• 로봇학회논문지
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• 제10권3호
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• pp.154-161
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• 2015

Conventional path tracking methods designed for two-wheeled differential drive robots are not suitable for omni-directional robots. In this study, we present a controller which can accomplish more accurate path tracking and orientation correction by exploiting the unconstrained movement capability of omni-directional robots. The proposed controller is proven to be stable using a Lyapunov stability criterion. Various experiments in real environments show that performance of path tracking and orientation correction has improved in the proposed controller.

• 대한의용생체공학회:의공학회지
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• 제32권2호
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• pp.118-126
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• 2011

This study proposes a human body orientation tracking system by inertial and earth magnetic sensors. These sensors were fused by indirect Kalman filter. The proposed tracking system was configured and the filter was implemented. The tracking performance was evaluated with static and dynamic tests. In static test, the sensor was fixed on the floor while its static characteristics was analyzed. In dynamic test, the sensor was held and moved manually for 30 seconds. The dynamic test included x, y, z axis rotations, and elbow flection/extension motions that mimic drinking. For these dynamic motions, the tracking angle error was under $4.1^{\circ}$ on average. The proposed tracking method is expected to be useful for various human body motion analysis.

• 한국멀티미디어학회논문지
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• 제19권5호
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• pp.865-873
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• 2016

In recent years, Tracking-Learning-Detection(TLD) system has been widely used as a detection and tracking algorithm for vision sensors. While conventional algorithms are vulnerable to occlusion, and changes in illumination and appearances, TLD system is capable of robust tracking by conducting tracking, detection, and learning in real time. However, the detection and tracking algorithms of TLD system utilize rotation-variant features, and the margin of tracking error becomes greater when an object makes a full out-of-plane rotation. Thus, we propose a rotation-invariant TLD system(RI-TLD). we propose a simplified average orientation histogram and rotation matrix for a rotation inference algorithm. Experimental results with various tracking tests demonstrate the robustness and efficiency of the proposed system.

• 대한인간공학회지
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• 제19권1호
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• pp.77-90
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• 2000

The aim of this study is to develop and evaluate an efficient camera calibration method for vision-based head tracking. Tracking head movements is important in the design of an eye-controlled human/computer interface. A vision-based head tracking system was proposed to allow the user's head movements in the design of the eye-controlled human/computer interface. We proposed an efficient camera calibration method to track the 3D position and orientation of the user's head accurately. We also evaluated the performance of the proposed method. The experimental error analysis results showed that the proposed method can provide more accurate and stable pose (i.e. position and orientation) of the camera than the conventional direct linear transformation method which has been used in camera calibration. The results of this study can be applied to the tracking head movements related to the eye-controlled human/computer interface and the virtual reality technology.

• 대한인간공학회지
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• 제16권3호
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• pp.1-10
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• 1997

This paper is concerned with the development and evaluation of the camera calibration method for a real-time head tracking system. Tracking of head movements is important in the design of an eye-controlled human/computer interface and the area of virtual environment. We proposed a video-based head tracking system. A camera was mounted on the subject's head and it took the front view containing eight 3-dimensional reference points(passive retr0-reflecting markers) fixed at the known position(computer monitor). The reference points were captured by image processing board. These points were used to calculate the position (3-dimensional) and orientation of the camera. A suitable camera calibration method for providing accurate extrinsic camera parameters was proposed. The method has three steps. In the first step, the image center was calibrated using the method of varying focal length. In the second step, the focal length and the scale factor were calibrated from the Direct Linear Transformation (DLT) matrix obtained from the known position and orientation of the camera. In the third step, the position and orientation of the camera was calculated from the DLT matrix, using the calibrated intrinsic camera parameters. Experimental results showed that the average error of camera positions (3- dimensional) is about $0.53^{\circ}C$, the angular errors of camera orientations are less than $0.55^{\circ}C$and the data aquisition rate is about 10Hz. The results of this study can be applied to the tracking of head movements related to the eye-controlled human/computer interface and the virtual environment.

• 전기학회논문지
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• 제63권1호
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• pp.132-138
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• 2014

The use of AGVs(Automated Guided Vehicles) are increasing in many factories. The most widely used AGV system is that magnetic tapes are attached on the factory floor to make guided path and an AGV equipped with a magnetic sensor follows the path by sensing magnetic flux. In this AGV system, usually a magnetic sensor is attached on the front end of an AGV to detect the guided path and the sensor generates analog voltages proportional to the magnetic flux. The problem is that the AGV in use has rather big tracking errors because the accurate orientation of the AGV can not be detected by using only one magnetic sensor. In this paper, we propose a method to minimize the path tracking errors. In our method, one additional sensor is attached on the rear end of the AGV to estimate the orientation of the AGV and to control more accurately the AGV according to the estimated orientation of the AGV. We performed several experiments and the results successfully show the feasibility of the proposed method.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.593-596
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• 1996

A seam tracking control system with a tool position control and a camera orientation control, has been developed here. For the camera orientation contro, SOFNN was used to learn the expert control signal. The SOFNN algorithm can adjust the fuzzy set parameters and determine the fuzzy logic structure.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권4호
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• pp.2075-2092
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• 2017

Person re-identification is to match pedestrians observed from non-overlapping camera views. It has important applications in video surveillance such as person retrieval, person tracking, and activity analysis. However, it is a very challenging problem due to illumination, pose and viewpoint variations between non-overlapping camera views. In this work, we propose a viewpoint invariant method for matching pedestrian images using orientation of pedestrian. First, the proposed method divides a pedestrian image into patches and assigns angle to a patch using the orientation of the pedestrian under the assumption that a person body has the cylindrical shape. The difference between angles are then used to compute the similarity between patches. We applied the proposed method to real-time global multi-object tracking across multiple disjoint cameras with non-overlapping field of views. Re-identification algorithm makes global trajectories by connecting local trajectories obtained by different local trackers. The effectiveness of the viewpoint invariant method for person re-identification was validated on the VIPeR dataset. In addition, we demonstrated the effectiveness of the proposed approach for the inter-camera multiple object tracking on the MCT dataset with ground truth data for local tracking.

• 한국콘텐츠학회논문지
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• 제8권2호
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• pp.27-32
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• 2008

본 논문은 각변위 방식을 이용한 소화경로 모델링 및 경로에 대한 캡슐의 오리엔테이션 측정 방법을 제안하였다. 제안하는 방법은 캡슐 내시경의 자세를 3차원 방향벡터와 이의 회전성분으로 표현하였다. 소화경로에 대한 캡슐의 오리엔테이션 정보인 롤, 피치 그리고 요우 값은 각각 $1.6^{\circ}$ 이내의 오차를 보였다. 제안된 방법은 자기장을 이용한 오리엔테이션 측정에서 롤값 측정 문제를 해결하였다. 오일러 각을 이용한 기존의 오리엔테이션 측정 방식과 비교하여 알고리즘의 복잡도를 줄였다.

• 전자공학회논문지CI
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• 제47권3호
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• pp.1-10
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• 2010

손동작을 통한 입력방법은 컴퓨터와 디지털 기기의 발전에 따라 요구되는 새로운 HCI(Human-Computer Interaction) 방법으로써 그 가능성을 가지고 있으며 이에 대한 다양한 시도가 있었다. 본 논문에서는 컴퓨터 비전을 기반으로 단일 카메라를 사용하는 손 영역 검출 및 추적방법을 제시하고 이에 의한 컴퓨터 인터페이스를 제안한다. 기존에 많이 쓰이는 피부색 매치 방법에 추가하여 형태 정보를 더함으로써 손 영역 검출능력을 향상 시켰다. 이러한 형태 정보를 추출하는 방법으로써 주요 방향 에지 기술자라는 방법을 제안하였고 이는 강력하여 학습 시간 없이 한 가지 손 모델만을 사용하여 손 영역 검출을 할 수 있다. 또한 손 영역 검출과 추적하는 방법을 나누어 추적할 때는 회전에 대한 자유도를 높이도록 설계 하였다. 위 방법을 이용하여 3차원 공간에 그려지는 필기체 숫자 인식에 적용해 보았으며 분류 방법으로 DNAC 알고리즘을 사용하였다. 결과적으로 손 영역 검출은 82%의 검출률을 보였고 필기체 숫자 인식은 90%의 인식률을 보였다.