularly polarized film 35 (described later), the mounting base 60, the glass bottle 10, the second circularly polarized film 36, and the camera 4 are arranged in order along the central axis 12. Therefore, both infrared light and visible light reach the bottom 15. By using two types of light with different wavelengths (infrared light and visible light), the camera 4 can detect the two types of light with separate light receiving units. Here, the visible light has a wavelength of 380 nm to 630 nm, and the infrared light has a wavelength of 800 nm to 1000 nm.

[0021] The first illumination unit 21 includes a first light source 22 that emits diffuse infrared light, and a louver film 24 having a plurality of louvers 24a (Figure 2) that limit the angle through which the infrared light incident from the first light source 22 is transmitted. The infrared light transmitted through the louver film 24 becomes directional.

[0022] The first light source 22 includes, for example, a plurality of LEDs (light-emitting diodes) (not shown) and a diffuser plate 23 positioned on the bottom 15 side so as to cover the plurality of LEDs. Organic EL may be used instead of LEDs. The first light source 22 is a flat surface light source that extends on a plane perpendicular to the central axis 12, with a plurality of LEDs evenly arranged on the surface on the diffuser plate 23 side, and the bottom 15 of the glass bottle 10. Diffuse light is irradiated from the entire surface toward the object. The infrared light emitted from the first illumination unit 21 is preferably near-infrared light having a peak wavelength of 800 nm to 1000 nm.

[0023] As shown in Figure 2, the louver film 24 can have multiple louvers 24a extending in a grid pattern in a direction perpendicular to the central axis 12 of the glass bottle 10. The louver film 24 is arranged so as to overlap with the entire first light source 22 when viewed from the bottom 15 side. As the grid-shaped louver film 24, for example, Shin-Etsu Polymer's cross louver film can be used. The louver film 24 is constructed by laminating two louver films vertically, with multiple plate-shaped louvers 24a with excellent light-shielding properties and portions with excellent light transmission between the louvers 24a arranged alternately, so that the upper and lower louvers 24a form a grid pattern when viewed from the central axis 12. The louver film 24 can be made of resin, for example. The louver film 24 makes the diffused light from the first light source 22 directional. The viewing angle of the louver film 24 at the central axis 12 is preferably set to 15 to 45 degrees, and more preferably to 25 to 35 degrees. Here, the field of view is the angle through which light can pass (visible angle), and in this embodiment, it is the angle at which light passes through when viewing the louver film 24 from the bottom 15 side. A narrower field of view increases the directivity of infrared light. In addition, infrared light can reduce the effect of transmittance on various bottle colors, making it easier to recognize patterns in images of the bottom 15. If the field of view is less than 15 degrees, the image of the bottom 15 other than the center of the captured image becomes too dark and unsuitable for visual inspection, and if it exceeds 45 degrees, the directivity is low and the outline of the pattern becomes unclear.

[0024] The second illumination unit 31 includes a second light source 32 and a light guide plate 34. The second illumination unit 31 is a flat surface light source that extends on a plane perpendicular to the central axis 12, and emits diffused light from substantially its entire surface toward the bottom 15 of the glass bottle 10. The second illumination unit 31 is preferably a plate with a substantially rectangular shape because it is superior in terms of uniform illumination, but it is not limited to this and may be circular, for example. The second illumination unit 31 can employ known illumination, such as CCS's Flat Dome® illumination (International Publication No. WO2020 / 045557A1). The second illumination unit 31 has a flat light guide plate 34 in the center to transmit infrared light from the first illumination unit 21, and the second light source 32 is positioned on the outer edge of the light guide plate 34.

[0025] The second light source 32 is, for example, a plurality of LEDs (not shown) that emit visible light from the outer edge of the light guide plate 34 toward the center of the light guide plate 34. For example, the LEDs are arranged in a line on the inner surface of the frame-shaped body surrounding the light guide plate 34. Organic EL may be used instead of LEDs. The second light source 32 preferably emits visible light having a peak wavelength of 400 nm to 630 nm. Furthermore, the second light source 32 preferably includes, for example, a red LED with a peak wavelength of around 630 nm and a blue LED with a peak wavelength of around 470 nm, and it is preferable to switch between the two wavelengths of visible light depending on the color of the glass bottle 10. This is because the light transmittance differs depending on the bottle color. For example, red LEDs have high transmittance in a relatively wide range of bottle colors, but tend to have lower transmittance in light blue and blue bottles. Therefore, it is preferable to apply blue LEDs, which have high transmittance, to light blue and blue bottles.

[0026] The light guide plate 34 transmits infrared light from the first light source 22 while diffusing and emitting visible light incident from the second light source 32 at its outer edge from the surface on the bottom 15 side. A known type of light guide plate can be used for the light guide plate 34.

[0027] Visible light emitted from the second illumination unit 31 is polarized by the first circular polarizing film 35, passes through the bottom 15, through the opening of the mouth 13, passes through the second circular polarizing film 36, and is received by the camera 4. The first circular polarizing film 35 is placed between the illumination device 2 and the bottom 15. The second circular polarizing film 36 is placed between the mouth 13 of the glass bottle 10 and the camera 4. The first circular polarizing film 35 and the second circular polarizing film 36 are basically the same shape, and have the mouth 13 attached. The first circular polarizing film 35 is positioned in planes perpendicular to the central axis 12 near the front and bottom 15. The first circular polarizing film 35 is positioned with a predetermined distance D1 from the mounting base 60. The distance D1 between the first circular polarizing film 35 and the mounting base 60 is preferably 20 mm to 40 mm, for example, 30 mm. The first circular polarizing film 35 and the second circular polarizing film 36 have the same polarization direction. The polarization direction can be either a clockwise rotation direction or a counterclockwise rotation direction with respect to the direction along the central axis 12. For example, the first circular polarizing film 35 and the second circular polarizing film 36 can both employ right-handed circular polarizing waves with a polarization direction of, for example, a clockwise rotation direction, or they may both employ left-handed circular polarizing waves. The first circular polarizing film 35 and the second circular polarizing film 36 can both be constructed by laminating a linear polarizing plate and a quarter-wave plate. When the diffuse visible light from the second illumination unit 31 is received by the camera 4 as a linearly polarized wave by the first circular polarizing film 35 and the second circular polarizing film 36, defects such as foreign objects and foreign glass on the bottom 15 can be recognized as black areas (areas with low brightness and darkness) in the captured image. Note that the first circular polarizing film 35 and the second circular polarizing film 36 do not polarize infrared light, so they do not affect the infrared light from the first illumination unit 21.

[0028] Camera 4 is positioned with the glass bottle 10 in between the illumination device 2 and captures an image of the bottom 15. Camera 4 includes a first light-receiving unit 41 that detects only infrared light and a second light-receiving unit 42 that detects only visible light. Camera 4 splits the light incident from the mouth 13 side through the lens 45 into infrared light and visible light and receives the light with the first light-receiving unit 41 and the second light-receiving unit 42. The optical axis of the lens 45 is on the central axis 12 and the focal length and other settings can be adjusted so that an image of the bottom 15 can be captured.

[0029] Camera 4 may be equipped with a beam splitter 44 that spectrally separates infrared and visible light. The beam splitter 44 is an optical component that splits the incident light from lens 45 into infrared and visible light. A known beam splitter 44 can be used, and may be a cube type made by combining two prisms, or a plate type in which an optical thin film for spectral separation is deposited on a thin flat glass plate. In the example in Figure 1, the beam splitter 44 reflects the infrared light from the incident light and receives it at a first light receiving unit 41 located at a 90-degree angle to the central axis 12, and transmits the visible light along the central axis 12 and receives it at a second light receiving unit 42 located on the central axis 12. In the image captured by the first light receiving unit 41, the outline of the pattern formed by the uneven engraving on the surface of the bottom 15 appears in a dark color. In the image captured by the second light receiving unit 42, there is no difference in brightness due to the pattern, and defects appear in a dark color.

[0030] The first light-receiving unit 41 and the second light-receiving unit 42 are separate solid-state image sensors, and can be, for example, a CCD image sensor or a CMOS image sensor, with a CMOS image sensor being preferred. By providing two light-receiving units, each sensor can be set to an appropriate camera gain and shutter speed, and the brightness of each image can be adjusted. Furthermore, since an image of the bottom 15 using infrared light and an image of the bottom 15 using visible light can be acquired simultaneously by a single bottom inspection device 1, inspection efficiency can be improved and space can be saved. It is preferable that the first light-receiving unit 41 and the second light-receiving unit 42 have a light-receiving sensitivity of 0% in the wavelength range between infrared light and visible light, for example, 650 nm to 790 nm.

[0031] The control unit 50 is electrically connected to the lighting device 2 and the camera 4, and performs, for example, processing related to turning the lighting device 2 on and off and processing related to taking pictures with the camera 4, and performs processing related to inspection using the captured images. The control unit 50 may further perform processing related to the operation of the loading and unloading mechanism (not shown) of the glass bottle 10. The control unit 50 may include, for example, a processor such as a CPU (Central Processing Unit) or GPU (Graphics Processing Unit), a storage device such as an HDD (Hard Disk Drive), SSD (Solid State Drive), ROM (Read-Only Memory), RAM (Random Access Memory), a keyboard, It consists of input devices such as a mouse and touchpad, display devices such as a liquid crystal display and an organic EL (Electro-Luminescence) display, and digital input / output boards such as an I / O board. The CPU and memory of the control unit 50 may be not just one but multiple, for example, physically separated devices, and in that case they may be connected via a communication network.

[0032] The control unit 50 includes a determination unit 52, an image processing unit 53, a reading unit 54, and a storage unit 55. The determination unit 52 determines the presence or absence of defects based on the image acquired from the camera 4. Defects determined by the determination unit 52 include, for example, foreign matter on the inner surface of the bottom 15, conjugated foreign matter on the bottom 15, and defects during glass bottle molding such as foreign glass on the bottom 15. The control unit 50 can output the determination result of the determination unit 52 to the outside for each glass bottle 10, and for example, glass bottles 10 determined to have defects may be discarded by an unillustrated discharge unit of the bottom inspection device 1. Some of the processing of the control unit 50 may be performed by devices other than the control unit 50, for example, some of the processing of the image processing unit 53 and the reading unit 54 may be performed by a CPU provided in the camera 4. Specific processing in each part of the control unit 50 will be explained below in "2. Bottom Inspection Method".

[0033] 2. Bottom inspection method Using Figures 1 to 6, a detailed explanation of the bottom inspection method for the glass bottle 10 according to this embodiment will be given, specifically an example using the bottom inspection device 1. Figure 3 is a flowchart of the inspection method using the bottom inspection device 1, Figure 4 is an example of the first image 101, Figure 5 is an example of the second image 102, and Figure 6 is a diagram illustrating the inspection area setting step (S40).

[0034] As shown in Figure 3, the bottom inspection method according to this embodiment is a bottom inspection method for a glass bottle 10 having an engraving on the surface of the bottom 15, and includes, for example, an imaging step (S10), a pattern detection step (S20), a mask creation step (S30), an inspection area setting step (S40), a detection step (S50), a determination step (S60), a step of processing as a good product (S70), and a step of processing as a defective product (S80). Each step will be described below in order with reference to Figures 1 and 2.

[0035] S10: The control unit 50 executes the shooting process. It is preferable that the control unit 50 executes the lighting process prior to S10. The lighting process involves the control unit 50 outputting a signal to the lighting device 2 to turn on the first lighting unit 21 and the second lighting unit 31. The shooting process involves the control unit 50 outputting a signal to the camera 4 to execute shooting, causing the camera 4 to transmit the captured image data to the control unit 50. The camera 4 captures, for example, the first image 101 of the bottom 15 in Figure 4 by having the first light receiving unit 41 receive directional infrared light from the first lighting unit 21, and captures, for example, the second image 102 of the bottom 15 in Figure 5 by having the second light receiving unit 42 receive diffusive visible light from the second lighting unit 31. The control unit 50 can acquire each image data from the output of the camera 4. The acquired image data may be stored in the storage unit 55.

[0036] S20: The control unit 50 executes pattern detection processing. For example, in the pattern detection processing, the determination unit 52 detects a pattern 70 enhanced with infrared light from the first image 101 acquired in S10. The determination unit 52 may detect the pattern 70 by, for example, "pattern search". The image processing unit 53 may perform image preprocessing on the pattern 70 before S20 in order to more reliably perform the detection of the pattern 70 by the determination unit 52. In addition, the reading unit 54 can read, for example, the model number from the pattern 70 detected in the first image 101. Among the pattern 70, ten substantially elliptical codes arranged at intervals along a circular orbit are assigned as barcode-like codes called CID marks (see Japanese Patent Application Publication No. 2001-270719) corresponding to the model number, so the reading unit 54 can read the model number from the position and number of codes. Since the model number can be read together with the defect determination described later in a single inspection device, space-saving and efficient inspection can be realized. It can be done.

[0037] The first image 101 shown in Figure 4 is an image captured by the first light-receiving unit 41. In the first image 101, the outlines of multiple patterns 70 derived from the engraving on the bottom 15 and the foreign object (detected object 72) appear as dark shadows. The multiple patterns 70 include, for example, knurling arranged along the outer edge of the bottom 15, a company logo indicating the manufacturer of the glass bottle 10, a mold number, a CID mark, etc. Since these patterns 70 originate from the engraving on the mold, they have a predetermined regularity. It is desirable to store the patterns of the patterns 70 based on this regularity in the storage unit 55 in advance. If the patterns 70 can be detected from the first image 101, then, for example, the position and shape of the outer edge of the bottom 15, the position of the center of the bottom 15 from the position of the outer edge, the distance from the center position to each pattern 70, their shape and arrangement, etc., can be used to estimate the rotation angle around the central axis 12 of the bottom 15.

[0038] Image preprocessing can include, for example, "blurring" in order to perform "pattern search" by the determination unit 52. "Blurring" can be performed, for example, by an averaging filter, which is a two-dimensional filter that replaces the pixel value of the pixel of interest with the average value of all pixel values ​​within the filter size range and outputs it. Alternatively, other image preprocessing methods such as "dilation" to expand the black of shadows may be employed.

[0039] The determination unit 52 performs pattern detection processing on the first image 101, for example, after image preprocessing has been performed. In the pattern detection processing, the determination unit 52 detects the pattern 70 by performing a pattern search on the first image 101 using a pattern registration image that has been created in advance based on the outline of the engraving on the bottom 15. The pattern search searches for a detectable object that matches the pattern registration image within the first image 101, and detects the object as the pattern 70 when the pattern registration image matches the outline of the pattern 70 to a certain extent. In the first image 101, the outline of the pattern 70 is emphasized by highly directional infrared light, so the detection accuracy by pattern search is high, and moreover, as disclosed in Japanese Patent Application Publication No. 2001-270719, there is regularity in the CID marks on the bottom 15, so the position of the pattern 70 can be detected with high accuracy.

[0040] S30: The control unit 50 executes the mask creation process. For example, in the mask creation process, the image processing unit 53 creates a mask based on the first image 101 (Figure 4) in which the pattern 70 was detected in S20, and places the mask 80 on the second image 102 (Figure 5) (Figure 6). The corresponding positional relationship between the first image 101 captured by the first light receiving unit 41 and the second image 102 captured by the second light receiving unit 42 is measured and adjusted in advance, so if the positional information of the pattern 70 detected in the first image 101 is known, the position where the pattern 70 exists in the second image 102 can be determined. Therefore, the mask 80 is placed at the correct position in the second image 102.

[0041] To explain in detail using Figures 4 to 6, the mask creation process first creates multiple masks 80 (Figure 6) of a size that fits multiple regions including the pattern 70 from the first image 101 in Figure 4. As shown in Figure 5, in the second image 102 captured by the second light receiving unit 42, the detection object 72, which is a defect, can be recognized as a dark dot, but the pattern 70 is almost unrecognizable. Next, based on the positional information of each pattern 70 in the first image 101 in Figure 4, the masks 80 are placed in the second image 102 in Figure 5 so as to cover each pattern 70, resulting in the state shown in Figure 6. Some of the masks 80 may be created in advance to match the engraving (or pattern registration image) of the glass bottle 10 to be inspected and stored in the storage unit 55. The size of each mask 80 may be approximately the same as each pattern 70, or it may be large enough to cover multiple clusters of patterns 70 with a single mask 80.

[0042] S40: The control unit 50 executes the inspection area setting step. For example, the inspection area setting step may be executed simultaneously with S30, and is based on the position of the pattern 70 detected by pattern search. The image processing unit 53 then places one or more inspection gates 83 of a predetermined shape on the second image 102. Since the pattern 70 has regularity, by pre-setting the relative positions of the pattern 70 and each inspection gate 83, once the position of the pattern 70 is determined, the positions of the inspection gates 82 and 83 can be automatically laid out on the second image 102. The inspection gates 82 and 83 can be set, for example, as one or more annular ranges concentric with the central axis 12 at the bottom 15. In Figure 6, two inspection gates 82 and 83 are set. The inspection gates 82 and 83 can be set to different sensitivities. For example, if there are parts of the glass bottle 10 that are prone to defects, the inspection gate 82 that includes those parts can be set to a higher sensitivity than the inspection gate 83.

[0043] S50: The control unit 50 executes a detection process for each inspection gate 82, 83. For example, the detection process detects dark areas (detected objects 72) within the inspection gates 82, 83, excluding the mask 80, for the second image 102 in which the mask 80 and inspection gates 82, 83 are arranged in S30 as shown in Figure 6. The detected objects 72 in the dark areas of the second image 102 are detected by executing an inspection algorithm for each inspection gate 82 that has been previously stored in the storage unit 55. Examples of inspection algorithms include a process that binarizes the illuminance data read into the inspection gates 82, 83 and detects the detected objects 72 by comparing it with the surrounding pixels, or a process that creates a small detection area (segment) within the inspection gates 82, 83, moves this segment in a circular or radial direction to calculate the average density, and detects the detected objects 72 by comparing the density difference. High-sensitivity inspection can be performed by executing the inspection algorithm for the inspection gates 82, 83, excluding the part of the mask 80. The judgment process (S60) may be executed simultaneously when executing the inspection algorithm.

[0044] S60: The control unit 50 executes a determination step. For example, the determination step determines whether the detected object 72 in the second image 102 detected in S50 is defective or not, and determines whether the glass bottle 10 is a good product or not based on the result. The determination criteria use reference data stored in the storage unit 55 in advance. Examples of determination criteria include the area and shape of the detected object 72. If the result of the determination step is that the detected object 72 is not defective, the control unit 50 executes S70 with the glass bottle 10 classified as a "good product". If the result is that the detected object 72 is defective, the control unit 50 executes S80 with the glass bottle 10 classified as a "defective product". Of course, if the detected object 72 itself is not detected in S50, the determination result is "good product" and S70 is executed.

[0045] S70: The control unit 50 executes a process to process the product as good. For example, in the process to process the product as good, the control unit 50 outputs a signal to a transport means (not shown) to transport the glass bottle 10 to be inspected as a "good product" to the next process.

[0046] S80: The control unit 50 executes a process to process the product as defective. For example, in the process to process a product as defective, the control unit 50 reads the model number from the pattern 70 detected in S20, stores the data linking the judgment result and the model number in the storage unit 55, and outputs a signal to discharge the glass bottle 10 to be inspected as a "defective product" to a waste unit (not shown). The data of the "defective product" judgment result and model number stored in the storage unit 55 may be output from the control unit 50 to a glass bottle 10 manufacturing apparatus (not shown).

[0047] Thus, conventionally, it is difficult to distinguish between the pattern 70 and other detectable objects 72 when inspecting the bottom 15. However, according to this embodiment, the pattern 70 can be detected from the first image 101, making it easier to determine the presence or absence of detectable objects 72 in areas without the pattern 70 (inspection gate 82) using the second image 102.

[0048] 3. Variant Using Figure 7, the bottom inspection device 1 is used to describe the bottom inspection method of the modified glass bottle 10. The example used will be explained in detail. Figure 7 is an example of the third image 103. The modified version is basically the same as in "2. Bottom Inspection Method," so redundant explanations will be omitted.

[0049] The third image 103 shown in Figure 7 is an image of the bottom 15 of a glass bottle 10, whose body 14 has a rectangular cross-section, captured by the second light-receiving unit 42. Multiple masks 80 are placed for each pattern, and an inspection gate 82 is set outside the knurling that forms the contact surface of the bottom 15, aligned with the outer edge (rectangle) of the body 14. Since the pattern on the bottom 15 and the orientation (rotation angle) of the outer edge of the body 14 correspond, by detecting the pattern in S20, a rectangular inspection gate 82 can be set according to the orientation of the body 14. This makes it possible to inspect areas outside the contact surface. [Examples]

[0050] As Example 1, a glass bottle 10 with foreign matter inside was inspected using the bottom inspection device 1 shown in Figure 1. The camera 4 is a 1.55-megapixel 2CMOS area sensor camera, the first circular polarizing film 35 and the second circular polarizing film 36 are both equally oriented in the clockwise direction, the spacing D1 is 30 mm, the first illumination unit 21 is infrared light diffuse illumination, a cross louver film with a field of view of 30 degrees is placed between the first illumination unit 21 and the second illumination unit 31 as a louver film 24, and the second illumination unit 31 is visible light flat dome (registered trademark) illumination with a peak at 630 nm.

[0051] The upper part of Figure 8 shows the first image captured by the first light-receiving unit 41 of camera 4, and the lower part of Figure 8 shows the second image captured by the second light-receiving unit 42. In the first image, the CID mark and other elements are clearly recognizable, and in the second image, the foreign object lying in the center is clearly recognizable as black, leading the control unit 50 to determine it as a "defective product".

[0052] Furthermore, as Comparative Example 1, the same glass bottle 10 containing foreign matter was inspected after removing the first circular polarizing film 35 and the second circular polarizing film 36 from the bottom inspection device 1 shown in Figure 1.

[0053] The upper part of Figure 9 shows the first image captured by the first light-receiving unit 41 of camera 4, and the lower part of Figure 9 shows the second image captured by the second light-receiving unit 42. Neither the first nor the second image could recognize the foreign object in the center, and the control unit 50 determined it to be a "good product".

[0054] The present invention is not limited to the embodiments described above, and various further modifications are possible, including configurations that are substantially identical to those described in the embodiments. Here, "identical configuration" means a configuration that has the same function, method, and result, or a configuration that has the same purpose and effect. The present invention also includes configurations in which non-essential parts of the configuration described in the embodiments are replaced. Furthermore, the present invention includes configurations that produce the same effects or achieve the same purpose as the configuration described in the embodiments. Furthermore, the present invention includes configurations that add known technology to the configuration described in the embodiments. [Explanation of symbols]

[0055] 1...Bottom inspection device, 2...Illumination device, 4...Camera, 10...Glass bottle, 12...Central axis, 13...Mouth, 14...Body, 15...Bottom, 21...First illumination unit, 22...First light source, 23...Diffuser plate, 24...Louver film, 24a...Louver, 24b...Light transmission unit, 31...Second illumination unit, 32...Second light source, 34...Light guide plate, 35...First circular polarizing film, 36...Second Circular polarizing film, 41...First light receiving unit, 42...Second light receiving unit, 44...Beam splitter, 45...Lens, 50...Control unit, 52...Determination unit, 53...Image processing unit, 54...Reading unit, 55...Storage unit, 60...Plating stage, 70...Pattern, 72...Detection object, 80...Mask, 82,83...Inspection gate, 101...First image, 102...Second image, 103...Third image, D1...Interval

Claims

1. A lighting device that shines light towards the bottom of a glass bottle, A camera is positioned with respect to the aforementioned lighting device, sandwiching the glass bottle, and capturing an image of the bottom of the bottle. A first circular polarizing film is placed between the lighting device and the bottom, A second circular polarizing film is placed between the mouth of the glass bottle and the camera, A determination unit that determines whether or not there are defects based on the aforementioned image, Equipped with, The illumination device comprises a first illumination unit that emits directional infrared light toward the bottom, and a second illumination unit positioned between the first illumination unit and the bottom that emits diffusive visible light toward the bottom. The camera comprises a first light-receiving unit that detects only infrared light and a second light-receiving unit that detects only visible light. The first circular polarizing film and the second circular polarizing film have the same polarization direction, The first illumination unit comprises a first light source that emits diffusive infrared light, and a louver film having a plurality of louvers that limit the angle through which the infrared light incident from the first light source is transmitted. The louver film has the plurality of louvers extending in a direction perpendicular to the central axis of the glass bottle, The louver film is arranged so as to overlap the entire first light source when viewed from the bottom side. The louver film is arranged in an alternating pattern of multiple plate-shaped louvers with excellent light-blocking properties and portions with excellent light-transmitting properties between adjacent louvers. By stacking two of the aforementioned louver films vertically, the louvers, which extend in different directions vertically, are configured to form a grid when viewed from the central axis. The bottom portion has a carving, The bottom inspection device for glass bottles is characterized in that the determination unit detects a pattern originating from the engraving from a first image captured by the first light-receiving unit, and determines whether or not there is a defect in the area without the pattern using a second image captured by the second light-receiving unit.

2. In claim 1, The camera is equipped with a beam splitter that spectrally separates infrared light and visible light, and is used as a bottom inspection device for glass bottles.

3. In claim 1 or claim 2, The bottom inspection device for glass bottles is characterized in that the louver film has a viewing angle of 15 to 45 degrees along the central axis.

4. In any one of claims 1 to 3, The bottom inspection device for glass bottles is characterized in that the determination unit detects dark shadows other than the pattern in the first image as detection objects.

Images