Foreign object inspection device and foreign object inspection method
The device captures and classifies foreign matter on moving sheet-like materials by processing image data from a capturing body illuminated with a light source, effectively addressing the challenge of continuous imaging accuracy.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- TORAY INDUSTRIES INC
- Filing Date
- 2022-06-22
- Publication Date
- 2026-06-23
AI Technical Summary
Existing inspection methods for foreign matters in sheet-like materials, such as films, struggle to accurately detect and classify minute foreign objects without causing them to slip through during continuous imaging, especially when the material is in motion.
A device and method that captures foreign matter on a moving sheet-like material using a capturing body, illuminates the captured area with a light source, and processes image data to determine the presence, type, and amount of foreign matter using feature quantities and distribution states.
Enables accurate detection and classification of minute foreign matter on moving sheet-like materials without slippage, ensuring high-speed inspection without missing defects.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to an apparatus and method for inspecting foreign matters in a sheet-like material such as a film.
Background Art
[0002] In the process of continuously manufacturing a sheet-like material such as a film, foreign matter defects may occur in the sheet-like material, which has been a problem.
[0003] Polyester resin is excellent in mechanical properties, thermal properties, electrical properties, chemical resistance, moldability, etc., and is therefore used in various applications. Among them, a polyester film formed from the polyester resin, especially a biaxially oriented polyester film stretched in the biaxial direction to orient the molecules, is widely used as various industrial materials such as members of optical devices, backsheets of solar cells, electrical insulating materials, thermal transfer applications, and process papers.
[0004] Particularly, in optical applications having transparency, when used as a base material for the hard coat layer of a liquid crystal device, defects of the film itself are hardly recognized as small, but when used as a component such as a liquid crystal device, defects are easily recognized due to diffusion of a light source or the like, resulting in product defects. Further, when used as a protective film for suppressing surface scratches of an optical film, if there are defects in the protective film, it may be unclear whether the defects are those of the protective film or those of the optical film as a product, which may affect quality inspection.
[0005] As one of such film defects, lubricating oil or iron powder from a conveying device may scatter during film formation and adhere to the film, or dust, oligomers, etc. in the air may adhere to the film. As an apparatus for inspecting such foreign matters, a method of imaging with a camera has been proposed (for example, Patent Documents 1 and 2).
Prior Art Documents
Patent Documents
[0006]
Patent Document 1
[0007] However, the inspection apparatus and inspection method disclosed in Patent Documents 1 and 2 are methods that directly image a sheet-like object with a camera to inspect for foreign matter adhering to the sheet-like object. In practice, it is difficult to inspect for foreign matter by continuously imaging the sheet-like object in the longitudinal direction with a resolution that can recognize minute foreign matter. If, as a countermeasure, imaging is performed intermittently in the longitudinal direction of the sheet-like object, parts will slip through the inspection.
[0008] The present invention solves the above problems and provides an apparatus and method for determining whether minute foreign matter is attached to a sheet-like material without coming off in the longitudinal direction, classifying the type of foreign matter attached to the sheet-like material, and / or measuring the amount of foreign matter attached to the sheet-like material. [Means for solving the problem]
[0009] [1] The present invention, which solves the above problems, is a device for inspecting foreign matter in a sheet-like material that is in motion, A capturing body that captures foreign matter adhering to the surface of a sheet-like object while the sheet-like object is moving, an imaging device that images the area of the capturing body that captures the foreign matter, and a light source that illuminates the imaging range of the imaging device with light. A determination device that processes image data captured by the above-mentioned imaging device and, based on the feature quantities obtained from the processing results, determines whether foreign matter was attached to the sheet-like object, classifies the type of foreign matter attached to the sheet-like object, and / or measures the amount of foreign matter attached to the sheet-like object. It is equipped with.
[0010] Here, "when the sheet-like object is moving" means that the capture unit, imaging device, and light source are arranged so that they can capture, image, and illuminate the aforementioned locations on the moving sheet-like object, respectively, and does not mean that the foreign object inspection device includes a sheet-like object in its configuration.
[0011] [2] The foreign matter inspection device described in [1] above preferably has a determination device that determines whether foreign matter was attached to the sheet-like material, classifies the type of foreign matter attached to the sheet-like material, and / or measures the amount of foreign matter attached to the sheet-like material, based on the feature quantities, the time change of the feature quantities, the distribution state of the feature quantities, or the time change of the distribution state of the feature quantities.
[0012] [3] The foreign matter inspection device described in [1] or [2] above preferably uses at least one selected from the group consisting of magnetism, static electricity, and air to capture foreign matter adhering to the sheet-like material without contacting the sheet-like material.
[0013] [4] The foreign matter inspection device described in [1] or [2] above is an adhesive roll in which the capturing body contacts one side of the sheet-like material to capture foreign matter adhering to the sheet-like material. The imaging device captures the area of the adhesive roll that captures the foreign object from one side of the sheet-like material. It is preferable that the light source illuminates the imaging range of the imaging device from one side of the sheet-like material.
[0014] [5] The foreign matter inspection device described in [1] above is a capture sheet in which the capture body contacts one side of the sheet-like material to capture foreign matter adhering to the sheet-like material. The imaging device captures the area in contact between the sheet-like material and the capture sheet from the other side of the sheet-like material, through the sheet-like material. It is preferable that the light source illuminates the imaging range of the imaging device from the other side of the sheet-like material.
[0015] [6] Preferably, in the foreign matter inspection apparatus of [5] above, the determination apparatus determines whether a foreign object is attached to the sheet-like material from the distribution state of the feature amount.
[0016] [7] Preferably, in the foreign matter inspection apparatus of [5] or [6] above, the capture sheet is a non-woven fabric.
[0017] [8] Preferably, in the foreign matter inspection apparatus of any one of [5] to [7] above, when the sheet-like material is running, it is arranged on the side opposite to the side where the sheet-like material is located on the capture sheet, and is irradiated by the light source and transmits through the sheet-like material and the capture sheet. It is preferable to have a scatterer that scatters light.
[0018] [9] Preferably, in the foreign matter inspection apparatus of any one of [1] to [7] above, the determination apparatus calculates the total sum of the feature amounts from the distribution state of the feature amounts, It is preferable to compare the total sum of the feature amounts or the increase rate of the total sum of the feature amounts with respect to time with a predetermined threshold value to determine whether a foreign object is attached to the sheet-like material.
[0019]
[10] Preferably, in the foreign matter inspection apparatus of any one of [1] to [9] above, the feature amount is the luminance and / or size of the foreign object.
[0020]
[11] Preferably, in the foreign matter inspection apparatus of any one of [1] to
[10] above, the feature amount is either one of the values obtained by binarizing the luminance of the image data.
[0021]
[12] The method for inspecting foreign matter on a sheet-like material according to the present invention that solves the above problems is a method for inspecting foreign matter on a running sheet-like material, captures foreign matter adhering to the surface of the running sheet-like material with a capture body, observes the area while irradiating light toward the area of the capture body that captures the foreign matter, Based on the above-observed results, determine whether foreign matter is attached to the sheet-like material, classify the types of foreign matter attached to the sheet-like material, and / or measure the amount of foreign matter attached to the sheet-like material.
[0022]
[13] The foreign matter inspection method of the above
[12] preferably determines whether foreign matter is attached to the sheet-like material, classifies the types of foreign matter attached to the sheet-like material, and / or measures the amount of foreign matter attached to the sheet-like material from the feature amount obtained by the above observation, the time change of the feature amount, the distribution state of the feature amount, or the time change of the distribution state of the feature amount.
[0023]
[14] The foreign matter inspection method of the above
[13] preferably uses the luminance and / or size of the foreign matter captured by the above capture body as the above feature amount.
[0024]
[15] The foreign matter inspection method of the above
[12] preferably determines whether foreign matter is attached to the sheet-like material by confirming whether foreign matter is attached to the capture body.
[0025]
[16] The foreign matter inspection method of any one of the above
[12] to
[15] preferably captures the foreign matter attached to the running sheet-like material without contacting the sheet-like material by using at least one selected from the group consisting of magnetism, static electricity, and air to capture the foreign matter attached to the sheet-like material.
[0026]
[17] The foreign matter inspection method of any one of the above
[12] to
[15] captures the foreign matter attached to the sheet-like material by bringing a capture sheet into contact with one surface of the running sheet-like material and capturing the foreign matter attached to the sheet-like material on the capture sheet. It is preferable to observe the region where the capture body captures foreign matter by irradiating light from the other surface side of the sheet-like material toward the sheet-like material while observing the region where the sheet-like material and the capture sheet are in contact through the sheet-like material from the other surface side of the sheet-like material.
[0027]
[18] The foreign object inspection method described in
[17] above preferably involves placing a scatterer on the side of the capture sheet opposite to the side of the sheet that is on the sheet when the sheet is moving, thereby scattering the light that is irradiated from the light source and passes through the sheet and the capture sheet.
[0028]
[19] Any of the foreign matter inspection methods described in
[12] to
[15] above is performed by capturing with the capturing body by bringing an adhesive roll into contact with one side of the moving sheet-like material and capturing the foreign matter attached to the sheet-like material with the adhesive roll. It is preferable to observe the area of the trapping body that traps foreign matter by irradiating light from one side of the sheet-like material toward the sheet-like material while observing the area of the adhesive roll that traps foreign matter. [Effects of the Invention]
[0029] According to the foreign matter inspection device and foreign matter inspection method of the present invention, despite its simple configuration, it is possible to determine whether minute foreign matter is attached to a sheet-like material without it falling out in the longitudinal direction of the sheet-like material, to classify the type of foreign matter attached to the sheet-like material, and / or to measure the amount of foreign matter attached to the sheet-like material. [Brief explanation of the drawing]
[0030] [Figure 1] This is a schematic diagram showing one embodiment of the foreign object inspection device of the present invention, observed from the width direction of a sheet-like material. [Figure 2] This is a schematic diagram showing a foreign object inspection device using a non-contact mechanism as a capture element, observed from the width direction of a sheet-like material. [Figure 3] This is a schematic diagram showing a foreign object inspection device that uses a capture sheet, which is a contact mechanism, as a capture body, as observed from the width direction of a sheet-like material. [Figure 4] This is a schematic diagram showing a foreign object inspection device that uses an adhesive roll as a contact mechanism for capturing foreign objects, observed from the width direction of a sheet-like material. [Figure 5]This diagram illustrates an example of a procedure for classifying the type of foreign matter attached to a sheet-like object based on its features. [Figure 6] This figure illustrates an example of a procedure for determining whether foreign matter was attached to a sheet-like material based on the time change of feature quantities, classifying the type of foreign matter attached to the sheet-like material, and measuring the amount of foreign matter attached to the sheet-like material. [Figure 7] This figure schematically shows an example of an image obtained by binarizing image data captured by the foreign object inspection device of the present invention based on brightness. [Figure 8] This figure schematically shows an example of a graph illustrating the time-dependent change in the sum of feature quantities calculated from image data captured by the foreign object inspection device of the present invention. [Modes for carrying out the invention]
[0031] Embodiments of the present invention will be described below with reference to the drawings. However, the present invention is not limited to these embodiments.
[0032] Figure 1 is a schematic diagram of one embodiment of the foreign object inspection device of the present invention when a sheet-like object is in motion, observed from the width direction of the sheet-like object. The foreign object inspection device 1 consists of a capture body 2, an imaging device 3, a light source 4, and a determination device 5. The sheet-like object 10 is assumed to be continuously transported. Furthermore, the foreign object inspection device 1 does not directly image and inspect foreign objects attached to the sheet-like object 10, but rather captures foreign objects attached to the surface of the sheet-like object 10 with the capture body 2, and performs inspection by imaging the foreign objects captured by the capture body 2.
[0033] The capture unit 2 captures foreign matter adhering to the surface of the moving sheet-like object 10. The capture unit 2 may be a mechanism that captures foreign matter adhering to the sheet-like object 10 without contacting it (hereinafter referred to as a non-contact mechanism), or a mechanism that captures foreign matter adhering to one side of the sheet-like object 10 by contacting it (hereinafter referred to as a contact mechanism). Examples of non-contact mechanisms include magnetic bars using magnetism, mechanisms using static electricity, and mechanisms that capture foreign matter using air. Examples of contact mechanisms include capture sheets and adhesive rolls. If too much captured foreign matter accumulates in the capture unit 2, its capture capacity will decrease and there is a possibility that the foreign matter may leak out, so it is preferable to clean or replace it periodically. Multiple capture units 2 may be installed in the TD direction depending on the location where the foreign matter is generated. For example, they may be installed in the center of the sheet-like object 10, at the ends, or both in the center and at the ends. The size and number of the imaging device 3 and light source 4, which will be described later, will be changed according to the number of capture units 2 installed.
[0034] The imaging device 3 images the capture body 2. More specifically, it images the area of the capture body 2 that captures foreign matter (hereinafter referred to as the foreign matter capture area). The imaging device 3 may be an area sensor camera or a line sensor camera. An area sensor camera is preferred when a non-contact mechanism and a capture sheet are used as the capture body 2, and a line sensor camera is preferred when an adhesive roll is used.
[0035] The light source 4 illuminates the imaging range of the imaging device 3 with light. For example, means of illuminating with wavelengths in the visible light range include LEDs, fluorescent lamps, halogens, or metal halide illumination irradiated from a transmission rod or optical fiber. The wavelength band, irradiation angle, and shape of the light source 4 can be arbitrarily determined depending on the type of capture body 2 or foreign object. It is preferable that the light source 4 irradiates the imaging range with uniform light.
[0036] The determination device 5 processes the image data captured by the imaging device 3 and, based on the feature quantities obtained from the processing results, determines whether foreign matter was attached to the sheet-like object 10, classifies the type of foreign matter attached to the sheet-like object 10, and / or measures the amount of foreign matter attached to the sheet-like object 10. The determination device 5 may use not only the feature quantities obtained from the processing results, but also the time change of the feature quantities, the distribution state of the feature quantities, and the time change of the distribution state of the feature quantities. The determination device 5 may use the brightness and / or size of the foreign matter as feature quantities. The determination device 5 may use either one of the values obtained by binarizing the brightness of the image data as feature quantities.
[0037] Figure 2 is a schematic diagram of a foreign object inspection device using a non-contact mechanism as a capture body, observed from the width direction of a sheet-like material.
[0038] If the non-contact mechanism 2a is a magnetic mechanism, the non-contact mechanism 2a is positioned facing the sheet-like object 10 to attract and capture magnetic foreign objects such as metal attached to the sheet-like object 10. As a magnetic mechanism, for example, a magnetic bar is used. The surface of the magnetic bar facing the sheet-like object 10 becomes the foreign object capture area 20.
[0039] If the non-contact mechanism 2a is an electrostatic mechanism, the non-contact mechanism 2a is positioned facing the sheet-like object 10 to attract and capture foreign matter adhering to the sheet-like object 10. As an electrostatic mechanism, for example, a charged metal plate or sheet-like object is used. This causes the Coulomb force to peel off and attract foreign matter adhering to the sheet-like object 10. The surface of the charged metal plate or sheet-like object facing the sheet-like object 10 becomes the foreign matter capture area 20.
[0040] If the non-contact mechanism 2a is an air-based mechanism, the non-contact mechanism 2a is positioned facing the sheet-like object 10 to suck up and capture foreign matter adhering to the sheet-like object 10. As an air-based mechanism, for example, a suction device can be used. The suction device may suck up foreign matter and capture it on a filter or the like, or it may blow air onto the sheet-like object 10 to float the foreign matter, suck up the floated foreign matter, and have it adsorbed on a filter or the like. This filter becomes the foreign matter capture area 20. Alternatively, the non-contact mechanism 2a may use a mechanism that combines these elements of magnetism, electrostatics, and air.
[0041] The imaging device 3 is preferably positioned on the side opposite to the side on which the non-contact mechanism 2a is located, and it images the foreign object capture area 20 of the non-contact mechanism 2a via the sheet-like material 10. The reason for this is that in order to improve the capture capability of the non-contact mechanism 2a, it is preferable to bring the non-contact mechanism 2a closer to the sheet-like material 10, and in that case, it is difficult to position the imaging device 3, which images the foreign object capture area 20, on the same side as the side on which the non-contact mechanism 2a is located.
[0042] The light source 4 is positioned on the side opposite to the side where the non-contact mechanism 2a is located, and illuminates the imaging area of the imaging device 3, i.e., the foreign object capture area 20, with light. The reason for this is that in order to improve the capture capability of the non-contact mechanism 2a, it is preferable to position the non-contact mechanism 2a close to the sheet-like object 10, and in that case, it is difficult to position the light source 4, which illuminates the foreign object capture area 20 with light, on the same side as the side where the non-contact mechanism 2a is located.
[0043] Figure 3 is a schematic diagram of a foreign object inspection device that uses a capture sheet, which is a contact mechanism, as a capture body, as observed from the width direction of a sheet-like material.
[0044] The capture sheet 2b is positioned so as to be in contact with one side of the sheet-like object 10. The material of the capture sheet 2b is preferably a single color so as to be able to easily capture foreign objects and to easily image the captured foreign objects. For example, nonwoven fabric is preferred. The imaging device 3 is positioned on the side of the sheet-like object 10 opposite to the side in contact with the capture sheet 2b, and images the area in contact between the sheet-like object 10 and the capture sheet 2b (foreign object capture area 20) via the sheet-like object 10.
[0045] The light source 4 is positioned on the side of the sheet-like object 10 opposite to the side in contact with the capture sheet 2b, and illuminates the imaging area of the imaging device 3 with light. Furthermore, the shape of the light-emitting part of the light source 4 is preferably annular so as to illuminate the capture sheet 2b uniformly in both the transport direction and the width direction of the sheet-like object 10.
[0046] The scatterer 6 is positioned on the side of the capture sheet 2b opposite to the side with the sheet-like material 10. In Figure 3, the scatterer 6 is positioned inside the cylindrical capture sheet 2b, and if we focus on the part of the capture sheet 2b that is in contact with the sheet-like material 10, the scatterer 6 is positioned on the side of the capture sheet 2b opposite to the side with the sheet-like material 10. The material of the scatterer 6 is preferably one that has high light-shielding properties and scatters light uniformly. The scatterer 6 causes the light irradiated from the light source 4 and transmitted through the capture sheet 2b to be uniformly scattered on the back side of the capture sheet 2b, making it easier for the imaging device 3 to image the foreign object captured by the capture sheet 2b. Inspection can be performed without the scatterer 6, but the accuracy of the inspection is increased by placing the scatterer 6. The scatterer 6 may or may not be in contact with the capture sheet 2b.
[0047] Figure 4 is a schematic diagram of a foreign object inspection device that uses an adhesive roll as a contact mechanism for capturing foreign objects, observed from the width direction of a sheet-like material.
[0048] The adhesive roll 2c is positioned to contact one side of the sheet-like material 10. The adhesive roll 2c is preferably made of a material that is adhesive, allowing for easy capture of foreign objects and easy imaging of the captured objects. For example, an adhesive rubber roll is preferred. The entire circumferential surface of the adhesive roll 2c becomes the foreign object capture area 20.
[0049] The imaging device 3 is positioned on the same side of the sheet-like object 10 as the surface in contact with the adhesive roll 2c, and images a portion of the foreign object capture area 20 of the adhesive roll 2c that is not in contact with the sheet-like object 10.
[0050] The light source 4 is positioned on the same side of the sheet-like material 10 as the surface in contact with the adhesive roll 2c, and irradiates the imaging area of the imaging device 3 with light. Furthermore, the shape of the light-emitting part of the light source 4 is preferably a bar or a flat surface in order to uniformly illuminate the adhesive roll 2c in the width direction of the sheet-like material 10.
[0051] The sheet-like material 10 to be inspected is not particularly limited as long as it is continuously transported and transmits light, such as a film. For example, it is preferably used as a colorless, transparent film such as a polyester film like polyethylene terephthalate film. However, as in the embodiment of Figure 4, if the foreign object capture area 20 is not imaged through the film, it is not limited to a transparent material.
[0052] Figure 5 shows an example of a procedure for classifying the type of foreign matter attached to a sheet-like object based on its features. Figure 5(A) is the image data, showing foreign matter (iron powder 30, lubricating oil, dust in the air, oligomers 31, etc.) captured by the capture body 2. Areas with foreign matter appear darker than normal areas, but the iron powder 30 appears very dark (low brightness value in the image data). Lubricating oil, dust in the air, and oligomers 31 appear darker than normal areas, but brighter than the iron powder 30. Figure 5(B) is a schematic diagram showing an example of an image obtained by binarizing the image data by brightness. Areas with foreign matter appear black when binarized by brightness. The threshold for binarizing the image data is set arbitrarily by looking at the captured image, as the balance of brightness changes depending on the light intensity from the sheet-like object 10, the capture body 2, the light source 4, and the performance and arrangement of the imaging device 3. Figure 5(C) is a graph (horizontal axis: brightness, vertical axis: size) for each defect using features obtained from the processed image data. The process involves obtaining feature quantities from the image data in Figure 5(A) for each defect detected by the binarization process in Figure 5(B). The feature quantities obtained are the size of each defect and the minimum brightness of each defect. Since iron powder 30 has a lower brightness and smaller size than other foreign matter (lubricating oil, dust in the air, oligosaccharides, etc.), the type of foreign matter attached to the sheet-like object 10 can be classified by using brightness and size as feature quantities. It is also possible to distinguish between normal and abnormal based on the number of each foreign matter and the total area. In Figure 5, the minimum brightness value for each defect is obtained as brightness, but the average or median brightness value for each defect could also be obtained.
[0053] Figure 6 shows an example of a procedure for determining whether foreign matter was attached to a sheet-like material based on the time change of feature quantities, and for measuring the amount of foreign matter attached to the sheet-like material. Figure 6(A) is a time change graph of the total area of the foreign matter (the sum of the sizes of each defect detected by binarization), and Figure 6(B) is a time change graph of the area of iron powder 30 only (the sum of the sizes of each defect detected by binarization). Figures 6(A) and 6(B) are graphs at the same time. Before time T0, lubricating oil, dust from the air, and oligomers 31 are generated, and after time T0, in addition to these, iron powder 30 (in small amounts compared to lubricating oil, dust from the air, and oligomers 31) is generated. In both Figure 6(A) and Figure 6(B), the area gradually increases over time, but in the case of Figure 6(A), the lubricating oil, dust from the air, and oligomers 31 are faintly visible, so they may not all be detected by binarization, and the area gradually increases while fluctuating over time. Therefore, even if metal is generated after time T0, it will be buried above and below the area. In the case of Figure 6(B), by classifying the type of foreign matter attached to the sheet-like material following the procedure shown in Figure 5, the graph shows only iron powder 30. As a result, it is not buried above and below the area, and it can be determined from the slope of the area (the amount of increase in area with respect to time) that iron powder 30 (foreign matter) is attached. In other words, it is possible to determine whether foreign matter was attached to the sheet-like material from the time change of the feature quantity. In addition, in both Figure 6(A) and Figure 6(B), it may be determined that foreign matter was attached when the absolute value or slope of the area exceeds a threshold, or the amount of each foreign matter attached may be measured. Normal / abnormal determination may also be made from the slope and absolute amount of the area of iron powder 30, lubricating oil, dust in the air, or oligomer 31.
[0054] In the foreign object inspection device 1 of the present invention, the determination device 5 may calculate the sum of feature quantities and compare the rate of increase of the sum of feature quantities with respect to time to a predetermined threshold to determine whether or not foreign matter is attached to the sheet-like object 10.
[0055] If the manufacturing location of the sheet-like material 10 is extremely clean and no dust or other particles fall onto the sheet-like material 10, then everything captured by the capture body can be considered a defective foreign object. Therefore, instead of comparing the rate of increase of the sum of features over time to a predetermined threshold, it is possible to determine whether or not foreign objects were attached to the sheet-like material 10 by comparing the sum of features to a predetermined threshold.
[0056] In the foreign object inspection apparatus 1 of the present invention, the imaging device 3 captures an image of the capture object 2, and the determination device 5 determines whether or not a foreign object is attached to the sheet-like object 10. However, a person may also visually observe the capture object 2 to determine whether or not a foreign object is attached. With this inspection method, inspection can be performed as long as the capture object 2 and light source 4 are installed.
[0057] As described above, by capturing foreign objects with a capture device, imaging the capture area, and processing the captured image data, it is possible to prevent foreign objects from escaping in the longitudinal direction of the sheet-like material even during high-speed transport processes, to determine whether minute foreign objects were attached to the sheet-like material, to classify the type of foreign object attached to the sheet-like material, and / or to measure the amount of foreign object attached to the sheet-like material. [Examples]
[0058] The following describes an example in which a PET film was inspected as the sheet-like material 10, but the present invention is not limited to this example.
[0059] (Testing method) The capture body 2 was a white nonwoven fabric (capture sheet 2b), the scattering body 6 was suede-like artificial leather, the light source 4 was a white ring illumination (OPR-S85-58W) from Optex FA, the imaging device 3 was a monochrome area sensor camera (acA1300-60gm) from Basler, and the judgment device 5 was a general-purpose computer. As shown in Figure 3, the inspection method involved illuminating the area where the nonwoven fabric and film were in contact from below and capturing an image with the camera. The captured image was binarized by a computer program based on brightness, as shown in Figure 7, with foreign objects appearing black. Image capture and image processing were performed every minute, and as shown in Figure 8, the rate of increase in the area of low brightness over time was calculated.
[0060] In addition, while imaging was being performed, the nonwoven fabric was periodically removed and visually inspected for the presence of foreign matter. When no foreign matter was found during the visual inspection, the image processing results showed a gradual increase as shown in Figure 8(A). However, when foreign matter was found during the visual inspection, the image processing results showed a sharp increase at a certain point as shown in Figure 8(B), suggesting that the foreign matter was attached to the film at that time. [Explanation of symbols]
[0061] 1: Foreign object inspection device 2: Captured body 2a: Non-contact mechanism 2b: Supplementary sheet 2c: Adhesive roll 3: Imaging device 4:Light source 5: Judgment device 6: Scatterer 10: Sheet-like material 20: Foreign object capture area 30: Iron powder 31: Lubricants, dust in the air, oligosaccharides, etc.
Claims
1. A device for inspecting foreign objects in a moving sheet-like object, When a sheet-like object is moving, A capture sheet that contacts one side of the aforementioned sheet-like material and captures foreign matter adhering to the sheet-like material, An imaging device that images the area in contact between the sheet-like material and the capture sheet from the other side of the sheet-like material, through the sheet-like material; A light source that illuminates the imaging range of the imaging device from the other side of the sheet-like material, A scattering body is positioned on the opposite side of the capturing sheet from the side with the sheet-like material, and scatters the light that is irradiated from the light source and passes through the sheet-like material and the capturing sheet. A determination device that processes image data captured by the imaging device and, based on the feature quantities obtained from the processing results, determines whether foreign matter was attached to the sheet-like object, classifies the type of foreign matter attached to the sheet-like object, and / or measures the amount of foreign matter attached to the sheet-like object. A foreign object inspection device equipped with the following features.
2. The foreign matter inspection apparatus according to claim 1, wherein the determination device determines whether foreign matter was attached to the sheet-like material, classifies the type of foreign matter attached to the sheet-like material, and / or measures the amount of foreign matter attached to the sheet-like material, based on the feature quantity, the time change of the feature quantity, the distribution state of the feature quantity, or the time change of the distribution state of the feature quantity.
3. The foreign matter inspection apparatus according to claim 1, wherein the determination device determines whether or not foreign matter was attached to the sheet-like object based on the distribution state of the feature quantities.
4. The foreign object inspection apparatus according to claim 1 or 3, wherein the capture sheet is made of nonwoven fabric.
5. The determination device, The sum of the features is calculated from the distribution state of the aforementioned features. The sum of the aforementioned features, or the rate of increase of the sum of the aforementioned features over time, is compared with a predetermined threshold to determine whether foreign matter was attached to the sheet-like material. A foreign object inspection device according to claim 1.
6. A foreign object inspection apparatus according to any one of claims 1 to 3, wherein the feature quantity is the brightness and / or size of the foreign object.
7. The foreign object inspection apparatus according to any one of claims 1 to 3, wherein the feature quantity is one of the values obtained by binarizing the brightness of the image data.
8. A method for inspecting foreign objects in a moving sheet-like object, The capture sheet is brought into contact with one side of a moving sheet-like object, and any foreign matter adhering to the sheet-like object is captured by the capture sheet. Light is shone from the other side of the sheet-like material toward the sheet-like material, A scattering body is placed on the side of the capture sheet opposite to the side with the sheet-like material, and the irradiated light is transmitted through the sheet-like material and the capture sheet and scattered by the scattering body. Observe the area in contact between the sheet-like material and the capture sheet from the other side of the sheet-like material, Based on the results of the observations described above, a determination is made as to whether foreign matter was attached to the sheet-like material, the type of foreign matter attached to the sheet-like material is classified, and / or the amount of foreign matter attached to the sheet-like material is measured. Foreign object inspection methods.
9. A method for inspecting foreign matter according to claim 8, comprising determining whether foreign matter was attached to the sheet-like material, classifying the type of foreign matter attached to the sheet-like material, and / or measuring the amount of foreign matter attached to the sheet-like material, based on the features obtained by the aforementioned observation, the change in the features over time, the distribution state of the features, or the change in the distribution state of the features over time.
10. The foreign object inspection method according to claim 9, wherein the brightness and / or size of the foreign object captured by the capture body are used as the feature quantities.
11. The foreign matter inspection method according to claim 8, wherein it is determined whether foreign matter was attached to the sheet-like material by checking whether foreign matter was attached to the capture body.