JPH0656366B2 - Cable surface defect detector - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a non-contact optical surface defect detection device, and is particularly suitable for detecting uneven defects on a cable surface in a manufacturing process of a power cable or the like. It is a surface defect detection device for various cables.

[Conventional technology]

The fourth method is to detect irregularities on the cable surface.
An example as shown in the figure is known. In this example, the light emitted from the annular light source 13 composed of a fluorescent tube having no directivity is supplied to the cable 9
The reflected light is received by the image pickup devices 51, 54 (52, 53 are not shown) arranged in the radial direction of the cable 9, and the reflected light is reflected by the image processing devices 61, 62, 63, 64. The signal processing determination device 7 digitizes and performs determination processing.

[Problems to be solved by the invention]

As in the example of FIG. 4 described above, a plurality of image pickup elements are required to inspect the entire circumference of the moving cable surface, and image pickup is performed in terms of processing speed in order to perform signal determination processing during the manufacturing process. Image processing must be individually arranged for each element and controlled simultaneously. Therefore, there is a drawback in that the structure of the device is complicated and the size becomes large, and the device becomes expensive.

Further, since the reflected light from the omnidirectional light source is received by the image pickup element arranged in the radial direction of the cable, the signal value / noise value ratio is small and it is difficult to detect the minute defect.

[Means for solving problems]

A cable surface defect detecting device according to the present invention includes an annular light source in which a plurality of optical fibers are arranged on a conical surface having a central axis as an axis of the cable, and a plurality of lens systems for receiving reflected light from a cable surface inspection unit. A plurality of optical fiber scopes each having an entrance and an exit corresponding to each one of the plurality of lens systems, and one end of which is arranged to receive an image of an inspection unit by the lens system as an input; The optical fiber scope comprises an image pickup device in which output ends of the optical fiber scope are aligned, and an image output of the output end is used as an input, and a signal processing unit for processing and determining a signal from the image pickup device.

[Action]

Irregularities on the surface of the cable are used as bright spots, and the defect-free area is darkly observed by a plurality of lens systems arranged around the cable and connected to one end of each optical fiber scope corresponding to the lens system. An image is formed and the other ends of the flexible optical fiber scopes are collectively input to the image pickup device as an output end. The input is binarized by one image processing device to extract bright spots and detect defects.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows the overall configuration of this embodiment, FIG. 2 shows both ends of the optical fiber scope used in this embodiment, and FIG. 3 shows the annular light source used in this embodiment.

In each of the above figures, the cable surface defect detecting apparatus according to the present embodiment is an annular light source in which a large number of plastic optical fibers are arranged on the conical surface of a half angle β outside the cable 9 transferred from the cable manufacturing apparatus at a predetermined speed. 11 and six lens systems 21, 26 (22, 2) arranged so as to face the annular light source 11 and the reflected light from the surface of the cable.
3, 24 and 25 are not shown and will be referred to as 21-26 hereinafter) The angle α formed by the respective optical axes and the axis of the cable 9, the annular light source 11, and the optical axes and cables of the lens systems 21-26, respectively. The lens system 21-26 is arranged so that the distance of the intersection with the surface of 9 is d, and one end 31a, 36a (32a, 33a, 34) is provided for each lens system 21-26.
a and 35a are not shown, and will be hereinafter referred to as 31a-36a). Six optical fiber scopes 31, which are arranged so as to receive the image of the reflected light of the inspection portion of the cable 9 by the lens system 21-26, 32, 33, 34, 35, 36 (hereinafter referred to as 31-36) and the optical fiber scope 31-3
6 output terminals 31b, 32b, 33b, 34b, 35b,
36b (hereinafter referred to as 31b-36b), an image sensor 5 that receives an image output, an image processing device 6 that binarizes a signal from the image sensor 5, and a signal processing determination device 7. . In this embodiment, the optimum values of the angle α, the conical half angle β, and the distance d between the intersections of the optical axes are 25 respectively.
Deg.-35 °, 15 ° -25 °, and 10-40 mm.

Next, the operation of this embodiment based on the above configuration will be described. The light from the annular light source 11 irradiates the surface of the cable 9 with a width in the axial direction of the cable 9, and the image of the inspection portion of the cable 9 by the reflected light from the surface is taken by the lens system 21-26 by the optical fiber scope 31-36. An image is formed on one end 31a-36a of the. The image of the inspection unit is input to the image sensor 5 by collectively using the other ends 31b-36b of the flexible optical fiber scopes 31-36 as output ends. The image processing device 6 binarizes the input, and the signal processing determination device 7 detects a defect. When the inspection portion on the surface of the cable 9 has irregularities, the irregularities are extracted as bright spots and defects are detected.

By the way, although the case where the number of lens systems is 6 has been described in the above description, four or eight lens systems are used depending on the required detection accuracy.
There is no problem even if the number is changed to 12 or 12.

[Effects of the Invention] As described above, the distance d between the intersections of the optical axis and the annular light source in which a plurality of optical fibers are arranged on the conical surface with a conical half-angle β with respect to the axis of the cable has an optimum value. Since it is configured to receive the reflected light from the cable surface inspection section arranged at the angle α, it is possible to accurately detect defects such as various harmful irregularities on the outer surface of the cable, and to obtain an extremely high-quality cable. It has a remarkable effect that it can be provided to the industrial world, and since it is possible to inspect the entire circumference of the cable with one image processing device, it is possible to inexpensively provide a cable defect detection device with a simple structure and good controllability. It also has an effect.

Further, since the irradiation light has directivity by using the optical fiber as the annular light source, there is an effect that the signal value / noise value ratio becomes large and the minute defect can be detected.

[Brief description of drawings]

FIG. 1 is a schematic view of the entire structure of a surface defect detecting device for a cable according to an embodiment of the present invention, FIG. 2 is a perspective view of an end portion of an optical fiber scope used in this embodiment, and FIG. FIG. 4 is a perspective view of the annular light source used, and FIG. 4 is a schematic view of the entire structure of a conventional surface defect detecting device for a cable. 1 ... Light source, 12 ... Power supply, 11, 13 ... Annular light source,
21, 26 ... Lens system, 31, 32, 33, 34, 3
5, 36 ... Optical fiber scope, 4 ... Dark box, 5, 5
1, 54 ... Image sensor, 6, 61, 62, 63, 64 ...
... image processing device, 7 ... signal processing determination device, 9 ... cable.

Claims (1)

[Claims] 1. A cable for detecting a defect by irradiating light from an annular light source arranged outside a cable to be measured, and electrically detecting and measuring the amount of light reflected from the surface of the cable using an image sensor. In the surface defect detecting device, a distance d between intersections of an optical axis and an annular light source in which a plurality of optical fibers are arranged on a conical surface with a conical half angle β with respect to the axis of the cable.
A plurality of lens systems that receive the reflected light from the cable surface inspection unit arranged at the angle α so that the optimal value is, and the entrances and the exits of the plurality of lens systems correspond one-to-one. A plurality of optical fiber scopes arranged at one end so as to receive the image of the inspection section by the lens system and output ends of the plurality of optical fiber scopes are aligned and the video output of the output end is input. An apparatus for detecting a surface defect of a cable, comprising: an image sensor; and a signal processing unit for processing and determining a signal from the image sensor.