JPH0424275A - Automatically examining device and examining method - Google Patents

Abstract

PURPOSE:To enable accurate automatic inspection subjected to zigzag correction under high speed by observing a traveling long article to be inspected by an optical linear sensor and converting the output signal into binary digit and simultaneously recording coordinates of defect position. CONSTITUTION:An article 1 to be inspected of fiber structure such as woven fabric, knit fabric or nonwoven fabric or film-like structure is continuously or intermittently traveled and the surface of the above-mentioned article 1 to be inspected illuminated by a standard light source is observed by an optical linear sensor 4 having wider view than width of the article 1 to be inspected and the output signal is passed through shading correction circuit 5 and gamma correction circuit 6 and converted into binary digit by shreshold and simultaneously passed through window producing circuit 8 to clock generation circuit 9, where clock signals designating coordinates in width direction of the above- mentioned article 1 to be inspected are output and these signals are housed through CPU 10 into a memory 11.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an automatic inspection device and inspection method for detecting defects inherent in fibrous structures such as woven fabrics, knits, nonwoven fabrics, or film-like articles. More specifically, the present invention relates to an automatic inspection and inspection method having a function of detecting defects in the fiber structure or film-like material and mapping the position of the defects.

(Prior Art) Conventionally, inspection of defects inherent in these fibrous structures or film-like materials has relied entirely on the visual or tactile sense of an expert. However, in recent years, COD sensors have become available at low cost as solid-state video devices to replace image pickup tubes, and signal processing technology has improved.
With the development of image processing technology, many attempts are being made to replace these sensory tests, which have traditionally relied on human vision, with machines.

Now, in automatic inspection using these machines, which originally aims to save labor, it is necessary to map the positions of detected defects and store them on a memory medium. As a mapping method, a method in which an orthogonal coordinate system is established in the length direction and width direction of the object to be inspected, and is displayed and recorded in xy coordinates is the most common and most practical method.

It is not very difficult to record the defect coordinates. For example, as shown in Figure 1, a roller system is used to convey the object to be inspected (fibrous structure or film-like object continuously or intermittently). In automatic inspection machines, defects are detected by observing the object to be inspected using a linear sensor, etc. that has a field of view in the width direction, and processing (for example, binarizing) the signals obtained by the linear sensor. The position within the field of view of the linear sensor at the time of detection (in the width direction) and the feed length (length direction) of the object to be inspected may be recorded (see Figures 2 and 3).

The obtained map can be used as information for repairing defects or in subsequent processes, such as when the object to be inspected is a textile and sewing is performed as a secondary processing step, to avoid defective parts when cutting. used.

(Problem to be solved by the invention) Defect maps are originally recorded in the coordinate system on the object to be inspected.If the sensor that detects defects is fixed, from the point of view of the automatic inspection machine, the position of the detected defect is simply the defect position within the field of view of the linear sensor that observes the object to be inspected. That is, the defect coordinates recorded are based on the coordinate system on the hardware of the automatic inspection machine. If the object to be inspected is transported without meandering, the coordinate system on the object to be inspected and the coordinate system on the automatic fabric inspection machine will match as long as the initial position is matched, but if the object to be inspected is meandering, In this case, a ``difference'' immediately arises between the two.

Now, if the post-processing is performed manually, it is fine, but if the defect map is inaccurate when the post-processing is performed automatically, the purpose of defect mapping becomes questionable in the first place. Therefore, in defect mapping, it is necessary to use some method to correct the defect coordinate position due to the meandering of the inspected object.

Of course, efforts are being made to improve the meandering of the object to be inspected by fine-tuning the inclination of the rollers, etc., but although these measures can suppress the degree of meandering to a certain extent, it is difficult to use limiters. Meandering cannot be completely eliminated as long as feedback control is used. With the current state of the art, it is not impossible to eliminate meandering of the object to be inspected to a practically sufficient extent. However, this unnecessarily complicates the conveyance mechanism and increases the cost of the automatic inspection machine itself, which is not realistic.

Although it is conceivable to move the linear sensor in synchronization with the meandering of the fabric, it is not a desirable method as it would unnecessarily increase the number of moving parts and complicate the control system.

It is possible to detect the meandering of the inspected object by some means and correct the coordinate position using software when mapping defects. However, in this case,
This places a burden on the software and requires time for processing, which may impair real-time performance in some cases.

In view of this situation, the present inventors have conducted extensive research, and as a result,
The following invention has been achieved regarding an automatic inspection device and an inspection method that develop a function to correct positional deviation of defect coordinates on a defect map due to meandering of an inspected object.

(Means for Solving the Problems) That is, the present invention provides a mechanism for conveying an object to be inspected continuously or intermittently, and a defect detection mechanism having an optical linear sensor having a field of view wider than the width of the object to be inspected. , an automatic inspection device having means for recording the coordinates of detected defects on the inspected object, and a field of view sufficiently wider than the width of the inspected object while conveying the inspected object continuously or intermittently. By observing defects with an optical linear sensor having a Automatic inspection characterized by having a function of correcting deviation of defect coordinates in the width direction due to meandering of the object to be inspected by starting a clock signal specifying the coordinates in the width direction of the object at the rising edge of the window signal. Method.

In the present invention, for example, defects in a fibrous structure or film-like object to be inspected are detected in a part of a roller system that continuously conveys the fibrous structure or film-like object. .

As a defect detection method in the present invention, known contact or non-contact sensors such as magnetic sensors, optical sensors, load cells, electrostatic sensors, etc. can be used. In any case, the sensor used in the present invention is required to be a linear sensor that has a linear field of view in the width direction of the object to be inspected. A sensor that can be preferably used in the present invention is C
It is an OD linear sensor.

A feature of the present invention is that the meandering correction of the object to be inspected is performed on a map by processing the signal output obtained from the sensor, and that no mechanical movable parts are used.

(Operation) According to FIG. 4, the signal processing of the present invention will be explained in more detail.

The object to be inspected is observed with an optical linear sensor that has a field of view sufficiently wider than the width of the object to be inspected. The visual field width of the optical linear sensor is 1.01 to 1.01 times the width of the object to be inspected.
It is sufficient if it is 1.5. The signal obtained from the linear sensor schematically has a form as shown in figure (4-1). If the tone of the background is suppressed so that it is easy to distinguish between the background and the object to be inspected, (4
-2) As shown in the figure, by setting an appropriate threshold, it is possible to form a window that indicates the position of the object to be inspected within the field of view of the linear sensor (one scanning time of the linear sensor).

A clock signal specifying the coordinates in the width direction of the object to be inspected is started at the rising edge of the window. As a result, the clock that specifies the coordinates in the width direction always starts from the edge of the object to be inspected, so even if the object to be inspected meanders,
On the map, the deviation of the defect coordinates in the width direction is corrected.

In conventional technology, the beginning of the field of view of the linear sensor (
Since the clock signal indicating the coordinates in the width direction is started at the same time as the start of running, even if the object to be inspected is meandering, the position of the defect is determined based on the coordinate system based on the field of view of the linear sensor. It was recorded in

In other words, the present invention does not have any mechanical moving parts, and all signal processing is performed in hardware on electric circuits, so there is no burden on software, in other words, the meandering process can be performed at high speed in real time. This allows for correction.

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

(Embodiment) Embodiment FIG. 5 is a schematic explanatory diagram showing a detection section and a signal processing block of an "automatic inspection device" according to 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 fiber structure is placed in the center of the two rollers. This system illuminates the object to be inspected, observes the object using a linear sensor, and detects defects.

A DG5 standard light source is used for illumination, and the light source is placed at the center of the object to be inspected.The roller width is 190 cm1.The feeding speed of the fiber structure or film-like object is between 0 and 75 m/min by controlling the drive motor of the conveyance system with an inverter. I made it more variable.

Among the outputs of the linear sensor, the signal used for defect detection is binarized by a predetermined threshold after passing through a shading correction circuit and a γ (gamma) correction circuit, and the presence or absence of a defect is determined. Defect mapping is also performed in the manner described in FIG.

Width 10c shown in Figure 8, with model defects
Defect detection and mapping tests were conducted using a test fabric with a length of 30 m. During the test, the model fabric had a width of 45
It was forced to meander across cs. Figure 7 shows the defect map obtained. The location of the defect matched the location of the model.

Comparative Example Using the same device as in the example, a clock signal indicating the coordinates in the width direction was started at the same time as the start of the field of view of the linear sensor (start of running), and the following tests were conducted in the same manner as in the example. The defect map obtained is shown in FIG. The defect position recorded on the map reflected the meandering.

(Effects of the Invention) According to the present invention, there is no mechanical moving part and all signal processing is performed on the electric circuit in an X-ware manner, so there is no burden on the software, in other words, the speed is increased. It has become possible to obtain a device with excellent characteristics that allows meandering correction to be performed in real time.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of an automatic inspection machine. FIG. 2 is an example of a signal obtained from a defect-free part in an automatic inspection machine. FIG. 3 is an example of a signal obtained from a defective part in an automatic inspection machine. FIG. 4 is a schematic explanatory diagram of the signal processing system of the automatic inspection device according to the present invention. FIG. 5 is a schematic explanatory diagram showing the detection section and signal processing block of the automatic inspection device according to the present invention. FIG. 6 shows the fabrics used in the test of the automatic fabric inspection device in Examples and Comparative Examples. FIG. 7 shows the defect mass obtained in the example. FIG. 8 is a defect map obtained in a comparative example. ■ Object to be inspected ■ Feed roller ■ Standard light source ■ Linear sensor Shading correction circuit Gamma correction circuit Judgment circuit Window generation circuit Clock generation circuit PU Memory (magneto-optical disk)

Claims (2)

[Claims] (1) A mechanism that continuously or intermittently transports the inspected object, a defect detection mechanism having an optical linear sensor having a field of view wider than the width of the inspected object, and a defect detecting mechanism that moves the detected defect onto the inspected object. automatic inspection equipment having means for recording the coordinates at (2) While conveying the inspected object continuously or intermittently,
By observing defects with an optical linear sensor that has a field of view sufficiently wider than the width of the object to be inspected, and applying a predetermined threshold to the output of the linear sensor, the object to be inspected within one travel time of the linear sensor is By forming a window that indicates the position of the object to be inspected and starting the clock signal that specifies the coordinates in the width direction of the object to be inspected at the rising edge of the window, the deviation of the defect coordinates in the width direction due to meandering of the object to be inspected is corrected. An automatic inspection method characterized by having a function.