JP2016148520A - Faulty scratch checkup device, and faulty scratch checkup method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a checkup device for detecting faulty scratches that may occur in sheets, such as films, in all directions in accordance with fixed standards, and a checkup method to detect the faults that may occur in the sheets in accordance with fixed standards.SOLUTION: By a fault checkup device, the angle of a faulty scratch occurring in a consecutively carried sheet is extracted, a correction value is calculated on the basis of this angle, this correction value is added to the signal value of a faulty scratched part, and by comparing this correction value-added signal value of the faulty scratched part and a preset rank determination reference value, the faulty scratch occurring in the consecutively carried sheet can be ranked in accordance with fixed standards.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an inspection apparatus for detecting scratch defects in all directions generated on a sheet such as a film with a constant reference, and an inspection method for detecting the defects generated on the sheet with a fixed reference.

  In the process of continuously producing sheets such as films, scratch defects may occur in the sheets, which is a problem.

  As a mechanism for the generation of this scratch defect, when a foreign object adheres to the transport roll and the foreign object is pressed against the film surface, the scratch defect occurs, and the tension applied to the film and the film transport speed are not constant, and the film is transported. There may be a case where a scratch defect is generated by rubbing the roll.

  Therefore, as the shape of the scratch defect, in the former case, it is a dot shape or a shape that is long in the film conveyance direction, whereas in the latter case, the film and the conveyance roll are rubbed with respect to the film conveyance direction, Scratches with long shapes occur in all directions.

  As described above, it is known that scratch defects occur at all angles depending on the film conveyance state.

  Since this scratch defect becomes a problem in the user's processing process, it must be avoided that a film having a scratch defect is shipped as a product.

  Conventionally, when such a defect is inspected, the film being conveyed is irradiated with light by an illuminating device, and when there is a defect on the film, scattered light that is irregularly reflected by the defect is detected. A flaw defect has been detected by capturing an image with a CCD camera or the like and processing the captured image.

  Here, Patent Document 1 discloses an apparatus for automatically inspecting a scratch defect generated on a film with a CCD camera.

  As shown in FIG. 2, the defect inspection apparatus of Patent Document 1 detects an illumination light source 14 that irradiates the surface of the film 11 with illumination light L <b> 1 and reflected light from the illumination light L <b> 1 that is irradiated on the surface of the film 11. The illumination light L1 of the illumination light source 14 is irradiated at an incident angle of 15 ° to 45 ° with respect to the surface of the film 11, and the CCD camera 15 reflects the light reflected by the film 11. By detecting only the reflected light L3 that reflects in the direction perpendicular to the film 11 out of L2, the flaw defect 12 generated in the film 11 can be detected with high sensitivity.

  Patent Document 2 discloses an inspection apparatus that can inspect a scratch defect generated in a continuously traveling sheet with high accuracy regardless of an angle.

  As shown in FIG. 3, the defect inspection apparatus of Patent Document 2 includes a light irradiating unit 2 that irradiates a sheet 1 that continuously travels a linear light beam, and a light receiving unit that receives the linear light beam reflected by the sheet 1. 3 and image processing means 4 for detecting a scratch defect of the sheet 1 in accordance with a signal received by the light receiving means 3, and the light irradiation means 2 and the light receiving means 3 are simultaneously rotated while maintaining the relative positions. Rotating means 6 for rotating, and for the flaw defects that occur periodically, the angle of the light irradiating means 2 and the light receiving means 3 is sequentially changed by the rotating means 6, thereby increasing the flaw defects in all directions. Sensitivity can be detected.

JP 2008-8819 A JP2013-53860A

  However, although the technique of Patent Document 1 can detect defects with high sensitivity for defects generated in a direction parallel to the longitudinal direction of the illumination light source 14, the detection sensitivity for defects with defects in other directions is high. descend.

  In other words, the scattered light of the light emitted from the illumination light source 14 in the scratch defect generates the same scattered light at any angle of the scratch defect, but the scattered light received by the CCD camera 14 is the angle of the scratch defect. The angle of the scratch defect becomes smaller as it approaches the direction perpendicular to the longitudinal direction of the illumination light source 14.

  As described above, the method of Patent Document 1 has a problem that the detection sensitivity differs depending on the angle at which a scratch defect occurs.

  In addition, the technique of Patent Document 2 can detect a flaw defect generated periodically in all directions with high sensitivity by rotating the light irradiation means 2 and the light receiving means 3 while maintaining the relative positions thereof. However, there is a problem in that the continuously traveling sheet 1 cannot be detected continuously with a constant sensitivity, and it is impossible to correctly inspect other than defects that occur periodically.

  The present invention solves the above-mentioned conventional problems, and provides an inspection apparatus and an inspection method for detecting scratch defects in all directions generated on the surface of a continuously traveling sheet on a constant basis.

The scratch defect inspection apparatus of the present invention that solves the above problems is as follows.
A scratch defect inspection apparatus for a sheet for inspecting a scratch defect of a continuously conveyed sheet, a light irradiation means for irradiating light from one surface side of the sheet, and a surface on which the light irradiation means of the sheet is installed A light receiving means for receiving the light irradiated from the light irradiating means and reflected by the sheet, or installed on the surface side opposite to the surface side of the sheet on which the light irradiating means is installed. A light receiving means for receiving light irradiated from the means and transmitted through the sheet, an image processing means for detecting a scratch defect portion generated on the surface of the sheet from a signal value corresponding to the intensity of the light received by the light receiving means, and An angle with respect to the sheet conveyance direction of the flaw defect portion detected by the image processing means is extracted, a correction value is calculated based on the angle, and the correction value is added to the signal value of the flaw defect portion. But By comparing the signal value of the calculated been flaw defect portion and the preset rank determination reference value, the sheet flaw defect inspection device provided with a, and determines the rank determination unit ranks of the flaw defect portion.

Another scratch defect inspection apparatus of the present invention that solves the above problems is as follows.
A scratch defect inspection apparatus for a sheet for inspecting a scratch defect of a continuously conveyed sheet, a light irradiation means for irradiating light from one surface side of the sheet, and a surface on which the light irradiation means of the sheet is installed A light receiving means for receiving the light irradiated from the light irradiating means and reflected by the sheet, or installed on the surface side opposite to the surface side of the sheet on which the light irradiating means is installed. A light receiving means for receiving light irradiated from the means and transmitted through the sheet, an image processing means for detecting a scratch defect portion generated on the surface of the sheet from a signal value corresponding to the intensity of the light received by the light receiving means, and The angle with respect to the sheet conveyance direction of the flaw defect portion detected by the image processing means is extracted, a correction value is calculated based on this angle, and the correction value is subtracted from a preset rank determination reference value The flaw by comparing the signal value with the rank criterion value the correction value is subtracted the defect portion, and rank determining means for determining a rank of the flaw defect, the sheet flaw defect inspection device provided with a.

The scratch defect detection apparatus for a sheet of the present invention is:
It is preferable that the light irradiation means irradiates a linear light beam parallel to the width direction of the sheet,
The correction value is preferably a value calculated from α (cos2θ + 1) (where α: constant, θ: angle of the scratch defect portion detected by the image processing means with respect to the sheet conveyance direction),
The constant α is preferably a value calculated by regression analysis using angles and intensities of a plurality of scratch defects occurring at the same position in the sheet width direction.

  The sheet defect inspection method of the present invention is a method for inspecting a sheet using the sheet defect inspection apparatus of the present invention.

  In the inspection apparatus and the inspection method of the present invention, it is possible to detect scratch defects in all directions generated on the surface of a continuously traveling sheet on a constant basis.

FIG. 1 is a schematic diagram showing an example of an embodiment of the present invention. FIG. 2 is a schematic diagram for explaining the technique of Patent Document 1. In FIG. FIG. 3 is a schematic diagram for explaining the technique of Patent Document 2. In FIG. FIG. 4 is a diagram showing the positional relationship between the light irradiation means and the light receiving means for detecting a defect defect. FIG. 5 is a diagram illustrating the difference in detection sensitivity depending on the angle of the scratch defect. FIG. 6 is a diagram showing details of the rank determination means. FIG. 7 is a diagram showing details of the embodiment of the rank determination means. FIG. 8 is an image of the scratch defect (1) and the scratch defect (2) detected in the example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited by this embodiment.

(First embodiment)
FIG. 1 is a diagram showing an embodiment of the present invention. In FIG. 1, 1 is a continuously running sheet, which is an object to be inspected, 2 is a light irradiation means, 3 is a light receiving means, 4 is an image processing means, and 5 is a scratch defect fixed from a defect image extracted by the image processing means 4. It is a rank determination means to determine by reference.

  The sheet 1 is not particularly limited as long as it is a film that is continuously conveyed and transmits or reflects light. For example, a colorless and transparent film such as a polyester film such as a polyethylene terephthalate film is preferably used.

  The light irradiation means 2 is disposed on one side of the sheet 1 and irradiates the sheet 1 with light. As a light irradiation means for irradiating a wavelength in the visible light region, an LED, a fluorescent lamp, a device that irradiates a halogen or metal halide illumination from a transmission rod or an optical fiber, or the like can be used. In addition, the light irradiation part of the light irradiation means 2 preferably has a linear shape corresponding to the light receiving range of the light receiving means 3 to be described later. It is preferable to arrange the light irradiation means 3 so that the direction of the light irradiation means 3 is parallel to the longitudinal direction.

  The light receiving means 3 is disposed on the same surface side of the light irradiating means 2 with respect to the sheet 1 so as to receive light irradiated from the light irradiating means 2 and reflected by the sheet 1. The light receiving means 3 may be disposed on the surface opposite to the light irradiating means 2 with respect to the sheet 1 so as to receive light irradiated from the light irradiating means 2 and transmitted through the sheet 1. The light receiving means 3 is preferably arranged so as to receive scattered light due to scratch defects generated in the sheet 1, and the light irradiated from the light irradiating means 2 and regularly reflected or directly transmitted by the film 1 is received. It is not preferable to receive light. Here, in order to receive the light scattered by the flaw defect generated in the film 1, the positional relationship between the light irradiation means 2 and the light receiving means 3 is important. This positional relationship will be described with reference to FIG. FIG. 4 is a diagram showing the positional relationship between the light irradiating means 2 and the light receiving means 3 for receiving scattered reflected light due to scratch defects. As shown in FIG. 4, it is important that the light receiving means 3 is arranged so as not to receive the light irradiated by the light irradiation means 2 and regularly reflected by the sheet 1. This can be realized by shifting the angle φ from the optical axis. Here, the angle φ is preferably in the range of 5 ° to 30 °. The light receiving means 3 can be a line sensor camera in which light receiving elements are arranged one-dimensionally or an area sensor camera in which light receiving elements are arranged two-dimensionally. It is arrange | positioned so that it may become parallel to a longitudinal direction. When inspecting continuously conveyed sheets 1, it is preferable to use a line sensor camera. The light receiving means 3 can be a monochrome or color camera.

  The image processing unit 4 receives the output signal of the light receiving unit 3 and detects a change in the amount of light received by the light receiving unit 3 to inspect for the presence of a flaw defect on the sheet surface. An analog or digital signal corresponding to the amount of light received by the light receiving means 3 is output from the light receiving means 3, and when an analog signal is output, it is converted into a digital signal in the image processing means 4. The image processing means 4 detects the digital signal and performs image processing, and extracts a scratch defect on the surface of the sheet 1 based on the image processing result. This defect defect extraction can be performed by hardware such as an image processing board or by software such as a personal computer. However, hardware processing is preferable because it can be processed at high speed.

  The rank determination unit 5 receives the output signal from the image processing unit 4 and analyzes the shape of the defect defect image extracted by the image processing unit 4 to thereby characterize the angle of the defect defect from the conveyance direction of the sheet 1. Can be output as a quantity. A correction value is calculated on the basis of the feature value of the angle of the scratch defect, the correction value is added to the signal value of the scratch defect portion, and the added value is compared with a preset rank criterion value so as to be scratched. The strength of the defect can be determined and classified based on a certain standard.

This correction value depends on the method of applying a predetermined value according to the angle of the scratch defect and the angle of the scratch defect from the conveyance direction of the sheet 1.
α (cos 2θ + 1)
α: Constant θ: There is a method of calculating by the angle of the scratch defect from the sheet conveyance direction, but the latter is preferable because even a slight angle change of several degrees can be obtained by calculation each time.

In addition, the constant α is a regression analysis based on the method of applying a preset value and the angle θ and the signal value Y of each scratch defect periodically generated in the same series,
ΣY = −α · Σ (cos 2θ) + β
However, since the value of the constant α slightly changes for each defect defect series, the latter can be obtained by calculation each time.

  Next, the principle of detecting flaw defects periodically generated at the same position in the width direction of the sheet 1 according to the present invention will be described.

  Of the light transmitted through or reflected by the sheet 1, the light receiving means 3 does not receive the directly transmitted light or specularly reflected light, but only the scattered light due to the scratch defect. As a result, the amount of light at the scratch defect portion is larger than that at the normal portion, and the image processing means 4 becomes a bright portion. Then, by binarizing this bright part, it is detected as a bright defect.

  Also, scratch defects are mostly caused by the transport roll, so when a foreign object adheres to a part of the transport roll, the scratch defect occurs at the same position as the width direction position of the foreign object attached to the transport roll. However, since the transport roll is rotating, it is generated continuously in the transport roll cycle. In addition, there is a feature that scratch defects at various angles occur due to the process of stretching the sheet 1 and the meandering of the conveyance of the sheet 1.

  Here, the difference in detection sensitivity depending on the angle of the scratch defect will be described with reference to FIG.

  FIG. 5 is a diagram showing the difference in the amount of scattered light received by the light receiving means 3 when the angle of the scratch defect with respect to the conveying direction of the sheet 1 is 0 ° and 90 °.

  Scattered light due to a flaw defect generates a lot of scattered light on the surface of the sheet 1 in a direction perpendicular to the longitudinal direction of the flaw defect.

  Therefore, when the angle of the scratch defect with respect to the conveyance direction of the sheet 1 shown in FIG. 5A is 0 °, the light receiving axis of the light receiving means 3 is an angle perpendicular to the scattered light due to the scratch defect. The amount of light emitted is the smallest.

  Further, when the angle of the scratch defect with respect to the conveyance direction of the sheet 1 shown in FIG. 5B is 90 °, the light receiving axis of the light receiving unit 3 is parallel to the scattered light due to the scratch defect. The amount of light emitted is the largest.

  As described above, the detection sensitivity varies greatly depending on the angle of the scratch defect with respect to the conveyance direction of the film 1.

  Therefore, in the present apparatus, as described above, the defect determination angle θ is calculated by the rank determination means 5, the correction value is calculated according to the angle θ, and added to the signal value of the defect defect to determine the defect defect rank. By doing so, rank classification can be performed on a constant basis regardless of the angle of the scratch defect.

  This method will be described with reference to FIG.

  FIG. 6 is a diagram showing the details of the rank determination means 5 for determining the rank of the defect defect detected by the image processing means 4 on a constant basis regardless of the angle.

  As shown in FIG. 6, the rank determination unit 5 first receives a scratch defect region detected by the image processing unit 4 and calculates an angle and a signal value of the region. The angle of the flaw defect calculated here is calculated with the conveyance direction of the sheet 1 being 0 °.

  Next, a correction value is calculated according to the calculated defect angle θ, and the correction value is added to the signal value of the defect. This correction value varies depending on the angle of the scratch defect, and is the largest when the angle of the scratch defect is 0 ° with respect to the sheet conveyance direction, and the smallest when the angle is 90 °.

  Thereafter, the value obtained by adding the correction value to the signal value of the scratch defect can be compared with a predetermined rank determination threshold to determine whether the scratch defect is good or bad.

  As described above, in the first embodiment, by adding a correction value to the signal value of the scratch defect according to the angle of the scratch defect, the rank is determined based on a constant reference regardless of the angle of the scratch defect. Can do.

(Second Embodiment)
As shown in FIG. 6, the rank determination means 5 adds a correction value to the signal value of the scratch defect, so that the rank determination unit 5 determines the rank based on a constant reference regardless of the angle of the scratch defect. By using the value as it is and subtracting the correction value corresponding to the angle from the threshold value for determining the rank of the scratch defect, the rank can be determined on a constant basis regardless of the angle of the scratch defect.

  As shown in FIG. 7, the rank determination unit 5 first receives a scratch defect region detected by the image processing unit 4 and calculates an angle and a signal value of the region.

  Next, a correction value is calculated according to the calculated scratch defect angle θ, and a correction value corresponding to the scratch defect angle is subtracted from the scratch defect rank determination threshold. Then, the quality of the scratch defect can be determined by comparing the signal value of the scratch defect with a value obtained by subtracting the correction value corresponding to the angle of the scratch defect from a predetermined rank determination threshold.

  As described above, in the second embodiment, by subtracting the correction value from the rank determination threshold according to the angle of the scratch defect, the rank can be determined based on a constant reference regardless of the angle of the scratch defect. .

  Scratch defects were inspected using an apparatus according to the arrangement of FIG. A PET film having a width of 1000 mm and a thickness of 50 μm was used as the film, and the film was run at 10 m / min. Furthermore, as the light irradiating means, linear LED illumination that irradiates white light was used, and the angle formed by the film surface and the optical axis of the LED illumination was set to 80 °, and the distance between the film surface and the LED illumination was set to 150 mm.

  In addition, a monochrome line sensor camera was used as the light receiving means, and was arranged so as to receive scattered light due to scratch defects generated on the film surface. At this time, the angle between the film surface and the light receiving axis of the monochrome line sensor camera was set to 75 °, and the distance between the film surface and the line sensor camera was set to 200 mm.

  In the image processing means, two series of scratch defects, which are bright defects received by the line sensor camera, are detected, and the information is transferred to the rank determining means. Table 1 shows an image of the detected defect and FIG. 8 shows an image of the defect.

  The rank determination means calculates the angle and signal value for each scratch defect. The angle of the scratch defect was calculated with the film transport direction as 0 °, and the signal value of the scratch defect was calculated by dividing the average brightness of the scratch defect area by the texture of the film surface.

  Furthermore, a constant α of the correction value based on the angle of the scratch defect is calculated by regression analysis using each angle and the signal value of the scratch defect occurring at the same film width direction position, and the correction value is calculated using the constant α. Calculated. Further, this correction value was added to the signal value of the scratch defect.

  When the pass / fail threshold value of the scratch defect is 1.4, it is determined that the scratch defect (1) is “fail” and the scratch defect (2) is “pass” in the determination from the scratch defect strength before correction. However, in the determination based on the defect defect strength after correction, both defect defects were determined to be “failed”.

  As a result of sampling and visual confirmation of actual scratch defects, it was confirmed that both scratch defects are problematic scratch defects and that the rank of the scratch defect can be correctly determined.

1: Continuously traveling sheet 2: Light irradiating means 3: Light receiving means 4: Image processing means 5: Rank determining means 6: Rotating means 7: Regular reflection optical axis 8: Scattered reflection optical axis 9: Scattered light due to flaws 11: Film 12: Scratch defect 13: Inspection table 14: Illumination light source 15: CCD camera L1: Illumination light L2: Reflection light L3: Vertical reflection light α: Constant θ: Scratch defect angle φ: Optical axis of light irradiation means and light reception means Angle formed by the light receiving axis

Claims (6)

It is a sheet defect inspection apparatus for inspecting a defect defect of a continuously conveyed sheet,
Light irradiation means for irradiating light from one side of the sheet;
A light receiving means for receiving the light irradiated from the light irradiating means and reflected by the sheet, or the surface side of the sheet on which the light irradiating means is installed. A light receiving means for receiving the light irradiated from the light irradiating means and transmitted through the sheet;
Image processing means for detecting a scratch defect portion generated on the surface of the sheet from a signal value corresponding to the intensity of light received by the light receiving means;
The angle with respect to the sheet conveyance direction of the flaw defect portion detected by the image processing means is extracted, a correction value is calculated based on this angle, the correction value is added to the signal value of the flaw defect portion, and this correction is performed. A scratch defect inspection apparatus for a sheet, comprising: rank determination means for comparing the signal value of the defect defect portion to which the value has been added and a predetermined rank determination reference value to determine the rank of the defect defect portion. It is a sheet defect inspection apparatus for inspecting a defect defect of a continuously conveyed sheet,
Light irradiation means for irradiating light from one side of the sheet;
A light receiving means for receiving the light irradiated from the light irradiating means and reflected by the sheet, or the surface side of the sheet on which the light irradiating means is installed. A light receiving means for receiving the light irradiated from the light irradiating means and transmitted through the sheet;
Image processing means for detecting a scratch defect portion generated on the surface of the sheet from a signal value corresponding to the intensity of light received by the light receiving means;
The angle of the scratch defect detected by the image processing unit with respect to the sheet conveyance direction is extracted, a correction value is calculated based on the angle, and the correction value is subtracted from a preset rank determination reference value. A scratch defect inspection apparatus for a sheet, comprising: rank determination means for comparing the signal value of the defect defect portion with a rank determination reference value obtained by subtracting the correction value to determine the rank of the defect defect.   The scratch defect inspection apparatus for a sheet according to claim 1 or 2, wherein the light irradiation means irradiates a linear light beam parallel to the width direction of the sheet. The scratch defect inspection apparatus for a sheet according to any one of claims 1 to 3, wherein the correction value is a value calculated from α (cos2θ + 1).
Where α: constant θ: angle of the flaw defect detected by the image processing means with respect to the sheet conveyance direction   5. The scratch defect inspection of a sheet according to claim 4, wherein the constant α is a value calculated by regression analysis using angles and intensities of a plurality of defect defects generated at the same position in the width direction of the sheet.   A scratch defect inspection method for inspecting a sheet using the scratch defect inspection apparatus for a sheet according to claim 1.