이미지 블롭 할당을 이용한 축구 선수 추적

최규형(Kyuhyoung Choi),제창수(Changsoo Je),서용덕(Yongdeuk Seo) 한국정보과학회 2003 한국정보과학회 학술발표논문집 Vol.30 No.2Ⅱ

In this paper particle filter is used as an underlying algorithm to track multiple objects, which are soccer players. Multi-object tracking becomes difficult when two or more players get close to and overlap each other because particles of the filters tend to move to a region of higher posterior probability. To resolve this problem, a blob assignation algorithm which identifies the separated image blobs after occlusion, based on the predicted states according to the dynamic model is suggested. This method performed well on the sequences under general camera work.

카메라 보정을 위한 교차비 분포 최적화

최규형(Kyuhyoung Choi),이영민(Yongmin Lee),서용덕(Yongduek Seo) 한국정보기술학회 2010 Proceedings of KIIT Conference Vol.2010 No.-

카메라 보정을 위해서는 물체의 3차원 좌표와 그에 해당하는 2차원 이미지 좌표 시이의 대응 (correspondence)이 필요하다. 사영기하학적인 면에서 시점 불변의 성질을 가지는 교차비(cross ratio)를 이용하면 이미지의 직선상의 한 점에 해당하는 3차원 공간상의 고유한 지점을 알 수 있다. 본 논문에서는 고유의 교차비들의 집합을 만들어내는 체크보드(check board) 패턴을 효과적으로 생성하는 방법을 제안한다. 체크보드 상의 꼭지점(corner) 검출시의 측정에러를 고려할 때, 가장 이상적인 교차비의 분포는 각 교차비들이 가능한 한 서로 멀리 떨어져 있는 형태가 되어야 하며, 이를 위해 무향변환(unscented transform)을 이용하여 교차비의 에러분포를 가우시안으로 근사화하고, 교차비 분포들 간의 거리의 합을 목적함수로 가지는 최적화를 실시한다. 제안하는 방법으로 제작한 체크보드는 2차원-3차원 대응 관계를 구하는데 있어서, 측정 오차에 강건함을 실험적으로 보여주고 있다. In general, to calibrated a camera, we need a set of 2D-3D correspondences. Due to its invariance under projective automorphisms, cross ratio has been used to identify 2D points on a grid pattern yielding 2D-3D correspondences. However the pixel errors in detecting grid corner points make the identification hard. This even gets harder if the given cross ratios are not distributed separatively enough. To build such a distribution of cross ratio, we approximate the error propagation from corner point detection to cross ratio calculation by unscented transform and optimize the distribution by particle swarm optimization with objective function in terms of the distance between cross ratios.

다중물체추적을 이용한 유동인구 행태 분석

최규형(Choi Kyuhyoung),최영주(Choi Youngju),정지홍(Jung Ji hong),서용덕(Seo Yongduek) 한국방송·미디어공학회 2007 한국방송공학회 학술발표대회 논문집 Vol.2007 No.-

비디오에서의 물체 추적은 컴퓨터비젼(computer vision)의 주요 연구 분야로 지능형 로봇, 무인 감시 체제 등의 영역의 핵심 기술로 여겨지고 있다. 본 논문에서는 다중물체추적을 통해 카메라로 부터 입력된 동영상에서 특정 장소를 지나가는 사람들을 추적함으로서, 그 지역에서의 인구의 이동 패턴을 추출하고 자 한다. 물체 추적은 블롭 추적(blob tracking) 방식을 이용하며, 이를 위해 정확한 전경물체 추출, 추출된 이미지 블롭(blob)과 기존 트랙과의 연결, 새로운 물체(사람)의 등장과 퇴장등의 작업을 수행한다. 추적된 물체들이 궤적을 통해, 시간의 변화에 따른 그 지역에서의 인구의 밀도, 주 이동 경로, 방향 등의 변화를 추출한다. 이러한 통계치는 해당 지역의 개발 정책 수립 및 시장성 조사를 위한 2차 데이타로 활용할 수 있다.

효율적인 대규모 다중 카메라 보정 시스템

최규형(Kyuhyoung Choi),서용덕(Yongduek Seo) 한국정보기술학회 2011 한국정보기술학회논문지 Vol.9 No.7

This paper presents an efficient multi-camera calibration system where a relatively larger number of cameras and a bigger volume of interest than those of usual laboratory experiments are required. For better usability and portability, we have made chessboards with the maximum size and weight one can carry and hold for a while. Also for fast calibration, this system uses minimum number of chessboard images since the most of process time is spent for image processing, namely chessboard detection. For experiments with 20 cameras, our system showed promising results giving the mean reprojection error less than one pixel in less than five minutes of average processing time.

전동차 자동열차정지장치와 지상신호설비 간의 전자파 간섭

최규형(Kyuhyoung Choi),윤선호(Sunho Yoon),고영환(Youngwhan Kho) 한국자동차공학회 2009 한국자동차공학회 부문종합 학술대회 Vol.2009 No.4

The ATS(Automatic Train Stop) system have only a train stop function at the time of emergency, and Seoul Metro is planning to replaced them with ATC(Automatic Train Control)/ATO(Automatic Train Operation) system which can provide dedicated train speed control for headway reduction and unmanned operation of train. Until all the ATS system is replaced with the new ATC system, both systems are to operate simultaneously at the same metro line. In this situation, ATS system sometimes reveals improper operation: train stops suddenly without any obstacles in front of it. These improper stop cause interruption of passenger service. The authors make it clear that these interruptions are caused by EMI phenomena between ATS on-board device and track circuit of ATC system: Signal current flowing in the track circuit is turn out to be a EMI source that prevent the ATS on-board device from normal operation. This is investigated by frequency spectrum analysis of signaling currents and frequency response of ATS on-board device analyzed by FFT(Fast Fourier Transform). The analysis shows that ATS on-board device has a frequency response covering the frequency of signaling current flowing in the track circuit. Although the two systems have different frequency range. The countermeasures to prevent these EMI phenomena are suggested in two ways. One is elimination of EMI source: blocking the signaling current of track circuit when ATS-mounted train pass. Dedicated device for automatic blocking of signaling current is developed and installed at the site. The other is enforcement of EMS(Electromagnetic Susceptibility) : setting a high-pass filter to the circuit of ATS on-board device. These measures make a success in preventing the EMI problem of Seoul Metro line 2.

전동차 DC견인전동기 노후고장률 분석

최규형(Kyuhyoung Choi) 한국자동차공학회 2008 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

A reliability analysis is provided for DC traction motors of electrical railways which might have low reliability and short lifetime compared to AC traction motors because they have rotor windings and commutators. The reliability analysis was made using the field reliability data of DC traction motors operating on the electric railways around the Metropolitan area, which have been investigated at the maintenance depot. Failure analysis of these data shows insulation deterioration of windings and flashover over commutator slots induce the failures of DC traction motors. Minitab has been used for the reliability analysis which show that 3-parameter Weibull distributions are good for the simulation of the failure rate distribution of DC traction motors which have been used for more than 20 years. The shape parameters of Weibull distributions are 2.9 for the stators and 2.2 for the rotors of DC traction motors. The results of analysis clarified the failure rate characteristics of DC traction motors in wear out condition.

객체지향 철도 모델에 의한 다중 열차운행 시뮬레이션

최규형(Kyuhyoung Choi) 한국자동차공학회 2003 한국 자동차공학회논문집 Vol.11 No.5

녹 - 청 띠 패턴을 이용한 단일이미지로부터의 거리영상획득

제창수(Changsoo Je),최규형(Kyuhyoung Choi),이상욱(Sang Wook Lee) 한국정보과학회 2003 한국정보과학회 학술발표논문집 Vol.30 No.2Ⅱ

In this paper, we present new methods for rapid high-resolution range sensing using green-blue stripe pattern. We use green and blue for designing high-frequency stripe projection pattern. For accurate and reliable range recovery, we identify the stripe patterns by our color-stripe segmentation and unwrapping method. The experimental result for a naked human face shows the effectiveness of our method.

열차운전에너지 절약기법에 관한 연구

서일권(Seo Iikwon),최규형(Choi Kyuhyoung) 한국철도학회 2009 한국철도학회 학술발표대회논문집 Vol.2009 No.11월

High speed trains having 20 electric-rail cars need very high power supply near 10[㎿] and energy saving is an important topic for railway operators. This paper presents train operation strategies for energy saving with minimum increasing of train running time. Train performance simulation and artificial intelligence techniques are applied to investigate the optimum solution of the train operation strategy for energy saving. Studies are made on energy saving strategies of train operation such as reduction of maximum speed, acceleration rate, anticipatory coasting for minimum breaking, and saw-tooth coasting. Among the train operation strategies, the anticipatory coasting for minimum breaking is most effective as it has considerable reduction of energy consumption and small running time loss. Artificial intelligence approach is applied to improve the train operation strategies and derive a more practical solution. It is reported that veteran drivers can save 20 percents of energy consumption while keeping train schedule, compared with that of inexperienced drivers. An expert system is established from the know-how of veteran drivers, which can make energy saving operation while keeping train schedule. The proposed expert system can be embedded in train control and monitoring system(TCMS) to achieve optimal operation of train by assisting drivers.

모바일 핫스팟 네트워크 기반의 도시철도 무선백홀망 구현

김동하(Dongha Kim),김일규(Ilgyu Kim),최규형(Kyuhyoung Choi) 한국철도학회 2015 한국철도학회논문집 Vol.18 No.3