• 한국정밀공학회지
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• 제31권11호
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• pp.1007-1013
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• 2014

In this study to improve the productivity, advantage Tandem circumferential weld process of seam tracking system was applied for the laser vision sensor. Weld geometry scanning laser vision sensor and PLC control unit are used to scan correct positioning of welding torch when the program is implemented so that it can correctly track the welding line. The welding experiment was conducted to evaluate the performance of laser vision seam tracking sensor in tandem welding process. The seam tracking several experiments was to determine the reliability of the system, welding experiments relatively good quality welding bead was confirmed. Furthermore, the PLC program for seam tracking was used to confirm the validity of the application of tandem welding process according to the benefits of increased productivity, which is expected to contribute to national competitiveness.

• 한국BIM학회 논문집
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• 제5권2호
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• pp.46-54
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• 2015

Vision-based tracking has been proposed as a means to efficiently track a large number of construction resources operating in a congested site. In order to obtain 3D coordinates of an object, it is necessary to employ stereo-vision theories. Detecting and tracking of multiple objects require an entity matching process that finds corresponding pairs of detected entities across the two camera views. This paper proposes an efficient way of entity matching for tracking of construction workers. The proposed method basically uses epipolar geometry which represents the relationship between the two fixed cameras. Each pixel coordinate in a camera view is projected onto the other camera view as an epipolar line. The proposed method finds the matching pair of a worker entity by comparing the proximity of the all detected entities in the other view to the epipolar line. Experimental results demonstrate its suitability for automated entity matching for 3D vision-based tracking of construction workers.

• 로봇학회논문지
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• 제5권2호
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• pp.120-126
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• 2010

This paper presents to study the path tracking method of AGV(autonomous guided vehicle) which has a laser guidance system. An existing automatic guided vehicles(AGVs) which were able to drive on wired line only had a automatic guidance system. However, the automatic guidance systems that those used had the high cost of installation and maintenance, and the difficulty of system change according to variation of working environment. To solve such problems, we make the laser guidance system which is consisted of a laser navigation and gyro, encoder. That is robust against noise, and flexible according to working environment through sensor fusion. The laser guidance system can do a perfect autonomous driving. However, the commercialization of perfect autonomous driving system is difficult, because the perfect autonomous driving system must recognize the whole environment of working space. Hence, this paper studied the path tracking of AGV using laser guidance system without wired line. The path tracking method is consisted of virtual path generation method and driving control method. To experiment, we use the fork-type AGV which is made by ourselves, and do a path tracking experiments repeatedly on same experimental environment. In result, we verified that proposed system is efficient and stable for actual fork-type AGV.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.505-506
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• 2013

• 한국전기전자재료학회논문지
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• 제18권1호
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• pp.62-67
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• 2005

Recently, polymer insulators that are used for high voltage applications have some advantages such as light weight, small size, vandalism resistance, hydrophobicity and easy making process. During outdoor service of polymer insulators, the surface of the insulating material is frequently subjected to moisture and contamination that lead to dry band arcing. Their tracking resistance, erosion resistance, end sealing and shed design are very important because dry band arcing causes degradation of polymer surface. Aging test to estimate life property of polymer insulator is executed through several international standard such as IEC 61109 and CEA tracking wheel test, but is not getting clear conclusion yet. There are two methods in the diagnosis method of polymer insulator such as off-line and on-line. The diagnosis methods in off-line are external condition analysis by the eye, contaminant analysis on surface, surface analysis, pollution withstand voltage test, power frequency flashover voltage test, lightning impulse flashover test, tensile fracture load test and flexural load test. Polymer material is also investigated it's tracking resistance by adding surface active agent in IEC 587. In this paper, the tracking performance of polymer insulator with salt solution which is added surface active agent. The diagnosis of insulator sample has been analyzed by leakage current and visual examination, STRI guide and thermal image camera.

• 한국지능시스템학회논문지
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• 제15권6호
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• pp.709-713
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• 2005

고해상도의 항공영상으로부터 3차원 와이어프레임(wire-frame) 구성을 위한 새로운 선소 추출 알고리듬을 제안하였다. 본 연구의 목적은 기존의 방식들의 문제점인 라인 불일치 문제, 에지부분의 Blurring 문제 등을 고려하여 보다 정밀하고 효과적인 선소를 추출하는데 있다. 먼저 항공영상으로부터 에지맵을 추출한 후, 에지 점들의 체인 코드 추적을 수행하고 에지강도와 방향성분을 고려한 선소의 추출을 행하였다. 에지맵의 추출은 Smith가 제안한 SUSAN(Smallest Univalue Segment Assimilating Nucleus) 알고리듬을 이용하였다. 제안한 알고리듬은 다음의 4 단계로 구성된다. 에지 맵의 체인코드 추적 결과에 기반하여 비선소 후보점을 감소시키기 위한 수평/수직/대각 성분 제거, 인접점 제거, 각도 일치점 제거, 선소를 이루는 시작점 및 끝점 검출 등의 과정을 통하여 선소추출을 행하였다. 제안한 알고리듬과 기존의 Boldt 알고리듬을 비교한 결과 제안한 알고리듬이 건물을 이루고 있는 주요 선소를 더욱 충실히 찾아냈고 불필요한 선소는 적게 찾아냄을 확인하였다.

• 한국정밀공학회지
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• 제18권9호
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• pp.179-185
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• 2001

In this study, a visual sensor system for weld seam tracking the I-butt weld joints in GMA welding was constructed. The sensor system consists of a CCD camera, a diode laser with a cylindrical lens and a band-pass-filter to overcome the degrading of image due to spatters and arc light. In order to obtain the enhanced image, quantitative relationship between laser intensity and iris number was investigated. Throughout the repeated experiments, the shutter speed was set at 1-milisecond for minimizing the effect of spatters on the image, and therefore most of the spatter trace in the image have been found to be reduced. Region of interest was defined from the entire image and gray level of searched laser line was compared to that of weld line. The differences between these gray levels lead to spot the position of weld joint using central difference method. The results showed that, as long as weld line was within $^\pm$15$^\circ$from the longitudinal straight fine, the system constructed in this study could track the weld line successful1y. Since the processing time reduced to 0.05 sec, it is expected that the developed method could be adopted to high speed welding such as laser welding.

• Journal of Mechanical Science and Technology
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• 제19권10호
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• pp.1856-1863
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• 2005

In this study, a visual sensor system for weld seam tracking the I-butt weld joints in GMA welding was constructed. The sensor system consists of a CCD camera, a diode laser with a cylindrical lens and a band-pass-filter to overcome the degrading of image due to spatters and arc light. In order to obtain the enhanced image, quantitative relationship between laser intensity and iris opening was investigated. Throughout the repeated experiments, the shutter speed was set at 1/1000 second for minimizing the effect of spatters on the image, and therefore the image without the spatter traces could be obtained. Region of interest was defined from the entire image and gray level of the searched laser stripe was compared to that of weld line. The differences between these gray levels lead to spot the position of weld joint using central difference method. The results showed that, as long as weld line is within $\pm15^{o}$ from the longitudinal straight line, the system constructed in this study could track the weld line successfully. Since the processing time is no longer than 0.05 sec, it is expected that the developed method could be adopted to high speed welding such as laser welding.

• 한국전자통신학회논문지
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• 제13권4호
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• pp.685-694
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• 2018

본 논문에서는 Ku대역 추적레이더의 핵심부품인 고주파 헤드 내 주파수 믹서(혼합기)의 설계 및 제작 결과에 대해서 다룬다. 단일종단(Single-Ended) 및 단일평형(Single-Balanced) 믹서의 단점을 보완하기 위해서, Fine-Line 구조의 평형(Balanced) 믹서를 설계하여 낮은 변환손실 특성을 가지도록 하였으며, Ku대역 RF신호를 입력받아 L밴드 IF신호를 생성하도록 하였다. 제작된 믹서에 대해서 Ku밴드 5개 샘플주파수를 대상으로 실험한 결과, 최대 잡음지수(Noise Figure Max) 6.823dB, 이득(Gain) 4.159dB ~ 4.676dB, 통과대역(Band Pass) 61MHz의 값을 확인하였다.

• 한국컴퓨터정보학회논문지
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• 제29권5호
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• pp.47-53
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• 2024

본 연구는 어포던스 개념을 적용하여 가상 환경에서의 제스처 인식 과정에서 자연스러운 동작을 유도함으로써 상호작용과 몰입감을 향상하기 위한 인터랙티브 기술 활용을 제안한다. 이를 위해 샘플링 및 정규화 과정을 포함한 선분 인식 알고리즘을 활용하여 실제 손동작과 유사한 제스처를 인식하는 기법을 제안한다. 이러한 선분 인식은 본 논문에서 설계한 <VR Spell> 게임에서 마법진을 그리는 동작에 적용되었다. 실험 방법으로는 4개의 선분 인식 동작에 대한 인식률을 검증하였다. 본 논문은 실시간 핸드 트래킹 기술을 가상 환경, 특히 VR 게임과 같은 실감 콘텐츠에 적용하여 사용자에게 더 높은 몰입감과 재미를 추구하는 VR 게임을 제안하고자 한다.