KR100406425B1 - An apparatus for detecting surface defect using diffused infra-red illumination - Google Patents

An apparatus for detecting surface defect using diffused infra-red illumination Download PDF

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KR100406425B1
KR100406425B1 KR10-1999-0064145A KR19990064145A KR100406425B1 KR 100406425 B1 KR100406425 B1 KR 100406425B1 KR 19990064145 A KR19990064145 A KR 19990064145A KR 100406425 B1 KR100406425 B1 KR 100406425B1
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coil
camera
surface defect
distributed
infrared
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KR10-1999-0064145A
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KR20010061647A (en
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박창현
정진양
이종학
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주식회사 포스코
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/88—Investigating the presence of flaws or contamination
    • G01N21/8806—Specially adapted optical and illumination features
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/88—Investigating the presence of flaws or contamination
    • G01N21/8851—Scan or image signal processing specially adapted therefor, e.g. for scan signal adjustment, for detecting different kinds of defects, for compensating for structures, markings, edges
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/88—Investigating the presence of flaws or contamination
    • G01N21/8806—Specially adapted optical and illumination features
    • G01N2021/8812—Diffuse illumination, e.g. "sky"
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/88—Investigating the presence of flaws or contamination
    • G01N21/8851—Scan or image signal processing specially adapted therefor, e.g. for scan signal adjustment, for detecting different kinds of defects, for compensating for structures, markings, edges
    • G01N2021/8887—Scan or image signal processing specially adapted therefor, e.g. for scan signal adjustment, for detecting different kinds of defects, for compensating for structures, markings, edges based on image processing techniques
    • G01N2021/8893—Scan or image signal processing specially adapted therefor, e.g. for scan signal adjustment, for detecting different kinds of defects, for compensating for structures, markings, edges based on image processing techniques providing a video image and a processed signal for helping visual decision

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  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
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  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
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  • Pathology (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Vision & Pattern Recognition (AREA)
  • Signal Processing (AREA)
  • Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)

Abstract

본 발명은 코일의 표면결함을 검출하기 위한 장치에 관한 것으로, 특히 조업중 온라인 상에서 고속으로 주행하는 스트립의 표면결함을 보다 정확하게 검출할 수 있도록 한 분산 적외선 조명을 이용한 표면결함 검출장치에 관한 것이다.BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting surface defects of coils, and more particularly, to a surface defect detection device using distributed infrared illumination, which enables more accurate detection of surface defects of strips traveling at high speed on-line during operation.

이에 본 발명은 코일 표면에 분산된 적외선을 투사하는 분산 적외선 조명과 코일 표면의 영상을 획득하는 면적(Area) CCD 카메라, 그리고 카메라에서 받아들인 영상신호를 분석하고 처리하는 신호처리 장치를 구성하여, 코일의 표면결함을 용이하게 검출할 수 있는 것으로, 조업자가 코일 표면을 항상 관찰하지 않아도 되므로 조업의 생산성을 향상시킬 수 있고, 레이저 방식에 의한 원래의 표면결함 형태를 유지하지 못하는 단점을 극복할 수 있으며, 조업 주변 조명의 간섭을 없앨 수 있고, 또한 코일의 표면상태가 최대한 반영되어 착색성 결함을 잘 검출할 수 있는 효과가 있다.Accordingly, the present invention comprises a distributed infrared illumination for projecting infrared rays distributed on the coil surface, an area CCD camera for acquiring an image of the coil surface, and a signal processing apparatus for analyzing and processing the image signal received from the camera, The surface defect of the coil can be easily detected, and the operator does not have to observe the coil surface all the time, thereby improving the productivity of the operation and overcoming the disadvantage of not maintaining the original surface defect form by the laser method. In addition, it is possible to eliminate the interference of the ambient lighting, and also the surface state of the coil is reflected to the maximum, there is an effect that can detect the coloring defect well.

Description

분산 적외선 조명을 이용한 표면결함 검출장치{AN APPARATUS FOR DETECTING SURFACE DEFECT USING DIFFUSED INFRA-RED ILLUMINATION}Surface defect detection device using distributed infrared lighting {AN APPARATUS FOR DETECTING SURFACE DEFECT USING DIFFUSED INFRA-RED ILLUMINATION}

본 발명은 코일의 표면결함을 검출하기 위한 장치에 관한 것으로, 더욱 상세하게는 조업중 온라인 상으로 고속으로 주행하는 스트립의 표면결함을 보다 정확하게 검출할 수 있도록 한 분산 적외선 조명을 이용한 표면결함 검출장치에 관한 것이다.The present invention relates to a device for detecting a surface defect of a coil, and more particularly, to a surface defect detection device using distributed infrared illumination, which can more accurately detect a surface defect of a strip traveling at high speed online during operation. It is about.

일반적으로 코일의 표면결함을 검출하기 위한 방법은 조업자가 직접 조업중에 작업하고 있는 코일의 표면을 직접 관찰함으로써 표면결함을 검출하는 방법과 레이저를 코일 표면에 주사하고 레이저 수광부로 이를 받아들여 일정한 신호처리를 하는 방법, 그리고 면적 CCD(전하결합소자) 카메라와 가시광선 영역의 조명 또는 적외선 조명을 사용하여 표면결함을 검출하는 방법 등이 있다.In general, the method for detecting the surface defect of the coil is a method of detecting the surface defect by directly observing the surface of the coil in which the operator is working, and scanning the laser on the surface of the coil and accepting it as a laser receiver to process a constant signal. And a method of detecting surface defects using an area CCD (charge coupled device) camera and visible or infrared illumination.

상기 첫 번째 방법인 조업자가 직접 냉연강판의 표면을 관찰하는 방법은 조업자가 항상 냉연강판의 표면을 관찰하고 있어야 하는 점과 특히 고속라인의 경우는 사람의 육안으로 관찰하기 어렵다는 단점이 있다.The first method, the operator directly observes the surface of the cold rolled steel sheet has the disadvantage that the operator must always observe the surface of the cold rolled steel sheet, and especially in the case of the high-speed line is difficult to observe with the naked eye.

상기 두 번재 방법인 레이저를 이용한 방법(신일본제철, 특개평6-308051)은 레이저 수광부에서 받아들인 신호가 원래의 표면 결함형태를 유지하지 못하기 때문에 결함의 종류를 구별하기 어려운 문제점이 잇다.The second method, which uses a laser (New Nippon Iron Works, Japanese Patent Laid-Open No. Hei 6-308051), has a problem that it is difficult to distinguish the type of defect because the signal received from the laser receiver does not maintain the original surface defect shape.

상기 세 번째 방법인 면적 CCD 카메라와 가시광선 조명을 이용한 방법(포항제철, 출원번호:98-58742)은 착색성 결함을 잘 검출하지만 조업환경에 의한 주변 조명의 간섭으로 검출율이 떨어지는 문제점이 있다. 그리고, 면적 CCD 카메라와 적외선 조명을 이용한 방법(포항제철, 출원번호: 1998-42769)은 요철성 결함은 잘 검출할 수 있지만 착색성 결함은 검출하지 못하는 단점이 있다.The third method, an area CCD camera and a method using visible light illumination (Pohang Steel, Application No. 98-58742), detects coloring defects well, but has a problem in that the detection rate decreases due to interference of ambient lighting caused by an operating environment. In addition, the method using an area CCD camera and infrared illumination (Pohang Steel, Application No .: 1998-42769) has a disadvantage in that it can detect unevenness well but not detectable coloration defect.

따라서, 본 발명은 상기한 종래 방법의 문제점들을 해결하기 위해 연구와 실험을 행하고, 그 연구 결과에 근거하여 본 발명을 제안하게 된 것으로서, 상기 출원된 면적 CCD 카메라와 가시광선 조명을 이용한 방법과 면적 CCD 카메라와 적외선 조명을 이용한 방법을 개선한 것으로서 발광소자(LED) 조명을 분산(Diffuse)시킴으로서 결함 종류를 쉽게 구별할 수 있고, 조업 환경의 주변 조명에도 영향을 받지 않는 코일의 표면 결함 검출장치를 제공함에 그 목적이 있다.Accordingly, the present invention has been conducted in order to solve the problems of the conventional method described above, and the present invention is proposed based on the results of the research, and the method and area using the applied area CCD camera and visible light illumination It is an improvement on the method using CCD camera and infrared light. By distributing LED light, it is easy to distinguish the kind of defects, and the surface defect detection device of the coil is not affected by the ambient light in the operating environment. The purpose is to provide.

도 1은 본 발명에 따른 분산 적외선 조명을 이용한 표면결함 검출장치의 구성도이다.1 is a block diagram of a surface defect detection apparatus using distributed infrared illumination according to the present invention.

도 2는 본 발명에 따른 분산 적외선 조명장치 및 카메라의 구성도이다.2 is a block diagram of a distributed infrared lighting apparatus and a camera according to the present invention.

도 3은 본 발명에 따른 적외선 발광소자의 배열상태를 보인 도이다.3 is a view showing the arrangement of the infrared light emitting device according to the present invention.

도 4는 본 발명에 따른 분산 적외선 조명의 구성도이다.4 is a block diagram of distributed infrared light according to the present invention.

*도면의 주요 부분에 대한 부호 설명** Description of symbols on the main parts of the drawings *

1... 코일1 ... coil

2... 롤(Roll)2 ... Roll

3... 신호처리부3. Signal Processing Unit

10... 면적 CCD 카메라10 ... area CCD camera

20... 분산 적외선 조명부20 ... Distributed Infrared Illumination

21... 적외선 발광소자(Infrared LED)21. Infrared LED

22... 밀키 글래스(Milky Glass).22 ... Milky Glass.

상기한 목적을 달성하기 위하여 본 발명에 따른 분산적외선 조명을 이용한 표면결함 검출장치는 코일의 표면결함을 검출하는 장치에 있어서 적외선 영역의 빛을 발생시키는 적외선 발광소자, 상기 적외선 발광소자로부터 출력되는 빛을 분산시켜 상기 코일에 투사하는 밀키글래스, 코일 표면의 영상을 획득하는 면적 CCD 카메라, 그리고 카메라에서 받아들인 영상신호 흐름을 분석하고 처치하는 신호처리 장치를 구비함을 특징으로 한다.In order to achieve the above object, the surface defect detection apparatus using distributed infrared illumination according to the present invention is an infrared light emitting device for generating light in the infrared region, the light output from the infrared light emitting device in the device for detecting the surface defect of the coil And a milky glass projected onto the coil, an area CCD camera to obtain an image of the coil surface, and a signal processing device to analyze and process the flow of image signals received from the camera.

이하, 본 발명에 따른 분산 적외선 조명을 이용한 표면결함 검출장치의 구성 및 작용효과에 대해서 첨부한 도면을 상세하게 설명한다.DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Hereinafter, a configuration and an effect of a surface defect detection apparatus using distributed infrared light according to the present invention will be described in detail.

도 1은 본 발명에 따른 분산 적외선 조명을 이용한 표면결함 검출장치의 구성도로서, 도 1에 도시한 바와 같이, 본 발명에 따른 표면결함 검출장치는 코일 표면에 분산된(Diffused) 적외선 조명을 투사하기 위한 분산 적외선 조명(20)과, 가시광선 영역의 파장을 제거시키는 필터를 부착한 면적(Area) CCD 카메라(10), 그리고 상기 카메라(10)에서 획득한 코일 표면 영상을 분석 처리하는 신호처리 장치(3)를 구비한다.1 is a block diagram of a surface defect detection apparatus using distributed infrared illumination according to the present invention. As shown in FIG. 1, the surface defect detection apparatus according to the present invention projects diffused infrared illumination onto a coil surface. Signal processing for analyzing and processing distributed infrared illumination 20, an area CCD camera 10 having a filter for removing wavelengths in the visible light region, and a coil surface image obtained by the camera 10. The apparatus 3 is provided.

상기 면적 CCD카메라(10)는 2차원 CCD카메라로써, 강판 표면의 일정한 면적을 동시에 측정함으로써 강판표면의 진동에도 선명한 영상정보를 획득할 수 있도록 한다.The area CCD camera 10 is a two-dimensional CCD camera, by simultaneously measuring a constant area of the surface of the steel sheet to obtain clear image information even in the vibration of the steel surface.

도 2는 분산 적외선 조명(20)과 이 조명의 빛을 받아들여 코일 표명 영상을 획득하는 카메라(10)의 구성도로서, 상기 분산 적외선 조명(20)은 적외석 빛을 분산된 형태로 코일(1)에 조사하고, 코일(1)로부터 반사되는 빛이 카메라(10)에 입력된다. 상기 카메라의 위치는 분산 적외선 조명(20)이 입사되는 입사각과 동일한 각도 즉, 정반사 각도에 위치되도록 형성한다.FIG. 2 is a configuration diagram of a distributed infrared light 20 and a camera 10 that receives a light of the illumination to obtain a coil manifestation image. The distributed infrared light 20 is a coil (infrared light) in a dispersed form. 1), the light reflected from the coil (1) is input to the camera (10). The position of the camera is formed to be positioned at the same angle as the incident angle at which the distributed infrared light 20 is incident, that is, a specular reflection angle.

한편, 본 발명에 따른 도 2의 양호한 실시예에서는 조명과 카메라의 투사 및 입사각도는 45도로 하였다. 이때, 분산 적외선 조명(20)와 카메라(10)를 정반사각도로 위치시키도록 한 것은 코일(1)의 표면에 발생하는 결함 특히 착색성 결함을 가장 용이하게 검출할 수 있도록 하기 위함이다. 착색성 결함이란 일반적으로 강판의 표면에 요철은 없지만 색깔에 의한 결합을 일컫는 것으로 조명의 정반사위치에서 가장 잘 검출될 수 있다.Meanwhile, in the preferred embodiment of FIG. 2 according to the present invention, the projection and the incident angle of the illumination and the camera are 45 degrees. In this case, the distributed infrared illumination 20 and the camera 10 are positioned at regular reflection angles in order to detect the defects occurring on the surface of the coil 1, in particular, the coloring defects most easily. Colored defects generally refer to bonding by color although there are no irregularities on the surface of the steel sheet and can be detected best at the specular reflection position of the lighting.

또한, 도 3은 본 발명의 일실시예에 따른 적외선 발광소자의 구성을 보인 도이고, 도 4는 본 발명의 일실시예에 따른 분산 적외선 조명장치의 구성도로써, 본 발명에 따른 카메라의 조명 장치는 분산 적외선 조명 장치(20)을 사용하여 조명장치의 적외선 발광소자(21) 일예로 적외선영역의 빛을 발광하는 적외선 발광 다이오드(LED)로 구성된다. 이때, 적외선 발광소자(21)에서 발광되는 적외선은 밀키 글래스(Miky glass)(22)를 통과하면서 분산된 형태로 코일에 조사된 후 코일 표면에서 반사되어 카메라(10)에 입사될 수 있도록 하였다.In addition, Figure 3 is a view showing the configuration of an infrared light emitting device according to an embodiment of the present invention, Figure 4 is a block diagram of a distributed infrared lighting apparatus according to an embodiment of the present invention, the illumination of the camera according to the present invention The device consists of an infrared light emitting diode (LED) which emits light in the infrared region, for example the infrared light emitting element 21 of the lighting device using the distributed infrared illuminating device 20. At this time, the infrared light emitted from the infrared light emitting device 21 is irradiated to the coil in a dispersed form while passing through the milky glass 22, and then reflected from the coil surface to be incident on the camera 10.

이때, 분산된 적외선 조명을 사용함으로써 코일 표면의 요철성분의 검출이 용이하게 이루어질 수 있다.At this time, the uneven component of the coil surface may be easily detected by using distributed infrared illumination.

이와 같은 상기한 두 가지 방법, 즉 분산된 광원의 사용과 조명의 정반사 각도에 카메라(10)를 위치시킴으로서 코일의 표면상태가 최대한 반영되어 착색성 결함을 잘 검출하도록 고안하였다. 또한 분산된 적외선 조명(20)을 사용함으로서 조업환경 주변의 조명에 영향을 받지 않게 하였다.The two methods described above, namely, by using the distributed light source and placing the camera 10 at the specular reflection angle of the illumination, are designed to detect the chromatic defect well by reflecting the surface of the coil as much as possible. In addition, by using the distributed infrared light (20) was not affected by the lighting around the operating environment.

한편, 상기 카메라(10)의 수광부에 가시광선 제거 필터를 부착하여 적외선 조명의 빛만 받아들이도록 하였으며, 상기 카메라(10)는 면적(Area) 형태로 영상을 획득할 수 있는 2차원 CCD 카메라를 사용하여 카메라에서 검출한 결함이 원래의 결함형태를 유지하도록 하였다.Meanwhile, a visible light removing filter is attached to the light receiving unit of the camera 10 to receive only infrared light, and the camera 10 uses a two-dimensional CCD camera capable of acquiring an image in an area shape. The defects detected by the camera were to maintain the original defect shape.

이렇게 상기 분산 적외선 조명 장치(20) 및 CCD카메라(10)에 의해 검출된 표면 영상은 신호처리부(3)로 입력되어 분석, 처리되어 코일의 표면결함여부를 검출하게 되고, 이때 신호처리부(3)에서의 분석/처리는 이미 알려진 프로그램에 의해 실시된다.The surface image detected by the distributed infrared illuminating device 20 and the CCD camera 10 is input to the signal processor 3 to be analyzed and processed to detect the surface defect of the coil. In this case, the signal processor 3 The analysis / processing in is carried out by a program already known.

본 발명에 따른 분산적외선 조명을 이용한 표면결함 검출장치는 전술한 실시예에 국한되지 않고 본 발명의 기술 사상이 허용하는 범위내에서 다양하게 변형하여 실시될 수 있다.The apparatus for detecting surface defects using distributed infrared illumination according to the present invention is not limited to the above-described embodiments, and may be modified in various ways within the scope of the technical idea of the present invention.

상술한 바와같이 본 발명에 따르면, 코일의 표면결함을 용이하게 검출할 수 있는 것으로서, 조업자가 코일 표면을 항상 관찰하지 않아도 되므로 조업의 생산성을 향상시킬 수 있고, 레이저 방식에 의한 원래의 표면결함 형태를 유지하지 못하는 단점을 극복할 수 있는 효과가 있다. 특히, 가시광선 조명을 이용한 방법에 의한 조업 주변 조명의 간섭을 없앨 수 있고, 또한 적외선 조명을 이용한 방법에 의한 착색성 결함에 대한 검출율 저하를 막을 수 있는 이점이 있다.As described above, according to the present invention, it is possible to easily detect the surface defect of the coil, the operator does not always have to observe the surface of the coil can improve the productivity of the operation, the original surface defect form by the laser method There is an effect that can overcome the disadvantage of not maintaining. In particular, there is an advantage that the interference of the operation ambient light by the method using the visible light illumination can be eliminated, and also the reduction of the detection rate for the coloring defect by the method using the infrared light can be prevented.

Claims (3)

(정정)주행중인 코일의 표면결함을 검출하는 장치에 있어서,(Correction) A device for detecting a surface defect of a running coil, 적외선 영역의 빛을 발생시키는 적외선 발광소자와,An infrared light emitting device for generating light in the infrared region, 상기 적외선 발광소자로부터 출력되는 빛을 분산시켜 상기 코일에 투사하는 밀키글래스와,Milky glass for dispersing the light output from the infrared light emitting element and projecting to the coil; 상기 코일에 반사되는 적외선영역의 빛을 받아들여 코일의 표면에 대한 영상정보를 획득하는 2차원 씨씨디카메라와,A two-dimensional CD camera which receives the light in the infrared region reflected by the coil and obtains image information on the surface of the coil; 상기 씨씨디카메라에 의해 획득된 영상정보를 분석하고 소정 처리를 수행하여 표면결함여부를 판단하는 신호처리부를 구비하여 이루어진 것을 특징으로 하는 분산 적외선 조명을 이용한 표면결함검출장치.And a signal processing unit for analyzing image information acquired by the CD camera and performing a predetermined process to determine whether there is a surface defect. 삭제delete 제 1 항에 있어서,The method of claim 1, 상기 카메라는 상기 조명부로부터 코일로 투사되는 적외선빛의 입사각과 상기 코일로부터 반사되어 상기 카메라에 입사되는 반사각이 동일하게 설정되는 위치에 설치된 것을 특징으로 하는 분산 적외선 조명을 이용한 표면결함 검출장치.And the camera is installed at a position where an incident angle of infrared light projected from the illumination unit to a coil and a reflection angle reflected from the coil and incident to the camera are set to be equal to each other.
KR10-1999-0064145A 1999-12-28 1999-12-28 An apparatus for detecting surface defect using diffused infra-red illumination KR100406425B1 (en)

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