JPH07128024A - Device for detecting shape of coil tip - Google Patents

Abstract

PURPOSE:To provide a device for detecting shape of a coil tip, which can accurately detect the shape of the coil tip without the effects of oil and rust by simple image processing. CONSTITUTION:A spot light 11 is arranged at the angle of 45 deg. (60 deg. for a red-rust coil) with respect to a normal line assumed on a coil 15. At the same time, a CCD camera 12 is arranged at the angle of -10 deg. to 15 deg. (0 to 25 deg.C) for the red-rust coil). The distances between the coil 15 and the spot light 11 and the CCD camera 12 are made to be l-2 m, respectively. The brightness of the surface of the coil 15 is made to be 9,000-15,000LX. An image processor 13 performs differentiation for the original image, which is picked up with the CCD camera 12. Then, the present image is subtracted from the image after the differentiation. The image after the differentiation, from which the present image is substracted, is binary-coded, and histogram processing is performed. Thus, the position of the tip of the coil 15 can be detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coil tip shape detecting device for detecting the tip shape of a coil obtained by winding a thin plate into a coil.

[0002]

2. Description of the Related Art The coil to be detected by this type of coil tip shape detecting device is a coil as shown in FIG. This coil is formed by winding a thin plate such as a metal plate, and a band 41 is hung on the outer peripheral surface.

As shown in FIG. 5, a conventional coil tip shape detecting apparatus includes a light 52 for obliquely irradiating light so that a shadow 51 is formed by a step at the tip of the coil, and a CCD camera for picking up an image of the coil. It is provided with an optical sensor 53 and an image processing device (not shown) that performs arithmetic processing on the image signal from the optical sensor 53 and detects a shadow. As a method of detecting the tip of the coil using such a device, there is one disclosed in Japanese Patent Laid-Open No. 61-294305.

This method separately irradiates the coil with light from diagonally upper right and diagonally upper left to obtain two images, and synthesizes these two images to obtain the width direction of the tip of the coil. A shadow is also generated on the portion extending to the coil, the portion extending in the winding direction, and the band wound around the coil.

[0005]

However, in the conventional coil tip shape detecting method, when oil is attached to the surface of the coil or rust is generated, these oil and rust are shadowed. There is a problem of making a judgment.

In the conventional coil tip shape detecting method, it is necessary to perform image processing for each of the two images, and there is a problem that the image processing process is complicated.

It is an object of the present invention to provide a coil tip shape detecting device capable of accurately detecting the shape of the coil tip without being affected by oil attached to the coil surface and rust generated on the coil surface. To do.

It is another object of the present invention to provide a coil tip shape detecting device which is simple in image processing.

[0009]

According to the present invention, a light source for irradiating the surface of a coil obtained by winding a thin plate with light to generate a shadow of the tip of the coil, and an imaging device for imaging the surface of the coil. A coil tip shape detection device having an image processing unit that detects the shadow from the image signal from the image pickup device to detect the tip shape of the coil, and when the normal to the surface of the coil is assumed, the light source The light source is arranged so that the irradiation angle of light from the light source is at a first predetermined angle with respect to the normal line, and the imaging direction of the image pickup device is at a second predetermined angle with respect to the normal line. A coil tip shape detecting device is obtained in which the image pickup device is arranged.

According to the present invention, means for differentiating the image signal, means for subtracting the image signal from the differentiated image signal, means for binarizing the subtraction result, and binarizing subtraction There is obtained a coil tip shape detecting device provided with an image processing unit having means for performing histogram processing on the result and means for detecting the tip position of the coil from the histogram processing result.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a coil tip shape detecting device according to an embodiment of the present invention. The coil tip shape detecting device of the present embodiment includes a spotlight 11 and a CCD camera (line sensor) 1.
2, an image processing device 13, and a display 14.

The spotlight 11 is arranged at an angle α with respect to the normal to the coil surface. Here, α varies depending on the type of coil 15. For example, in a hot rolled coil in which red rust is not generated, α = 30 ° to 60 °, preferably α = 45 °, and a coil in which red rust is generated (hereinafter,
Red rust coil), α = 60 ° to 70 °, preferably α
= 60 °. Therefore, in order to be applicable to both the hot rolled coil and the red rust coil, α = 60 °. The distance between the spotlight 11 and the coil is preferably 1 to 2 m, and the illuminance on the coil surface is 9000 to 9000.
Make it 15000 LX. Further, in order to uniformly illuminate the coil surface in the width direction, it is desirable to arrange a plurality of spotlights 11 in parallel.

The CCD camera 12 is arranged at an angle β with respect to the normal to the coil surface. Where β is α
And the type of coil 15. For example, β = −10 ° to 15 ° in a hot rolled coil in which red rust has not occurred.
(-Means below the normal line in the figure), and in the red rust coil, β = 0 ° to 25 °. Therefore, β = 0 ° to 15 ° may be set in order to be applicable to both the hot rolled coil and the red rust coil. In addition, CCD
Similarly to the spotlight 11, the camera 12 is also arranged at a distance of 1 to 2 m from the coil surface.

Here, the distance between the spotlight 11 and the CCD camera 12 and the coil has a peak near 60 gradations when the output of the CCD camera 12 is output at 256 gradations (8 bits), and the output is saturated. It is set according to the brightness of the spotlight 11 and the sensitivity of the CCD camera 12 so as not to have an output component in the unit (256 gradations).

Next, the operation of this coil tip shape detecting device will be described. First, the coil 15 is rotated at a constant speed in the winding direction (arrow direction in the drawing). At the same time, the surface of the coil 15 is irradiated with the light of the spotlight 11 and is imaged by the CCD camera 12 to obtain image data for one round of the coil 15. To obtain the image data for one round of the coil 15,
A proximity switch or the like provided toward the coil surface may be used.

The image data captured by the CCD camera 12 is input to the image processing device 13. Image processing device 13
Performs gray-scale filtering processing on the input captured data (original image). That is, the differentiation process is applied to the original image using the differentiation filter. The differential process is performed in the winding direction of the coil 15 (vertical direction of the image) or the width direction of the coil (horizontal direction of the image). When the tip of the coil 15 is detected, differentiation processing is performed with respect to the winding direction of the coil.
Further, when the vertical band wound around the outer circumference of the coil 15 is detected, differentiation processing is performed in the width direction of the coil.

Next, the image processing device 13 subtracts the original image from the differentiated grayscale image obtained by the differentiation process. Then, the grayscale image after subtraction is subjected to simple binarization processing based on a predetermined binarization level. The binarization level is about 220 to 240 gradations when detecting the tip of the coil 15 and 35 gradations when detecting the vertical band when the output of the CCD camera 12 is output at 256 gradations. The degree depends on the surface rust condition.

Finally, the image processing device 13 performs histogram processing on the binarized image.

From the output of the CCD camera 12, FIG.
It is assumed that an original image as shown in (a) is obtained. The coil represented by this original image has two coil tip portions 21 and 22 and a coil recess 23 between the two coil tip portions 21 and 22. Further, in addition to the vertical bands 24 and 25 wound around the outer circumference of the coil, a horizontal band 26 is wound around the coil.

When the original image of FIG. 2 (a) is subjected to the density filtering processing in the winding direction (vertical direction in the figure) as described above, the original image is subjected to the subtraction processing, and the simple binarization processing is applied. A binarized image as shown in (b) is obtained (in the actual binarized image, a shadow portion (broken line in the figure) is represented by a bright point).

When a histogram process is applied to this binarized image, a histogram as shown in FIG. 2C is obtained. In the histogram shown in FIG. 2C, the vertical axis represents the scanning line number of the line sensor 12, and the horizontal axis represents the distribution of bright spots. In FIG. 2C, as the line number increases (as it goes downward in the figure), the distribution increases as shown in FIG. 2D, and then the portion where the distribution decreases sharply is the tip 21 of the coil. , 22 and as shown in FIG. 2 (e), the distribution degree rapidly increases as the line number increases, and thereafter the distribution degree gradually decreases to show the coil recess 23. Further, the lateral band 26 is projected and has a high degree of distribution, and can be easily identified.

When the original image of FIG. 2 (a) is subjected to the gray level filtering processing in the width direction (right and left directions in the figure), the original image is subjected to the subtraction processing, and the simple binarization processing is applied, FIG. The binarized image as shown in FIG. When the histogram processing is applied to this binarized image, a histogram as shown in FIG. 3B is obtained. Vertical band 2 from this histogram
The positions of 4 and 25 can be easily detected.

[0023]

According to the present invention, a light source and an image pickup device are provided.
By providing the coil at a predetermined angle with respect to the assumed normal, the tip of the coil can be detected without being affected by rust, oil, and the like.

Further, according to the present invention, the light source and the image pickup device are provided on the coil at a predetermined angle with respect to the assumed normal line, so that the original image is differentiated and the original image is obtained. The position of the tip of the coil and the band can be detected from one original image only by performing the subtraction process. That is, the image processing process is simplified.

Further, according to the present invention, since the coil tip shape can be accurately detected, the work of cutting (scraping) unnecessary parts can be automated with good yield.

[Brief description of drawings]

1A and 1B are configuration diagrams of an embodiment of the present invention, in which FIG. 1A is a front view and FIG. 1B is a side view when viewed in a B direction.

FIG. 2 is a diagram for explaining the operation of the image processing device used in the coil tip shape detection device of FIG. 1, FIG.
Is a current image, (b) is a binarized image, (c) is a histogram, and (d) and (e) are diagrams showing waveforms in the histogram.

3 is a diagram for explaining the operation of the image processing device used in the coil tip shape detection device of FIG. 1, FIG.
Is a current image, and (b) is a diagram showing a histogram.

FIG. 4 is a perspective view for explaining a coil.

FIG. 5 is a configuration diagram of a conventional coil tip shape detection device.

[Explanation of symbols]

 11 Spotlight 12 CCD Camera (Line Sensor) 13 Image Processing Device 14 Display 15 Coil 21, 22 Coil Tip 23 Coil Recess 24, 25 Vertical Band 26 Horizontal Band 41 Band 51 Shadow 52 Light 53 Optical Sensor

Claims (5)

[Claims] 1. A light source that irradiates light onto the surface of a coil obtained by winding a thin plate to generate a shadow of the tip of the coil, an imaging device that images the surface of the coil, and an image signal from the imaging device, In a coil tip shape detection device having an image processing unit for detecting a shadow to detect the tip shape of the coil, when a normal line is assumed on the surface of the coil, the irradiation angle of light from the light source is the normal line. Against 3
A coil, wherein the light source is arranged so as to be 0 ° to 60 °, and the image pickup device is arranged so that an image pickup direction of the image pickup device is −10 ° to 15 ° with respect to the normal line. Tip shape detector. 2. A light source for irradiating light on a surface of a coil obtained by winding a thin plate to generate a shadow of a coil tip, an imaging device for imaging the surface of the coil, and an image signal from the imaging device In a coil tip shape detection device having an image processing unit for detecting a shadow to detect the tip shape of the coil, when a normal line is assumed on the surface of the coil, the irradiation angle of light from the light source is the normal line. Against 6
The light source is arranged so as to be 0 ° to 70 °, and the imaging direction of the imaging device is 0 ° to 25 with respect to the normal line.
A coil tip shape detecting apparatus, wherein the image pickup device is arranged so that the angle becomes 0. 3. The light source and the imaging device are arranged at a distance of 1 to 2 meters from the coil surface so that the illuminance on the coil surface is 9000LX to 15000LX and the output of the imaging device is output in 256 gradations. 3. The coil tip shape detecting device according to claim 1, wherein the output peak has 60. +-. 30 gradations and the output saturation part has no output component. 4. The image processing section comprises means for differentiating the image signal with respect to the winding direction of the coil, means for subtracting the image signal from the differentiated image signal, and means for binarizing the subtraction result. 4. The coil tip shape detecting device according to claim 1, further comprising: means for histogram-processing the binarized subtraction result and means for detecting the tip position of the coil from the histogram processing result. . 5. The image processing unit differentiates the image signal with respect to the winding axis direction of the coil, subtracts the image signal from the differentiated image signal, and binarizes the subtraction result. A means, a means for histogram-processing the binarized subtraction result, and a means for detecting the position of the band wound around the coil from the histogram processing result. Alternatively, the coil tip shape detecting device of 4.