KR101115729B1 - Apparatus and Method for Detecting Surface Defect of Wire Rod - Google Patents

Abstract

The present invention photographs the surface of the specimen using a camera having a field of view size and focal length corresponding to the size and position of the specimen compressed by taking a sample from the wire coil, and the surface defect of the wire rod through the photographing screen An apparatus and method for inspecting are provided.

The present invention, the first camera for photographing the image of the wire specimen squeezed in the longitudinal direction; Size measuring means for measuring the size of the specimen from the image; A plurality of second cameras, each having a unique camera field size and a focal length, for photographing the surface image of the specimen for each size of the specimen; A moving member for moving the plurality of second cameras on an X axis and a Y axis, respectively; Storing the field of view and focal length of each of the second cameras in advance, selecting a camera having a field of view corresponding to the size of the measured specimen among the plurality of second cameras, and controlling a photographing position of the selected camera Camera position control means; And display means for displaying a surface image of the specimen taken by the selected camera.

Wire Rod, Specimen, Field of View, Focal Length, Camera, Image

Description

Wire rod defect inspection device and method {Apparatus and Method for Detecting Surface Defect of Wire Rod}

1 is a schematic configuration diagram of a wire surface defect inspection apparatus according to an embodiment of the present invention.

Figure 2 is an illustration of a wire rod compactor applied to the wire surface defect inspection apparatus of the present invention.

3 is a layout view of a lighting apparatus for inspecting wire surface defects according to the present invention.

4 is a flow chart showing a wire surface defect inspection method according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

10: wire rod specimen 20: first camera

30: size measuring means 40: camera position control means

41: X axis drive means 42: Y axis drive means

50: moving member 60: second camera

60a, b, c: camera selected from the second camera 70: display means

The present invention relates to the inspection of the surface defects of the wire rod, in particular, by taking a portion of the sample from the wire rod coil to move the camera according to the field of view size and focal length of the camera corresponding to the size of the compressed specimen to photograph the surface of the specimen And an apparatus and method for inspecting a surface defect of the wire rod through the photographing screen.

In the conventional wire surface defect inspection method, some samples are taken from the wire coil and compressed using a predetermined press, and then the operator observes the surface using a naked eye or a magnifying glass, and when the surface defect is found, depending on the degree of the defect. The grade was calculated. However, in this method, wire rod surface defect inspection and grading were not reliable because of the visual identification of the operator, and there was a problem that objective data management was difficult.

In order to solve this problem, conventionally, a method of photographing a wire rod surface using a camera and determining a defect of the wire rod through the photographed image has been proposed. However, the surface of the wire rod is curved, so it is bright on some surfaces and dark on other surfaces, making it difficult to determine the surface defects in the photographed image. Difficulties had limitations in obtaining clear images, which made it difficult to accurately inspect surface defects.

The present invention has been proposed to solve the above-described problems, after taking a sample from the wire coil to form a uniform illumination distribution for the compressed specimen, after measuring the size of the specimen using a camera, Inspection of wire surface defects by adjusting the position of the camera according to the field size and focal length of the specimen photographing camera corresponding to the size to take an image on the surface of the specimen, thereby inspecting the surface defects of the wire specimen in a clearer image. Its purpose is to provide an apparatus and method.

Wire rod surface defect inspection apparatus of the present invention for achieving the above object, the first camera for photographing the image of the wire specimen squeezed in the longitudinal direction; Size measuring means for measuring the size of the specimen from the image; A plurality of second cameras, each having a unique camera field size and a focal length, for photographing the surface image of the specimen for each size of the specimen; A moving member for moving the plurality of second cameras on an X axis and a Y axis, respectively; Storing the field of view and focal length of each of the second cameras in advance, selecting a camera having a field of view corresponding to the size of the measured specimen among the plurality of second cameras, and controlling a photographing position of the selected camera Camera position control means; And display means for displaying a surface image of the specimen taken by the selected camera.

In one embodiment of the present invention, the wire rod surface defect inspection apparatus of the present invention further comprises a crimping means for compressing the sample taken from the wire rod in the longitudinal direction with a predetermined crimping ratio to provide a wire specimen. can do.

In one embodiment of the present invention, the wire surface defect inspection apparatus of the present invention, the lighting means respectively installed on the upper and both sides of the specimen; And a scattering plate disposed between the specimen and each of the lighting means and scattering light generated from each of the lighting means for uniform illumination distribution on the surface of the specimen.

In addition, the wire surface defect inspection method of the present invention for achieving the above object, the first step of photographing the image of the wire specimen squeezed in the longitudinal direction with a camera; A second step of measuring the size of the specimen from the photographed image; A third step of selecting a camera having a view size corresponding to the measured size from among a plurality of second cameras each having a unique camera field size and a focal length, and controlling a photographing position of the selected camera; A fourth step of photographing a surface image of the specimen using the selected camera; And displaying a surface image of the photographed specimen on a display unit, and inspecting a surface defect of the specimen through the image.

In one embodiment of the present invention, the wire rod surface defect inspection method of the present invention may further comprise the step of pressing the sample taken from the wire rod in the longitudinal direction at a predetermined crimping rate.

In one embodiment of the present invention, the wire surface defect inspection method of the present invention, the step of irradiating light to the specimen from the upper and both sides of the specimen; And scattering light irradiated onto the specimen for uniform illumination distribution on the surface of the specimen.

The present invention provides an apparatus and method for inspecting surface defects of wire rods. In particular, the present invention, by taking the end of the wire coil (for example, about 30 ~ 40cm) and forming a uniform distribution of light on the wire specimen made by pressing it, measuring the size of the specimen using a specific CCD camera Then, by using a specimen camera CCD having a field size corresponding to the size, by taking an image of the entire surface of the specimen, the wire surface defect inspection apparatus for inspecting the surface defects of the wire specimen in a clearer image and Provide a method.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings. In describing the present invention, if it is determined that the detailed description of the related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

1 is a schematic configuration diagram of a wire surface defect inspection apparatus according to an embodiment of the present invention. As shown in Figure 1, the wire surface defect inspection apparatus 100 of the present invention, the first sample for taking an image of the wire specimen 10 is compressed in the longitudinal direction by taking a sample of a predetermined length from the wire to be measured The camera 20, the size measuring means 30 for measuring the size of the specimen 10 from the photographed image, each having a unique camera field size and focal length, the specimen (10) for each size of the specimen ( A plurality of second cameras 60 for photographing the surface image of the 10, a moving member 50 for moving the plurality of second cameras 60 in the X-axis and Y-axis, respectively, the second camera ( A field of view and a focal length of 60 are previously stored, a camera having a field of view corresponding to the measured size of the specimen 10 is selected from among the plurality of second cameras 60, and a photographing position of the selected camera Camera position control means 40 and the line to control the It comprises a display means 70 for displaying a surface image of the specimen 10 taken by the camera selected.

Here, although not shown in Figure 1, the wire surface defect inspection apparatus 100 of the present invention, the crimping means 80 for compressing the sample taken from the wire rod in the longitudinal direction with a predetermined crimping ratio to provide a wire specimen. (Shown in FIG. 2) may be further included. In addition, in one embodiment of the present invention, the wire surface defect inspection apparatus 100, three lighting means (91 ~ 93) (shown in Figure 3) installed on the upper side and both sides of the specimen 10, respectively And 3 installed between the specimen 10 and the respective lighting means 91 to 93, and scattering the light generated from the lighting means 91 to 93 for uniform distribution of light on the surface of the specimen. Dog scattering plate 94 to 96 (shown in Figure 3) may be further included.

Referring to Figure 1, the wire surface defect inspection apparatus 100 according to an embodiment of the present invention will be described in more detail. First, a sample of a predetermined length (for example, 30 to 40 cm) is taken from the wire to be measured and the wire specimen 10 compressed in the longitudinal direction is placed on the specimen stage 80. Specimen 10 compressed in this way is typically elliptical and its size may be provided in a variety of 5 ~ 45mm. The specimen stage 80 is preferably rotatable 360 °.

The first camera 20 captures an image of an object within a predetermined area. In one embodiment of the present invention, the first camera 20 takes an image of the wire specimen 10. Preferably, the first camera 20 includes the specimen 10 to capture a range of images. Although not shown in the drawing, the first camera controller (not shown) controls the overall operation of the first camera 20 and sets a range of an image to be captured. That is, the control unit (not shown) determines a range of the image to be acquired and transmits a control signal to the first camera 20, and the first camera 20 transmits a control signal to the control signal. Therefore, the image of the corresponding area is taken. Here, the first camera 20 may be sufficient as long as it is a device capable of capturing an image. More preferably, it is an infrared camera or a CCD camera, for example, but it is not limited to this.

The image photographed by the first camera 20 is transmitted to the size measuring means 30. The size measuring means 30 receives the photographed image, and measures the size (eg, diameter) of the specimen 10 using a graphic image processing method from the image. Such a graphic image processing method may be easily implemented by those skilled in the art. As described above, since the specimen 10 is typically elliptical, the size measuring means 30 preferably measures the largest diameter.

Meanwhile, in one embodiment of the present invention, a plurality of second cameras 60 are provided for photographing the surface image of the compressed specimen 10. In FIG. 1, three second cameras 60a, 60b, and 60c are illustrated as an example, but are not limited thereto. The second camera 60 has a unique field of view size and focal length, respectively. Table 1 below shows an example of each field of view size and focal length of the second camera 60 of the present invention.

Table 1

Camera number Lens specification Focal length (shooting distance) [mm] Field of view size [mm] One focus 50 196 12 × 15 F-number 1.8 2 focus 35 265 25 × 35 F-number 1.9 3 focus 16 206 48 × 64 F-number 1.4

Each of the second cameras 60a, 60b, and 60c is installed in the movable member 50 which can move in the X and Y axes. The moving member 50 is moved along the X-axis and the Y-axis according to the position control signal of the camera position control means 40 to adjust the position of the second camera (60a, 60b, 60c).

The camera position control means 40 receives the size information of the specimen 10 measured by the size measuring means 30, and has a camera having a field of view size corresponding to the size of the specimen 10, the plurality of The second camera 60 is selected. That is, the camera position control means 40 has one of the plurality of second camera 60 having a viewing size suitable for the size of the specimen 10 so that the specimen 10 can be photographed more accurately and clearly. Is to choose a camera. For example, in Table 1, when the size of the measured specimen 10 is 30mm, it is the second camera having a suitable viewing size. Because the field of view of the first camera is 12 x 15 mm, it is not suitable because it is smaller than the size of the specimen (10). In addition, the size of the field of view of the camera 3 is 48 × 64 mm, but is not suitable because it is much larger than the size of the specimen 10.

As such, when one camera is selected to measure the surface of the specimen 10 by the camera position control means 40, the camera position control means 40 indicates that the selected camera is located at the center of the specimen 10. The moving member 50 is moved on the X axis so as to be positioned. That is, the position of the selected camera to capture the surface image of the specimen 10 is adjusted on the X axis. Subsequently, the camera position control means 40 moves the moving member 50 on the Y axis so that the focal length of the selected camera is matched with the specimen 10. That is, in order to more clearly capture the surface image of the specimen 10, the moving member 50 is controlled so that the focal length of the selected camera fits the surface of the specimen 10. Here, the camera position control means 40 includes X-axis driving means 41 and Y-axis driving means 42 for driving the moving member 50 on the X-axis and the Y-axis, respectively. The moving member 50 moves on the XY Cartesian coordinates by the position control signals of the X-axis and Y-axis driving means 41, 42, thereby providing a plurality of second cameras 60 installed on the moving member 50. ) Moves to the appropriate shooting position.

As such, when the selected camera is moved by the position movement of the moving member 50 driven according to the control signal of the camera position control means 40, the selected camera captures the surface image of the specimen 10. do. In this case, the selected camera preferably photographs images of different surfaces in three or four directions with respect to the specimen 10. For this purpose, the specimen stage 80 on which the specimen 10 is placed is preferably rotatable 360 °. The surface image of the specimen 10 captured by the selected camera is displayed on the display means 70. As a result, the surface defect of the specimen is inspected using the surface image displayed on the display means 70.

The size measuring means 30, the camera position control means 40, and the X and Y axis driving means 41 and 42 described above may be implemented in software or hardware. Preferably implemented as a microprocessor or a predetermined program. In addition, the X, Y-axis driving means 41, 42 may be implemented as an electric motor or a motor. The implementation and operation of these configurations will be readily applicable to those skilled in the art.

Figure 2 is an exemplary view of a compactor applied to the wire surface defect inspection apparatus of the present invention. Compressor 80 applied to the present invention is a sample of a predetermined length (about 30 ~ 40cm) from the wire coil is compressed in the longitudinal direction. Referring to FIG. 2, the specimen sample 10 taken from the wire coil is placed on the holder 83 in the longitudinal direction, and then the specimen sample 10 is compressed at a constant pressure by using the crimping head 81. At this time, when the length of the crimped specimen 10 becomes a predetermined length and the falling detection limit switch 82 detects this, the crimping is completed. The presser 80 may use a known presser, preferably an upset machine.

3 is a layout view of a lighting apparatus for inspecting wire surface defects according to the present invention. As described above, the wire surface defect inspection apparatus 100 according to the present invention may further include a lighting device shown in FIG. Referring to Figure 3 will be described in detail the lighting apparatus of the present invention. First, in order to form a uniform illumination on the surface of the specimen 10 to be measured, the lighting means for irradiating light to the upper and both sides of the specimen 10 except the front surface where the second camera 60 is located ( 91-93) are arranged respectively. The luminaires 91 to 93 preferably each comprise three wavelength lamps. In addition, scattering plates 94 to 96 are disposed between the specimen 10 and the respective lighting means 91 to 93. The scattering plates 94 to 96 scatter light emitted from the lighting means 91 to 93 to the specimen 10 to uniformly distribute the illumination on the surface of the specimen 10. As a result, the illumination of the specimen 10, which is an elliptic surface, is uniformly spread over the entire surface, and thus a part of the surface that reflects or absorbs light is clear, and thus, a clear surface image is photographed.

4 is a flow chart showing a wire surface defect inspection method according to an embodiment of the present invention. Referring to FIG. 4, first, the sample taken from the wire rod is compressed in the longitudinal direction at a predetermined compression ratio using the pressing machine 80 (S41). The image of the crimped wire specimen 10 is photographed with a first camera (S42), and the size of the specimen 10 is measured from the photographed image (S43). Subsequently, one camera having a view size corresponding to the measured size is selected from among the plurality of second cameras 60 each having a unique camera field size and focal length (S44), and a photographing position of the selected camera. Control (S45). At this time, the step (S45) to move the selected camera is installed in the moving member 50 is installed on the X axis, in order to move the selected camera to the center position of the specimen (10). Subsequently, when the selected camera is moved to the center position of the specimen 10, the moving member 50 is moved on the Y axis so that the focal length of the selected camera is matched to the surface of the specimen 10. As such, when the selected camera is moved to the position where the specimen 10 is to be photographed according to its field size and focal length, the surface image of the specimen is photographed using the selected camera (S46). At this time, the image of the different surface in the 3 ~ 4 directions for the specimen 10 is taken. Subsequently, the photographed surface image of the specimen 10 is displayed on the display means (S47), and the surface defect of the specimen 10 is inspected through the image (S48).

Although not shown in the drawing, prior to photographing the surface image of the specimen, light is irradiated onto the surface of the specimen 10 from the upper side and both side portions of the specimen 10, and a uniform distribution of light on the surface of the specimen 10. In order to scatter the light irradiated to the specimen (10). To this end, three light source means 91 to 93 are provided on the upper side and both side surfaces of the specimen 10, and three scattering plates between the specimen 10 and the respective illumination means 91 to 93 ( 94-96). The process for such a uniform illumination distribution may be performed in any process before the surface image photographing of the specimen.

The detailed description and contents of the drawings described above are limited to the preferred embodiments of the present invention, and the present invention is not limited thereto. It will be possible to substitute, change or delete the components according to the present invention within the scope of the technical idea of the present invention. Accordingly, the scope of the present invention should be determined by the appended claims rather than by the foregoing description and drawings.

As described above, according to the wire surface defect inspection apparatus of the present invention, by selecting a CCD camera having a field of view and focus to match the size of the wire rod to take a surface image of the wire rod, it is possible to inspect the surface defects of the wire rod in a clearer image Can be.

In addition, according to the present invention, by ensuring a uniform illumination distribution over the entire surface of the wire rod having a curved surface, it is possible to obtain a clear image, thereby enabling reliable wire surface defect inspection.

Claims (14)

Crimping means (80) for compressing the sample taken from the wire rod in the longitudinal direction with a predetermined crimp rate to provide a specimen (10); A first camera 20 for capturing an image of the specimen 10; Size measuring means (30) for measuring the size of the specimen (10) from the image; A plurality of second cameras 60, each having a unique camera field size and a focal length, for photographing the surface image of the specimen 10 according to the size of the specimen 10; A moving member 50 for moving the plurality of second cameras 60 in X and Y axes, respectively; The field size and focal length of each of the second camera 60 is stored in advance, and a camera having a field size corresponding to the size of the measured specimen 10 is selected from the plurality of second cameras 60. Camera position control means (40) for controlling a shooting position of the selected camera; And Wire surface defect inspection apparatus, characterized in that it comprises a display means for displaying a surface image of the specimen (10) taken by the selected camera. delete The method of claim 1, wherein the second camera 60, Wire specimen defect inspection device, characterized in that for taking the image of the different surface in the 3 ~ 4 direction with respect to the specimen (10). The method of claim 1, wherein the camera position control means 40, The movement of the movable member 50 is controlled on the X axis so that the selected camera is located at the center of the specimen 10, and then the movement is performed on the Y axis so that the focal length of the selected camera is matched with the specimen 10. Wire surface defect inspection apparatus, characterized in that for controlling the movement of the member (50). The method according to claim 1, wherein the camera position control means (40), Wire surface defect inspection apparatus comprising an X-axis drive means (41) and a Y-axis drive means (42) for driving the moving member 50 in the X-axis and Y-axis, respectively. The method of claim 1, Lighting means (91 ~ 93) respectively installed on the upper side and both sides of the specimen (10); And Scattering plates disposed between the specimen 10 and the respective lighting means 91 to 93, and scattering the light generated from the lighting means 91 to 93 for uniform illumination distribution on the surface of the specimen. (94-96); Wire surface defect inspection apparatus further comprising a. The method of claim 6, wherein each of the lighting means (91 ~ 93), Wire rod surface defect inspection apparatus comprising a three-wavelength lamp. The method of claim 1, Each camera is a wire rod surface inspection device, characterized in that the CCD camera. A first step of photographing an image of the wire specimen 10 compressed in the longitudinal direction with a camera; A second step of measuring the size of the specimen 10 from the captured image; A third step of selecting a camera having a view size corresponding to the measured size from among a plurality of second cameras 60 each having a unique camera field size and focal length, and controlling a photographing position of the selected camera; A fourth step of photographing a surface image of the specimen using the selected camera; And And a fifth step of displaying the photographed surface image of the specimen 10 on a display means and inspecting the surface defect of the specimen 10 through the image. The first step, The wire rod surface defect inspection method further comprises the step of pressing the sample taken from the wire rod in the longitudinal direction at a predetermined compression rate. delete The method of claim 9, wherein the third step, If one of the plurality of second cameras is selected, controlling the position of the first camera so that the selected camera is located at the center of the specimen (10); And When the primary position control is performed, controlling the position of the second camera so that the focal length of the selected camera corresponds to the specimen (10); Wire surface defect inspection method comprising a. The method of claim 9, wherein the fourth step, Wire specimen surface defect inspection method characterized in that for taking the image of the different surface in the 3 ~ 4 directions with respect to the specimen (10). 10. The method of claim 9, Irradiating light onto the surface of the specimen (10) from the upper and both side portions of the specimen (10); And Scattering light irradiated onto the surface of the specimen (10) for uniform illumination distribution on the surface of the specimen (10); Wire surface defect inspection method comprising a further. The method of claim 13, wherein the luminaire comprises a three wavelength lamp.

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