JPH03255952A - Detecting method for wrinkle - Google Patents

Abstract

PURPOSE:To accurately detect the wrinkle with efficiency by lighting a body to be inspected such as a fiber structure while conveying it, and detecting the temperature difference between the lighted part and a shadow part which is formed because of the wrinkle in the body to be inspected. CONSTITUTION:The fiber structure or a filmy body which is the body 2 to be inspected is conveyed continuously or intermittently by two feed rollers 1 and lighted at the center part of the two rollers 1 and the temperature distribution of the shadow part of the body 2 to be inspected due to the 'wrinkle' is observed by a radiation type temperature distribution meter 4. For example, a daylight fluorescent lamp 5 is used for the lighting and arranged so that the center of the fluorescent lamp 5 is at a specific angle, e.g. 3 deg. from the horizontal direction of the body 2 to be inspected. The signal obtained by the temperature distribution meter 4 is passed through a shading correcting circuit 3 and a gamma correcting circuit 6 and then converted into a binary signal based upon a specific threshold value to decide whether or not there is a defect and makes its display 7.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for detecting wrinkles. For more details,
The present invention relates to a method for detecting wrinkles, which are a type of defect inherent in fibrous structures or film-like materials.

(Prior Art) "Wrinkles" are a type of defect inherent in fibrous structures such as woven fabrics, knits, nonwoven fabrics, or film-like materials. In the present invention, "wrinkles" that are treated as "defects", such as "wrinkles" or "creases" that occur when there is a partially unbalanced tension in a fiber structure or film-like material, are eliminated. set to target.

Conventionally, inspection of defects inherent in fibrous structures or film-like materials has relied heavily on the visual or tactile sense of an expert. In recent years, several proposals have been made to automatically detect defects in these fibrous structures or film-like materials using machines. however"
Detection of "wrinkles" still relies heavily on the visual sense of an expert, and no satisfactory proposal has been made regarding a method or device for automatically detecting wrinkles. Fiber structures have extremely complex structures even in their normal parts. Another advantage is that fibrous structures or film-like materials are inherently soft and can expand and contract appropriately. Therefore, when handling fiber structures or film-like objects, "wrinkles" that naturally occur due to the characteristics of such fiber structures or film-like objects are not recognized as defects.

It is difficult to distinguish between "wrinkles" that should be recognized as defects and "wrinkles" that are not recognized as defects, and even for experts, experience is said to be important, especially when it comes to detecting "wrinkles."

Detection of the presence of "wrinkles" by a skilled person is not simply based on the results obtained by observing the object to be inspected from a certain direction. Although it is extremely difficult to quantify or even explain qualitatively, it is known that humans recognize events based on extremely multidimensional information. The same applies to the detection of "wrinkles"; the recognition of "wrinkles" as a defect is the result of observing the inspected object from a very multifaceted perspective.

In contrast, the information obtained when observing an object to be inspected using a machine such as an optical sensor is merely the result of observing the object from one side, and the amount of information obtained is extremely small.

For example, when inspecting an object to be inspected while continuously transporting it, the image of the object at a certain moment is simply interpreted as "
Rather than recognizing "wrinkles", they read "wrinkles" from the subtle movements of the image that continuously change from moment to moment due to vibrations caused by transportation, fluctuations in lighting, etc.

(Problem H that the invention attempts to solve) As described above, the mechanism for detecting defects by human senses is surprising and even mysterious. It is extremely difficult for a machine to automatically make such advanced judgments in real time within a practical range, even with current signal processing technology and image processing technology using combinators. It is something to master.

However, these human visual and tactile inspections require skill on the part of those conducting the inspection, and are not always efficient and accurate. These problems are fatal when inspecting fibrous structures or film-like products that are produced in large quantities using a large number of production machines.

In particular, fiber structures have extremely complex structures even in their normal parts, and the variations and distribution of tension are not small at all. Wrinkle detection is the process of extracting particularly large deviations from this variation, and a certain high standard should originally be set for this.

However, even with the eyes of an experienced expert, it is virtually impossible to constantly inspect many fiber structures with a constant standard.

In recent years, it has become possible to stabilize the quality of industrial products at a high level through thorough QCl, or quality control. I can't hide my surprise at how well quality control has been carried out.

In recent years, COD sensors have become available at low cost as solid-state imaging devices that replace image pickup tubes, and with the development of signal processing technology and image processing technology, these sensory tests that have previously relied on human vision have changed. Many attempts are being made to replace them with machines. However, the automatic detection of "wrinkles" which is the object of the present invention is still not practical and satisfactory due to problems such as the diversity of "wrinkles" mentioned above and in particular the difficulty in setting the determination level. We are not getting what we should be getting.

In view of this situation, the present inventors have conducted extensive research, and as a result,
We have achieved the next invention related to a method for detecting wrinkles with good reproducibility and with a certain standard.

(Means for Solving the Problem) That is, the present invention illuminates the fiber structure or film-like object while conveying the fiber structure or film-like object continuously or intermittently, and "Wrinkle" is defined as the temperature difference between the part and the shaded part caused by the wrinkles inherent in the fiber structure or film-like material.
This is a wrinkle detection method characterized by detecting.

The present invention illuminates the fibrous structure or film-like object in a part of a roller system that continuously conveys the fibrous structure or film-like object to be inspected. This method attempts to detect "wrinkles" by observing the shadows caused by the underlying wrinkles.

The present invention is characterized by a method for detecting "shaded areas caused by wrinkles" that occur in a fiber structure or film that is an object to be inspected. That is, the "shaded area caused by wrinkles" is detected based on its temperature distribution.

The means for detecting temperature distribution is not particularly limited, but it is preferable to use a non-contact temperature sensor. As the non-contact temperature sensor, an infrared sensor, a radiation thermometer, an autothermograph, etc. can be used.

The present invention is not limited to the color tone, pattern, pattern, etc. of the object to be inspected. In particular, in the present invention, “
It can be applied extremely effectively not only to plain objects but also to patterned objects with any pattern.

In the present invention, in order to improve the ability to detect defects, it is also possible to adopt a method of detecting defects by applying a threshold silt after performing shading correction and γ (gamma) correction on the signal output of the sensor. Further, in this case, depending on the color tone, surface condition, etc. of the object to be inspected, a γ (gamma) correction level and threshold level setting method may be used for each object to be inspected. In addition, a plurality of sensors are installed in the direction of fabric conveyance, and the signal portion corresponding to the same location on the object to be inspected detected by the plurality of sensors is
By calculating the sum, it is also possible to perform signal processing such as canceling out noise and emphasizing signals caused by defects.

The lighting equipment used in the present invention is not particularly limited, and existing lighting equipment such as fluorescent lamps, incandescent lamps, arc lamps, gas discharge lamps, etc. may be used appropriately.

Further, an appropriate filter may be used depending on the color tone of the object to be inspected. However, particularly preferred illumination in the present invention is to use "light generated from a heating element",
More specifically, it is preferable to use a lighting device such as an incandescent bulb or a reflex lamp that has a wavelength distribution extending toward the longer wavelength side.

It is preferable that the center of the device for illuminating the fibrous structure or film is located at an angle of 0 to 35 degrees from the horizontal direction of the fibrous structure or film that is the object to be inspected; -15 degrees, more preferably a range of 0-10 degrees, and an even more preferable range is 0-15 degrees.
It is 5 degrees.

EXAMPLES The present invention will be explained in more detail by way of Examples below, but the present invention is not limited thereto.

(Examples) Example 1 FIG. 1 is a schematic explanatory diagram showing a detection part of a "fabric inspection device" used in the present invention. As shown in the figure, two feed rollers are installed as part of the roller system that continuously conveys the fibrous structure or film-like object to be inspected, and the fibrous structure or film-like object is conveyed at the center of the two rollers. The film-like material is illuminated and a radiation temperature distribution meter is used to observe the temperature distribution in the shaded areas of the fiber structure or film-like material caused by "wrinkles."

For illumination, the center of a daylight fluorescent lamp is placed at an angle of 3 degrees with respect to the center of the object to be inspected.

The roller width was 190 cm, and the feeding speed of the fibrous structure or film material was variable between 0 and 75 m7 minutes by controlling the drive motor of the conveying system with an inverter.

After passing through a shading correction circuit and a γ (gamma) correction circuit, the signal obtained from the radiation temperature distribution meter is binarized using a predetermined threshold, and the presence or absence of a defect is determined.

FIG. 2 is an example of the temperature distribution obtained from a normal part without wrinkles when the object to be inspected is a plain woven fabric.

The closed curves in the figure are equimixed lines.

FIG. 3 is an example of a temperature distribution obtained from a wrinkled area. The shaded areas caused by wrinkles are clearly captured as temperature distribution.

``Wrinkles'' were detected separately on a fabric having a total length of 1000 m prepared especially for wrinkle inspection training using this fabric inspection device and a skilled inspector at an average conveyance speed of 50 m/min. The cloth used in the test has been repeatedly inspected by multiple skilled inspectors beforehand.
The defects are mapped. There are a total of 57 "wrinkles" mapped as defects.

Now, the fabric inspection device detected 56 "wrinkles" and the skilled inspectors detected 49 "wrinkles." The positions of the detected wrinkles matched the previously obtained map.

(Effects) According to the present invention, compared to human visual inspection, fiber structures or This made it possible to detect wrinkles inherent in film-like objects.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of a fabric inspection device used in the present invention. FIG. 2 is an example of a signal obtained from a portion without "wrinkles" in the embodiment. FIG. 3 is an example of a signal obtained from a portion with "wrinkles" in the embodiment. ■Feed roller ■Clothing material ■Shading correction circuit ■Radiant temperature distribution meter ■Daylight color fluorescent lamp

Claims (1)

[Claims] (1) While conveying a fibrous structure or film-like object continuously or intermittently, the fibrous structure or film-like object is illuminated, and the portion illuminated by the lighting and the fibrous structure or film-like object are A method for detecting wrinkles, characterized in that wrinkles are detected based on the temperature difference between the wrinkles and the shaded areas caused by the wrinkles inherent in an object.