• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2005년도 춘계학술발표대회 개요집
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• pp.324-325
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• 2005

The primary aim of this paper is to develop an automated welding system capable of adapting to variation in the weld seam center in order to allow higher welding speeds and improved welding quality by using a laser vision sensor. The system is designed to compensate for production problems such as pipe ovality, variation in bevel geometry and track misalignment.

• 한국안전학회지
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• 제16권3호
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• pp.135-142
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• 2001

본 연구에서는 복합소재인 GFRP(Glass Fiber Reinforced Polyester)의 2차원 절삭공정에서 주파수 스팩트럼과 절삭 메커니즘과의 연관성에 관하여 논의한다. 해석방법으로는, 공정중 발생하는 절삭력 신호를 FFT에 의해 주파수 분석하고 주파수 스팩트럼과 다양한 칩형성 메커니즘과의 연관관계를 모델링한다. 특히, 섬유경사각(Fiber orientation angle), 절삭변수 그리고 공구형상이 절삭 메커니즘에 미치는 영향을 평가하였다.

• 한국항해학회지
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• 제23권4호
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• pp.105-114
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• 1999

Generally, though we use the vision sensor or arc sensor in welding process, it is difficult to define the welding parameters which can be applied to the weld quality control. Especially, the important Parameters is Arc Voltage, Welding Current, Welding Speed in arc welding process and they affect the decision of weld bead shape, the stability of welding process and the decision of weld quality. Therefore, it is difficult to determine the unique relationship between the weld bead geometry and the combination of various welding condition. Due to the various difficulties as mentioned, we intend to use Fuzzy Logic and Neural Network to solve these problems. Therefore, the combination of Fuzzy Logic and Neural network has an effect on removing the weld defects, improving the weld quality and turning the desired weld bead shape. Finally, this system can be used under what kind of welding recess adequately and help us make an estimate of the weld bead shape and remove the weld defects.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.24-27
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• 2003

High-resolution satellite images at sub-5m footprint are becoming increasingly available to the earth observation community and their respective clients. The related cameras are all using linear array CCD technology for image sensing. The possibility and need for accurate 3D object reconstruction requires a sophisticated camera model, being able to deal with such sensor geometry. We have recently developed a full suite of new methods and software for the precision processing of this kind of data. The software can accommodate images from IKONOS, QuickBird, ALOS PRISM, SPOT5 HRS and sensors of similar type to be expected in the future. We will report about the status of the software, the functionality and some new algorithmic approaches in support of the processing concept. The functionality will be verified by results from various pilot projects. We put particular emphasis on the automatic generation of DSMs, which can be done at sub-pixel accuracy and on the semi-automated generation of city models.

• 한국소음진동공학회논문집
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• 제18권12호
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• pp.1270-1277
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• 2008

For designing intensity modulation type optical microphone, the irradiance distribution which can be applied to inclined-cut geometrical configuration is suggested. The model is important in analysis of response characteristics for intensity modulation type optical microphone. To overcome low sensitivity problem in intensity modulation type optical microphone, inclined-cut optical fiber is considered here. Based on optical geometry, the inclined-cut optical fiber sensor is designed and fabricated. The experiments are carried out to evaluate sensor performance.

• 전자공학회논문지SC
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• 제46권3호
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• pp.22-30
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• 2009

GPS 와 INS 통합시스템은 저가 MEMS 기술의 결과에 따라 대중적으로 널리 사용되기에 이르렀다. 그러나 저가센서에 의한 현재의 성과는 관성센서의 큰 에러 때문에 여전히 낮은 실정이다. 이것은 제한된 도시환경 안에서의 비행범위 때문에 더욱 관련이 있다. 이러한 관성센서 에러를 줄이면서 동시에 위성의 활용성을 높이기 위하여 GPS 와 저가 INS 는 연성으로 결합되어 Kalman Filter 설계를 응용하여 상호 통합되어진다. 본 논문에서는 연성으로 결합된 Kalman Filter를 이용한 GPS/INS 센서 통합을 제공한다. 우리는 또한 경로의 기하학에 의해 또는 그 목적시간 위치 따라 수학적으로 설명하는 ZH45C 궤도장치에 의한 산출된 기준 Wander Azimuth Strapdown Mechanization의 시뮬레이터 결과를 비교하여 검증하다.

• 한국정밀공학회지
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• 제14권5호
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• pp.34-41
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• 1997

The dimension measurement problem of products has been a major concern in the quality control in the industrial fields. A non-contacting measurement system using the vision sensor is proposed in this paper. The system consists of a CCD camera for the image capture, a frame grabber for the acquired image processing, a laser unit for the illumination, scanning unit for the measurement, and a personal computer for the geometry computation. The slit beam which is generated by passing the laser beam through a cylin- drical lens is fired to the axial-symmetric object on the rotating plate. The image of objects reflected by the laser slit beam, acquired by the CCD camera, becomes much brighter than the other parts of objects. After the histogram of brightness for the captured image is calculated, low intensity pixels are filtered out by threshold method. The performance of proposed measurement system is obtained for several different axial symmetric objects. The proposed system is verified as a good tool for measuring axial-symmetric parts in a limited condition with a minor investment cost.

• 한국항공우주학회지
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• 제36권9호
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• pp.891-897
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• 2008

GPS는 정밀한 상대 항법 정보를 제공해 줄 수 있으나 해당 지역에 기준국이 설치되어 있어야 하고 위성 관측 환경에 영향을 받는다는 단점이 있다. 본 논문에서는 이러한 GPS 단독 사용 시의 한계를 극복하기 위해 사전에 알고 있는 랜드 마크의 기하학적인 배열을 이용한 INS/비전 센서 통합 시스템을 제안한다. 제안된 방법은 사전에 그려진 랜드 마크의 이미지만 있으면 GPS 기준국 없이도 상대 항법 정보를 제공할 수 있다. 제안된 시스템은 간단한 시뮬레이션에 의해 성능을 검증하였으며, 이러한 결과 상대 항법 정보를 향상 시킬 수 있음을 확인하였다.

• 한국측량학회지
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• 제29권2호
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• pp.157-164
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• 2011

As high-resolution satellite images have enabled large scale topographic mapping and monitoring on global scale with short revisit time, agile sensor orientation, and large swath width, many countries make effort to secure the satellite image information. In Korea, KOMPSAT-2 (KOrea Multi-Purpose SATellite-2) was launched in July 28 2006 with high specification. These satellites have stereo image acquisition capability for 3D mapping and monitoring. To efficiently handle stereo images such as stereo display and monitoring, the accurate epipolar image generation process is prerequisite. However, the process was highly limited due to complexity in epipolar geometry of pushbroom sensor. Recently, the piecewise approach to generate epipolar images using RPC was developed and tested for in-track IKONOS stereo images. In this paper, the piecewise approach was tested for KOMPSAT-2 across-track stereo images to see how accurately KOMPSAT-2 epipolar images can be generated for 3D geospatial applications. In the experiment, two across-track stereo sets from three KOMPSAT-2 images of different dates were tested using RPC as the sensor model. The test results showed that one-pixel level of y-parallax was achieved for manually measured tie points.

• 한국측량학회지
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• 제29권5호
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• pp.449-457
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• 2011

As automated image processing techniques have been required in multi-temporal/multi-sensor geospatial image applications, use of automated but highly invariant image matching technique has been a critical ingredient. Note that there is high possibility of geometric and spectral differences between multi-temporal/multi-sensor geospatial images due to differences in sensor, acquisition geometry, season, and weather, etc. Among many image matching techniques, the SIFT (Scale Invariant Feature Transform) is a popular method since it has been recognized to be very robust to diverse imaging conditions. Therefore, the SIFT has high potential for the geospatial image processing. This paper presents a performance test results of the SIFT on geospatial imagery by simulating various image differences such as shear, scale, rotation, intensity, noise, and spectral differences. Since a geospatial image application often requires a number of good matching points over the images, the number of matching points was analyzed with its matching positional accuracy. The test results show that the SIFT is highly invariant but could not overcome significant image differences. In addition, it guarantees no outlier-free matching such that it is highly recommended to use outlier removal techniques such as RANSAC (RANdom SAmple Consensus).