Container appearance inspection device

Abstract

To provide a container appearance inspection device that uses imaging means to pick up an image of a container having display to be inspected on an outer peripheral surface and inspects the appearance of the display to be inspected on the basis of acquired image data, and that can accurately inspect the appearance of the display to be inspected.SOLUTION: An appearance inspection device inspects the appearance of a container W having display to be inspected D on an outer peripheral surface Wa, and comprises: illumination means 10 that illuminates the container W; imaging means 20 that picks up an image of the appearance of the container W illuminated by the illumination means 10; and control means 30 that determines the quality of the appearance of the container W on the basis of the image data acquired by the imaging means 20. The illumination means 10 has a bar illumination 11 arranged between the container W and the imaging means 20, and the bar illumination 11 is configured to illuminate the container W only with indirect light Lb spreading to the surroundings from a light emitting surface 11a.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a container appearance inspection device. [Background technology]

[0002] Conventionally, there has been known an appearance inspection device that takes an image of a container, such as a PET bottle, glass bottle, or can, using an imaging means, and inspects the appearance of an inspection target mark attached (printed) to the outer surface of the container based on the acquired image data (see, for example, Patent Document 1). The above-mentioned appearance inspection device generally uses the imaging means to capture an image of a container, which is an inspection target, in a state where the container is entirely illuminated by direct light emitted from the lighting means.

[0003] Here, depending on the material, color, shape, etc. of the container, some are prone to causing halation when illuminated by the lighting means. When such a container is to be inspected, measures have been taken to remove halation that occurs on the outer surface of the container by imaging the container using an imaging means equipped with a polarizing plate or polarizing lens. Furthermore, for example, when the object to be inspected is a container with a mirror-like outer surface that can reflect light, even imaging means equipped with polarizing plates and polarized lenses may cause polarization breakdown, making it difficult to fully remove the halation that occurs on the outer surface of the container.In such cases, measures have been taken to suppress the occurrence of halation on the outer surface of the container by using dome lighting that can irradiate countless indirect light from various directions to illuminate the entire container approximately evenly. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-17810 Summary of the Invention [Problem to be solved by the invention]

[0005] However, for example, when the object to be inspected is a container made of a transparent material that allows the inside to be seen, even though it is possible to obtain image data of the container while removing halation that occurs on the outer surface of the container by using a polarizing plate or polarizing lens, the image data is likely to include not only the inspection object marking printed on the outer surface of the side being imaged (hereinafter referred to as the "front surface" as appropriate), but also the inspection object marking printed on the outer surface opposite to the front surface (hereinafter referred to as the "back surface" as appropriate), making it difficult to clearly distinguish between the area of ​​the inspection object marking where visual inspection is performed (i.e., the area printed on the front surface) and the background outside of that area (including the inspection object printed on the back surface), making it difficult to accurately inspect the appearance of the inspection object marking printed on the outer surface of the container.

[0006] Furthermore, when the object to be inspected is a cylindrical container, it is possible to somewhat suppress the occurrence of halation on the outer surface of the container by using dome lighting to illuminate the entire container approximately evenly. However, the indirect light emitted from the dome lighting is concentrated on the center of the surface that curves and bulges toward the imaging means, and therefore the contrast (brightness / darkness) between the center of the surface and other areas of the surface in the acquired image data becomes extremely large, making it difficult to accurately inspect the appearance of the inspection object marking printed on the outer surface of the container.

[0007] The present invention has been made in consideration of the current problems described above, and has an objective of providing an appearance inspection device for containers that uses an imaging means to capture an image of a container having an inspection target mark on its outer surface and inspects the appearance of the inspection target mark based on the acquired image data, and that is capable of accurately inspecting the appearance of the inspection target mark. [Means for solving the problem]

[0008] The problem to be solved by the present invention is as described above, and the means for solving this problem will now be described.

[0009] In other words, the container appearance inspection device of aspect 1 of the present invention is an appearance inspection device that inspects the appearance of a container having an inspection target marking on its outer surface, and is equipped with an illumination means that illuminates the container, an imaging means that images the appearance of the container illuminated by the illumination means, and a control means that judges whether the appearance of the container is good or bad based on image data acquired by the imaging means, wherein the illumination means has a bar light that is positioned between the container and the imaging means, and the bar light is configured to illuminate the container only with indirect light that spreads around from the light-emitting surface. In this way, in the container appearance inspection device of the present invention, the container, which is the object of inspection, is entirely illuminated not by direct light emitted from the lighting means (more specifically, bar lighting), but only by indirect light that spreads from the light-emitting surface of each bar lighting unit to the surrounding area, and which has a lower brightness than the direct light so that the inspection object display can be seen. As a result, the container appearance inspection device of the present invention can effectively suppress the occurrence of halation on the outer surface of the container when illuminated by the lighting means, regardless of the material, color, shape, etc. of the container. Furthermore, when a container made of a transparent material is used as the object to be inspected, it is possible to image the container using an imaging means while illuminating only the front surface of the container without illuminating the back surface of the container. This prevents the inspection object marking (printed) on the back surface of the container from appearing in the acquired image data, and clearly distinguishes between the area of ​​the inspection object marking where visual inspection is to be performed and the background outside of that area, thereby enabling accurate inspection of the appearance of the inspection object marking printed on the outer surface of the container. Furthermore, when a cylindrical container is used as the object to be inspected, the indirect light emitted from the lighting means is prevented from being excessively concentrated at the center of the surface of the container that curves and bulges toward the imaging means, and the entire surface can be illuminated with approximately uniform brightness, allowing the appearance of the inspection object marking printed on the outer surface of the container to be inspected accurately. Furthermore, the brightness of light captured by the imaging means is generally significantly reduced to about one-quarter when it passes through a polarizing plate or polarizing lens, so when using these polarizing plates or polarizing lenses, it is usually necessary to use a lighting means with a higher output value.However, with the container appearance inspection device of the present invention, by using only indirect light, the brightness of the light captured by the imaging means can be ensured to a certain extent without being significantly reduced, and there is no need to increase the output value of the lighting means, thereby avoiding increased equipment costs.

[0010] Furthermore, the container appearance inspection device according to aspect 2 of the present invention is characterized in that, in the above-mentioned aspect 1, the bar lights are provided as a pair and are arranged with their light-emitting surfaces facing each other. By having this configuration, the container appearance inspection device of the present invention can illuminate the entire container, which is the object of inspection, with indirect light from the light-emitting surface of the bar light in the lighting means in a more uniform state with less brightness gradient.

[0011] Furthermore, the container appearance inspection device according to aspect 3 of the present invention is characterized in that, in the above-mentioned aspect 1 or aspect 2, the pair of bar lights are arranged opposite each other with the container sandwiched between them when viewed in the imaging direction of the imaging means. By having such a configuration, the container appearance inspection device of the present invention can more effectively suppress the occurrence of halation on the outer surface of the container by reliably illuminating the entire container, which is the object of inspection, with only indirect light that spreads around from the light-emitting surface of each bar light in the lighting means. [Effects of the Invention]

[0012] The present invention has the following effects. That is, the container appearance inspection device according to the present invention can inspect the appearance of the inspection object marking attached to the outer peripheral surface of the container with high accuracy. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a side view showing the overall configuration of a container appearance inspection device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] Next, one embodiment of the present invention will be described with reference to FIG.

[0015] [Configuration of Appearance Inspection Device 1 for Container W] First, the configuration of a visual inspection device 1 for a container W (hereinafter simply referred to as "visual inspection device 1") in this embodiment will be described with reference to FIG.

[0016] The appearance inspection device 1 is installed, for example, in a filling assembly line that fills and seals a specified container W with contents, and is a device that inspects the appearance of an inspection target mark D that is attached (printed) to the outer surface Wa of the container W.

[0017] Here, the container W in this embodiment is, for example, a cylindrical container made of a transparent material that allows the interior to be seen, or a mirror-like material that can reflect light, and its outer surface Wa is printed with an inspection object marking D consisting of predetermined letters, symbols, or figures, etc. In addition, the inspection object marking D may be letters, symbols, figures, etc. printed directly on the outer surface Wa of the container W, as in this embodiment, or it may be a label, etc. on which these letters, symbols, figures, etc. are printed.

[0018] The container W is then transported to a predetermined inspection position P1 by a transport device (not shown), and a visual inspection of the inspection target mark D is carried out at the inspection position P1.

[0019] The configuration of the container W is not limited to this embodiment, and any material, color, shape, etc. can be adopted. For example, the container W may be any of a PET bottle, a glass bottle, a can, and the like. Furthermore, the shape of the container W is not limited to a cylindrical shape with curved sides, but may be any shape, such as a square tube shape with flat sides.

[0020] The appearance inspection device 1 mainly comprises an illumination means 10 that illuminates the container W, an imaging means 20 that captures an image of the appearance of the container W illuminated by the illumination means 10, and a control means 30 that determines whether the appearance of the container W (more specifically, the inspection target marking D printed on the outer surface of the container W) is good or bad based on the image data acquired by the imaging means 20.

[0021] The illumination means 10 is composed of a pair of bar lights 11, 11, and is disposed between the container W located at the inspection position P1 and the imaging means 20. Here, the bar light 11 refers to a light that shines linearly, such as in a bar or line shape.

[0022] The pair of bar lights 11 are arranged spaced apart in the vertical direction with their light emitting surfaces 11a facing each other. In addition, the pair of bar lights 11·11 are positioned in a position that can illuminate the container W to the extent that the inspection target marking D printed on the surface Wa1 of the container W (the outer surface Wa on the side imaged by the imaging means 20) can be seen.

[0023] The pair of bar lights 11·11 are configured to illuminate the container W not with direct light La emitted from each light-emitting surface 11a·11a, but only with indirect light Lb that leaks out from these light-emitting surfaces 11a·11a and spreads around.

[0024] Here, the pair of bar lights 11, 11 are arranged facing each other with the container W sandwiched between them when viewed in the imaging direction of the imaging means 20 (that is, when the container W is viewed from the imaging means 20).

[0025] By having such a configuration, the appearance inspection device 1 in this embodiment can reliably illuminate the entire container W, which is the object to be inspected, with only indirect light Lb that spreads from the light-emitting surface 11a of each bar light 11 in the lighting means 10, thereby more effectively suppressing the occurrence of halation on the outer surface Wa of the container W.

[0026] In this embodiment, the pair of bar lights 11 are arranged facing each other in the vertical direction (that is, in the height direction of the container W), but this is not limitative. In other words, the pair of bar lights 11-11 need only be arranged in a state in which they can illuminate the container W using only indirect light Lb, excluding direct light La, and may, for example, be arranged facing each other horizontally (i.e., in the width direction of the container W) or facing each other at a slight angle toward the imaging means 20 or the container W.

[0027] Furthermore, the number of bar lights 11 that make up the lighting means 10 is not limited to that in this embodiment, and may be, for example, two or more pairs of bar lights 11 arranged opposite each other, or, as long as unevenness of the lighting on the container W (brightness gradient) is not a problem, a single bar light 11 may be sufficient.

[0028] As the imaging means 20, for example, a so-called digital camera using an imaging element such as a CCD image sensor or a CMOS image sensor can be used. Moreover, the image data captured by the imaging means 20 may be either color or monochrome.

[0029] The imaging means 20 is provided on the opposite side of the illumination means 10 from the container W side, and is disposed so that at least the inspection object mark D falls within the field of view of the imaging means 20.

[0030] Then, the imaging means 20 images the container W illuminated by the lighting means 10 (more specifically, the area on the outer surface Wa of the container W where the inspection object marking D is printed), converts the acquired image data into an electrical signal, and transmits it to the control means 30.

[0031] The control means 30 controls the overall operation of the visual inspection device 1, and as described above, judges whether the visual appearance of the inspection object display D is good or bad based on the image data acquired by the imaging means 20.

[0032] The control means 30 includes an arithmetic processing unit consisting of a CPU (Central Processing Unit), a memory unit consisting of a ROM (Read Only Memory), RAM (Random Access Memory), HDD (Hard Disk Drive), etc., and the memory unit pre-stores programs for processing image data captured by the imaging means 20 and determining whether the appearance of the inspection target display D is good or bad.

[0033] The control means 30 may be provided with an input means such as a touch panel, and may also be provided with an output means such as a monitor.

[0034] Furthermore, as a program for determining whether the appearance of the inspection object display D is good or bad, any program may be adopted, such as a program that performs binarization processing on the image data captured by the imaging means 20, and then compares the image data with image data of the appearance of a reference inspection object display that has been stored in advance, to determine whether the appearance of the inspection object display D on the captured image data is good or bad.

[0035] Then, the control means 30 executes a predetermined program using the electrical signal of the image data received from the imaging means 20, and judges whether the appearance of the inspection object mark D is good or bad based on the image data.

[0036] As described above, the appearance inspection device 1 in this embodiment is an appearance inspection device that inspects the appearance of a container W having an inspection target mark D on its outer peripheral surface Wa, and is equipped with an illumination means 10 that illuminates the container W, an imaging means 20 that images the appearance of the container W illuminated by the illumination means 10, and a control means 30 that determines whether the appearance of the container W (more specifically, the inspection target mark D) is good or bad based on the image data acquired by the imaging means 20.

[0037] The lighting means 10 has a bar light 11 (in this embodiment, a pair of bar lights 11·11 arranged with their light-emitting surfaces 11a facing each other) placed between the container W and the imaging means 20, and the bar light 11 is configured to illuminate the container W only with indirect light Lb that spreads from the light-emitting surface 11a to the surrounding area.

[0038] In this way, in the visual inspection device 1 of this embodiment, the container W, which is the object to be inspected, is entirely illuminated not by direct light La irradiated from the lighting means 10 (more specifically, bar light 11), but only by indirect light Lb which is lower in brightness than the direct light La but is such that the inspection object display D can be seen, and which spreads from the light-emitting surface 11a of each bar light 11 to the surrounding area.

[0039] As a result, according to the appearance inspection device 1 of this embodiment, regardless of the material, color, shape, etc. of the container W, the occurrence of halation on the outer surface Wa of the container W when illuminated by the lighting means 10 can be effectively suppressed.

[0040] Furthermore, for example, when a container W made of a transparent material is used as the object to be inspected, it is possible to image the container W using the imaging means 20 while illuminating only the surface Wa1 of the container W without illuminating the back surface Wa2 (the outer surface Wa opposite the surface Wa1) of the container W.This prevents the inspection target mark D printed on the back surface Wa2 of the container W from appearing in the acquired image data, and clearly distinguishes between the area of ​​the inspection target mark D where visual inspection is to be performed (i.e., the area printed on the front surface Wa1) and the background outside that area (including the inspection target mark D printed on the back surface Wa2), allowing for accurate inspection of the appearance of the inspection target mark D printed on the outer surface Wa of the container W.

[0041] Furthermore, for example, when a cylindrical container W is used as the object to be inspected, the indirect light Lb emitted from the lighting means 10 is prevented from concentrating excessively at the center of the width of the surface Wa1 of the container W, which curves and bulges toward the imaging means 20, and the entire surface Wa1 can be illuminated with approximately uniform brightness, allowing the appearance of the inspection object marking D printed on the outer surface Wa of the container W to be inspected accurately.

[0042] Furthermore, the brightness of light captured by the imaging means 20 is generally significantly reduced to about one-quarter when it passes through a polarizing plate or polarizing lens, and therefore, when using these polarizing plates or polarizing lenses as in the past, it is usually necessary to use a lighting means with a higher output value.However, according to the appearance inspection device 1 of this embodiment, by using only indirect light Lb, it is possible to ensure a certain level of brightness of the light captured by the imaging means 20 without it being significantly reduced, and there is no need to increase the output value of the lighting means 10, thereby avoiding an increase in equipment costs.

[0043] [Verification experiment] Next, a verification experiment for confirming the effectiveness of the visual inspection device 1 in this embodiment will be described.

[0044] <Comparison with the container W made of mirror-like material> First, in this embodiment, the outer surface Wa of a cylindrical container W made of a mirror-like material was illuminated with indirect light Lb emitted from the lighting means 10, and the inspection object marking D printed on the outer surface Wa was imaged by the imaging means 20.

[0045] Next, as a comparative example, the outer surface Wa of a cylindrical container W, also made of a mirror-like material, was illuminated with indirect light from a general-purpose dome light, and the inspection target mark D printed on the outer surface Wa was imaged by the imaging means 20.

[0046] Then, the difference between the inspection object indication D on the image data in the example and the inspection object indication D on the image data in the comparative example was visually confirmed.

[0047] In the image data in this example, no halation occurred on the outer peripheral surface Wa of the container W, and the inspection object mark D was clearly imaged so as to be visible. On the other hand, in the image data of the comparative example, halation occurred due to the extreme concentration of indirect light irradiated from the dome lighting at the center of the width of the surface Wa1 of the container W, and the inspection object display D was imaged with some areas hidden by the halation.

[0048] <Comparison with container W made of transparent material> First, in this embodiment, with the surrounding light blocked, the outer surface Wa of a cylindrical container W made of a transparent material was illuminated by indirect light Lb emitted from the lighting means 10, and the inspection object marking D printed on the outer surface Wa was imaged by the imaging means 20.

[0049] Next, as a comparative example, the outer surface Wa of a cylindrical container W also made of a transparent material was illuminated by a fluorescent lamp, and the inspection target mark D printed on the outer surface Wa was imaged by the imaging means 20.

[0050] Then, the difference between the inspection object indication D on the image data in the example and the inspection object indication D on the image data in the comparative example was visually confirmed.

[0051] In the image data in this example, only the inspection object mark D printed on the front surface Wa1 of the container W was clearly imaged, and images were not taken of the back surface Wa2 of the container W, the inspection object mark printed on the back surface, or the front surface Wa1 on which the inspection object mark D was printed. In other words, in the image data in this example, the area in the inspection object mark D where the appearance inspection was to be performed (the range printed on the front surface Wa1) and the background outside this area (including the inspection object mark D printed on the back surface Wa2) were clearly depicted. On the other hand, in the image data in the comparative example, the front surface Wa1 of the container W on which the inspection target mark D is printed is imaged together with the back surface Wa2 of the container W and the inspection target mark D printed on the back surface Wa2, and the distinction between the area in the inspection target mark D where the visual inspection is performed (the area printed on the front surface Wa1) and the background outside that area (including the inspection target mark D printed on the back surface Wa2) is not clearly expressed and is unclear.

[0052] The above describes one embodiment of the present invention, but the present invention is not limited to such an embodiment, which is merely an example, and it goes without saying that the present invention can be embodied in various other forms without departing from the gist of the present invention. The scope of the present invention is indicated by the claims, and further includes the meaning of equivalents set forth in the claims, and all modifications within the scope of the claims. [Explanation of symbols]

[0053] 1. Container appearance inspection device 10 Lighting means 11 Bar Lighting 11a Light-emitting surface 20 Imaging means 30 Control Means D Inspection subject display Lb indirect light W container Wa outer perimeter

Claims

1. An appearance inspection device that inspects the appearance of a container having an inspection target mark on its outer peripheral surface, lighting means for illuminating the container; an imaging means for imaging the exterior of the container illuminated by the lighting means; and a control means for determining whether the appearance of the container is good or bad based on the image data acquired by the imaging means, The lighting means a bar light disposed between the container and the imaging means; The bar lighting is configured to illuminate the container only by indirect light radiating from the light-emitting surface to the surrounding area; A container appearance inspection device characterized by:

2. The bar lighting is provided in pairs, The light-emitting surfaces are arranged facing each other, 2. The container appearance inspection device according to claim 1, wherein:

3. When viewed from the imaging direction of the imaging means, The pair of bar lights are are arranged opposite each other with the container therebetween, 3. The container appearance inspection device according to claim 2.

Images