• Journal of Welding and Joining
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• v.14 no.4
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• pp.79-88
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• 1996

For improvement in productivity and weld quality, weld seam tracking and welding parameter control are very essential in the welding of a structure which can not be cxactly fit-up due to mismatch, discontinous gap, deflection, etc.. In this study, an automatic weld seam tracking system is developed for I-butt joint structure, and the system consists of XYZ working table, vision sensor and user interface program. In the developed vision sensor system, an image projection algorithm for weld-line detection and an adaptive current control algorithm for gap variation were implemented. The user interface program developed in this study by basing on the objct oriented concept could provide very convenient way to utilize the tracking system with the pull-down menu driven structure. The developed system showed a good seam tracking and weld quality control capability corresponding to deflected weld lines and gap variations.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.500-502
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• 2015

본 논문에서는 애견 안구 영상에서 백내장을 추출하고 분석하는 방법을 제안한다. 제안된 방법은 애견 안구 영상에 퍼지 스트레칭 기법을 적용하여 픽셀의 상한 값과 하한 값을 조정한다. 퍼지 스트레칭 기법이 적용된 영상에 ART2 기법을 적용하여 양자화를 수행한다. 양자화된 정보를 이용하여 영상을 이진화한다. 이진화된 영상에서 침식과 팽창 기법을 적용하여 영상의 픽셀 크기를 확대 또는 축소하여 타원 형태를 가진 객체 중에서 전체 영상 크기의 1/5보다 적은 객체를 잡음으로 간주하여 제거한다. 잡음이 제거된 영상에서 8방향 윤곽선 추적 기법을 적용하여 백내장 영역을 추출한다. 추출된 백내장 영역을 히스토그램으로 시각화 한다. 제안된 방법의 성능을 확인하기 위해서 히스토그램으로 시각화하여 분석한 결과, 제안된 방법이 백내장 추출에 효과적인 것을 확인할 수 있었다.

• Journal of Welding and Joining
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• v.9 no.2
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• pp.20-28
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• 1991

The main subject of this study is the construction of an automatic welding system that has the capability to trace the weld seam in GMA welding of lap joints. The system was composed of a vision sensor, moving torch, and personal computer(IBM-PC). In the developed vision sensor, an image was captured by the frame grabber at the time of short circuit during welding. The threshold method was adopted for determining the structured light and the central difference method for detecting the weld joint. And the seam tracing of the torch was performed by using the data regeneration algorithm. In this system using the image at the time of short circuit, weld seam tracking was performed without any relations to arc light and spatters.

• Journal of the Korean Institute of Telematics and Electronics
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• v.20 no.3
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• pp.6-12
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• 1983

The visual evoked potentials were measured using 19 electrodes attached to the scalp in 5 normal and 4 abnormal subjects during visual stimulation and these data were sampled for computer processing with 500 Hz sampling frequency. The center of potential distributions and its time-dependent locus were estimated from these potential distributions using weighting matrix which was determined by the electrodes' position coordinates. In normal subjects these estimated electrical signals were shown to propagate from the frontal lobe to the occipital lobe of the cortex following the known visual pathway. In abnormal subjects, there were significant differences in these estimated propagation pathway. The relationships among this model, the point source model and the dipole source model were analyzed.

• Journal of the Korean Society for Railway
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• v.18 no.6
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• pp.586-595
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• 2015

Based on an observation that tag-out times of passengers from Smart Card data were clustered, Hong et al.[1] recently developed a precise algorithm that detects a logical path for metro passengers. The logical path means the sequence of train boarding and alighting. In this paper, we observe that tag-out times of passengers in Seoul Metro Line 9 were also clustered; we trace an actual logical path of passengers by applying the algorithm. As a result, we identify 91% of passengers successfully and find their logical paths; we also investigate passengers'preferences between express and local trains.

• Bulletin of the Korean Space Science Society
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• 2000.10a
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• pp.28-28
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• 2000

• Proceedings of the KWS Conference
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• 2001.05a
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• pp.303-304
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• 2001

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.4B
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• pp.331-337
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• 2002

In this paper we propose extended Kalman filter (EKF)-trilateration method which associates EKF to conventional radiolocation technique, trilateration in order to improve the accuracy of dynamic orbit determination of geostationary satellite for broadcasting of highly accurate Standard Time/Frequency Signal (STFS). We then compare to analyze the time accuracies of three techniques which are differential mode, trilateration locating one of four calibrated earth stations on a neighboring country, and domestic-only baseline EKF-trilateration. Computer simulations have shown that in spite of domestic-only baseline EKF-trilateration of poor GDOP, it is possible to track and locate satellite with an accuracy of a few hundred meter which is the performance 10 times more accurate than trilateration can provide. Finally we can provide standard time service with the time accuracy better than a few ns (frequency stability : 10$\^$-14/ over 7 days) all around Korea peninsula.

• KIPS Transactions on Software and Data Engineering
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• v.4 no.4
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• pp.187-194
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• 2015

In this paper, we present an effective visual odometry estimation system to track the real-time pose of a camera moving in 3D space. In order to meet the real-time requirement as well as to make full use of rich information from color and depth images, our system adopts a feature-based sparse odometry estimation method. After matching features extracted from across image frames, it repeats both the additional inlier set refinement and the motion refinement to get more accurate estimate of camera odometry. Moreover, even when the remaining inlier set is not sufficient, our system computes the final odometry estimate in proportion to the size of the inlier set, which improves the tracking success rate greatly. Through experiments with TUM benchmark datasets and implementation of the 3D scene reconstruction application, we confirmed the high performance of the proposed visual odometry estimation method.

• The Journal of the Korea Contents Association
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• v.11 no.6
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• pp.135-143
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• 2011

Visual effect production by computer graphics techniques has become more important in these days. However, there are three problems in the domestic contents production environments. First of all, most Korean film companies have insufficient generally potential to maintain and support their R&D (Research and Development) teams. Secondly, they are much dependent on the abroad commercial software tools. Finally, many people have to participate in the image production pipeline, called the labor-intensive pipeline. In producing a demonstration work, "The Sixty -miles-an-hour man", we have evaluated the usefulness of the developed camera tracking and image composition methods and then examined various production consideration elements. In addition, in order to develop a productive technical element and write a competitive film script, mutual understanding between the developers and the production users should be achieved. Also, this paper describes a role of the technical supervisor to direct the production environment in detail.