• Proceedings of the Korean Magnestics Society Conference
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• 2002.12a
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• pp.12-12
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• 2002

We present the new jaw tracking system that utilizes five degrees of freedom of head and lower jaw. The proposed method does not disturb the physiology because the system does not need to fix magnetic field sensors or clutch on the patient's body or mouth. The impact of this result goes beyond the conventional optical and magnetic tracking system of jaw movement [1][2]. Position accuracy within 1mm and reasonable cost is necessary for practical use of the jaw tracking system. (omitted)

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2019.06a
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• pp.123-124
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• 2019

본 논문에서는 다중 깊이 및 RGB 카메라의 캘리브레이션 최적화 알고리즘을 제안한다. 컴퓨터 비전 분야에서 카메라의 자세 및 위치를 추정하는 것은 꼭 필요한 과정 중 하나이다. 기존의 방법들은 핀홀 카메라 모델을 이용하여 카메라 파라미터를 계산하기 때문에 오차가 존재한다. 따라서 이 문제점을 개선하기 위해 깊이 카메라에서 얻은 물체의 실제 거리와 함수 최적화 방식을 이용하여 카메라 외부 파라미터의 최적화를 진행한다. 이 알고리즘을 이용하여 카메라 간의 정합을 진행하면 보다 더 좋은 품질의 3D 모델을 얻을 수 있다.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.317-320
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• 2015

Documenting work-in-progress on construction sites using images captured with smartphones, point-and-shoot cameras, and Unmanned Aerial Vehicles (UAVs) has gained significant popularity among practitioners. The spatial and temporal density of these large-scale site image collections and the availability of 4D Building Information Models (BIM) provide a unique opportunity to develop BIM-driven visual analytics that can quickly and easily detect and visualize construction progress deviations. Building on these emerging sources of information this paper presents a pipeline for model-driven visual analytics of construction progress. It particularly focuses on the following key steps: 1) capturing, transferring, and storing images; 2) BIM-driven analytics to identify performance deviations, and 3) visualizations that enable root-cause assessments on performance deviations. The information requirements, and the challenges and opportunities for improvements in data collection, plan preparations, progress deviation analysis particularly under limited visibility, and transforming identified deviations into performance metrics to enable root-cause assessments are discussed using several real world case studies.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.43 no.6 s.312
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• pp.16-26
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• 2006

In this paper, we propose a 3D shape restoration system which measures height and surface shape of transparent ITO glass and delivers errors in focal length and incident angle of laser beam to femto-second laser micromachining. The proposed system is composed of a line scan laser, a high resolution camera, a linear motion guide synchronized to image capturing, and a control station. Also, we define the sensitivity indices that represent a relation between measurement error and a position of a camera and scan laser, and utilize it for optimum design. The results of the proposed system are compared with results of SPM(Scanning Probe Microscope) and prove the usefulness of the system.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.6
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• pp.228-237
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• 2013

In this paper, we propose a normalized cross correlation(NCC)-based multiview background subtraction method which is robust when an object and background have similar color. When the background of the capturing environment is not artificially composed, the regions in the background images which would be occluded by an object tends to have difference colors. The colors of those regions, however, becomes similar when an object enters the capturing environment. Based on this assumption, this paper proposes a concept of GoNCC(Graph of Normalized Cross Correlation). GoNCC is the distribution of NCC between a pixel in an image and pixels related by epipolar constraints with the pixel. The proposed multiview background subtraction method is performed by comparing GoNCC of the current images with the background images. To reduce computational complexity, we perform multiview background subtraction only to the pixels undetermined by single view background subtraction. Experimental results show that the proposed method is more robust to color similarity between an object and background than a single-view background subtraction method and a previous multiview background subtraction method.

• International Journal of Aeronautical and Space Sciences
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• v.9 no.2
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• pp.48-57
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• 2008

The noise is one of the serious problems concerning helicopters operations. The issue of helicopter external noise generated mainly from a helicopter rotor has always affected the use of rotorcrafts, especially in the urban environment. The noise sources depend on the flight configurations. In particular, a noise generated by the interaction between blades and tip vortices mainly occurs during descent flight. This noise is called blade-vortex interaction (BVI) noise, and this BVI noise is particularly penalizing for helicopters. In this paper, a numerical study to capture the BVI noise is carried out. The numerical study is performed in two phases. In the first phase, a 2D simulation based on parallel BYI event of Kitapliglu et al experiment is performed. In the second phase, 3D simulation based on HART Ⅱ experiment is performed. Several experimental data such as thrust, torque, blade sectional load, its derivative and vortex location are compared with calculation results and the comparison showed reasonably good agreement.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.7 no.2
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• pp.47-54
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• 2013

In this paper, we present an inertial sensor-based motion capturing system to measure and analyze whole body movements. This system implements a wireless AHRS(attitude heading reference system) we developed using a combination of rate gyroscope, accelerometer and magnetometer sensor signals. Several AHRS modules mounted on segments of the patient's body provide the quaternions representing the patient segments's orientation in space. We performed 3D motion capture using the quaternion data calculated. And a method is also proposed for calculating three-dimensional inter-segment joint angle which is an important bio-mechanical measure for a variety of applications related to rehabilitation. To evaluate the performance of our AHRS module, the Vicon motion capture system, which offers millimeter resolution of 3D spatial displacements and orientations, is used as a reference. The evaluation resulted in a RMSE of 2.56 degree. The results suggest that our system will provide an in-depth insight into the effectiveness, appropriate level of care, and feedback of the rehabilitation process by performing real-time limbs or gait analysis during the post-stroke recovery process.

• The KIPS Transactions:PartB
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• v.18B no.4
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• pp.193-200
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• 2011

This paper proposes a low-cost visual analyzer algorithm of human body motion for real-time applications such as human-computer interfacing, virtual reality applications in medicine and telemonitoring of patients. To reduce cost of its use, we design the algorithm to use a single camera. To make the proposed system to be used more conveniently, we avoid from using optical markers. To make the proposed algorithm be convenient for real-time applications, we design it to have a closed-form with high accuracy. To design a closed-form algorithm, we propose an idea that formulates motion of a human body joint as a 2D universal joint model instead of a common 3D spherical joint model, without any kins of approximation. To make the closed-form algorithm has high accuracy, we formulates the estimation process to be an optimization problem. Thus-desined algorithm is applied to each joint of the human body one after another. Through experiments we show that human body motion capturing can be performed in an efficient and robust manner by using our algorithm.

• The Journal of Engineering Geology
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• v.11 no.2
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• pp.205-214
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• 2001

A simple automated measuring method for planar or linear features on the rock excavation surface is presented. Attitude of the planar and linear feature is calculated from 3D coordinates of points on the structures. Spatial coordinates are calculated from overlapped stereo images. Factors used in the calculation are (1) local coordinates of the left and right images, (2) the focal length of cameras, and (3) the distance between two cameras. A simple image capturing device and an image treatment routine coded by Visual Basic and GIS components are constructed for the remote measurements, The methodology shows less than 1 cm error when a point is measured from 179 cm in distance. The methodology is tested at the excavation site in PaiChai University. Remotely measured result matches well with the manual measurement within the reasonable error range.

• Proceedings of the Korea Contents Association Conference
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• 2006.11a
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• pp.824-828
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• 2006

Introduction of motion capture system to the field of digital entertainment paved the way to accelerate the development of 3D character animation all the more. Motion capture system has been developed of the level that it can capture the fierce motions of character particularly in the digital game image and improve the dynamic characteristics by capturing the movement of human muscle or express the human's true emotion by capturing wrinkles and expression on face. Such an extension of realistic expression enables them to be used increasingly in movie, TV, advertisement, music video, etc centering around the game industry in the field of digital entertainment. The fact is, however, that many difficulties are held in the image production process compared with the competing countries such as USA and Japan, owing to inferiorities in technical expertise and capital in the image production process using the local motion capture, insufficient professional human resources of motion capture and small size of local motion capture image market. Hence, this study intends to suggest the plan to improve the technical problems in terms of integrated motion capture system, motion capture professional human resources and motion capture in-house program development in the production process of digital entertainment image using the motion capture system by surveying local and overseas examples of image production.