Thin film inspection device, thin film inspection method and procedure

Abstract

The objective of this invention is to easily detect defects in thin films without the need for human monitoring or operation. The means to solve the problem is a thin film inspection device that optically inspects defects generated in thin films in an overlapping state. It illuminates the thin film with light from a light source (step S1) and then detects at least the diffused light reflected from the thin film using a camera (optical sensor) (step S2). The thin film inspection device extracts the inspection area of ​​the inspection sequence from the first image data obtained from the output signal of the camera (step S5), and then detects defects by performing data processing on the second image data corresponding to the inspection area (step S6).

Description

Technical Field

[0001] The present invention relates to a thin film inspection device, a thin film inspection method and a program. Prior Art

[0002] When a long resin film is rolled into a roll, various defects may occur depending on the film state (film thickness deviation, residual stress, temperature, humidity) and the conditions of winding (tension, speed, accompanying air). Examples of film defects include gauge bands, longitudinal wrinkles, and oblique wrinkles.

[0003] Film rolls with defects need to be inspected as defective products. Instead of monitoring by human labor, a film inspection device has been proposed that uses a camera or the like to take an image of the film being rolled up to optically inspect defects occurring in the film (see Patent Document 1). [Prior Technical Literature] [Patent Document]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2023-017169 Summary of the invention

[0005] [Problems that the invention aims to solve] However, in order to observe the long film roll from the start to the end of winding, it is necessary to take a picture of the film roll at each time point. At this time, as the diameter of the film roll changes, the distance between the film roll surface and the fixed camera changes. As a result, the size of the film roll in the image obtained by the camera changes.

[0006] Therefore, at each inspection (video) sequence, it is necessary to extract the inspection area from the film rolls of different sizes in the image. In the above-mentioned prior art, there is no description of the method of extracting the inspection area from the image obtained by video. Generally, as a method of extracting the desired range from the image, the ROI function of the camera and the trimming processing of the image can be cited. However, in the general method, although a certain range can be extracted, it is not easy to extract the correct inspection area. Or, at each inspection sequence, the user must manually specify the extraction range.

[0007] The present invention is developed in view of the above-mentioned problems of the prior art, and its subject is to easily detect defects generated in the film without the need for human monitoring or operation. [Technical means to solve the problem]

[0008] In order to solve the above-mentioned problems, the invention described in claim 1 is: A film inspection device optically inspects defects generated in overlapping films, and is characterized by comprising: a light source that irradiates light to the film; an optical sensor that detects at least diffuse light in the light reflected by the film; an inspection area extraction unit that extracts an inspection area for each inspection sequence from a first image data obtained from an output signal of the optical sensor; and a defect detection unit that processes the second image data corresponding to the inspection area to detect the defects.

[0009] The invention described in claim 2 is a thin film inspection device as described in claim 1, wherein the device comprises a plurality of the aforementioned optical sensors, and the aforementioned inspection area extraction unit further removes overlapping ranges between the plurality of aforementioned first image data obtained from the plurality of aforementioned optical sensors respectively.

[0010] The invention described in claim 3 is a thin film inspection device as described in claim 1 or 2, wherein the inspection area extraction unit performs processing of the inspection area extraction unit by optical calculation using the size information of the thin film before the inspection sequence and the setting information of the optical sensor.

[0011] The invention described in claim 4 is a film inspection device as described in claim 1 or 2, wherein the film is wound into a roll shape, and the film inspection device inspects the defects generated in the film during the winding process.

[0012] The invention described in claim 5 is a thin film inspection device as described in claim 1 or 2, wherein the optical sensor is an area sensor.

[0013] The invention described in claim 6 is a thin film inspection device as described in claim 1 or 2, wherein a mapping prevention plate is provided so that the regular reflected light in the inspection area of ​​the aforementioned thin film does not enter the aforementioned optical sensor, and the aforementioned mapping prevention plate is composed of a diffusion plate.

[0014] The invention described in claim 7 is a thin film inspection device as described in claim 1 or 2, which is provided with a display control unit, which displays information about the inspection area extracted by the aforementioned inspection area extraction unit and / or the defects detected by the aforementioned defect detection unit on the display unit.

[0015] The invention described in claim 8 is a thin film inspection method that optically inspects defects generated in thin films in an overlapping state, and is characterized by comprising: a process of irradiating light to the aforementioned thin film by a light source; a process of detecting at least diffuse light in the light reflected by the aforementioned thin film by an optical sensor; a process of extracting an inspection area for each inspection sequence from the first image data obtained from the output signal of the aforementioned optical sensor by an inspection area extraction unit; and a process of detecting the aforementioned defects by performing data processing on the second image data corresponding to the aforementioned inspection area by a defect detection unit.

[0016] In the invention of claim 9, a program is provided in which a computer of a thin film inspection device functions as an inspection area extraction unit and a defect detection unit, and the thin film inspection device comprises: a light source, which irradiates light to the thin films in an overlapping state; an optical sensor, which detects at least diffuse light in the light reflected by the aforementioned thin film, and optically inspects the defects generated in the aforementioned thin film, the inspection area extraction unit extracts the inspection area of ​​each inspection sequence from the first image data obtained from the output signal of the aforementioned optical sensor, and the defect detection unit performs data processing on the second image data corresponding to the aforementioned inspection area to detect the aforementioned defects. [Effects of the invention]

[0017] According to the present invention, defects generated in the film can be easily detected without the need for human monitoring or operation. Simple diagram description

[0018] [ Fig. 1 ] is a diagram showing the functional structure of a thin film inspection device according to a first embodiment of the present invention. [Fig. 2] is a diagram for explaining the configuration of a light source and a camera. [Fig. 3] is a stereoscopic diagram showing the positional relationship between the light source and the camera with respect to the roller-shaped film. [Fig. 4] is a diagram used to illustrate the configuration of the mapping prevention plate. [Figure 5] is a flow chart showing the thin film defect detection process performed by the thin film inspection device. [Fig. 6] is a flowchart showing the first inspection area extraction process. [Fig. 7] is an example of a camera image. [Fig. 8] is a diagram for explaining the change in size of the inspection area accompanying the change in the roll diameter of the film roll. [Fig. 9] is a diagram used to illustrate a method for calculating the boundary position when extracting an inspection area from a camera image. FIG. 10A is a graph showing the relationship between the roll diameter of a film roll and the cut-out position. [Fig. 10B] is a graph showing the relationship between the roll diameter of the film roll and the cut-out lower position. [Fig. 11] is a diagram for explaining the imaging range in the width direction of the film, etc. [Figure 12] is a flow chart showing data processing. [Figure 13] is an example of the inspection result screen. [Fig. 14] is a diagram for explaining the overlap of the imaging ranges of the three cameras included in the thin film inspection apparatus of the second embodiment. [Fig. 15] is a flowchart showing the second inspection area extraction process. [Figure 16] is a diagram used to illustrate the method of calculating the overlap amount of the camera range. [Fig. 17A] is a diagram for explaining the overlapping range of the first image data obtained by each of the three cameras. [Fig. 17B] is a diagram showing the first image data after removing the repeated range. Implementation

[0019] Hereinafter, embodiments of the thin film inspection device, thin film inspection method, and program of the present invention will be described with reference to the drawings. However, the scope of the present invention is not limited to the drawings.

[0020] [First embodiment] FIG1 shows the functional structure of a thin film inspection device 10 according to a first embodiment. The thin film inspection device 10 includes a light source 11, a camera 12 as an optical sensor, and an information processing device 20. The thin film inspection device 10 optically inspects defects generated in a thin film F wound in a roll shape and in an overlapping state. The thin film inspection device 10 inspects defects generated in the winding of a long film F.

[0021] The material of the film F is not particularly limited, but generally includes polycarbonate resin, polysulfide resin, acrylic resin, polyolefin resin, cyclic olefin resin, polyether resin, polyester resin, polyamide resin, polysulfide resin, unsaturated polyester resin, epoxy resin, melamine resin, phenol resin, diallyl phthalate resin, polyimide resin, urethane resin, polyvinyl acetate resin, polyvinyl alcohol resin, styrene resin, cellulose acetate resin, vinyl chloride resin, etc. In addition, for example, the film F having a thickness of 1 to 1000 μm and a width of 0.1 to 5 m is used.

[0022] Examples of defects of the film F include gauge bands, longitudinal wrinkles, and oblique wrinkles. The gauge band is a defect that appears darker than the surrounding area. It is a dark stripe defect in the circumferential direction of the roll. The gauge band is caused by the tension between the films F. The gauge band is also called a black band or a knot. Longitudinal wrinkles are stripe-like deformations in the circumferential direction of the roll. Longitudinal wrinkles are also called lantern buckles. Oblique wrinkles are deformations that are inclined to the circumferential and width directions of the roll, with pyramid-shaped and chain-shaped bumps. Oblique wrinkles are also called diamond bends.

[0023] The light source 11 irradiates light to the region including the inspection region of the film F. The light source 11 irradiates light uniformly in the width direction of the roll-shaped film F. Here, the width direction of the film F refers to the direction perpendicular to the longitudinal direction of the film F and parallel to the film surface. Also, uniform in the width direction means that the illuminance of the film F is substantially the same in the width direction of the film F. The illuminance being substantially the same means, for example, that the difference between the maximum and minimum values ​​of the illuminance is less than a predetermined value.

[0024] The inspection area refers to the area that is the object of defect detection at each inspection sequence. The inspection area is the part that is illuminated by the light source 11 and then observed by the diffuse light in the light reflected by the film F, without the surrounding mapping range.

[0025] The camera 12 is an optical sensor that optically reads an area including the inspection area of ​​the film F. The camera 12 includes an imaging element, a lens, etc. As the imaging element, CCD (Charge Coupled Device), CMOS (Complementary Metal Oxide Semiconductor), etc. can be used. The camera 12 is an area sensor that generates two-dimensional image data from the output signals of each imaging element. The camera 12 detects at least diffuse light in the light reflected by the film F by the light source 11.

[0026] In the first embodiment, the camera 12 has an imaging range that covers the entire width direction of the film F. That is, the camera 12 can simultaneously read the entire width direction of the film F in one imaging. The camera 12 may be a camera that detects light in the visible light region or a camera that detects light in the infrared region.

[0027] The information processing device 20 includes a control unit 21, I / F (Interface) 22, 23, a communication unit 24, a display unit 25, an operation unit 26, a storage unit 27, a timing unit 28, a film size measuring unit 29, etc. The various units constituting the information processing device 20 are connected via a bus. The information processing device 20 is constituted by a PC (Personal Computer) or the like.

[0028] The control unit 21 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), etc. The control unit 21 coordinates and controls the processing actions of each unit of the information processing device 20 (thin film inspection device 10). Specifically, the CPU reads various processing programs stored in the storage unit 27 and expands them in the RAM, and performs various processing by cooperating with the programs.

[0029] The I / F 22 is an interface for connecting to the camera 12. The I / F 22 transmits a control signal to the camera 12, and receives image data (first image data) obtained by photographing the film F from the camera 12. The I / F 23 is an interface for connecting to the light source 11. The I / F 23 transmits a control signal for controlling the irradiation of light by the light source 11 to the light source 11.

[0030] The communication unit 24 is constituted by a network interface, etc. The communication unit 24 transmits and receives data with an external device connected via a communication network such as a LAN (Local Area Network).

[0031] The display unit 25 includes a display such as an LCD (Liquid Crystal Display). The display unit 25 displays various screens according to the instructions of the identification signal input from the control unit 21.

[0032] The operation unit 26 includes a keyboard with cursor keys, text and number input keys, and various function keys, and a pointing device such as a mouse. The operation unit 26 outputs an operation signal input by operating a key on the keyboard or operating the mouse to the control unit 21.

[0033] The storage unit 27 is composed of a HDD (Hard Disk Drive), an SSD (Solid State Drive), etc. The storage unit 27 stores various processing programs, data necessary for executing the programs, and the like. The storage unit 27 stores setting information (camera setting information) of the camera 12. The camera setting information includes the focal length of the camera lens, the sensor size, the number of sensor pixels, the distance between the camera lens and the center of the film roll, and the like. The sensor size is the size of the imaging element of the camera 12. Here, as the sensor size, the length of the imaging element in the width direction of the film F is used. The number of sensor pixels is the number of pixels of the imaging element of the camera 12. Here, as the number of sensor pixels, the number of pixels of the imaging element in the width direction of the film F is used. The film roll is a roller-shaped portion on which the film F is wound.

[0034] The timing unit 28 has a timing circuit (RTC: Real Time Clock), through which the current date and time are counted and output to the control unit 21.

[0035] The film size measuring unit 29 measures the size of the film F while the film F is being rolled up. That is, the film size measuring unit 29 obtains the size information (film size information) of the film F during the inspection sequence. The film size information includes the film width, the roll diameter, and the like. The film width is the length in the width direction of the film F. The film size measuring unit 29 measures the film width using a laser distance sensor, a photoelectric sensor, or the like. The roll diameter is the diameter of the roll of the film F. The film size measuring unit 29 uses a rotary encoder or the like to measure the roll length of the film F. The roll length is the length of the wound film F in the longitudinal direction. The film size measuring unit 29 uses laser, ultrasonic wave or the like to measure the film thickness of the film F. The film size measuring unit 29 calculates the roll diameter from the roll length and the film thickness. Furthermore, the control unit 21 can also obtain the roll length and the film thickness from the film size measuring unit 29 to calculate the roll diameter.

[0036] Furthermore, the film size measuring unit 29 can also use the data measured by an external measuring device during the winding process of the film F. In addition, regarding the film width, since the period during which the film F of the same width is wound up does not change, a value preset for the film F being wound up in advance may be used.

[0037] The control unit 21 extracts the inspection area of ​​the inspection sequence from the first image data (the entire imaging area) obtained from the output signal of the camera 12 (optical sensor). That is, the control unit 21 functions as an inspection area extraction unit.

[0038] In order to inspect all areas without omission in the entire length of the film F, the inspection sequence (full range inspection mode) can be set. Alternatively, in order to inspect a part of the area in the length direction of the film F, the inspection sequence (sampling inspection mode) can be set. In the full range inspection mode, all areas on the film F are included in the inspection area at any inspection sequence. The user can also specify which mode is the full range inspection mode or the sampling inspection mode.

[0039] The control unit 21 extracts the inspection area through optical calculation using the size information of the film at the inspection sequence and the camera setting information.

[0040] The control unit 21 detects defects of the film F by performing data processing on the second image data corresponding to the inspection area extracted from the first image data. That is, the control unit 21 functions as a defect detection unit. For example, the control unit 21 can detect the type of defect of the film F, the position of the defect, the intensity of the defect, etc.

[0041] Data processing includes image processing, defect determination processing, and quantitative evaluation processing. Here, the image processing is processing of the image data obtained from the output signal of the camera 12. Specifically, the second image data corresponding to the inspection area extracted from the first image data becomes the processing target. Defect determination processing is the process of determining defects based on the image processed data. Quantitative evaluation processing is to carry out quantitative evaluation of defects based on the data after image processing.

[0042] The control unit 21 displays the inspection area extracted from the first image data and / or information on the detected defects on the display unit 25. That is, the control unit 21 functions as a display control unit.

[0043] Next, the configuration of the light source 11 and the camera 12 will be described with reference to FIG. 2 . When observing the regular reflected light reflected by the inspection object (film F) irradiated by the light source 11, the brightness component of the light source 11 is observed. Whether in visual observation by a person or in machine vision such as a camera 12, it is difficult to detect defects in the film F with regular reflected light. If the camera 12 is arranged at the position P1 for receiving the regular reflected light (brightness component) from the light source 11, the camera 12 basically takes an image of the inspection object in the state of being mapped by the light source 11 (the inspection object overlapping with the posture of the light source 11), which is not conducive to defect detection.

[0044] As the position of the camera 12, the position P1 receiving the regular reflection light of the light irradiated from the light source 11 should be avoided. In addition, the position P2 near the position P1 is not suitable for defect detection. Here, the vicinity of the position P1 refers to the range that may be affected by the regular reflection light of the light irradiated from the light source 11. The camera 12 may be arranged at a position other than the position P1 and its vicinity (position P2, etc.) (position P3 to P6, etc.), that is, at a position for receiving diffuse light among the light reflected by the inspection object.

[0045] Furthermore, if the surface of the inspection object is photographed from a low angle (positions P5, P6, etc.), aberration problems are likely to occur. Therefore, it is desirable to set the camera 12 at a position where the angle formed by the imaging direction of the camera 12 and the inspection object surface is greater than a predetermined value.

[0046] Fig. 3 is a perspective view showing the positional relationship between the light source 11 and the camera 12 with respect to the roll-shaped film F. The light source 11 and the camera 12 are arranged in the vicinity, and the roll surface of the film F being wound (the film F in the overlapped state) is made an inspection object.

[0047] In addition, if the background (regular reflection) is reflected on the film surface in the observation range (corresponding to the inspection area) of the camera 12, it will cause the accuracy of defect determination to decrease. Therefore, in order to prevent the regular reflection light among the light reflected in the inspection area of ​​the film F from entering the camera 12, it is desirable to provide a reflection prevention plate in the film inspection device 10.

[0048] From the beginning of winding of the film F to the end of winding, the winding diameter of the roll gradually increases. As shown in Fig. 4, the roll diameter of the roll 41 immediately after winding is started is the smallest during the period from winding to the roll 42 at the end of winding. Therefore, the roll 41 immediately after winding is the largest in the area that becomes the object of mapping by regular reflection (the area where the light regularly reflected on the film surface enters the camera 12). From the camera 12, straight lines 43 and 44 are drawn to the two ends 41A and 41B in the circumferential direction of the observation range of the roll 41 just after winding, and these two straight lines 43 and 44 are drawn in the direction of regular reflection of the film surface (referred to as reflection straight lines) 45 and 46. The range 47 between these two reflection straight lines 45 and 46 is mapped to the observation range of the camera 12. Therefore, it is preferable to have a mapping prevention plate 48 throughout this range 47.

[0049] When image analysis is used, it is necessary to ensure sufficient light during imaging. If the light is insufficient, the difference between the normal part and the abnormal part on the film F becomes small, and the accuracy of defect determination may be reduced. To solve this problem, the anti-reflection plate 48 is formed of a diffuser plate with uniform surface roughness and color. The surface of the anti-reflection plate 48 facing the film F is preferably a color with high reflectivity such as white, blue, gray, etc.

[0050] Next, the operation of the thin film inspection device 10 will be described. FIG5 is a flow chart showing a film defect detection process performed by the film inspection device 10. The film defect detection process is a process for detecting defects from the film F in the overlapping state during winding. This process can be realized by software processing in which the control unit 21 cooperates with the program stored in the storage unit 27. The film F is wound up in such a way that the conveying speed (line speed) in the length direction of the film F becomes constant.

[0051] First, the control unit 21 controls the light source 11 via the I / F 23 to irradiate light onto the film F (step S1 ). The control unit 21 controls the camera 12 via the I / F 22 to capture an image of a region including the inspection region of the film F (step S2).

[0052] The control unit 21 obtains the two-dimensional first image data (the entire imaging area) generated by the camera 12 via the I / F 22 (step S3). The control unit 21 stores the acquired first image data in the storage unit 27 (step S4). Specifically, the control unit 21 acquires the current date and time from the timing unit 28 as the inspection date and time, and stores the first image data in the storage unit 27 corresponding to the inspection date and time. The image data (first image data) acquired in one imaging is a part of the area in the circumferential direction of the wound film F. Therefore, the inspection date and time corresponding to the first image data is equivalent to the position in the longitudinal direction of the film F.

[0053] Next, the control unit 21 performs a first inspection area extraction process on the first image data acquired from the camera 12 (step S5).

[0054] Here, the first inspection area extraction process will be described with reference to FIG. 6 . The control unit 21 obtains the film size information and camera setting information of the inspection sequence (step S11). Specifically, the control unit 21 obtains the film size information from the film size measuring unit 29. The film size information includes the film width, roll diameter, etc. In addition, the control unit 21 obtains the camera setting information stored in the storage unit 27. The camera setting information includes the focal length of the camera lens, the sensor size, the number of sensor pixels, the distance between the camera lens and the roll center of the film roll, etc.

[0055] Next, the control unit 21 extracts the inspection area from the first image data by optical calculation using the film size information and the camera setting information (step S12).

[0056] 7 shows an example of a captured image 51. The captured image 51 corresponds to the entire area of ​​the first image data obtained by the camera 12. The film roll 52 (roller-shaped film F) and the winding shaft 53 are shown in the captured image 51. The captured image 51 includes an inspection area 54 of the inspection sequence (at the time of capturing the image). In addition, the captured image 51 also includes a light source mapping area 55.

[0057] If the roll diameter of the film roll 52 gradually increases, the distance between the camera 12 and the surface of the film F decreases, and the size and position of the inspection area 54 of the camera image 51 change.

[0058] FIG8 shows examples of camera images 51A, camera images 51B, and camera images 51C at different inspection timings. The symbols used in each of the camera images 51A, 51B, and 51C are the same as those in FIG7. In the camera image 51A among the camera images 51A, 51B, and 51C, the roll diameter of the film roll 52 is the smallest, and in the camera image 51C, the roll diameter of the film roll 52 is the largest. As the roll diameter of the film roll 52 increases, the size of the inspection area 54 increases.

[0059] 9, a method for calculating the boundary position when extracting the inspection area 54 from the camera image 51 will be described. Since the position of the inspection area 54 gradually changes according to the roll diameter of the film roll 52, the cut-out range is changed for each roll diameter.

[0060] As a preparation, the upper cutting position 56 and the lower cutting position 57 of each roll diameter are recorded from the previously acquired image (from the start to the end of the roll winding). Fig. 10A shows the relationship between the roll diameter [mm] and the cut-out upper position [pixel position] of the film roll 52. From this relationship, a linear approximation calculation formula is prepared in advance. Cutting upper position [pixel position] = 0.24 × roll diameter [mm] + 338

[0061] Fig. 10B shows the relationship between the roll diameter [mm] and the cut-out lower position [pixel position] of the film roll 52. From this relationship, a linear approximation calculation formula is prepared in advance. Cutting position [pixel position] = 0.34 × roll diameter [mm] + 325

[0062] The control unit 21 inputs the roll diameter into the pre-made linear approximation equation for the inspection area 54 on the camera image 51, and obtains the upper cut position 56 and the lower cut position 57. That is, the control unit 21 calculates the pixel position of the end of the film roll 52 in the circumferential direction of the inspection area 54 using the roll diameter.

[0063] Next, the control unit 21 obtains the cutting width positions 58 and 59 in the width direction of the film F for the inspection area 54 on the captured image 51 (see FIG. 9 ).

[0064] As shown in FIG11 , the imaging range [mm] of the film F in the width direction on the surface of the film F during the inspection sequence is set as h range. In addition, the distance [mm] between the camera lens and the roll center of the film roll 52 is set as L r, and the roll radius [mm] of the film roll 52 during the inspection sequence is set as r. In addition, the focal length [mm] of the camera lens is set as f, and the sensor size [mm] in the width direction of the film F is set as ss, then h range is obtained by formula (1). In addition, the roll radius r is half the roll diameter (roll diameter) included in the film size information. [Calculation formula 1]

[0065] If the resolution [pix / mm] of the inspection sequence is set to resol and the number of sensor pixels [pix] in the width direction of the film F is set to sp, then resol is obtained by equation (2). [Calculation formula 2]

[0066] When the cutout amount [pix] in the width direction is t pix and the film width [mm] at the inspection timing is w (see FIG. 11 ), t pix is ​​obtained by equation (3). t pix is ​​the number of pixels corresponding to the film width w. [Calculation formula 3]

[0067] The control unit 21 uses the positions of ±tpix / 2 from the image center position in the width direction of the film F of the first image data as the cut-out width positions 58 and 59. That is, the control unit 21 calculates the pixel position of the end of the film roll 52 in the width direction of the inspection area 54 using the roll radius r, the film width w, the focal length f, the distance Lr between the camera lens and the roll center, the sensor size ss, and the number of sensor pixels sp.

[0068] The control unit 21 extracts the inspection region 54 from the first image data (captured image 51 ) based on the cutout upper position 56 , the cutout lower position 57 , and the cutout width positions 58 , 59 obtained in this way.

[0069] Next, the control unit 21 stores the second image data corresponding to the inspection area in the storage unit 27 (step S13). Specifically, in step S4, the control unit 21 stores the second image data in the storage unit 27 in accordance with the inspection date and time corresponding to the first image data.

[0070] After the first inspection region extraction process, returning to FIG. 5 , the control unit 21 performs data processing on the second image data corresponding to the extracted inspection region (step S6 ).

[0071] Here, data processing will be described with reference to FIG. 12 . The control unit 21 divides the second image data into a plurality of regions in the width direction of the film F (step S21). Specifically, the control unit 21 divides the second image data into n regions a1 to an.

[0072] Next, the control unit 21 obtains the image data of the area a1 (step S22), and then performs mathematical processing on the image data of the area a1 (step S23). According to the type of defect to be detected (gauge belt, longitudinal wrinkle, oblique wrinkle, etc.), appropriate mathematical processing is prepared.

[0073] Mathematical processing includes pre-processing, emphasis processing, signal processing and image feature extraction. As pre-processing, there are image retouching, low-pass filtering, high-pass filtering, Gaussian filtering, median filtering, bidirectional filtering, morphological transformation, color transformation (L*a*b* *, sRGB, HSV, HSL), contrast adjustment, noise removal, restoration of blurred and shaken images, mask processing, Hough transform, projection transformation, etc. Examples of the emphasis processing include Sobel filtering, Scharr filtering, Laplacian filtering, Gabor filtering, and Canny method. Signal processing includes obtaining basic statistics (maximum value, minimum value, mean value, median value, standard deviation, variance, quartile), square root, difference, sum, product, ratio, distance matrix processing; calculus, threshold processing (binarization, adaptive binarization, etc.), Fourier transform, wavelet transform, peak detection (peak value, number of peaks, half-width, etc.), etc. Examples of image feature extraction include template matching and SIFT features. The mathematical processing in step S23 is equivalent to "image processing" for the second image data.

[0074] Specifically, in the detection of the gauge band, low-pass filtering, Gaussian filtering, median filtering, morphological transformation, mask processing and other values ​​are used as pre-processing, and in signal processing, basic statistics and threshold processing are used. For longitudinal wrinkles and oblique wrinkles, high-pass filtering is used as pre-processing, Sobel filtering and Gabor filtering are used as emphasis processing, and square sum square root, Fourier transform, basic statistics, etc. are used as signal processing.

[0075] Next, the control unit 21 performs threshold processing on the value (feature quantity) obtained by mathematical processing of the image data of the area a1 (step S24). The threshold processing is a process of determining whether it is a defect of the inspection object based on one or more thresholds predetermined for the type of defect of each inspection object, and also determining the level (intensity) of the defect. The threshold processing in step S24, which determines the existence of defects and the type of defects, corresponds to "defect determination processing". In addition, the threshold processing in step S24, which classifies defects into a plurality of levels according to the threshold, corresponds to "quantitative evaluation processing".

[0076] For example, the control unit 21 classifies the defects into a plurality of levels in response to the acquired parameter (characteristic) having a value of 1 to 100. Specifically, the control unit 21 classifies the defects in such a manner that the parameter value is 1 to 10 as level 1, 11 to 30 as level 2, 31 to 60 as level 3, and 61 to 100 as level 4.

[0077] The same processing is performed for the areas other than the area a1. For example, the processing of steps S25 to S27 performed on the image data of the area an is the same as the processing of steps S22 to S24.

[0078] After processing each area a1 to an, the control unit 21 integrates the results for each area a1 to an (step S28) and ends the data processing. Specifically, the control unit 21 generates data corresponding to the type of defect detected and the level for each area (each position in the width direction of the film F).

[0079] After the data processing, returning to FIG. 5, the control unit 21 stores the processing results of the first inspection area extraction processing and / or the data processing in the storage unit 27, and displays the processing results on the display unit 25 (step S7). For example, the control unit 21 displays the inspection area extracted in the first inspection area extraction processing on the display unit 25. In addition, the control unit 21 associates the processing results of the data processing with the inspection date and time corresponding to the second image data, and stores them in the storage unit 27. The processing results of the data processing include the types and levels of defects detected in each area (position) divided in the width direction. The control unit 21 displays information such as the type, position, level (intensity) of the detected defects on the display unit 25. The above completes the film defect detection process.

[0080] 5 is a process for displaying the inspection range corresponding to one imaging. The inspection area in the length direction of the film F is changed along with the movement of the film F being rolled up, and the film defect inspection process is repeated, thereby obtaining the inspection results of each position in the length direction of the film F. In addition, FIG5 illustrates the case where the first inspection region extraction process (see FIG6 ) and data processing (see FIG12 ) are performed for each imaging. Alternatively, the control unit 21 may store image data obtained in a plurality of imagings in advance, and then perform the first inspection region extraction process and data processing collectively.

[0081] 13 shows an example of an inspection result screen 251 displayed on the display unit 25. The inspection result screen 251 displays the inspection result of the wound film F in real time. The inspection result screen 251 includes an inspection area image column 251A and a defect level column 251B.

[0082] In the inspection area image column 251A, images of the inspection areas extracted at each inspection sequence are displayed. Specifically, the control unit 21 arranges the inspection areas that are longer in the width direction of the film F along the roll length (corresponding to the inspection time). Here, the control unit 21 adjusts the magnification of the second image data corresponding to each inspection area at each inspection sequence so that the length of each inspection area in the width direction is consistent. In the inspection area image column 251A, the position in the width direction of the film F is displayed horizontally. In the vertical direction, the inspection sequence is displayed according to the position in the length direction (roll length) of the film F. In addition, the inspection is carried out on the entire range of the film F, but the inspection results shown in FIG. 13 are displayed for each roll length of 100 m.

[0083] The maximum level of defects generated at each inspection sequence is displayed in the defect level column 251B. The control unit 21 displays the maximum level of defects detected from the inspection area obtained at each inspection sequence in a graph with the horizontal axis being the roll length (corresponding to the inspection time). Here, the defect level is displayed for each defect type (gauge tape, oblique wrinkle). In the defect level column 251B, the defect level is also displayed for each roll length of 100m. The displayed defect level value may also be the maximum value of the level of defects detected from the inspection area obtained at the inspection sequence corresponding to the roll length. Alternatively, the maximum value of the level of defects detected by inspection of the roll length of 100m, including the inspection area not displayed in the inspection area image column 251A, may also be displayed in the defect level column 251B.

[0084] In addition to the above examples, the control unit 21 can also display the life and death monitoring information of the thin film inspection device 10 on the display unit 25. For example, the control unit 21 displays the status information (operating / stopped / error) of each inspection process of the thin film inspection device 10. In addition, the control unit 21 can also notify the error by an alarm sound when an error occurs. In addition, the control unit 21 may also display a search screen of past inspection results, search results, etc. on the display unit 25.

[0085] As described above, according to the first embodiment, the control unit 21 extracts the inspection area of ​​the inspection sequence from the first image data obtained from the output signal of the self-camera 12 (optical sensor). In this way, the control unit 21 can extract the inspection area whose size and position change in the first image data. In addition, since the control unit 21 detects defects of the film F based on the second image data corresponding to the inspection area, defects can be detected efficiently. Therefore, the thin film inspection device 10 can easily detect defects generated in the thin film F without requiring human monitoring or operation.

[0086] In addition, the control unit 21 extracts the inspection area by optical calculation using the size information of the film at the inspection time and the camera setting information. In this way, the control unit 21 can extract the inspection area by simple calculation.

[0087] In addition, by providing the film inspection device 10 with a reflection prevention plate 48, it is possible to prevent a decrease in the detection accuracy of defects due to reflection in the inspection area. The reflection prevention plate 48 is configured so that regular reflected light among the light reflected in the inspection area of ​​the film F does not enter the camera 12, thereby preventing the background from being reflected. In addition, the light reflected by the diffusion plate (anti-reflection plate 48) reaches the film F, is diffused by the film F, and the diffused light reaches the camera 12. Thus, a larger amount of light can be secured compared to a case where the anti-reflection plate 48 is not provided.

[0088] In addition, the control unit 21 displays the extracted inspection area, information on the detected defects, etc. on the display unit 25. Thus, the user can instantly check the quality of the film F. Therefore, it is possible to provide feedback to the production process instantly when the quality deteriorates, and improve the process through data analysis, which helps to improve quality and stabilize production. In addition, the control unit 21 stores the inspection area image, defect detection results, etc. in the storage unit 27, so that past data can be retrieved and used.

[0089] [Second embodiment] Next, a second embodiment of the present invention will be described. In order to ensure the imaging range in the width direction of the film due to the limitation of the camera installation position or the viewing angle of the camera lens, it is necessary to use a plurality of cameras. The second embodiment is different from the film inspection device 10 shown in the first embodiment in that it has a plurality of cameras. The characteristic structure and processing of the second embodiment are described below. Here, referring to FIG. 1, the description of the same structure as the first embodiment is omitted. In addition, it is assumed that the plurality of cameras including the same lenses are set at the same distance from the film roll.

[0090] As shown in FIG. 14 , the thin film inspection apparatus 10 according to the second embodiment includes three cameras 12 . The imaging range of each of the three cameras 12 covers the entire width direction of the film F. As the roll diameter of the film roll 52 changes, the distance between the camera 12 and the film surface changes. As a result, the overlap amount of the first image data (imaging range) obtained by the adjacent cameras 12 changes according to the roll diameter of the film roll 52. Specifically, the overlap amount d1 of the imaging range when the roll radius r1 of the film roll 52 is small is larger than the overlap amount d2 when the roll radius r2 is large.

[0091] The camera setting information stored in the storage unit 27 also includes the distance between the cameras 12. The distance between the cameras is the distance between the adjacent cameras 12 in the width direction of the film F.

[0092] The control unit 21 (inspection area extraction unit) removes overlapping ranges between a plurality of first image data obtained from a plurality of cameras 12 (optical sensors). Furthermore, the control unit 21 removes the overlapping ranges in such a way that each area included in the overlapping range remains in any one of the first image data. The control unit 21 combines the plurality of first image data in the width direction of the film F except for the overlapping range. The control unit 21 extracts the inspection area of ​​the inspection sequence from the combined first image data. Furthermore, either the removal of duplicate areas or the extraction of inspection areas can be performed first.

[0093] The control unit 21 extracts the inspection area and removes the overlapping range by optical calculation using the size information of the film and the camera setting information of the inspection sequence.

[0094] Next, the operation of the thin film inspection apparatus 10 according to the second embodiment will be described. Here, the difference from the thin film defect detection process of the first embodiment (see FIG. 5 ) will be described. In the second embodiment, the control unit 21 obtains the first image data from each of the plurality of cameras 12 in step S3 of the thin film defect detection process. In addition, the control unit 21 performs the second inspection area extraction process as shown in FIG. 15 instead of step S5 of the thin film defect detection process.

[0095] In the second inspection area extraction process, first, the control unit 21 obtains the film size information and camera setting information of the inspection sequence (step S31). Specifically, the control unit 21 obtains the film size information from the film size measuring unit 29. The film size information includes the film width, roll diameter, etc. In addition, the control unit 21 obtains the camera setting information stored in the storage unit 27. The camera setting information includes the focal length of the camera lens, the sensor size, the number of sensor pixels, the distance between the camera lens and the roll center of the film roll, the distance between cameras, etc.

[0096] Next, the control unit 21 removes the overlapping range from the first image data by optical calculation using the film size information and the camera setting information (step S32).

[0097] 16, the method for obtaining the amount of overlap in the imaging range will be described. Assuming that the repetition amount [mm] expressed as length (distance) is d mm, the imaging range [mm] in the width direction of the film F on the surface of the film F during the inspection sequence is h range, and the distance between cameras [mm] is L c, d mm can be obtained by equation (4). [Calculation formula 4] Furthermore, h range is obtained by the above formula (1).

[0098] If the repetition amount [pix] expressed in pixels is denoted as dpix and the resolution of the inspection sequence [pix / mm] is denoted as resol, dpix is ​​obtained by equation (5). [Calculation formula 5] Furthermore, resol is obtained by the above formula (2).

[0099] That is, the control unit 21 calculates the repetition amount dpix using the roll radius r, the focal length f, the distance Lr between the camera lens and the roll center, the sensor size ss, the number of sensor pixels sp, and the distance between cameras Lc.

[0100] As shown in FIG. 17A , the control unit 21 removes the overlapping range from the first image data 61, 62, and 63 obtained from the three cameras 12. Specifically, the control unit 21 removes the overlapping range 61A from the first image data 61. The control unit 21 removes the overlapping ranges 62A and 62B from the first image data 62. The control unit 21 removes the overlapping range 63A from the first image data 63. As the overlapping ranges 61A, 62A, 62B, and 63A, d pix / 2 is used here. For the first image data obtained by each camera 12, the overlapping range of d pix / 2 is removed from the boundary side in the width direction, thereby preventing leakage of data in the width direction of the film F. Fig. 17B shows the first image data 61, 62, and 63 after the overlapping range is removed. In Fig. 17A and Fig. 17B, flower-shaped marks and star-shaped marks are added to make it easy to know the removed parts, but they are actually not mapped in the image.

[0101] Next, the control unit 21 combines the first image data with the overlapped regions removed in the width direction of the film F (step S33). The image data generated by combining can be processed in the same manner as one connected image data (the first image data of the first embodiment).

[0102] Next, the control unit 21 extracts the inspection area from the combined image data by optical calculation using the film size information and the camera setting information (step S34). The processing of step S34 is the same as the processing of step S12 of the first inspection area extraction processing (see FIG. 6 ), except that the combined image data is used.

[0103] Next, the control unit 21 stores the second image data corresponding to the inspection region in the storage unit 27 (step S35). The process of step S35 is the same as the process of step S13 in the first inspection region extraction process (see FIG. 6). The above completes the second inspection area extraction process.

[0104] As described above, according to the second embodiment, in the film inspection apparatus 10 having the plurality of cameras 12, the control unit 21 removes the overlapping ranges of the plurality of first image data obtained from the plurality of cameras 12. Thus, the control unit 21 does not obtain too much or too little inspection area from the plurality of first image data.

[0105] Furthermore, the description of the above-mentioned embodiments is an example of the thin film inspection device, thin film inspection method and program of the present invention, but is not limited to this. The detailed structure and detailed operation of each part constituting the device can be appropriately changed without exceeding the scope of the technical concept of the present invention. For example, the structures or processes of the aforementioned embodiments may be combined.

[0106] In the above-mentioned embodiments, the case where defects generated when the film F is rolled up into a roll is described. Alternatively, the film inspection device 10 may detect defects generated when the film F cut into a predetermined size is gradually overlapped.

[0107] In addition, the control unit 21 can also use the learning results obtained by machine learning when detecting defects from the second image data corresponding to the inspection area. Specifically, the control unit 21 adopts a machine learning model in which the image-processed data is used as an explanation variable and the defect determination result by a person is used as a target variable in the defect determination process. In addition, the control unit 21 adopts a machine learning model in which the image-processed data is used as an explanation variable and the quantitative evaluation results of defects by personnel are used as a target variable in the quantitative evaluation process. The control unit 21 uses the machine learning results to quantitatively evaluate the defects based on the image-processed data, thereby classifying the defects into multiple levels. Furthermore, it is not necessary to perform the defect determination process and the quantitative evaluation process separately. The control unit 21 may also perform the defect determination process and the quantitative evaluation process collectively by using the image processed data as input data and the combination of the type and level of the defect evaluated by the person as output data to perform machine learning results.

[0108] As a computer-readable medium storing a program for executing each process, it is not limited to the above example, and a portable recording medium can also be applied. In addition, as a medium for providing program data via a communication line, a carrier wave can also be applied.

[0109] 10: Film inspection device 11: Light Source 12: Camera 20: Information processing device 21: Control Department 25: Display unit 26: Operation Department 27: Storage 28: Timing Department 29: Film size measurement unit 48: Mapping prevention board 51: Camera image 52:Film roll 53: Take-up shaft 54: Check area 56: Cut out upper position 57: Cut out the lower position 58,59: Cut-out width position 251: Inspection result screen F: Film

Claims

1. A thin film inspection apparatus for optically inspecting defects generated in thin films in an overlapping state, characterized by comprising: a light source that illuminates the thin film; an optical sensor that detects at least diffuse light in the light reflected from the thin film; an inspection area extraction unit that extracts an inspection area of ​​the inspection sequence from first image data obtained from the output signal of the optical sensor by optical calculation using the size information of the thin film and the setting information of the optical sensor prior to the inspection sequence; and a defect detection unit that performs data processing on second image data corresponding to the inspection area to detect the defect.

2. The film inspection apparatus as claimed in claim 1, wherein, Equipped with a plurality of the aforementioned optical sensors, the aforementioned inspection area extraction unit further removes the overlapping ranges of the plurality of aforementioned first image data obtained from the plurality of the aforementioned optical sensors.

3. The film inspection apparatus as described in claim 1 or 2, wherein, The aforementioned film is wound into a roller shape, and the film inspection device takes the aforementioned defects generated during the winding of the aforementioned film as the inspection object.

4. The film inspection apparatus as described in claim 1 or 2, wherein, The aforementioned optical sensor is a region sensor.

5. The film inspection apparatus as claimed in claim 1 or 2, wherein, In order to prevent positively reflected light from entering the optical sensor in the light reflected from the inspection area of ​​the aforementioned thin film, a mapping prevention plate is provided, which is composed of a diffusion plate.

6. The film inspection apparatus as claimed in claim 1 or 2, wherein, It also includes a display control unit, which displays information about the inspection area extracted by the aforementioned inspection area extraction unit and / or the defects detected by the aforementioned defect detection unit on the display unit.

7. A thin film inspection method for optically inspecting defects generated in thin films in an overlapping state, characterized by comprising: a process of irradiating the thin film with light by means of a light source; a process of detecting at least diffuse light in the light reflected from the thin film by means of an optical sensor; a process of extracting an inspection area of ​​the inspection sequence by means of an inspection area extraction unit from a first image data obtained from the output signal of the optical sensor by means of optical calculation using the size information of the thin film and the setting information of the optical sensor prior to the inspection sequence; and a process of detecting the defects by means of a defect detection unit performing data processing on a second image data corresponding to the inspection area.

8. A program for a computer of a thin film inspection apparatus to function as an inspection area extraction unit and a defect detection unit, the thin film inspection apparatus comprising: a light source that illuminates light onto thin films in an overlapping state; an optical sensor that detects at least diffuse light in the light reflected from the aforementioned thin film and optically inspects defects generated on the aforementioned thin film; the inspection area extraction unit extracts an inspection area of ​​the aforementioned inspection sequence from first image data obtained from the output signal of the aforementioned optical sensor by optical calculation using the size information of the aforementioned thin film and the setting information of the aforementioned optical sensor prior to the inspection sequence; and the defect detection unit performs data processing on second image data corresponding to the aforementioned inspection area to detect the aforementioned defects.

Images