• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1930-1931
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• 2011

세계적으로 많은 연구원들이 3차원 모델링에 대하여 연구하고 있다. 특히 무인자동차의 주행을 위한 센서시스템, 경로생성, 3차원 월드모델링 방법 등에 대한 연구가 많이 진행되고 있다. 이 논문은 스테레오 카메라를 이용한 3차원 도시환경복원을 위한 방법을 제안한다. 전체적인 시스템은 다중센서(스테레오 카메라, DGPS, IMU), PC, 이동로봇(전기차)으로 구성하였다. 스테레오 카메라를 통해 들어오는 이미지는 스테레오 정합기법을 이용하여 지역좌표계의 3차원 점군을 획득하는데 이용되며, DGPS와 IMU를 통해 얻은 정보는 이동로봇의 위치를 추정하는데 이용된다. 지역좌표계의 3차원 점군과 이동로봇의 위치를 융합하면 세계좌표계의 3차원 점군을 얻을 수 있으며, 이를 이용하여 도시환경을 복원을 시행하였다. 또한 스테레오 정합기법을 통해 얻어지는 점군의 중복복원을 회피하기 위하여 임시추적을 이용한다. 임시추적을 통해 동일한 점으로 판단되는 경우 중복복원을 방지하는 알고리즘을 제안한다. 실험결과는 3차원 도시환경 복원을 수행하여 점군으로 표현하였다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.10
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• pp.1219-1227
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• 2013

A new type of wearable robot is developed for a disabled person with disabled limbs, that is, a person who cannot intentionally move his/her legs and arms. This robot can enable the disabled person to grip an object using eye movements. A gaze tracking algorithm is employed to detect pupil movements by which the person observes the object to be gripped. By using this gaze tracking 2D information, the object is identified and the distance to the object is measured using a Kinect device installed on the robot shoulder. By using several coordinate transformations and a matching scheme, the final 3D information about the object from the base frame can be clearly identified, and the final position data is transmitted to the DSP-controlled robot controller, which enables the target object to be gripped successfully.

• Journal of Advanced Navigation Technology
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• v.20 no.1
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• pp.53-58
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• 2016

In this paper, we propose a novel quadratic Kalman filter based object tracking algorithm using moving pictures. Quadratic Kalman filter, which is introduced recently, has not yet been applied to the problem of 3-dimensional (3-D) object tracking. Since the mapping of a position in 2-D moving pictures into a 3-D world involves non-linear transformation, appropriate algorithm must be chosen for object tracking. In this situation, the quadratic Kalman filter can achieve better accuracy than extended Kalman filter. Under the same conditions, we compare extended Kalman filter, unscented Kalman filter and sequential importance resampling particle filter together with the proposed scheme. In conculsion, the proposed scheme decreases the divergence rate by half compared with the scheme based on extended Kalman filter and improves the accuracy by about 1% in comparison with the one based on unscented Kalman filter.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.3
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• pp.627-633
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• 2007

This paper describes position tracking system of a container trailer approaching to a gantry crane for loading or unloading a container into or from a ship, respectively. Proposed position tracking system informs the trailer driver of right position to stop the car under a gantry crane. To measure the location of a trailer, we used Cricket Mote modules which adopted RF and ultrasound technology. We present an elaborate method to improve position errors occurring at sensing and calculate three dimensional position by triangulation along with how to reduce location tracking interval for real-time monitoring. The location information was transmitted to a Personal Digital Assistant (PDA) periodically through Bluetooth communication for guidance of the trailer driver. In indoor and outdoor tests, position errors were less than 3 cm and location tracking interval was 0.5 second on average.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.173-175
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• 2011

In this paper, we present an user interface which can show some 3D objects at various angles using tracked 3d head position and orientation. In implemented user interface, First, when user's head moves left/right (X-Axis) and up/down(Y-Axis), displayed objects are moved towards user's eyes using 3d head position. Second, when user's head rotate upon an X-Axis(pitch) or an Y-Axis(yaw), displayed objects are rotated by the same value as user's. The results of experiment from a variety of user's position and orientation show good accuracy and reactivity for 3d visualization.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10d
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• pp.493-495
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• 2002

다시점 영상 부호화와 함께, 가상물체를 지능형으로 합성하기 위해서는 정합할 위치를 강인하게 추적(tracking)하여야 한다. 기존의 특징추적기법은 시점이 확장된 시스템에서, 광원의 영향과 가려진 영역의 발생으로 인하여, 추적 할 수 없게 되거나 시각적 혼동이 발생하는 등의 많은 문제점을 유발한다. 뿐만 아니라 다시점에 의한 정보의 급격한 증가는 시점간 움직임을 추적하여 정합하는 연산량의 추가적 발생을 초래한다. 이에 본 논문은 광원이나 가려진 영역(occtusion)의 영향이 적은 형상과 정보량이 많은 텍스쳐를 동시에 고려하여 영역의 변형에 따라 발생하는 최적 움직임을 예측하는 파라미터 모델을 결정함으로써 사각영역을 추적한다. 이 때 미리 연산된 카메라 파라미터와 투영관계를 사용해 시점간에 가상 객체를 지속적으로 3차원 정합한다. 결과적으로, 제안된 알고리즘은 기존의 특징추적 알고리즘에 비해 광원의 영향과 가려진 영역에 강인하며 정합의 오류가 적고 추적 할 때 시점간의 대응을 위한 연산을 줄이기 때문에 실감 혼합현실 시스템의 구현에 매우 효율적임을 실험을 통해 증명하였다.

• Smart Media Journal
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• v.7 no.2
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• pp.15-22
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• 2018

Pupil tracking technologies can be used as an efficient information provider means that provides convenience to the user by connecting with a smart device. In this paper, we measure the distance of user gaze point using the pupil tracking device which produced by Pupil-labs, also shows the experimental result with analyzing accuracy and precision. Based on that the pupil gaze point location which tracked by pupil tracking device is compared with object target in terms of error. Since the mobile pupil tracking device is also one kind of camera, we have to perform the calibration before using the device. Not only generally used 2-dimensional calibration, but also 3-dimensional calibration method is explained. To get the improved accuracy of 2-dimensional calibration result, the 3-dimensional calibration set an imaginary plane and executes the calibration in various 3-dimensional spaces. To show the efficiency of 3-dimensional calibration, we analyze the experimental result. It also introduces various using methods and information that can be obtained through the device.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.11 s.114
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• pp.1058-1064
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• 2006

In this paper, the channel capacity of a specified wireless indoor multiple-input multiple-output(MIMO) channel is estimated by analyzing spatial characteristics of this channel using the three-dimensional ray tracing method, and a technique for deriving an optimized separation of multi-antenna elements is proposed. At first, the ray paths, the path losses, and the time-delay profile are computed using the three-dimensional ray tracing method in an indoor corridor environment, which has the line of sight(LOS) and non-line of sight(NLOS) regions. The ray tracing method is verified by a comparison between the computation results and the measurements which are obtained with dipole antennas, an amplifier and a network analyzer. Then, an MIMO system is positioned in the indoor channel environment and the ray paths and path losses are computed for four antenna-position combinations and various values of the antenna separation to obtain the channel capacity for the MIMO system. An optimum antenna-separation is derived by averaging the channel capacities of 100 receiver positions with four different antenna combinations.

• The KIPS Transactions:PartB
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• v.16B no.3
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• pp.203-214
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• 2009

In this paper, we could simply compute the user's gaze position based on 2D relations between the pupil center and four corneal specular reflections formed by four IR-illuminators attached on each corner of a monitor, without considering the complex 3D relations among the camera, the monitor, and the pupil coordinates. Therefore, the objectives of our paper are to detect the pupil center and four corneal specular reflections exactly and to compensate for error factors which affect the gaze accuracy. In our method, we compensated for the kappa error between the calculated gaze position through the pupil center and actual gaze vector. We performed one time user calibration to compensate when the system started. Also, we robustly detected four corneal specular reflections that were important to calculate gaze position based on Kalman filter irrespective of the abrupt change of eye movement. Experimental results showed that the gaze detection error was about 1.0 degrees though there was the abrupt change of eye movement.

• Spatial Information Research
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• v.13 no.2 s.33
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• pp.129-138
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• 2005

In this paper, a 3D position tracking algorithm for a moving objects using a stereo CCD cameras was proposed. This paper purposed the method to extract the coordinates of the moving objects. That is improve the operating and data processing efficiency. We were applied the relative orientation far the stereo CCD cameras and image coordinates extraction in the left and right images after the moving object segmentation. Also, it is decided on 3D position far moving objects using an acquired image coordinates in the left and right images. We were used independent relative orientation to decide the relative location and attitude of the stereo CCD cameras and RGB pixel values to segment the moving objects. To calculate the coordinates of the moving objects by space intersection. And, We conducted the experiment the system and compared the accuracy of the results.