JP3290927B2 - Winding inspection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for automatically detecting winding deviation between winding layers in a part or product manufactured by winding a band-shaped or strip-shaped sheet material such as an electrode of a lithium ion battery or a film capacitor by image processing. The present invention relates to a winding misalignment inspection device for performing an inspection.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for automating an inspection process of exterior and interior conditions of various mechanical parts and electronic products. Research and development on non-contact and automatic inspection by signal processing and image recognition have been actively conducted. By the way, in parts or products manufactured by winding a band-shaped or strip-shaped sheet material such as electrodes of lithium ion batteries or film capacitors,
Inspection of the winding deviation between the winding layers is extremely important in view of these characteristics, and a device as shown in FIG. 7 is known as an apparatus for automatically inspecting this kind of winding deviation by image processing. .

[0003] This winding deviation inspection apparatus will be described.
An X-ray irradiator 3 irradiates one side surface of the inspection object 2 placed on the positioning table 1 with X-rays and includes an image intensifier 4 for absorbing X-rays. The inspection object 2 is imaged from the other side by the television camera 7. This TV camera 7
Is controlled by the television camera control means 9 to obtain an X-ray transmission image corresponding to a tomographic image of the inspection object 2. The video signal from the television camera 7 is input to the A / D conversion circuit 10 and the density of the image is set to, for example, 256 gradations (0 to 255).
The image data is converted into a numerical value, and is input to the image processing unit 11.

FIG. 8 is a flowchart showing the image processing in the image processing section 11, and the image processing of the above-described winding deviation inspection apparatus will be described below with reference to FIGS. In the image processing unit 11, a central processing unit (CPU)
Reference numeral 12 controls the entire system based on a preset control program and control data. First, in the image integrator 13, the image data of the A / D conversion circuit 10 is input a plurality of times, and these image data are added and averaged to obtain integrated image data (step S1). Next, the processing area setting means 14 sets a range to be processed on the image as a processing area in order to detect each position in the arrangement direction of each winding layer to be inspected (step S2). Subsequently, the binarizing means 17 converts the image data into two.
Then, a winding layer transmission image corresponding to the vertical cross-sectional shape of the inspection object 2 is extracted.

Next, the winding layer position detecting means 18 combines the respective winding layer transmission images in the set processing areas in the tomographic direction (the width direction of the sheet material constituting the inspection object 2). The projection data is created, and a change point equal to or greater than a predetermined threshold value is detected as the position coordinates in the winding layer arrangement direction in the winding layer transmission image in the projection data (step S3). Furthermore, the winding layer tip detecting means 19
Sets a processing area for detecting the leading edge of the winding layer which is longer in the tomographic direction with the detected position coordinates as the center for each of the winding layer transmission images (step S4). The intersection point of the created projection data and a certain threshold value is detected as the tip of the winding layer transmission image in the tomographic direction (step S5). Finally, the pass / fail determination means 20 calculates the amount of deviation of the leading end of each of the detected winding layer transmission images, and then determines whether or not the amount of deviation is within an allowable range to determine the quality of the winding deviation. Judgment (Step S
6).

[0006]

However, in the above-described winding deviation inspection apparatus, the image data is binarized to extract the individual winding layer transmission images, and then the length direction of each winding layer transmission image is extracted. And the intersection of the projection data with a certain threshold is determined as the tip of the tomographic direction of the wound layer transmission image, but the density of the X-ray transmission image changes according to the magnitude of the unwind state. Therefore, there is a problem that it is not possible to cope with the variation in the density and it is easy to erroneously recognize the leading end in the winding layer direction of each winding layer transmission image. Further, since the number of winding layers when X-rays pass through the portion to be inspected increases from the outermost periphery toward the center, the X-ray transmission image is composed of the outermost winding layer transmission image and the center winding layer. The image quality is low, having a large density difference with the transmitted image.
Therefore, it is difficult for the conventional winding deviation inspection means to recognize the position of the wound layer transmission image in the arrangement direction, and it is easy to make an erroneous recognition. Therefore, it is difficult to accurately inspect the state of the inside of the inspection object, and there is a problem that it is not possible to accurately determine the quality of the winding deviation.

Therefore, the present invention solves the above-mentioned problems,
An object of the present invention is to provide a winding deviation inspection device capable of determining the quality of a winding deviation of an inspection object formed by winding a strip-shaped sheet material with high accuracy by an automatic inspection based on an X-ray transmission image. It is assumed that.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a winding deviation inspection apparatus for inspecting, by image processing, a winding deviation state of an inspection object formed by winding a band-shaped or strip-shaped sheet material. A tomographic image capturing means for obtaining an X-ray transmission image of the inspection object, and detecting a position in the arrangement direction of each winding layer transmission image corresponding to each winding layer of the sheet material in the X-ray transmission image. Winding layer position detection means, winding layer tip assumed point detecting means for detecting an assumed point at the longitudinal end of each winding layer transmission image, and a tip estimation for each of a plurality of adjacent winding layer transmission images There are provided a tip continuity evaluation means for detecting a true tip position from the continuity of mutual positions of points, and a good / bad judgment means for judging the quality of a winding deviation based on the detected positional relationship between the respective tips.

In this winding deviation inspection apparatus, even if the density of the leading end in the wound layer transmission image varies, after detecting a plurality of assumed points of the leading end, the true leading end position is determined from the mutual positional relationship between these assumed points. Since it is detected, it is possible to accurately detect the leading end of the wound layer transmission image without being affected by the variation in density due to the magnitude of the winding deviation, and to inspect the winding deviation of the inspection object with high accuracy. .

Further, another invention is provided with a tip density change regularity evaluation means for detecting the tip from the regularity of density change around the assumed tip point, instead of the tip continuity evaluation means.

[0011] In this winding deviation inspection apparatus, even if the density of the leading end in the wound layer transmission image varies, after detecting a plurality of assumed points of the leading end, the regularity of the density change around each assumed leading end point. The true tip can be accurately detected.

[0012] In the above invention, the tomographic image capturing means includes:
An X-ray irradiator for irradiating one side surface of the inspection object with X-rays,
A camera that captures an X-ray transmission image from the other side of the inspection target, and is disposed between the X-ray irradiation device and the inspection target;
And a filter for reducing shading of the X-ray transmission image by the camera.

As a result, it is possible to obtain a uniform X-ray transmission image without density unevenness over the entire inner and outer peripheral sides of the winding layer, and to perform image processing on this high-quality X-ray transmission image. Dramatically improved.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing a winding deviation inspection device according to an embodiment of the present invention. In FIG. 1, the same or equivalent components as those in FIG. Hereinafter, only the different configuration will be described.

FIG. 3 shows an example of the inspection object 2 by this winding deviation inspection apparatus. In this embodiment, two types of strip-shaped first and second sheet materials 21 and 22 having different widths and lengths are shown. A case will be described in which the inspection object 2 is inspected for a winding deviation by superimposing and spirally winding.
The inspection object 2 is placed on the positioning table 1, and one side is irradiated with X-rays from the X-ray irradiator 3 via the filter 23, and is inspected by the television camera 7 having the image intensifier 4. The inspection object 2 is taken from an X-ray transmission image taken from the other side and taken by the TV camera 7.
Is obtained.

The filter 23 disposed between the inspection object 2 and the X-ray irradiator 3 has a substantially semicircular horizontal cross section as shown in FIG. It has a function of reducing shading when obtaining an X-ray transmission image of the rotating inspection object 2. In other words, the X-ray radiated to this type of inspection object 2 only transmits through a single winding layer at the outermost periphery, but sequentially increases the number of winding layers toward the center toward the center. Since the image is transmitted, the X-ray transmission image of the inspection object 2 obtained by the television camera 7 has low image quality in which the density is considerably different between the outer peripheral side and the central part. Therefore, by irradiating the X-ray emitted from the X-ray irradiator 3 with a uniform distribution to the inspection target 2 through the filter 23 having a semicircular cross section, the amount of X-ray irradiation to the inspection target 2 is adjusted. The X-ray transmission image picked up by the television camera 7 has almost no difference in density over the entire image, and has high image quality without density unevenness. Therefore, the subsequent inspection performance can be improved.

FIG. 4A schematically shows an X-ray transmission image 25 of the inspection object 2 obtained by imaging with the television camera 7, and the first sheet material 21 in the X-ray transmission image 25. And the respective winding layer transmission images 27 of the second sheet material 22 are arranged in the arrangement direction X.
Irrespective of the position, the density is almost uniform. In this winding misalignment inspection apparatus, as shown in section C, the leading end of the wound layer transmission image 27 of the second sheet material 22 having a small width is located outside the leading end of the winding layer transmission image 24 of the first sheet material 21. When a protruding winding deviation state is detected, it is determined that the inspection is defective. In order to make the determination, each winding layer transmission image 2
The position of the leading end in the tomographic direction 4 (that is, the width direction of the sheet materials 21 and 22) Y is detected. This will be described later. The video signal of this TV camera 7 is A / D
The image density is input to the conversion circuit 10 and, for example, 256
After being digitized into image data converted to gradation (0 to 255), it is input to the image processing unit 28.

FIG. 2 is a flowchart showing the image processing in the image processing section 28. Hereinafter, the image processing of the winding deviation inspection apparatus will be described with reference to FIGS. In the image processing unit 28, a central processing unit (CPU) 12 controls the whole based on a control program and control data set in advance. First, the image data of the A / D conversion circuit 10 is input a plurality of times in the image integrator 13, and the image data is added and averaged to obtain integrated image data (step S11). Thereby, the influence of random noise generated in the X-ray transmission image 25 is removed.

Next, in the winding layer position detecting processing area setting means 29, each of the winding layer transmission images 24 and 27 to be inspected is checked.
In order to detect the respective positions in the arrangement direction X, as shown in FIG. 4A, the range to be processed is set as a winding layer position detection processing area E1 (step S1).
2).

Further, in the winding layer position detecting means 30, the pixel density of each of the winding layer transmission images 24 and 27 in the set processing area E1 is added in the tomographic direction Y, as shown in FIG. Create such projection data. FIG. 4B illustrates the projection data of each wound layer transmission image 24 of the first sheet material 21.
Similarly, projection data is created for each of the winding layer transmission images 27 of No. 2. Further, a convolution process is performed on the created projection data by using predetermined mask data to create differential data as shown in FIG. 4C, and a lower threshold S1 and an upper threshold S2 in the differential data are generated.
The minimum value position of the projection data in the density change region D that exceeds
(Step S1)
3). FIG. 4C illustrates the differential data of the wound layer transmission image 24 of the first sheet material 21, but the winding layer transmission image 27 of the second sheet material 22 is similarly illustrated. It goes without saying that the projection data is created and the position coordinates in the arrangement direction X of each winding layer transmission image 27 are detected.

Next, as shown in FIG. 4 (a), the winding layer leading edge detection processing area setting means 31 detects a winding layer leading edge longer in the tomographic direction Y about the detected position coordinate M. The processing area E2 is sequentially set for each of the wound layer transmission images 24 and 27 (step S14). Further, the winding layer leading end assumed point detecting means 32 detects the processing area E set as described above.
4 in the tomographic direction Y, the pixel density in FIG.
Projection data as shown in FIG. 4D is created, and a convolution process is performed on the created projection data with predetermined mask data to create differential data as shown in FIG. A change point equal to or greater than the threshold value S3 in the data is detected as a leading end assumed point (step S1).
5). FIG. 4E shows the outermost winding layer transmission image 2
4 shows the differential data, there is only one change point, and the coordinate of the maximum value of this change point is the tip. That is, in this case, not the assumed point but the true tip is detected. Hereinafter, the assumed end points of all the wound layer transmission images 24 and 27 are sequentially detected in the same manner.

Subsequently, the tip continuity evaluation means 33 calculates the continuity of a plurality of assumed tip points detected for each of the wound layer transmission images 24 and 27 from the positional relationship between a plurality of adjacent assumed tip points. The evaluation is performed, and a true tip position is extracted from each assumed tip point (step S16). Now, as shown in FIG. 5A, each winding layer transmission image 2 of the first sheet material 21 from the outermost circumference to the third circumference inward is obtained.
4A, 24B and 24C as examples, only the tip position T1 of the outermost winding layer transmission image 24A is known as described above, and a certain tip of the winding layer transmission image 24B inward from this tip position T1. A straight line connecting the assumed points T2 is assumed, and a combination calculation is performed to determine whether or not any of the assumed end points T3 of the inner winding layer transmission image 24C is located on the straight line, and an optimum combination is determined.

For example, as shown in FIG. 5 (b), the known tip T1 and the assumed tip T2 are connected by a straight line, and the intersection of the straight line and the detected position coordinate M in the arrangement direction X of the wound layer transmission image 24C. Set the allowable range R on both sides around
If the assumed end point T3 exists within the allowable range R, the combination is determined as the optimum combination, and the assumed end point T2 at that time is determined as a true end position.
Next, continuity evaluation similar to that described above is performed based on the known tip T2 to determine the true tip position T3 in the tomographic direction Y of the wound layer transmission image 24C. Hereinafter, similarly, the tip positions in the tomographic direction Y of all the wound layer transmission images 24 and 27 are detected.

Finally, the pass / fail judgment means 34 checks the length of each of the detected winding layer transmission images 24 and 27 from the leading end thereof, calculates the shift amount, and sets the shift amount within an allowable range. It is determined whether or not there is, and the quality of the winding deviation is determined (step S17).

When the true tip is detected from the assumed tip point, instead of the tip continuity evaluation means 33, the tip density change regularity evaluation means 37 shown in FIG. The true tip may be detected from the evaluation (step S18).

That is, as shown in FIG. 6, the density difference of each area which is separated from the assumed point T by a fixed distance L on both sides in the tomographic direction Y is obtained, and this density difference is equal to or more than a predetermined value. Is detected as the true tip.

[0027]

According to the winding deviation inspection apparatus of the present invention, after detecting a plurality of assumed points at the tip, the true tip position is detected from the mutual positional relationship between these assumed points, or each assumed point is detected. Since the true tip is detected from the regularity of the density change around, the tip of the wound layer transmission image can be accurately detected even if the density of the tip in the wound layer transmission image varies, and the inspection object can be detected. Can be inspected with high accuracy.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a winding deviation inspection apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart showing image processing of the above device.

FIG. 3 is a perspective view of an inspection object of the above device.

4A and 4B are explanatory diagrams of image processing performed by the same device, wherein FIG. 4A is an X-ray transmission image of an inspection object, FIG. 4B is projection data of the X-ray transmission image in the arrangement direction, and FIG. Differential data of the data, (d) shows projection data in the tomographic direction of the X-ray transmission image, and (e) shows differential data of the projection data in the tomographic direction.

FIGS. 5A and 5B are explanatory diagrams of image processing for detecting the leading end of the wound layer transmission image in the tomographic direction by continuity evaluation in the same device.

FIG. 6 is an explanatory view of image processing for detecting the leading end of the wound layer transmission image in the tomographic direction from the regularity of density change in the same device.

FIG. 7 is a configuration diagram of a conventional winding deviation detecting device.

FIG. 8 is a flowchart showing image processing of the above device.

[Explanation of symbols]

 2 Inspection object 3 X-ray irradiator 7 TV camera 21, 22 Sheet material 23 Filter 24, 27 Winding layer transmission image 25 X-ray transmission image 30 Winding layer position detecting means 32 Winding layer assumed point detection means 33 Tip continuity evaluation Means 34 Pass / Fail Judgment Means 37 Tip Concentration Change Regularity Evaluation Means X Arrangement Direction Y Fault Direction (Length Direction) T, T1 to T3 Tip Presumption Point

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-326367 (JP, A) JP-A-63-173906 (JP, A) JP-A-63-274808 (JP, A) 175310 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01B 15/00-15/08 G06T 7/60 H01G 13/00 361 H01M 6/02

Claims (3)

(57) [Claims] 1. A tomographic image pickup means for obtaining an X-ray transmission image of an inspection object in a winding deviation inspection apparatus for inspecting, by image processing, a winding deviation state of an inspection object formed by winding a band-shaped or strip-shaped sheet material. And a winding layer position detecting means for detecting a position in the arrangement direction of each winding layer transmission image corresponding to each winding layer of the sheet material in the X-ray transmission image, and Winding layer leading end point detection means for detecting an assumed point at each end in the longitudinal direction, and a true leading end position from the continuity of mutual positions of the leading end assumed points of a plurality of adjacent winding layer transmission images. What is claimed is: 1. A winding misalignment inspection apparatus comprising: tip continuity evaluating means for detecting; and good or bad judgment means for judging whether or not the winding is misaligned based on a positional relationship between the detected front ends. 2. A winding deviation inspection comprising a tip density change regularity evaluation means for detecting a tip based on a regularity of density change around an assumed tip point, instead of the tip continuity evaluation means according to claim 1. apparatus. 3. An X-ray irradiator for irradiating one side surface of an inspection object with X-rays, a camera for imaging an X-ray transmission image from another side surface of the inspection object, and the X-ray irradiation device. The winding deviation inspection apparatus according to claim 1, further comprising a filter disposed between the apparatus and the inspection target, and configured to reduce shading of the X-ray transmission image by the camera.