• 대한전기학회논문지:시스템및제어부문D
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• 제49권5호
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• pp.235-240
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• 2000

A low cost lighting system for line-scan cameras has been developed with 3-phase power. When exposure time of line-scan camera is shorter than fluctuation period of illumination, the average gray value of each acquired 1-D image varies. Detecting defects on the objects's surface under such illuminating environment is very difficult. The proposed lighting system is composed of low-cost fluorescent lights based on 3-phase power. The specially designed lighting pack and the properly selected lighting position enable to get the rippleless lighting. The principle of the proposed lighting system has been explained analytically. The lighting system has been tested for fabric inspection with line-scan camera and it's efficacy has been proved.

• 한국전기전자재료학회논문지
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• 제34권5호
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• pp.371-381
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• 2021

A machine vision inspection system consists of a camera, optics, illumination, and image acquisition system. Especially a scanning system has to be made to measure a large inspection area. Therefore, a machine vision line scan camera needs a line scan light source. A line scan light source should have a high light intensity and a uniform intensity distribution. In this paper, an offset calibration and slope calibration methods are introduced to obtain a uniform light intensity profile. Offset calibration method is to remove the deviation of light intensity among channels through adding intensity difference. Slope calibration is to remove variation of light intensity slope according to the control step among channels through multiplying slope difference. We can obtain an improved light intensity profile through applying offset and slope calibration simultaneously. The proposed method can help to obtain clearer image with a high precision in a machine vision inspection system.

• Journal of the Optical Society of Korea
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• 제14권3호
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• pp.266-276
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• 2010

In the present study, an optical system is proposed for maskless lithography using a digital micromirror device (DMD). The system consists of an illumination optical system, a DMD, and a projection lens system. The illumination optical system, developed for 95% uniformity, is composed of fly's eye lens plates, a 405 nm narrow band pass filter (NBPF), condensing lenses, a field lens and a 250W halogen lamp. The projection lens system, composed of 8 optical elements, is developed for 4 ${\mu}m$ resolution. The proposed system plays a role of an optical engine for PCB and/or FPD maskless lithography. Furthermore, many problems arising from the presence of masks in a conventional lithography system, such as expense and time in fabricating the masks, contamination by masks, disposal of masks, and the alignment of masks, may be solved by the proposed system. The proposed system is verified by lithography experiments which produce a line pattern with the resolution of 4 ${\mu}m$ line width.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2001년도 추계종합학술대회
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• pp.737-741
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• 2001

본 논문에서는 태양광을 이용한 조명시스템이 설계되었다. 개발되고 있는 시스템은 태양추적을 위한 제어부와 Cds센서 모듈 그리고 태양광 전송부로 이루어져있다. $\pm$2$^{\circ}$의 허용오차 범위내에서 집광판이 태양에 수직으로 추적하기 위하여 Cds센서를 이용한 on-line 알고리즘이 설계되었다. 재발되고 있는 시스템의 효율성을 입증하기 위하여 몇가지의 야외 실험이 진행 중에 있다.

• 한국컴퓨터산업학회논문지
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• 제10권3호
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• pp.99-104
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• 2009

본 논문에서는 형광등 on/off 제어 및 조도를 전력선 통신을 이용하여 원격으로 제어할 수 있는 시스템을 설계하고자 하였다. 각각의 조명기기를 전력선으로 구성되는 네트워크를 구현하였으며 원격 제어 및 조명기기의 on/off 및 조도를 제어하기 위하여 서버를 구성하고 서버에서 각각의 크라이언트를 제어할 수 있도록 하였다. 또한 기존 on/off 시스템을 디지털화하여 에러율을 감소시켰으며 회로를 단순화하는데 주안점을 두었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 B
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• pp.668-670
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• 1999

We have developed a automatic surface inspection system for cold Rolled strips in steel making process for several years. We have experienced the various kinds of surface inspection systems, including linear CCD camera type and the laser type inspection system which was installed in cold rolled strips production lines. But, we did not satisfied with these inspection systems owing to insufficient detection and classification rate, real time processing performance and limited line speed of real production lines. In order to increase detection and computing power, we have used the Dark Field illumination with Infra_Red LED, Bright Field illumination with Xenon Lamp, Parallel Computing Processor with Area typed CCD camera and full software based image processing technique for the ease up_grading and maintenance. In this paper, we introduced the automatic inspection system and real time image processing technique using the Object Detection, Defect Detection, Classification algorithms. As a result of experiment, under the situation of the high speed processed line(max 1000 meter per minute) defect detection is above 90% for all occurred defects in real line, defect name classification rate is about 80% for most frequently occurred 8 defect, and defect grade classification rate is 84% for name classified defect.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2003년도 추계종합학술대회
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• pp.277-279
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• 2003

본 논문은 단일 광원의 CIS에서 조도제어를 적용한 흑백 이미지 스케닝시스템 설계 및 구현에 관한 연구이다. 스케닝 방법은 이미지 스켄센서를 고정한 상태에서 스텝모터를 이용하여 스케닝 하고자 하는 문서를 이동하는 종이공급 방식을 사용하였다. 소형의 최적화된 시스템을 구현하기 위해 전용의 영상처리프로세서를 사용하여 시스템을 구성하였고, 센서를 통해 피딩 스텝마다 1라인의 스케닝된 입력된 데이터는 시스템 메모리에 저장된다. 스케닝을 시작하면 CIS 광원을 ON하여 스케닝하는 문서에서 반사되는 데이터를 수집하게 되는데, CIS 광원을 주기적으로 ON/OFF 하여 스케닝하고자 하는 문서의 조도를 제어하도록 하였다 스케닝 환경에 따라 조도를 제어함으로서 스케닝 이미지에서 적용전의 이미지에 비하여 PSNR이 0.3% 향상 되었다.

• 한국태양에너지학회 논문집
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• 제31권6호
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• pp.132-138
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• 2011

Inducing the natural lighting into building has been commonly applied to the spaces where artistic objects are displayed to create better visual environment for the appreciation. The direct natural lighting, especially through top lighting system may, however, bring forth discoloing of highly light-sensitive materials such as paintings or demanding additional cooling load. In addition, it causes to create glare against appreciators or to yield in visual distraction due to the extreme contrast on the inner surfaces of the spaces. Shading device such as louver is capable of preventing such voidable cases with careful manipulation. This study aims to provide basic design guide-line when the flat-form louver has to be applied to top lighting system. Interaction between the daylight and louver was simulated by Reluxpro program with variation of the attachment location, the angle of the lover, surface reflectivity, to obtain the illumination of the floor surface. This study yields the louver just under the top lighting window with 90 degree angle gives the most desirable way of employment when the uniform illumination on the floor surface is required.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 하계종합학술대회논문집
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• pp.769-772
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• 1998

This paper present an efficient techniques for visual inspection of taped electronic parts, suitable for real time implementation. The main environments of developed system are IBM-compatible personal computer, frame grabber, digital input-output board. It is connected to the programmable logic controller unit of the taping machine in real time. Using a queuing structure, operator or extractor machine can remove easily the defect one from production line. Also, we design a new illumination system for sacquring shape and subface features of object. Therefore, it redue pre-processing step and processing time.

• 한국광학회지
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• 제12권3호
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• pp.190-199
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• 2001

본 연구에서는 193nm의 ArF excimer laser 광원과 0.65의 NA를 갖는 광학계에서 기본 선폭이 $0.1{\mu}m$이고 duty ratio 가 1:1인 dense line & space(LS) 패턴에 대하여 여러사입사 조명 조건에 따른 초점심도(Depth of Focus; DOF)와 cutoff intensity를 확인하고 기본 capacitor 패턴에서 광학적 근접효과 보정을 위한 hammer head형 보조 패턴의 크기와 여러사입사 조건에 다른 DOF와 cutoff intensity의 변화에 대하여 알아보았다. 그결과 0.1$\mu$m급의 dense 패턴 구현을 위해서는 전형적인 X자형 사구 조명보다는 십자(+)형 사구 조명이나 환형조명이 보다 효과적인 것을 알수 있었다. 이와 더불어 보조 패턴의 크기가 약간 변한다 하더라도 일정한 초점심도와 cutoff intensity를 유지하는 경향을 보이는 특정한 조명 조건이 존재함을 밝히고 그에 따라 최적의 조명 조건과 보조 패턴의 크기에 대하여 알아보았다.