JPH09152323A - Fibrous body inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inspect non-whitened defect of hollow yarn by applying image processing technique, by irradiating a fibrous body with the light from a polarization/emission means, and extracting/measuring an image of a non- whitened part of it with an image processing/measuring means, and recording the measured result in a memory for outputting to an output means. SOLUTION: A lightening device 10 is provided next a drawing device 7, and a polarizing plate 11 is attached an it. A CCD camera 14 is fitted separating from a fibrous body (hollow yarn) manufacturing device 6 by about 70cm, and a polarizing plate 12 is attached to a lens 13. The camera 14 is connected to an image processing device 16 with a camera cable. The processing device 16 performs binarization of image and image measurement, and has an image process-only processor, a line memory for a single line and a 64K image data processing run length buffer within. A host computer 17 controls the image process-only processor, for performing various image process, transfer of image data, reading/writing of the image data to a memory 15. The hollow yarn 8 is irradiated with exit light from the device 10, and only the transmitted light is detected with the camera 14, for processing with the device 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus to which an image processing technique for inspecting a defect of a fibrous material while in contact with the fibrous material without contact is applied. In the present invention, a hollow fiber is used as an example of the fibrous material to be inspected. Hollow fibers are also called hollow fibers, and are generally 10 different from the diameter of fibers for clothing.
It is a so-called straw-like fiber having a diameter of 0 to 1000 μm and a hollow inside. In the present invention, examples of the hollow fiber include filamentary fiber made of regenerated and synthesized polymer.

When a hollow fiber is used as a polymer having a function as a separation membrane, the membrane area per unit area is remarkably increased, so that it is often used in the form of a hollow fiber for practical use.
Examples include dialysis with artificial kidneys, production of semiconductor ultrapure water, oxygen enrichment, hydrogen separation and the like. In the manufacturing process, the hollow fiber is subjected to a heat treatment, if necessary, and then subjected to a stretching treatment, and as a result of the hollow fiber being pulled, a myriad of micropores at the submicron level are formed in the hollow fiber. When observing that part under natural light, the part where the fine holes are formed diffusely reflects the light and appears white, and the part where stretching is not performed has extremely few fine holes, so the light does not diffuse. It passes through and looks transparent. Therefore, this portion is called a non-whitened portion.

The whitening rate increases with an increase in the number of fine holes and an increase in the hole diameter. However, if the hole diameter is too large, the function as a separation membrane is lost. Of course, it goes without saying that the pore size is changed according to the size of the separated substance. However, when observing by irradiating not the natural light but the light from the bottom of the hollow fiber, the non-whitened portion has a small number of fine pores or no pores, and thus the light is transmitted and looks bright. On the contrary, the normal part without defects looks dark because almost all the light is diffusely reflected.

The stretching treatment is a step of imparting a function as a separation membrane that allows only molecules smaller than the pore diameter formed by stretching the unstretched yarn to pass through. Insufficient parts will reduce the cross-sectional area, so not only the function of the separation membrane itself will not be exhibited, but when used in the medical field such as artificial kidney dialysis, the blood in the hollow fiber can be seen through and the value as a product Also decreases.

The present invention describes the inspection and measurement of such non-whitening defects in hollow fibers.

[0006]

2. Description of the Related Art FIG. 7 is a diagram showing an example of the basic structure of a conventional hollow fiber inspection apparatus. As a hollow fiber defect inspection method,
For example, a known example (Japanese Patent Laid-Open No. 3-213129) discloses a method for inspecting a hollow fiber defect in which an unwhitened transmitted light amount is measured by irradiating polarized parallel light to measure an unwhitened portion. In the known example, the incandescent lamp 2 of the light source unit 20
The light emitted from No. 1 is collimated by the condenser lens 22, is linearly polarized by the polarizer 23, and irradiates the hollow fiber 8. In the detection unit 30, the light that is incident on the hollow fiber 8 and depolarized is passed through the filter 26 by the projection lens 25 to form an image on the optical sensor 27, and the amount of light is detected. In this figure, the optical sensor 27 is a point sensor that detects a defect.

[0007]

In the above-mentioned conventional hollow fiber inspection apparatus, since the light receiving field of view of the point sensor is wider than the width of one hollow fiber, the length, thickness, etc. of each unwhitened hollow fiber There was a problem that could not be measured.
Further, since the light receiving field is wide, it is necessary to make it a dark field, which causes a problem that operability in a production line is deteriorated.

Furthermore, if a point sensor is used, polarized parallel light must be generated, and an optical component such as a lens is required. Moreover, since the field of view of the point sensor is narrow, only one weight can be measured by one unit, and in order to inspect a plurality of weights at a time, the number of point sensors corresponding to the weight is required, which is not practical. The present invention applies not only the high-precision and large-quantity inspection by applying the image processing technology to the inspection of the unwhitened defects of the hollow fiber, but also the fundamental analysis of the unwhitened defects such as the defect classification analysis and the pursuit of the cause. The purpose is to take appropriate measures.

[0009]

FIG. 1 is a diagram showing the basic structure of a fibrous material (hollow fiber) inspection apparatus according to the present invention.
The same components as those already described with reference to FIG. 7 are designated by the same reference numerals or symbols. The basic configuration of the present invention is different from the conventional hollow fiber inspection apparatus, in that a polarized light emitting means 1, an imaging means 2, an image processing / measuring means 3, and an output means 4 are added. However, it is not just a function addition to the conventional device,
A high-speed, high-precision image processing device using a CCD camera is applied. The fibrous material 8 is irradiated with light from the polarized light emitting means 1, the image processing / measuring means 3 extracts and measures the image of the unwhitened portion, and the measurement result is recorded in a memory and output to the output means 4. .

[0010]

FIG. 2 is a diagram showing an embodiment according to the present invention. The significance of this embodiment is as follows. According to the embodiment of the present invention, the illumination device 10 and the CCD camera 1
4, an image processing device 16, and a host computer 17. The lighting device 10 is, as shown in FIG.
Polarizer (including film) 11 installed next to
Is attached. The CCD camera 14 is a fibrous material (hollow fiber).
The manufacturing machine 6 is mounted at a position shown in the figure at a distance of about 70 cm, and the lens 13 is equipped with the polarizing plate 12. The CCD camera 14 is connected to the image processing device 16 by a camera cable.
The image processing device 16 is for performing image binarization and image measurement, which will be described later, and includes an image processing dedicated processor (not shown) and
A line memory (not shown) for lines and a run length buffer (not shown) for processing 64K image data are built-in. The host computer 17 controls the image processing dedicated processor to perform various types of image processing, transfer of image data,
Image data is read from and written in the memory 15.

The image processing device 16 is an LSC-100.
(Mitsubishi Rayon Co., Ltd.) is used. The host computer 17 may be a commercially available PC or EWS. The image processing device 16 and the printer 19, which is a means for outputting the result, are connected by a printer cable. The hollow fiber 8'is irradiated with the light emitted from the illuminating device 10. Then, only the light transmitted through the hollow fiber 8'is received by the CCD camera 14, processed by the image processing device 16, and then the size of the defect is measured, and the results are classified and arranged for CRT.
Output to the monitor 18 and the printer 19.

[0012] Thus, according to the embodiment of the present invention, it is possible to inspect a large number of hollow fibers with high accuracy and continuously. The embodiment of the present invention shown in FIG. 2 will be described in more detail. Reference numeral 10 denotes a lighting device, which uses a fluorescent lamp. When a fluorescent lamp is used, it is desirable to use a high frequency of 20 KHz or higher in order to prevent flicker that occurs when the CCD camera 14 takes an image due to a change in luminous intensity when the power supply frequency of the fluorescent lamp is low. In the present invention, a commercially available 40 W fluorescent lamp is used. In addition to this, lighting equipment such as an incandescent lamp, a light emitting diode, and various lasers can also be used.

The light emitted from the illuminating device 10 is arranged so that the polarization axis of the light is at an angle of α1 (about 45 °) with respect to the traveling direction (fiber axis direction) of the hollow fiber 8'which continuously travels. It is polarized by the polarizing plate 11 using a dichroic film.
In this case, for example, it is linearly polarized. The reason why the light is polarized by the polarizing plate 11 is to lighten the unwhitened portion of the hollow fiber and darken the whitened portion and the background to draw the unwhitened portion.

The hollow fiber 8'is irradiated with the light polarized by the polarizing plate 11. At this time, the light that has not passed through the hollow fiber 8 ′ and has passed through as it is and the surrounding background light are difficult to be removed unless they pass through the two polarizing plates. In a normal whitened portion, there is almost no amount of light that is diffusely reflected by a myriad of fine holes and is incident on the polarizing plate 12. On the other hand, in the unwhitened portion, the polarization is eliminated, and the light transmittance is high due to the birefringence due to the orientation crystallization, and thus the polarizing plate 12
Since the amount of light reaching the area is larger than that in the normal area, the white area without defects appears dark and the unwhite area with defects appears bright. The polarized light is birefringent in the unwhitened portion and the polarized light is eliminated. Therefore, the polarized light is transmitted through the polarizing plate 12 arranged with a polarization axis of about 90 ° with respect to the polarizing plate 12 with a high transmittance and the lens 13
to go into.

The lens 13 has, for example, a focal length of f = 5.
A 0 mm commercially available lens is used. The distance from the resolution of the lens 13 to the hollow fiber 8 ′ is, for example, L (about 677).
mm), from the hollow fiber 8'to the lighting device 10 L2 (about 4
0 mm). The light passes through the lens 13 and is received by the light receiving element of the CCD camera 14. In the present invention, for example,
A line sensor with 5000 pixels, a resolution of 80 μm, a scanning resolution of 0.33 mm / pixel in the traveling direction, and a scanning cycle of 1 msec is used. This sensor can be inspected even in the bright field, and the vibration of the hollow fiber 8 ′ during traveling Not easily affected. When the traveling speed of the hollow fiber 8'changes, it is necessary to change the scanning cycle. CCD due to lens distortion
Although the resolution around the camera 14 is slightly lowered, the unwhitened portion of the hollow fiber can be detected practically with sufficient accuracy.

A light receiving element of the CCD camera 14 converts an optical signal into an electric signal and sends it to the image processing device 16 via a cable. The image processing device 16 extracts images from the CCD camera 14 that are equal to or greater than a certain threshold value. The threshold is CC in FIG.
As can be seen from the diagram in which the output level of the D camera 14 is measured, the output of the unwhitened portion is about 1.0 V and the output of the whitened portion is about 0.1 V, so there is no influence of noise in the middle.
The maximum output of the CD camera 14 is set to about 20%. That is, it is possible to extract only the unwhitened portion without extracting the whitened portion. When the hollow fiber 8'is not present between the illuminating device 10 and the CCD camera 14, the output is at the GND level as shown in FIG.

The image processing and image measurement of the present invention are performed in the following order. (1) A / D conversion (2) Binarization processing (3) Run length coding (4) Connectivity processing (expansion / reduction) (5) Image measurement The following description will be given in the order of actual processing. First, the density level of the captured image is converted into 256 levels from 0 to 255, and then, 1 is added to the defective portion to be extracted and 0 is added to the other portions, and the binarization processing is expressed by the density gradation. I do.
The criterion for separating and extracting defects is a fixed threshold (about 0.1 V-
The intermediate value of 1.0V) is used.

After the binarization process, run length coding is performed. Run-length coding is also called one-dimensional coding,
This is an encoding method that uses the correlation between adjacent pixels on the same line. As a coding method, a method used in facsimile is adopted. The reason for adopting this method is that the coding efficiency is high. After the binarization and the run-length coding, the connectivity process, which is a pre-process for image measurement, is performed next. In this connectivity processing, noise mixed by vibration during traveling such as discontinuous portions and isolated portions of the image is removed. Even if the hollow fibers are divided, the noise is smoothed, and the images are connected by the image expansion / reduction processing that facilitates later image measurement. The image expansion / reduction process is a process of removing discontinuous portions with a specified interval or less.

Image measurement generally means extracting features from a target image and measuring the shape, size, position, number and the like. Actually, assuming that a certain point is P (x, y), the number of pixels or clock pulses from the corresponding horizontal and vertical synchronization signals to this point is counted, and converted from this to coordinate values. Where the horizontal sync signal is x
The coordinate and the vertical synchronizing signal serve as a reference for obtaining the y coordinate.

(A) Position The position is measured by counting scanning lines up to coordinates or clock pulses as described above. (B) Area The number of pixels or clock pulses included in the image is counted to obtain the area.

(C) Count The number of defects generated for each weight is counted by software. The size of the extracted defect is determined by the host computer 17
The images are displayed on the CRT monitor 18 classified by size. The maximum number that can be displayed on the screen is eight, and if more than that, scroll display is performed. Measurement data is CRT
It can be output to the monitor 18 and the printer 19. By keeping a history of the measurement results in this way, it can be useful for later investigating the cause of defects in the hollow fibers 8'and taking countermeasures, and contributes to the reduction of defects in the hollow fibers 8 ', that is, the improvement in yield.

FIG. 3 is a view showing the arrangement of the CCD camera 14 detection section. FIG. 3A is a view seen from the CCD camera 14 side. The polarizing plate (polarizer) 11 mounted on the illuminating device 10 is α1 (about 4 mm) with respect to the traveling direction of the hollow fiber 8 ′.
The polarization axis is 5 °. When the light emitted from the illuminating device 10 enters the polarizing plate 11, it is linearly polarized and irradiated on the hollow fiber 8 ′.

Further, the polarizing plate (analyzer) 12 mounted on the lens 13 of the CCD camera 14 is arranged with the polarization axis of α2 (about 45 °) with respect to the hollow fiber 8 ', similarly to the polarizing plate 11. As a result, the angle between the polarizing plate 11 and the polarizing plate 12 is θ (about 90 °) and they are orthogonal to each other. When the polarizing plate 11 and the polarizing plate 12 are arranged so as to be orthogonal to each other in this manner, the amount of light transmitted through the hollow fiber 8'is minimized. This utilizes the optical principle that when the polarizer and the analyzer are arranged orthogonally, the amount of light passing through the polarizer and incident on the analyzer is minimized. The polarization axis does not have to be strictly arranged at 45 °, and there is practically no problem if it has an allowable range of about 45 ± 15 °, that is, about 30 to 60 °. The polarizing plate 11 is a linear polarizing sheet based on a transparent plastic sheet, and the polarizing plate 12 is a glass polarizing plate.

FIG. 3B is a view seen from the traveling direction of the hollow fiber 8 ', and the CCD camera 14 is the CCD camera 1 as shown in FIG.
The polarizing plate 12 is attached to the lens 13 of No. 4, and the lighting device 1
A polarizing plate 11 is attached on top of 0. The distance from the polarizing plate 12 to the hollow fiber 8 ′ is, for example, L1 (about 677 m
m), the distance from the hollow fiber 8 ′ to the polarizing plate 11 of the lighting device 10 is set to L2 (about 40 mm). Both of these values are calculated from the resolution of the CCD camera 14. The CCD camera 14 uses SCC-5000 (manufactured by Mitsubishi Rayon Co., Ltd.) and has a resolution of about 0.0.
8 mm / pixel, field of view is about 400 mm. Lens 13
Has a focal length of about f = 50 mm.

FIG. 4 is a diagram showing the relationship between the inspection position of the CCD camera 14 and the output value. FIG. 4A is a diagram showing the relationship between the angle of the hollow fiber 8 ′ and the polarizing plate 11 and the output value of the unwhitened portion. The polarizing plate 11 and the polarizing plate 12 are arranged so as to be orthogonal to each other (FIG. 4A). 45 °), the intensity of light emitted from the polarizing plate 12 is maximized, which is a diagram showing the theoretical basis of FIG. The vertical axis represents the output value (unit mV), and the horizontal axis represents the angle (unit deg). From this figure, it can be seen that the output reaches a maximum of 800 mV or more at an angle of about 45 °. However, in reality, it is about 45 ± 15 °, that is, about 30-60.
There is an allowable range of °.

FIG. 4B is a diagram showing the relationship between the detection position and the output value. If it is within the permissible range of the visual field of about 400 mm,
It is a figure which shows the theoretical basis of FIG.3 (b) that there is little change of an output value. The vertical axis represents the output value (unit mV), and the horizontal axis represents the distance from the center of the field of view of the CCD camera 14 (unit m).
m). From this figure, of course, about 100 to 1 at the center of the visual field
At the maximum output level of about 800 mV at 50 mm, C
In the peripheral part of the CD camera 14, due to the distortion of the angle between the lens 13 and the polarizing plate, about 200 mm (W (about 400 m as a whole
m)) output is slightly reduced around the field of view, but
It can be seen that there is no problem in practical use and the unwhitened portion around the CCD camera 14 can be sufficiently detected. Further, since the angle of view is wide, it is not necessary to use a condenser lens to generate parallel light as in the conventional case.

FIG. 5 is a diagram showing the output level of the CCD camera 14 measured by the measuring device (oscilloscope). FIG. 5 (a) is a diagram showing the output level of the unwhitened portion of the hollow fiber 8 '. The thick white line below is the GND level indicating the output level of the transmitted light when the hollow fiber 8 does not exist between the illumination device 10 and the CCD camera 14. Since the hollow fiber 8 does not exist, the light polarized by the polarizing film 11 enters the polarizing plate 12 as it is without being birefringent, is blocked by the polarizing plate 12, and the transmittance becomes almost 0. The output value is close to 0V. On the other hand, since the non-whitened portion is transparent or semi-transparent, the transmitted light of the polarized component is depolarized and is transmitted through the polarizing plate 12 with a high transmittance to have an output value of about 1.0V.

FIG. 5 (b) is a diagram showing the output level of the whitened portion of the hollow fiber 8 '. When the whitened portion of the hollow fiber 8'is irradiated with polarized light, it is diffusely reflected or absorbed, so that transmitted light is not output, and therefore the output level is about 0.
It becomes 1V. The present invention pays attention to the difference between the output levels of the unwhitened part and the whitened part, and sets an inspection threshold between the unwhitened part (about 1.0 V) and the whitened part (about 0.1 V). To extract the image.

The inspection result is CR of the host computer 17.
FIG. 6 is a diagram showing a state of outputting to a T monitor 18 and a printer 19. The host computer 17 incorporates newly developed software for classifying and displaying the results of inspection of the hollow fibers 8'according to the present invention. The CRT screen is divided into two areas at the center, and the size of the defect for each weight and the time of occurrence are displayed on the right side of the screen on the upper screen. Depending on the size of the defect, S (Small: 10 mm or less), M (Med
ium: 100 mm or less), L (Large: 1000)
mm or less). The screen below is S,
It is the number of defects generated for each weight classified into three stages of M and L.
The display is constantly updated in real time. Up to eight can be displayed on one screen, and if more than that, scroll display is performed. Further, these detection results can be output to the printer 19 connected to the host computer 17.

Although the above description has been made with respect to the hollow fiber, it can be applied to other fibers.

[0031]

As described above, the present invention has the following remarkable effects. (I) It is possible to measure the length, thickness, area, number, etc. of each unwhitened portion of the hollow fiber 8'in a bright field. (Ii) Since the space around the running hollow fiber 8'is sufficiently large, it is possible to inspect tens or hundreds of hollow fibers 8'with one fibrous material (hollow fiber) inspection device 5. The operability in the production line does not deteriorate, and the effect of the practical fibrous material (hollow fiber) inspection device 5 is great.

(Iii) The measurement results of the defective portion of the hollow fiber 8'can be recorded on a disk or a printer, which can be used for investigating the cause of the defect occurrence, analysis, and countermeasures.
Improves defect reduction, reliability and yield. (Iii) The hollow fiber 8'is not easily affected by vibration during traveling, and installation and maintenance are easy.

[Brief description of the drawings]

FIG. 1 is a diagram showing a basic configuration of a fibrous material (hollow fiber) inspection device based on the present invention.

FIG. 2 is a block diagram showing an embodiment of a fibrous material (hollow fiber) inspection device according to the present invention.

FIG. 3 is a diagram showing a configuration of a CCD camera detection unit.

FIG. 4 is a diagram showing a relationship between an inspection position of a CCD camera detection unit and an output value.

FIG. 5 is a diagram showing an output level of a CCD camera.

FIG. 6 is a diagram showing a configuration of a conventional hollow fiber inspection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Polarized light emission means 2 ... Imaging means 3 ... Image processing / measurement means 4 ... Output means 5 ... Fibrous material (hollow fiber) inspection apparatus 6 ... Fibrous material (hollow fiber) manufacturing machine 6 '... Hollow fiber manufacturing machine 7 ... Stretching device 8 ... Fibrous material 8 '... Hollow fiber 10 ... Illuminating device 11 ... Polarizing plate 12 ... Polarizing plate 13 ... Lens 14 ... CCD camera 15 ... Memory 16 ... Image processing device 17 ... Host computer 18 ... CRT monitor 19 ... Printer 20 ... Light source part 21 ... Incandescent lamp 22 ... Condensing lens 23 ... Polarizer 24 ... Analyzer 25 ... Projection lens 26 ... Filter 27 ... Optical sensor 30 ... Detection part

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Junichi Harada 4-1, Ushikawa-dori, Toyohashi-shi, Aichi Prefecture

Claims (13)

[Claims] 1. A fibrous material inspection device (5) for inspecting a non-whitening defect of a fibrous material, comprising polarized light emitting means (1) for emitting polarized light and transmitting the light through the fibrous material (8). An image pickup means (2) for extracting the light emitted from the polarized light emission means (1) and transmitted through the fibrous material (8) as an image, and after applying image processing to the image extracted by the image pickup means (2), A fibrous material inspection characterized by comprising an image processing / measuring means (3) for measuring a defect and an output means (4) for outputting a result measured by the image processing / measuring means (3). apparatus. 2. The polarized light emitting means (1) includes an illuminating device (10) for emitting light for inspecting the fibrous material (8), and a polarizing plate (9) for polarizing the light from the illuminating device (10). 1
The fibrous material inspection device according to claim 1, which is composed of 1) and 3. The image pickup means (2) includes a polarizing plate (12) for transmitting depolarized light transmitted through the fibrous material, and a lens (1) for inputting light from the polarization filter (12).
The fibrous material inspection device according to claim 1, comprising 3) and a CCD camera (14) for receiving light that has passed through the lens (13). 4. The fibrous material according to claim 1, wherein the image processing / measuring means (3) comprises an image processing device (16) for extracting and measuring an image taken by the imaging means (2). Inspection device. 5. The output means (4) displays the result measured by the image processing device (16).
The fibrous material inspection device according to claim 1, comprising an RT monitor (18) and a means (19) for printing the measurement result from the image processing device (16). 6. The fibrous material inspection apparatus according to claim 2, wherein the polarizing plate (11) is arranged with a polarization axis of about 45 ° with respect to the fiber axis of the running fibrous material (8). 7. The polarizing plate (12) is arranged with a polarization axis of about 45 ° with respect to the fiber axis of the fibrous material (8) in running, and an angle formed by the polarizing plate (11) is The fibrous substance inspection device according to claim 3, wherein the fibrous substance inspection device has an angle of about 90 °. 8. The fibrous material according to claim 6, wherein the polarizing plate (11) has a permissible range of a polarization axis of about 45 ° ± 15 ° with respect to the fiber axis of the fibrous material (8) during running. Inspection equipment. 9. The fibrous material according to claim 7, wherein the polarizing plate (12) has an allowable range of a polarization axis of about 45 ° ± 15 ° with respect to the traveling direction of the fibrous material (8) during traveling. Inspection equipment. 10. The fibrous material inspection device according to claim 3, wherein the polarizing plate (12) is attached to the lens (13). 11. The fibrous material according to claim 4, wherein the image processing device (16) has an expansion / contraction processing function for connecting images separated by vibration and noise of the fibrous material (8) during traveling. Inspection equipment. 12. The image processing device (16) performs processing such as binarization and expansion / reduction of the image of the unwhitened portion, and measures the length and position of defects in the fibrous material (8). The fibrous material inspection device according to claim 4. 13. The image processing device (16) sets a threshold between the unwhitened portion output and the whitened portion output, and extracts only the output of the unwhitened portion of the fibrous material (8). Item 5. The fibrous material inspection device according to item 4.