• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2008.11a
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• pp.243-246
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• 2008

본 논문은 손을 이용하여 가상 객체와 상호작용이 가능한 모바일 증강현실 기술을 소개한다. 제안된 방법은 마커나 센서 없이 손바닥의 특징점만을 이용하여 손바닥 포즈(위치와 방향)를 계산하고, 손바닥 위에 가상 객체를 생성한다. 또한, 손가락 움직임을 추적하여 가상 객체와 자연스러운 상호작용을 가능하게 한다. 본 논문에서는 Ultra-Mobile PC (UMPC)를 이용하여 제안된 방법을 구현하고, 그 유용성을 검증한다.

• Journal of Korea Spatial Information System Society
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• v.11 no.1
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• pp.183-188
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• 2009

In this paper, we preset a method for the development of u-GIS outdoor augmented reality(AR) system. The proposed system is consist of three parts. First, sensor acquisition and calibration for AR, Second, camera and sensor based tracking for AR, Third, integration of sensor information and 3D models. We combine spatial information of real and virtual spaces through u-GIS AR system.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.12
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• pp.1045-1050
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• 2005

This paper describes a design experience of a low-cost 6 DOF spatial tracker system where relative low accuracy and relatively long ranges, wireless communication will be achieved by means of low cost accelerometers and gyros with contemporary microprocessor. However, there are two key problems; one is the bias drift problem and the other is that single or double integration of acceleration signal suffers not only from noise but also from nonlinear effects caused by gravity. To be specific, beginning and stopping of hand motions needs to be accurately detected to initiate and terminate integration process to get position and pose of the hand from accelerometer and gyro signals, since errors due to noise and/or hand-shaking motions accumulated by integration processes. Several experimental results are shown to validate our proposed algorithms.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.6
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• pp.553-562
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• 2015

This paper presents a strategy and an algorithm for levitation control of an over-actuated passive maglev tray system. The passive maglev tray system has more actuators than its degrees of freedom. The actuators of the system are switching when the tray travels longitudinally. Furthermore, the levitation forces of the actuators are non-homogeneous because the actuation devices are not in the moving platform. These characteristics make a limit in using conventional control approaches for levitation. For smooth actuator switching, the actuator force generation should be dependent on longitudinal positions of the tray. To enable constant pose tracking, this research introduces a control strategy and a control algorithm based on integral controllers on virtual variables. The states of the tray are estimated using a Kalman filter and fed to the proposed controller. The performances of the proposed control strategy and the algorithm are validated through tests.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06c
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• pp.390-392
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• 2011

가려진 상태에 있는 인체 구성요소에 대한 관측치 모델은 영상에서 인체 구성요소가 차지하고 있는 화소들에 대한 정확한 평가를 해야 하는 저수준에서의 문제와, 권투 동작과 같이 역동적으로 변화하는 인체 구성요소 간의 가려짐 관계에 대한 문맥적인 상황을 같이 고려해야 하는 어려움을 갖고 있다. 본 논문에서는 자체 가려짐이 발생한 상황에서도 강인하게 인체 포즈 추적을 하기 위한 가려짐에 강인한 관측치 모델을 제안한다. 포즈 추적 성능을 비교평가 할 수 있는 HumanEva 데이터 셋을 이용하여 제안하는 관측치 모델의 강인함을 확인하였으며, 기존 방법과의 성능 비교에서도 우수한 추적 성능을 보였다.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.2
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• pp.178-183
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• 2008

Human motion analysis is researched as a new method for human-robot interaction (HRI) because it concerns with the key techniques of HRI such as motion tracking and pose recognition. To analysis human motion, extracting features of human body from sequential images plays an important role. After finding the silhouette of human body from the sequential images obtained by CCD color camera, the skeleton model is frequently used in order to represent the human motion. In this paper, using the silhouette of human body, we propose the feature extraction method based on hybrid skeleton for detecting human motion. Finally, we show the effectiveness and feasibility of the proposed method through some experiments.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.11a
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• pp.185-188
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• 2015

미리 저장된 객체의 3차원 특징점(Feature point) 좌표와 카메라 영상의 2차원 특징점 좌표를 매칭(Matching)하여 객체를 추적하는 방식의 경우, 카메라의 시점이 변할 때 특징점에서 발생되는 원근 효과(Perspective effect)가 반영되지 못하여 특징점 매칭 오류가 발생한다. 따라서 특징점에서 발생하는 원근 효과를 반영하여 정확한 카메라 포즈를 추정하기 위해 이전 프레임(Frame)의 카메라 포즈(Camera Pose)에 맞추어 텍스쳐가 포함 된 3차원 객체의 모델을 렌더링 하여 원근 효과를 적용한 후, 현재 카메라 영상과 특징점 매칭하여 프레임 사이의 카메라 움직임을 구하여 객체를 추적한다. 더 나아가 본 논문에서는 특징점 매칭에서 발생하는 작은 오류들로 인한 미세한 카메라 움직임은 2단계의 임계치(Threshold)를 적용하여 떨림 현상으로 간주하여 떨림 현상이 제거된 객체 추적을 수행한다. 매 프레임마다 카메라 포즈에 맞춘 추적 객체를 렌더링 하기 때문에 떨림 현상으로 간주되어 제거된 카메라 움직임은 누적되지 않고, 추적 오류도 발생시키지 않는다.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.3
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• pp.258-266
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• 2012

This paper describes a biped walking algorithm for a hydraulic humanoid robot on inclined floors. To realize stable and robust biped walking, the walking algorithm was divided into five control strategies. The first is a joint position control strategy. This strategy is for tracking desired joint position trajectories with a gain switching. The second is a multi-model based ZMP (Zero Moment Point) control strategy for dynamic balance. The third is a walking pattern flow control strategy for smooth transition from step to step. The fourth is an ankle compliance control, which increases the dynamic stability at the moment of floor contact. The last is an upright pose control strategy for robust walking on an inclined floor. All strategies are based on simple pendulum models and include practical sensory feedback in order to implement the strategies on a physical robot. Finally, the performance of the control strategies are evaluated and verified through dynamic simulations of a hydraulic humanoid on level and inclined floors.

• Journal of Drive and Control
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• v.17 no.4
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• pp.72-79
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• 2020

To ensure the safety of Advanced Driver Assistance Systems (ADAS) or autonomous vehicles, it is important to recognize the vehicle position, and specifically, the increased accuracy of the lateral position of the vehicle is required. In recent years, the quality of GPS signals has improved a lot and the price has decreased significantly, but extreme urban environments such as tunnels still pose a critical challenge. In this study, we proposed stable and precise lane recognition and tracking methods to solve these two issues via fusion of AVM images and vehicle sensor data using an extended Kalman filter. In addition, the vehicle's lateral position recognition and the abnormal state of RTK GPS were determined using this approach. The proposed method was validated via actual vehicle experiments in urban areas reporting multipath and signal disconnections.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• fall
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• pp.215-217
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• 2021

본 논문은 3D 공간에서 사용자를 추출한 뒤, 체적 정보 분석을 통한 3D 스켈레톤(skeleton) 분석 과정을 통해 정확도 높은 다수 사용자의 위치 추적 기술에 대해 연구하였다. 이를 위하여 YOLO(You Only Look Once)를 활용하여 실시간으로 객체를 검출(Real-Time Object Detection)한 뒤 Google의 Mediapipe를 활용해 스켈레톤 추출, 스켈레톤 정규화(normalization)를 통한 스켈레톤의 크기 및 상대적 비율 계산, RGB 영상 스케일링(Scaling) 후 주요 마디 인접 영역의 RGB 색상 정보를 추출하는 방법을 통해 정확도가 개선된 높은 성능의 다중 사용자 추적 기술을 연구하였다.