JP2013088293A - Method for detecting cutting plane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new cutting plane detection method capable of easily and accurately distinguishing a cutting plane by reducing the load of image processing.SOLUTION: A first image is acquired by turning a polarization direction 2a of a first polarization filter 2 in a predetermined direction to make the polarization direction 2a of the first polarization filter 2 and a polarization direction 4a of a second polarization filter 4 perpendicular to each other, making illumination light 1 transmit the first polarization filter 2 to be reflected on cutting planes 3b and 3c of a sample 3, then making the illumination light transmit the second polarization filter 4 to be photographed by a digital camera 5. A second image is acquired by tilting the polarization direction 2a of the first polarization filter 2 by 45 degrees from a predetermined direction, and a third image is acquired by making the polarization direction 2a of the first polarization filter 2 parallel with the polarization direction 4a of the second polarization filter 4. The first, second and third images are added.

Description

  The present invention relates to a method for detecting a cut surface used for edge detection in measuring the shape, hole position, size, and the like of a cut and perforated metal flat plate.

  When detecting the shape of a metal flat plate using an industrial digital camera or a consumer digital camera, an edge detection method is used. This edge detection method detects the edge of a sample by applying light from the bottom of the sample and capturing the light transmitted from the holed area of the sample with a camera and setting a threshold value at a certain value to perform image processing. A certain shape can be measured by this method. However, when the area of the sample is large, a wide-angle lens is required, and there is a problem that the image is distorted at the periphery of the sample. In addition, when the sample is thick, the cut surface is captured as an image, and there is a problem that accurate measurement cannot be performed. And in an image that is distorted and the cut surface is reflected, it is often impossible to distinguish the cut surface by simply setting a threshold value. There was a problem of having to spend time.

JP 2007-33240 A

  In view of the above problems, an object of the present invention is to provide a novel cut surface detection method that can reduce the burden of image processing and can easily and accurately distinguish cut surfaces.

  In order to solve the above-mentioned problems, the present inventors have intensively studied with an emphasis on an optical method rather than image processing by a computer. As a result, paying attention to the fact that the cut surface is rough and the polarization state of the reflected light on the rough surface changes, it is possible to detect the cut surface easily and accurately by using a polarizing filter. The headline and the present invention were conceived.

  That is, according to the first aspect of the present invention, the cutting plane detection method is arranged in the order of the illumination means, the first polarizing filter, the sample, the second polarizing filter, and the photographing means, and the polarization of the first polarizing filter. The polarization direction of the first polarizing filter and the polarization direction of the second polarizing filter are orthogonal to each other with the direction directed to a predetermined direction, and the light emitted by the illumination means is transmitted through the first polarizing filter and the sample In addition to reflecting the light at the cut surface and transmitting through the second polarizing filter and photographing with the photographing means to obtain the first image, the polarization direction of the first polarizing filter is tilted from the predetermined direction. Is characterized in that a second image is acquired under the same conditions as those for photographing the first image, and the cut surface is detected by adding the first and second images.

  According to a second aspect of the present invention, in the method for detecting a cut surface according to the first aspect, the first image is obtained except that the polarization direction of the first polarizing filter is parallel to the second polarization direction. A third image is acquired under the same condition as the imaged condition, and the cut surface is detected by adding the first, second, and third images.

  According to a third aspect of the present invention, in the method for detecting a cut surface according to the first or second aspect, the polarization direction of the first polarizing filter is inclined by approximately 45 degrees from the predetermined direction. It is characterized by acquiring.

  According to the present invention, it is possible to obtain an image in which a cut surface is highlighted by adding the first and second images or the first, second, and third images. As described above, the shape detection of the cut surface, which has been difficult in the past, can be easily performed by using the polarization filter, so that it is possible to reduce the burden of software when performing image processing for edge detection, Processing time can be greatly reduced.

It is the bird's-eye view (a) which shows arrangement | positioning at the time of acquiring the 1st image in Example 1, and a top view (b). It is the bird's-eye view (a) which shows arrangement | positioning at the time of acquiring the 2nd image in Example 1, and a top view (b). FIG. 3 is a first image in Embodiment 1. FIG. 2 is a second image according to the first embodiment. FIG. 3 is a third image in Embodiment 1. FIG. It is the image which added the 1st and 2nd image in Example 1. FIG. It is the image which added the 1st, 2nd, 3rd image in Example 1. FIG.

  Hereinafter, an embodiment of the method for detecting a cut surface of the present invention will be described.

  In the cut surface detection method of the present embodiment, first, as shown in FIG. 1, reference numeral 1 denotes illumination light emitted by illumination means such as a halogen lamp, and the first polarizing filter is arranged in the direction in which the illumination light 1 is irradiated. 2, the sample 3, the second polarizing filter 4, and the digital camera 5 as the photographing means are arranged in this order.

  Then, the polarization direction 2a of the first polarization filter 2 is set as a predetermined direction, and is aligned with the direction 3a of the long side of the sample, and further, the polarization direction 2a of the first polarization filter 2 and the polarization direction 4a of the second polarization filter 4 Are orthogonal. In the present embodiment, the polarization direction 2a of the first polarizing filter 2 is aligned with the long-side direction 3a of the sample as the predetermined direction, but the polarization direction 2a of the first polarizing filter 2 is arbitrary. It is good also as a direction. Then, the illumination light 1 is transmitted through the first polarizing filter 2 and reflected by the cut surface of the sample 3, and then transmitted through the second polarizing filter 4 and photographed by the digital camera 5 to obtain a first image. At this time, an image in which the vicinity of the cut surfaces 3b and 3c forming an angle of 45 degrees with the polarization directions 2a and 4a is brightly emphasized is obtained.

  Further, as shown in FIG. 2, the polarization direction 2a of the first polarizing filter 2 is inclined 45 degrees from the long side direction 3a of the sample, and the polarization direction 2a of the first polarizing filter 2 and the second polarization The polarization direction 4a of the filter 4 is made orthogonal. In other respects, the second image is acquired under the same conditions as those for capturing the first image. At this time, an image in which the vicinity of the cut surface 3d forming an angle of 45 degrees with the polarization directions 2a and 4a is brightly emphasized is obtained. The inclination of the polarization direction 2a with respect to the direction 3a of the long side of the sample is preferably 45 degrees in order to obtain an image in which the cut surface is emphasized as uniformly as possible regardless of the direction of the cut surface. For example, it may be 40 to 50 degrees.

  Although not shown, the polarization direction 2a of the first polarization filter 2 and the polarization direction 4a of the second polarization filter 4 are made parallel. In other respects, the third image is acquired under the same conditions as those for capturing the first image. At this time, the inclination of the polarization direction 2a with respect to the direction 3a of the long side of the sample may be an arbitrary angle.

  Next, the first, second and third images are added. Note that the addition of images can be performed using a known image processing method, and thus detailed description thereof is omitted here.

  The first image actually taken by the method of this embodiment is shown in FIG. 3 and the second image is shown in FIG. A third image is shown in FIG. 3 and 4, only the cut surface of the metal flat plate processed product is brightly emphasized. On the other hand, in FIG. 5, the cut surface is not emphasized and is difficult to distinguish from other parts.

  FIG. 6 shows an image obtained by adding the first and second images, and FIG. 7 shows an image obtained by adding the first, second, and third images. By adding two or three images, the cut surface can be detected clearly, and edge detection becomes easy.

  Therefore, according to this embodiment, it is possible to easily detect the shape of the cut surface of the metal material, measure the processed shape of the metal flat plate product, the hole position, and measure the dimensions.

  As described above, the detection method of the cut surface of the present embodiment is arranged in the order of the illuminating means, the first polarizing filter 2, the sample 3, the second polarizing filter 4, and the digital camera 5 as the photographing means. The polarization direction 2a of the first polarization filter 2 and the polarization direction 4a of the second polarization filter 4 are directed toward the long side direction 3a of the sample 3 with the polarization direction 2a of the first polarization filter 2 as a predetermined direction. Are orthogonal to each other, and the illumination light 1 as light emitted from the illumination means is transmitted through the first polarizing filter 2 and reflected by the cut surfaces 3b and 3c of the sample 3, and then transmitted through the second polarizing filter 4. The first image is obtained by photographing with the digital camera 5, and the first image is photographed except that the polarization direction 2a of the first polarizing filter 2 is tilted from the long side direction 3a of the sample 3. Same conditions as A second image acquired by matter, the first, can be cut surface by adding the second image to obtain a highlighted image.

  Further, a third image is obtained under the same conditions as those for photographing the first image except that the polarization direction 2a of the first polarization filter 2 and the polarization direction 4a of the second polarization filter 4 are parallel. Then, the first, second, and third images are added to detect the cut surfaces 3b, 3c, and 3d, and the cut surfaces are obtained by adding the first, second, and third images. A highlighted image can be obtained.

  In addition, the second image is acquired by tilting the polarization direction 2a of the first polarizing filter 2 by approximately 45 degrees from the predetermined direction, and the cut surface is uniformly enhanced regardless of the direction of the cut surface. Images can be obtained.

  The present invention is not limited to this embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, three images obtained by orthogonalizing the polarization directions of two polarization filters and tilting the polarization directions of the polarization filters by 0 degrees, 30 degrees, and 60 degrees from a predetermined direction, and the polarization directions of the two polarization filters A total of four images of images obtained in parallel may be added.

Claims (3)

The illumination unit, the first polarizing filter, the sample, the second polarizing filter, and the photographing unit are arranged in this order, and the polarization direction of the first polarizing filter is set so that the polarization direction of the first polarizing filter is directed to a predetermined direction. And the polarization direction of the second polarizing filter are orthogonal to each other, the light emitted from the illumination means is transmitted through the first polarizing filter and reflected by the cut surface of the sample, and then transmitted through the second polarizing filter. The first image is obtained by photographing with the photographing means,
A second image is obtained under the same conditions as those for photographing the first image except that the polarization direction of the first polarizing filter is tilted from the predetermined direction,
A method for detecting a cut surface, comprising: adding the first and second images to detect a cut surface. A third image is acquired under the same conditions as the conditions for capturing the first image except that the polarization direction of the first polarization filter and the second polarization direction are parallel.
2. The method of detecting a cut surface according to claim 1, wherein the cut surface is detected by adding the first, second, and third images. The method of detecting a cut surface according to claim 1 or 2, wherein the second image is acquired by tilting the polarization direction of the first polarizing filter by approximately 45 degrees from the predetermined direction.