Film shrinkage defects inspection system

Abstract

To provide a film shrinkage defects inspection system and method which can easily and surely detect shrinkage defects generated in the surface of a product package of wrapped products.SOLUTION: A film shrinkage defects inspection system (100) of the present invention includes: a carrying device (1) for carrying a product package (30); and a camera (2) and an LED light (3) provided on a side of the carrying device. The LED light has a function of radiating illumination light so that the camera takes images of wrinkles generated in the film of the product package as white glosses. The relative positional relation of the camera (2) and the LED light (3) and the product (30) and the shutter speed are set so that wrinkles are imaged as white glosses. The controller (10) has a function of counting the white glosses in the taken image and a function of comparing the number of the counted white glosses and a threshold value and determining that a product is not defective when the number is the threshold value at a maximum and that a product is defective when the number is larger than the threshold value.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a technology for detecting film shrinkage defects such as wrinkles and distortions in the package (product package) of a product packaged in film when the product is packaged in film (e.g., multi-shrink film or label). [Background technology]

[0002] For example, when a beverage is shipped from a manufacturing factory, the product may be a container filled with the beverage (e.g., a rectangular paper container), and a certain number of such products may be bundled together and packaged in film to form a product package. In packaging using such a film, for example, the product package is surrounded by a multi-shrink film and the multi-shrink film is then shrunk to perform packaging.

[0003] Here, if the multi-shrink film does not shrink properly due to various factors, wrinkles and other shrinkage defects may be present on the surface of the product package after the film has shrunk. Such shrinkage defects not only look bad, but if a consumer witnesses such shrinkage defects, it can cause problems such as making the characters on the film difficult to read, and the consumer may develop serious distrust for the beverage and the manufacturer (manufacturing company) of the beverage. For this reason, at the manufacturing site, product packages having film shrinkage defects are detected and removed as much as possible by, for example, visual inspection by an operator. However, it is difficult for an operator to completely detect and remove product packages that have suffered from film shrinkage defects by visual inspection alone.

[0004] Therefore, it is desirable to automatically detect product packages having film shrinkage defects using equipment, rather than relying on visual inspection by an operator. The inventors have carried out various studies to see whether film shrinkage defects can be detected using commercially available cameras or the like. The idea was to use an "X" shaped laser pointer to project a figure onto the film on the surface of the product packaging and determine shrinkage defects based on distortion of the figure, but there were problems in that the laser pointer could be shone into the workers' eyes, and also that it was not practical to create software to detect and process distortion of the figure. In addition, a prototype program was created that shines light diagonally onto the product package and counts the number of shadows created by wrinkles in the film that wraps the package, but this revealed a problem with frequent false positives, as darker parts of the film design were also counted as shadows.To address this problem, a program was added to remove specific colors, but this involved problems such as the enormous number of parameters required for detection, strict setting values ​​being required, and the angle of the light shining on the product needing strict positioning.

[0005] As another conventional technique, a technique for detecting wrinkles that occur during film transport has been proposed (see, for example, Patent Document 1). However, this conventional technology (Patent Document 1) is intended to detect wrinkles that occur on the film itself while it is transported in a flat state, and is not intended to detect shrinkage defects (e.g. wrinkles) that occur on the surface of the film packaging the products when a certain number of products have been packaged in the film. For this reason, no technology has yet been proposed that can meet the demand for automatically detecting product packages that have experienced film shrinkage defects using equipment. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2003-42756 A Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been proposed in consideration of the problems of the prior art described above, and aims to provide a film shrinkage defect inspection system and method that can easily and reliably detect shrinkage defects that occur on the surface of a product package when a container (e.g., multiple beverage products) is packaged in film to form a product package. [Means for solving the problem]

[0008] The film shrinkage defect inspection system (100) of the present invention includes: A conveying member (1: conveyor) for conveying a product package (30) in which a container (e.g., a container for multiple beverage products: a product) is wrapped in a film (e.g., a multi-shrink film or a label); The system includes a camera (2) and a light source (3: for example, an LED light) provided in a region to the side of the transport member (1), The light source (3) has a function of irradiating illumination light (3A) so that wrinkles (W) occurring in the film of the product package (30) are photographed by the camera (2) as a white gloss, The relative positions of the camera (2), the light source (3), and the product (30) and the shutter speed are set so that the wrinkles (W) are photographed as a white gloss. The control device (10: control unit) includes: A function for counting white gloss in an image captured by a camera (2); The counted number of white glosses is compared with a threshold value, and if the number is below the threshold value, the product is judged to be good, and if the number is above the threshold, the product is judged to be defective. In the system (100) of the present invention, the control device (10) is preferably configured by an electronic device having an information processing function (such as a personal computer).

[0009] In the present invention, the control device (10) has a function of inverting black and white of an image captured by the camera (2), (When the black and white of the image is inverted) instead of the function of counting the white gloss in the image captured by the camera (2), a function of counting the black parts in the inverted black and white image is provided, Instead of the function of comparing the number of counted white glosses with a threshold value (when the black and white of the image are inverted) and judging the product to be a good product if the number is below the threshold value and a defective product if the number is above the threshold value, it is preferable to have a function of comparing the number of counted black portions with a threshold value and judging the product to be a good product if the number is below the threshold value and a defective product if the number is above the threshold value.

[0010] The film shrinkage defect inspection method of the present invention further comprises the steps of: A conveying member (1: conveyor) for conveying a product package (30) in which a container (e.g., a container for a plurality of beverage products: a product) is wrapped in a film; The system includes a camera (2) and a light source (3: for example, an LED light) provided in a region to the side of the transport member (1), The light source (3) has a function of irradiating illumination light (3A) so that wrinkles (W) occurring in the film of the product package (30) are photographed by the camera (2) as a white gloss, In a film shrinkage defect inspection method using a film shrinkage defect inspection system (100), the relative positions of a camera (2), a light source (3), and a product (30) and the shutter speed are set so that wrinkles (W) are photographed as white gloss, Counting the white luster in the image captured by the camera (2); The method is characterized by having a step of comparing the number of counted white glosses with a threshold value, and judging the product as a non-defective product when the number of white glosses is equal to or less than the threshold value, and judging the product as a defective product when the number of white glosses is greater than the threshold value. In the method of the present invention, it is preferable to have a control device (10) that is constituted by an electronic device having an information processing function (such as a personal computer).

[0011] In the present invention, a step of inverting black and white of an image captured by the camera (2); Instead of the step of counting the white gloss in the image captured by the camera (if the image is inverted), a step of counting the black parts in the inverted image is included, Instead of the above-mentioned process of comparing the number of white glosses counted with a threshold value and judging the product to be good if the number of white glosses is below the threshold value and judging the product to be defective if the number of white glosses is more than the threshold value (when the image is inverted), it is preferable to have a process of comparing the number of black portions of the inverted image with a threshold value and judging the product to be good if the number of black portions counted is below the threshold value and judging the product to be defective if the number of black portions counted is more than the threshold value. In the present invention, the "product package" is not particularly limited as long as the container is wrapped in a film or the like, and examples include a form in which a single container is wrapped in a film or the like, a form in which multiple containers are wrapped in a film or the like, and a form in which multiple or more of these are bundled together and wrapped in a film or the like. In order to increase the accuracy of the inspection, a form in which multiple containers (whether or not wrapped in a film or the like) are wrapped in a film or the like, or a form having at least one flat surface, is preferred. In the present invention, the term "film" is used to include labels that are applied to beverage products. Effect of the Invention

[0012] According to the present invention having the above-mentioned configuration, the illuminating light (3A) is applied so that the wrinkles (W) are photographed as a white luster, and the number of the white luster is counted, so that the various set values ​​are not as strict as the above-mentioned method (background art) in which the number of shadows of the wrinkles (W) in the film is counted by illuminating the product package from an oblique angle, and the angle of the light illuminating the product is not as strict. Furthermore, since the judgment is based on a monochrome image, there is no need to remove only a specific color, and even if the film adopts a design using a specific color, the influence of the design is reduced. Here, if the black and white of the image are inverted, the black parts on a white background correspond to the wrinkles (W), making it easier to count the relevant parts. Even if the black and white of the image are inverted, the above-mentioned advantages remain the same, that is, the various setting values ​​are not strict, the angle of the light irradiating the product is not strict, and the influence of the film design is small. [Brief description of the drawings]

[0013] [Figure 1] FIG. 13 is an explanatory diagram showing an example of a photograph showing the gloss of wrinkles in a defective product. [Diagram 2] FIG. 2 is an explanatory diagram showing an example in which the photograph in FIG. 1 is inverted in black and white. [Diagram 3] FIG. 13 is an explanatory diagram showing a photograph of wrinkle gloss in a non-defective product, inverted black and white. [Figure 4] FIG. 1 is an explanatory plan view showing a state in which an inspection system according to an embodiment of the present invention is used. [Diagram 5] FIG. 5 is an explanatory view taken along the arrow A in FIG. 4. [Figure 6] FIG. 2 is a functional block diagram of a control unit used in the illustrated embodiment. [Figure 7] This is an explanatory diagram showing the product-camera distance and the camera-LED distance. [Figure 8] FIG. 8 is a table showing the ranges of distances and camera settings shown in FIG. 7. [Figure 9] FIG. 4 is a control flowchart in the illustrated embodiment. [Figure 10] FIG. 11 is a control flowchart for determining whether or not a product has arrived at a measurement position in the illustrated embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In the illustrated embodiment, a defect occurring in a film is exemplified by "wrinkles." First, with reference to Figs. 1 to 3, the principle of detecting film shrinkage defects such as wrinkles in packaging of a multi-shrink film and judging whether the product is good or bad will be described. When operating the film shrinkage defect inspection system 100 in Fig. 4 and Fig. 5, various parameters such as the distance (relative distance) between the product (product package 30), camera 2, and light source 3 (hereinafter sometimes referred to as "LED lighting 3"), the shutter speed of the camera 2, etc. are appropriately selected, so that in an image taken by the camera 2 of the surface of the product package 30 (a product package in which a multi-shrink fill has shrunk and covered multiple products), wrinkles (parts of the film that have not shrunk) become white areas, as shown in Fig. 1. Fig. 1 is an example of an image of a defective product, and the white areas in Fig. 1 are wrinkles, indicated by the symbol W. Note that the inspection system 100, camera 2, and LED lighting 3 are not shown in Figs. 1 to 3. In other words, by irradiating the illumination light 3A (FIG. 5) from the LED illumination 3, wrinkles, which are poorly shrunk portions, appear as a white luster in the image captured by the camera 2. On the other hand, areas where there are no wrinkles resulting from shrinkage defects appear black when photographed by camera 2. In the illustrated embodiment, a so-called "monochrome" image is photographed, and therefore, in the photographed image (photograph), areas with shrinkage defects (wrinkles) and areas without shrinkage defects can be clearly distinguished in black and white. According to the inventor's experiments and studies, detecting wrinkles, which are areas of poor shrinkage, based on the number of white gloss spots in this manner makes it easier to detect defective areas and is more accurate than the technique of calculating the area of ​​white gloss spots to determine pass / fail.

[0015] The image shown in Fig. 1 is inverted, and the inverted image is shown in Fig. 2. In Fig. 2, wrinkles W are displayed as black parts. Figure 3 shows a state where the image of the surface of a product package made of the same product as shown in Figures 1 and 2, which has no (or very few) wrinkles W and is judged to be a "good product", is inverted from black to white. In Figure 3, as in Figure 2, the black parts are wrinkles. As is clear from a comparison of Figures 2 and 3, the defective product (Figure 2) has far more black areas W (wrinkles in the film) than the non-defective product (Figure 3).

[0016] 1 to 3, it is sufficient to apply illumination light so that wrinkles are photographed as a white luster, so compared to the above-mentioned method (the technology described in the background art) in which illumination is applied obliquely to the product package to count the number of wrinkle shadows in the film, various setting values ​​are not strict, and the angle of illumination applied to the product is also not strict. Furthermore, since the judgment is based on a monochrome image, there is no need to remove only specific colors, and even if the film adopts a design using a specific color, the influence of that (design) is reduced. Here, it is possible to omit the black and white inversion of the image. Even if the black and white inversion is omitted, the above-mentioned advantages, that is, various setting values ​​are not strict, the angle of the light irradiating the product is not strict, and the influence of the film design is small, remain the same.

[0017] Next, with reference to FIG. 4, a description will be given of an embodiment in which the film shrinkage defect inspection system 100 according to the illustrated embodiment is incorporated into a production line for beverage product packages. In FIG. 4, the manufacturing line for the product package 30 includes a multi-shrink mechanism 11 for manufacturing the product package 30, a conveying member 1 (a plastic conveyor: Unipla), and a guide 12. In the multi-shrink mechanism 11, multiple beverages (products) are packaged in multiple shrink films and bundled together as a product package 30. The product package 30 discharged from the multi-shrink mechanism 11 is placed on the conveying member 1, and the product package 30 is conveyed to the downstream process side by the conveying member 1. The guide 12 extends in a bar shape along the conveying member 1 in the traveling direction of the conveying member 1, and has the function of preventing the product package 30 (or product) from falling over. In FIG. 4, the conveying direction of the conveying member 1 is indicated by an arrow C1.

[0018] The film shrinkage defect inspection system 100 according to the illustrated embodiment includes a camera 2 (e.g., a USB camera) and an LED light 3 provided in a side area of ​​a transport member 1, a control device 10 (control unit), a rejection air ejection device 4, and a rejected product receiving basket 5. The control device 10 is configured by a device having an information processing function such as a personal computer. The camera 2 and the LED lighting 3 are disposed near the exit of the multi-shrink mechanism 11 and to the side of the conveying member 1. On the conveying member 1, a rejection air jetting device 4 and a rejected product receiving basket 5 are disposed to the side downstream of where the camera 2 and the LED lighting 3 are disposed. The rejection air jetting device 4, the rejected product receiving basket 5, and the air jetting control valve 6 (see FIG. 5) constitute a defective product rejection mechanism 14. The control device 10 (control unit) is connected to the camera 2 and the control valve 6 of the exclusion air ejection device 4 by signal transmission lines SL1 and SL2, respectively. The control device 10 has a function of determining whether or not the product package 30 is defective by counting the amount of white gloss in the image captured by the camera 2. When the product package 30 to be inspected is placed on the transport member 1 and transported, the first image is taken when it arrives at a position for photography by the camera 2, and then the camera 2 takes a total of a predetermined number of images to create a predetermined number of image data. The reason for using the predetermined number (multiple images) of image data is to increase the accuracy of defective product detection. The determination of pass / fail products will be described in detail with reference to FIG. 6. Here, in the illustrated embodiment, the surface (of the product package 30) that is configured by the surface of the product package 30 that does not have a straw (the surface opposite to the surface that has a straw) is photographed and is the subject of quality inspection. The side of the product package 30 that is configured by the surface that has a straw is less likely to develop wrinkles when a shrinkage defect occurs, whereas the side of the package 30 that is configured by the surface that does not have a straw is the first to develop wrinkles or the most likely to develop wrinkles when a shrinkage defect occurs. Therefore, it has been confirmed through experiments by the inventor that there is no problem even if only the side of the product package 30 that is configured by the surface that does not have a straw is subject to quality inspection.

[0019] In Figure 4, a single product package 30 is shown placed on the conveying member 1, and the product package 30 is located at a position where the camera 2 and the LED light 3, which serves as a light source, are provided (position B1 in Figure 4), and has not yet reached the position where the rejection air ejection device 4 and the rejected product receiving basket 5 are provided (position B2 in Figure 4). In Fig. 5, which shows the state as viewed from the arrow A in Fig. 4, the product package 30, camera 2, and LED light 3 at position B1 are shown above, and the rejection air ejection device 4 and rejected product receiving basket 5 at position B2 are shown below. In Fig. 5, the product package 30 at position B1 is shown in solid lines, but at the lower position B2, the product package 30 is shown in dashed lines. This is because the product package 30 has not yet reached position B2 in Fig. 4. If a special light source (such as a colored bright red light or a bright blue light) is used, it may interfere with the product design and make it difficult to detect the luster (wrinkles). Therefore, it is preferable to use a light source with the color of normal lighting (incandescent white, warm white, neutral white, daylight white). Although it is possible to adjust the shutter speed to a certain extent to suit the lighting used, problems may occur if the light is too weak or too strong. For example, in the illustrated embodiment, the illuminance of the light source is 90 lm and 30 lx, and settings such as 30 to 200 lm and 3 to 60 lx are preferable.

[0020] In Fig. 5, the LED lighting 3 irradiates the product package 30 with illumination light 3A, so that wrinkles (poorly shrunk parts) that occur on the surface of the product package 30 when the multi-shrink film shrinks are photographed by the camera 2 as a white gloss. In Fig. 5, the reference numeral 15 denotes a commercial power source. By adjusting the relative positional relationship between the camera 2, the LED lighting 3, and the product package 30 to an appropriate positional relationship and adjusting the shutter speed of the camera 2 and the like to appropriate values, only the wrinkles are captured as a white gloss in an image of the surface of the product package 30 captured by the camera 2. Here, the camera 2 is supported by a camera support mechanism 13, and the relative position with respect to the product package 30 is appropriately adjusted. When photographing the product package 30, areas where there are no shrinkage defects are photographed as black. In the illustrated embodiment, the image is photographed as a so-called "monochrome" image, so that wrinkles (photographed as white) and areas where there are no shrinkage defects (photographed as black) are clearly distinguished in the photographed image. Appropriate values ​​for the distances between the camera 2, the LED lighting 3, and the product package 30, the shutter speed, etc. will be described later with reference to FIGS. Image data captured by the camera 2 is transmitted to a control device 10, which will be described later, via a signal transmission line SL1.

[0021] 5, the rejection air jetting device 4 and the rejected product receiving basket 5 are disposed on either side of the transport member 1 on the downstream side of the camera 2 and the LED lighting 3. The rejection air jetting device 4 is connected to a compressed air source 7 (or a blower) via an air jet control valve 6. The rejection air jetting device 4 is operated by a control signal sent from the control device 10 to the air jetting control valve 6 via the signal transmission line SL2, and if the product package 30 is defective, it jets air toward the defective product package 30 placed on the conveying member 1. Then, it presses and rejects the product package 30 from above the conveying member 1, and moves it into the rejected product receiving basket 5. Although not clearly shown in the figure, the operating time (delay time) from the determination (detection) of a "defective product" in the control device 10 to the opening and closing of the air ejection control valve 6 is preset, and the opening and closing of the air ejection control valve 6 is programmed taking this operating time into account.

[0022] In FIG. 5, the control device 10 has a function of acquiring image data of wrinkles (white gloss) on the surface of the product package 30 taken by the camera 2 (for example, a USB camera) via a signal transmission line SL1, and counting the number of white glosses in the image. The control device 10 has a function of comparing the integrated value of the number of the counted white glosses (integrated value based on a predetermined number of image data, described in detail in FIG. 6 and FIG. 9) with a threshold value, and judging the product as a good product if it is equal to or less than the threshold value, and judging the product as a defective product if it is greater than the threshold value. Here, glosses of a certain size or less may not be counted as noise. The standard for noise may be set appropriately according to the type of the product package 30, and is preferably, for example, 50 pixels or less, more preferably 30 pixels or less, and even more preferably 15 pixels or less. The entire image data may be set as the gloss counting range, or a specific part of the image data may be set as the gloss counting range according to the type of the product package 30. The control device 10 also has a function of inverting the black and white of the image captured by the camera 2, and when the black and white of the image is inverted, instead of counting the white gloss in the image data, the control device counts the black portions in the inverted black and white image data. When the black and white of the image is inverted, instead of comparing the integrated value of the number of counted white gloss with a threshold value, the control device compares the integrated value of the number of counted black portions with a threshold value, and judges the product to be good if the number is equal to or less than the threshold value, and judges the product to be defective if the number is greater than the threshold value. The integrated value is an integrated value based on a predetermined number of image data, and will be described later with reference to Figures 6 and 9. By inverting the image, wrinkle counting becomes even easier since it is done by counting the black areas against the white.

[0023] In FIG. 5, when the product package 30 has many wrinkles on the surface and is judged to be a "defective product," the control device 10 sends a control signal to the air ejection control valve 6 of the rejection air ejection device 4 via the signal transmission line SL2. The air ejection control valve 6 receives the control signal and opens, and air from the compressed air source 7 is ejected via the rejection air ejection device 4 toward the product package 30 that has been determined to be a defective product and that is placed on the conveying member 1. As a result, the product package 30 is pressed and rejected from above the conveying member 1, and moves into the rejected product receiving basket 5. If the product package 30 is rejected by the expulsion air jetting device 4, there is less mechanical contact and therefore less risk of damage to the product. Also, since the multi-shrink mechanism 11 is often equipped with an air device as standard, the expulsion air jetting device 4 can be easily installed. It is also possible to reject defective products using a piston of a piston-cylinder mechanism or other devices instead of the rejection air jetting device 4. When rejecting defective products using a piston of a piston-cylinder mechanism or other devices instead of the rejection air jetting device 4, another device is provided instead of the compressed air source 7 (or blower) and the air jetting control valve 6.

[0024] Next, the control device 10 (control unit: FIGS. 4 and 5) will be described with reference to FIG. In FIG. 6, the control device 10 has an image number determination block 10A, an image processing block 10B, a wrinkle gloss number counting block 10C, a wrinkle gloss number accumulation block 10D, a pass / fail determination block 10E, a control signal generation block 10F, and a memory block 10G. 4 and 5, when the product package 30 to be inspected is placed on the conveying member 1 and conveyed, it is photographed a predetermined number of times by the camera 2 and a predetermined number of image data are created in order to improve the accuracy of defective product detection. Then, using the multiple (predetermined number) image data, an integrated value of the number of glossy wrinkles on the surface is calculated, and the integrated value is used to judge whether the product is good or defective.

[0025] The image number determination block 10A sequentially acquires image data (image data including wrinkles captured as white gloss) of the surface of the product package 30 from the camera 2 via the signal transmission lines SL1 and SL1-1. At that time, the image number determination block 10A counts every time image data is acquired from the camera 2, and accumulates the number of images acquired for the product package 30 to be inspected. The image number determination block 10A has the function of obtaining a predetermined value of the number of images for the product package 30 to be inspected from the memory block 10G via the signal transmission line SL3, and comparing the accumulated number of images with the predetermined value.When the accumulated number of images for the product package 30 to be inspected reaches a predetermined value (predetermined number of images), it transmits a message to that effect to the wrinkle gloss number accumulation block 10D via the signal transmission line SL4.

[0026] The image processing block 10B has the function of acquiring image data of the product package 30 (image data including wrinkles captured as white gloss) from the camera 2 via signal transmission lines SL1 and SL1-2, and performing image processing to invert the image data to black and white. The image data that has been subjected to black-and-white inversion processing in the image processing block 10B is sent to the wrinkle gloss counting block 10C via a signal transmission line SL5.

[0027] The wrinkle gloss counting block 10C has the function of counting the number of black areas (areas corresponding to wrinkles) in the black and white inverted image obtained from the image processing block 10B, i.e., the function of counting the number of wrinkle glosses. The count data of the number of wrinkle glossiness counted by the wrinkle glossiness counting block 10C is transmitted to the wrinkle glossiness number accumulating block 10D via a signal transmission line SL6. When the image data from the camera 2 is not subjected to black and white inversion processing, the image data from the camera 2 is sent to the wrinkle gloss number counting block 10C without passing through the image processing block 10B. The wrinkle gloss number counting block 10C then counts the number of white glosses (portions corresponding to wrinkles) in the image. Here, for the counting in the wrinkle gloss count block 10C, the number of parts in the image data from the camera 2 that correspond to wrinkles (inverted black parts: white gloss when black-and-white inversion processing is not performed) can be counted using not only known software, but also the "function to count the number of areas in an image" of a library (OpenCV) used for creating programs. In other words, software using a known library can be created, and a functional block called a wrinkle gloss count block can be configured using this software. Of course, it is also possible to configure a functional block called a wrinkle gloss count block using software having a function for counting the number of wrinkle glosses.

[0028] The wrinkle gloss number accumulation block 10D is count data of the number of wrinkle glosses obtained from the wrinkle gloss number counting block 10C, and has the function of accumulating the count data of the number of wrinkle glosses for a specified number of images on the product package 30 being inspected. When accumulating the count data of the number of wrinkle glosses, the wrinkle gloss number accumulation block 10D determines the accumulated data of the number of wrinkle glosses based on information (information obtained from the image number determination block 10A) that the accumulated number of images of the product package 30 being inspected has reached a predetermined value. The integrated value of the number of glossy wrinkles determined by the wrinkle gloss number integration block 10D is transmitted to the pass / fail judgment block 10E via a signal transmission line SL7.

[0029] The pass / fail judgment block 10E obtains accumulated data (accumulated value) of the number of wrinkle glosses in the product package 30 to be inspected from the wrinkle gloss number accumulation block 10D, and also obtains the accumulated value of the number of wrinkle glosses, which is the threshold value for pass / fail judgment, from the memory block 10G via the signal transmission line SL8. As described above, wrinkles appear as black parts in a black-and-white inverted image, and wrinkles appear as white gloss in an image that has not been subjected to black-and-white inversion processing. The pass / fail judgment block 10E has the function of comparing the accumulated value of the number of glossy wrinkles with a pass / fail judgment threshold value, and judging the product package 30 being inspected as a "good product" if the accumulated value of the number of glossy wrinkles is less than the threshold value, and judging it as a "defective product" if the accumulated value of the number of glossy wrinkles is more than the threshold value. The result of the pass / fail judgment block 10E (the pass / fail judgment result of the product package 30 to be inspected) is transmitted to the control signal generation block 10F via a signal transmission line SL9.

[0030] The control signal generating block 10F has a function of transmitting a control signal to open the valve to the air ejection control valve 6 (defective product ejection mechanism 14: FIG. 5) of the rejection air ejection device 4 via the signal transmission line SL2 when the product is judged to be a "defective product" by the pass / fail judgment block 10E. The air ejection control valve 6 is then opened by the control signal, and air is ejected from the rejection air ejection device 4 onto the product package 30 placed on the conveying member 1. The ejected air presses and ejects the product package 30 judged to be a defective product from above the conveying member 1, and the product package 30 is moved into the rejected product receiving basket 5. On the other hand, if the product is judged as a "good product" by the quality judgment block 10E, then either no control signal is sent from the control signal generation block 10F, or a control signal to close the valve 6 is sent. As a result, air is not sprayed from the rejection air jetting device 4 to the product package 30 judged as a "good product", and the product package 30 judged as a "good product" passes in front of the rejection air jetting device 4 while remaining placed on the conveying member 1, and is conveyed downstream.

[0031] The memory block 10G stores a predetermined value for the number of images of the product package 30 to be inspected, a threshold value for the integrated value of the number of wrinkle glosses, and other data. The data stored in the memory block 10G is transmitted to the image number determination block 10A, the quality determination block 10E, etc. as required, and necessary control is performed.

[0032] As described above, when the distance between the product package 30 and the camera 2 and LED lighting 3, the shutter speed of the camera 2, and other settings are appropriately adjusted, wrinkles and other shrinkage defects in the film wrapping the product package 30 are captured as white areas in the image captured by the camera 2 by the light 3A emitted from the LED lighting 3, as shown in Figure 1. When the image is inverted from black to white, wrinkles and other shrinkage defects become black areas (portions) in the image data, as shown in Figures 2 and 3. Here, depending on the position of the camera 2 or the position of the LED lighting 3, the image captured by the camera 2 may, for example, appear gray or black overall, making it difficult to judge whether the product is good or bad as described with reference to Figures 1 to 3. For this reason, the relative positional relationship between the camera 2, the LED lighting 3, and the product package 30, the shutter speed, and other setting values ​​are very important for judgment in the illustrated embodiment. In order to detect wrinkles or the like in the film in the illustrated embodiment, the relative positions of the camera 2, LED lighting 3, and product package 30, the shutter speed, and other settings must be set to appropriate values ​​or values ​​within a range and maintained at those values ​​before the start of the packaging work with the film.

[0033] For example, if the distance between the camera 2 and the product package 30 is too long, the captured image will be completely dark, making it impossible to count the number of wrinkles. Alternatively, the background will be captured in the image, which will cause glossiness in addition to the wrinkles, which is inconvenient. On the other hand, if the distance between the camera 2 and the product package 30 is too short, the camera will not be able to focus, and the illumination light 3A from the LED light 3 will not hit the location to be photographed. Furthermore, if the shutter speed is fast (a low setting value in the illustrated embodiment), the image will be dark, and if the shutter speed is slow (a high setting value in the illustrated embodiment), the background will be captured, and something other than the gloss of the wrinkles will be detected as a shrinkage defect.

[0034] The distance between the camera 2 and the LED light 3, and the distance between the camera 2 and the product package 30 will be described with reference to FIG. In Fig. 7, the distance L1 between the camera 2 and the LED lighting 3 is set as the horizontal distance (in Fig. 7) between the vicinity of the upper end 3B of the LED lighting 3 and the center 2A of the camera 2. The distance L2 between the camera 2 and the product package 30 is the horizontal distance (in Fig. 7) between the center 2A of the camera 2 and the product package 30 placed on the conveying member 1. In Fig. 7, reference numeral 12 denotes a guide for preventing the product package 30 from falling over. It should be noted that the illumination angle θ1 of the LED lighting 3 with respect to the product package 30 and the installation angle θ2 of the camera 2 with respect to the product package 30 also need to be set within appropriate predetermined ranges.

[0035] The table shown in FIG. 8 indicates the predetermined ranges within which the illustrated embodiment can be implemented for the distance L1 between the camera 2 and the LED lighting 3, the distance L2 between the camera 2 and the product package 30, focus (adjusting the focus of the camera), shutter speed (adjusting the brightness of the camera image), contrast (adjusting the color contrast of the image), and luminosity (adjusting the brightness of the image). By keeping the relative positional relationship between the camera 2, LED lighting 3, and product package 30, the shutter speed, and other settings within the specified ranges shown in Figure 8, it is possible to detect wrinkles, etc. in the multi-shrink film of the product package 30 from the image captured by the camera 2. In Fig. 8, a shutter speed of "-8" means that the camera's exposure time for the set value is 3.9 milliseconds, and "-11" means that the camera's exposure time is 488.3 microseconds. Therefore, the effective range of shutter speeds "-8 to -11" in Fig. 8 means that the effective range of exposure time is 3.9 milliseconds to 488.3 microseconds, and shows an example of the exposure time. If the focus exceeds the range shown in FIG. 8, the captured image of the product package 30 will be blurred, making it impossible to detect the gloss. 8, the image of the product package 30 becomes too dark, and the difference between the gloss and other parts disappears, making it impossible to detect the gloss of the wrinkles. Alternatively, the image of the product package 30 becomes too bright, and so-called "whiteout" occurs in parts other than the gloss of the wrinkles, making it impossible to detect the gloss of the wrinkles. The camera used in the illustrated embodiment is a commercially available product (manufactured by Logitech: product name C922n-Pro-Stream Webcam), and the setting values ​​are determined appropriately depending on the camera used.

[0036] Next, control in the illustrated embodiment will be described with reference mainly to FIG. 9, but also to FIGS. 9, in step S1, it is determined whether or not the number of images of the conveyed product package 30 captured by the camera 2 has reached a predetermined value. This determination is made by the image number determination block 10A of the control device 10. In step S1, if the number of images reaches the predetermined value (step S1 is "Yes"), the process proceeds to step S7, and if the number of images does not reach the predetermined value (step S1 is "No"), the process proceeds to step S2. In step S2, one image (next image) of the product package 30 is captured by the camera 2. The captured image data is acquired by the control device 10 (number of images determination block 10A, image processing block 10B). Then, the process proceeds to step S3.

[0037] In step S3, black and white inversion processing is performed on the image data of one image captured in step S2. The black and white inversion processing in step S3 is executed by the image processing block 10B of the control device 10. Then, the process proceeds to step S4. In step S4, the number of wrinkle glosses in the image that has been subjected to black-white inversion processing in step S3 is counted. In other words, in step S4, the number of black parts (corresponding to wrinkles) in the image that has been subjected to black-white inversion processing is counted. The process of counting the black parts corresponding to wrinkles in step S4 is executed by the wrinkle gloss number counting block 10C of the control device 10. 6, the image data from the camera 2 may not be subjected to black and white inversion processing. If black and white inversion processing is not performed, step S3 is omitted and the process proceeds to step S4, where the number of white glosses (corresponding to wrinkles) in the image data from the camera 2 is counted.

[0038] In step S5 following step S4, the counting results (number of wrinkle glosses) in step S4 are accumulated. In step S6, in response to the increment by one of the images in which the number of wrinkle glosses is counted or accumulated in steps S4 and S5, the number of processed images is incremented by one, and the number of processed images is set to a value (number of images + 1) that is one more than the previous number of images. The loop of steps S1 to S6 is repeated until it is determined in step S1 that the number of images has reached a predetermined value. At that time, in step S4, the number of glossy wrinkles in the images for the predetermined value is counted, and in step S5, the integrated value of the number of glossy wrinkles in the images for the predetermined value counted in step S4 is calculated. When step S6 is completed, the process returns to step S1.

[0039] If the result of the determination in step S1 is that "the number of images has reached a predetermined value," the number of images is reset in step S7, and the process proceeds to step S8. In step S8, a comparison is made to determine whether the accumulated value of the count data of the number of glossy wrinkles in a predetermined amount of image data (in the loop of steps S1 to S6, the latest accumulated value of the number of glossy wrinkles in step S5: the accumulated value when the number of images reaches a predetermined value) is less than or equal to the threshold value for determining whether the film shrinkage is good or bad (threshold value of the accumulated value of the number of glossy wrinkles). Here, the determination in step S8 is made by the pass / fail determination block 10E of the control device 10, which acquires a threshold value for determining pass / fail of the film shrinkage from the memory block 10G. If the result of the judgment in step S8 is that the integrated value of the number of glossy wrinkles is equal to or less than the threshold value for determining pass / fail (threshold value for the integrated value of the number of glossy wrinkles) (step S8 is "Yes"), the process proceeds to step S9. On the other hand, if the integrated value of the number of glossy wrinkles is greater than the threshold value for determining pass / fail (threshold value for the integrated value of the number of glossy wrinkles) (step S8 is "No"), the process proceeds to step S10.

[0040] In step S9, since the integrated value of the number of wrinkle glosses is equal to or less than the pass / fail judgment threshold, the product package 30 being inspected is judged to be a "good product." The product package 30 judged to be a "good product" remains placed on the conveying member 1, passes in front of the rejection air ejection device 4, and is conveyed downstream. Then, the process proceeds to step S12. On the other hand, in step S10, since the integrated value of the number of wrinkle glosses is greater than the pass / fail judgment threshold value, the product package 30 being inspected is judged to be a "defective product." The determinations in steps S9 and S10 are executed by the quality determination block 10E of the control device 10, similarly to step S8. In step S11, in response to the product package 30 being determined to be a "defective product," air is sprayed from the rejection air spraying device 4 toward the product package 30 on the conveying member 1. The product package 30 that has had air sprayed from the rejection air spraying device 4 (the product package 30 determined to be a "defective product") is pressed and rejected from above the conveying member 1, and moves into the rejected product receiving basket 5. The control of step S11 is executed by the control signal generating block 10F.

[0041] In step S12, after steps S1 to S11 have been used to determine whether the film shrinkage of the product package 30 being inspected is good or bad using a predetermined number of image data and action has been taken based on the determination result (passing through the production line or rejecting it from the production line), it is determined whether to further inspect the next product package to be transported (step S12 is "No") or to end without inspection (step S12 is "Yes"). As a result of the determination in step S12, if the inspection is to be ended, the control shown in FIG. 9 is ended, whereas if the inspection is not to be ended and the next product package is to be inspected, the control returns to step S1 and continues.

[0042] As described above, when the product package 30 to be inspected, which is placed on the conveying member 1 and conveyed, arrives at the position to be photographed by the camera 2, the first photograph is taken, and thereafter, photographs are taken a predetermined number of times by the camera 2. Here, the control of whether or not the product package 30 to be inspected has arrived at the position to be photographed by the camera 2 will be described with reference to FIG. In FIG. 10, in step S21, it is determined whether the image captured by camera 2 (the image before black and white inversion) is completely dark or in a different state (for example, a state in which glossy or gray areas are mixed in). In the illustrated embodiment, the relative positions between the camera 2, LED lighting 3, and product package 30, the camera focus adjustment, shutter speed (adjustment of the brightness of the camera image), contrast, and brightness are set within the predetermined ranges shown in the table of Fig. 8, and if the product package 30 is not at the shooting position of the camera 2, the image captured by the camera 2 will be completely dark. On the other hand, if the product package 30 is located at the shooting position of the camera 2, the image captured by the camera 2 will be in a state other than "completely dark" (for example, a state in which glossy or gray parts are mixed). If the result of the judgment in step S21 is that the image captured by camera 2 (the image before black and white inversion) is pitch black, the process proceeds to step S22; if the image is in a state other than "pitch black" (for example, a state in which glossy or gray areas are mixed in), the process proceeds to step S24.

[0043] In step S22, since the image captured by the camera 2 is completely dark, it is determined that the product package 30 has not yet reached the position where it can be photographed by the camera 2. In step S23 following step S22, since it is determined that the product package 30 has not yet reached the position where it is photographed by the camera 2, determination of the number of images, counting, and other related determinations are not performed. When step S23 is completed, the process returns to step S21. The determination and judgment of steps S21 to S23, and step S24 described later, are executed by the image number determination block 10A of the control device 10.

[0044] On the other hand, in step S24, since the image captured by camera 2 is not completely dark but is otherwise (for example, has a mixture of glossy or gray areas), it is determined that the product package 30 has reached the position to be photographed by camera 2. In step S25 following step S24, it is determined that the product package 30 has reached the position to be photographed by the camera 2, and the process executes a series of controls in the flowchart of Fig. 9, such as determining the number of images, counting, photographing the product package 30 by the camera 2, image processing, counting the number of wrinkle glosses, accumulating, determining whether the product package 30 is good or bad, and processing the bad ones, etc. Then, the process proceeds to step S26.

[0045] In step S26, it is determined whether to carry out inspection of the next product package for the product package 30 being inspected (step S26: No) or to end the inspection (step S26: Yes). If the result of the determination in step S26 is to end (step S26 is "Yes"), the control in Fig. 10 ends. If it is not to end and the next product package is to be inspected (step S26 is "No"), the process returns to step S21 and the control in Fig. 10 continues. Incidentally, instead of the control as shown in FIG. 10, it is also possible to determine whether or not the product package 30 has arrived at a position where it can be photographed by the camera 2 using various sensors such as a proximity sensor.

[0046] It should be noted that the illustrated embodiment is merely an example and is not intended to limit the technical scope of the present invention. [Explanation of symbols]

[0047] 1. Transporting member (conveyor) 2. Camera 3. LED lighting 3A...Illumination light 4. Exhaust air ejection device 5. Rejected product receiving basket 10. Control device (control unit) 30···Product Package 100 ···Film shrinkage defect inspection system W... Wrinkles

Claims

1. a conveying member for conveying a product package in which a container is wrapped in a film; A camera and a light source provided in a region to the side of the conveying member; A control device is provided. the light source has a function of irradiating illumination light so that wrinkles occurring in a film of a product package are photographed by the camera as a white gloss, The relative positions of the camera, light source, and product, as well as the shutter speed, were set so that the wrinkles would be photographed as a white sheen. The control device includes: A function for counting white gloss in an image captured by a camera; A film shrinkage defect inspection system having a function of comparing the counted number of white glosses with a threshold value and judging the product to be good if the number is below the threshold value and judging the product to be defective if the number is above the threshold value.

2. the control device has a function of inverting black and white of an image captured by the camera, Instead of the function of counting white gloss in an image captured by a camera, a function of counting black parts in an image in which black and white are inverted is provided, The film shrinkage defect inspection system of claim 1, further comprising a function for comparing the number of counted black portions with a threshold value, and determining that a product is a good product if the number is below the threshold value, and determining that a product is a defective product if the number is above the threshold value, instead of the function for comparing the number of counted white gloss portions with a threshold value, and determining that a product is a good product if the number is below the threshold value, and determining that a product is a defective product if the number is above the threshold value.

3. a conveying member for conveying a product package in which a container is wrapped in a film; A camera and a light source are provided in a region to the side of the conveying member, the light source has a function of irradiating illumination light so that wrinkles occurring in a film of a product package are photographed by the camera as a white gloss, In a film shrinkage defect inspection method using a film shrinkage defect inspection system, a relative positional relationship between a camera, a light source, and a product and a shutter speed are set so that wrinkles are photographed as white gloss, counting white gloss in an image captured by the camera; A film shrinkage defect inspection method comprising the steps of: comparing the number of counted white glossiness with a threshold value; determining a product as good if the number of white glossiness is equal to or less than the threshold value; and determining a product as defective if the number of white glossiness is greater than the threshold value.

4. inverting the black and white of the image captured by the camera; Instead of the step of counting white gloss in an image captured by a camera, a step of counting black parts in an image inverted from black and white is included, 4. The method for inspecting a film for shrinkage defects according to claim 3, further comprising the step of comparing the number of black portions of the image inverted from black and white with a threshold value, determining a product as a good product if the number of white gloss portions is equal to or less than the threshold value, and determining a product as a defective product if the number of white gloss portions is greater than the threshold value, instead of the step of comparing the number of black portions of the image inverted from black and white with a threshold value, determining a product as a good product if the number of black portions is equal to or less than the threshold value, and determining a product as a defective product if the number of black portions is greater than the threshold value.

Images