• 한국정보통신학회논문지
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• 제10권5호
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• pp.890-896
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• 2006

GPS 측량은 Multi-path 오차가 발생하기 때문에 도심지역이나 숲이 있는 항공사진에서는 지상기준점을 잡기 위해 GPS측량이 어렵다. 본 논문은 소규모 지역에서 3차원 정사사진 구현을 위한 GPS와 EDM의 적용에 관한 연구이다. 삼각점에서 연구대상지역에 대한 기준점을 내린 다음 EDM으로 정밀삼각측량으로 지상기준점을 선정하였다. 그리고 항공사진을 정사투영사진으로 변환하기 위해 획득된 지상기준점을 적용하였다. 그리고 연구대상지역에 대하여 항공정사사진을 이용한 3차원 모델링을 구현하여 향 후 추진될 3차원 GIS 구축을 위한 항공사진의 활용방안에 대해서 연구하였다. Multi-path 오차로 기인하는 GPS수신이 어려운 지점을 EDM을 이용하여 영상에서 균등히 분포된 지상기준점의 획득이 가능하였고 3차원 공간정보 자료구축에서 가장 기본이 되는 소규모 지역에서 항공사진의 활용이 가능할 것으로 판단되었다.

• 대한의용생체공학회:의공학회지
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• 제26권4호
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• pp.231-241
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• 2005

New methods to register multiple hemispheric slices of the postmortem brain to anatomically corresponding in-vivo MRI slices within a 3D volumetric MRI are presented. Gel-embedding and fiducial markers are used to reduce geometrical distortions in the postmortem brain volume. The registration algorithm relies on a recursive extraction of warped MRI slices from the reference MRI volume using a modified non-linear polynomial transformation until matching slices are found. Eight different voxel similarity measures are tested to get the best co-registration cost and the results show that combination of two different similarity measures shows the best performance. After validating the implementation and approach through simulation studies, the presented methods are applied to real data. The results demonstrate the feasibility and practicability of the presented co­registration methods, thus providing a means of MR signal analysis and histological examination of tissue lesions via co­registered images of postmortem brain slices and their corresponding MRI sections. With this approach, it is possible to investigate the pathology of a disease through both routinely acquired MRls and postmortem brain slices, thus improving the understanding of the pathological substrates and their progression.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제4권4호
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• pp.618-632
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• 2010

This paper presents a novel approach to control the augmented reality (AR) objects robustly in a marker-less AR system by fingertip tracking and hand pattern recognition. It is known that one of the promising ways to develop a marker-less AR system is using human's body such as hand or face for replacing traditional fiducial markers. This paper introduces a real-time method to manipulate the overlaid virtual objects dynamically in a marker-less AR system using both hands with a single camera. The left bare hand is considered as a virtual marker in the marker-less AR system and the right hand is used as a hand mouse. To build the marker-less system, we utilize a skin-color model for hand shape detection and curvature-based fingertip detection from an input video image. Using the detected fingertips the camera pose are estimated to overlay virtual objects on the hand coordinate system. In order to manipulate the virtual objects rendered on the marker-less AR system dynamically, a vision-based hand control interface, which exploits the fingertip tracking for the movement of the objects and pattern matching for the hand command initiation, is developed. From the experiments, we can prove that the proposed and developed system can control the objects dynamically in a convenient fashion.

• 대한의용생체공학회:의공학회지
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• 제26권3호
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• pp.129-132
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• 2005

It is one of the most important issues to determine a target brain image that gives a common coordinate system for a constructing population-based brain atlas. The purpose of this study is to provide a simple and reliable procedure that determines the target brain image among the group based on the inherent structural information of three-dimensional magnetic resonance (MR) images. It uses only 11 lines defined automatically as a feature vector representing structural variations based on the Talairach coordinate system. Average characteristic vector of the group and the difference vectors of each one from the average vector were obtained. Finally, the individual data that had the minimum difference vector was determined as the target. We determined the target brain image by both our algorithm and conventional visual inspection for 20 healthy young volunteers. Eighteen fiducial points were marked independently for each data to evaluate the similarity. Target brain image obtained by our algorithm showed the best result, and the visual inspection determined the second one. We concluded that our method could be used to determine an appropriate target brain image in constructing brain atlases such as disease-specific ones.

• 반도체디스플레이기술학회지
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• 제5권4호
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• pp.11-15
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• 2006

Expose equipment system that is used for manufacturing process of Flat Panel Display, is most important equipment in whole process. Expose equipment that is for making pattern of mask on substrate, consists of optical part, stage part and transport part. The stage is an important part that aligns mask and substrate for delivering pattern of mask to substrate exactly. In this paper, control system of expose stage that is able to use mask and substrate of diverse size, with PC controller using GUI interface instead of PLC control system. The existing PLC control system does not have the suitable structure for using mask of diverse size. GUI interface integration control system is based on PC. So it has the advantage of convenient use and active operation. We embodied PLC control system in integration control system based on PC, and verified utility possibility through the standard test course.

• 대한토목학회논문집
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• 제7권4호
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• pp.125-132
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• 1987

사진측량(寫眞測量)에서 이용되는 번들조정(調整)은 공선조건(共線條件)을 기초로 하며, 많은 비지형(非地形)분야에서 이용되고 있다. 그러나 비측량용(非測量用)사진기의 경우 지표(指標)가 없고 내부(內部) 및 외부표정요소(外部標定要素)의 초기근사값을 모르기 때문에, 이를 필요로 하는 번들조정(調整)에는 적용할 수 없다. 상좌표(像座標)로 부터 절대좌표(絶對座標)가 근사값을 요구하지 않고 직접변환되는 DLT(direct linear transformation) 프로그램이 Marzan과 Karara에 의해 개발되었다. 본(本) 논문(論文)에서는, 비측량용(非測量用)사진기에 의한 근거리사진측량(近距離寫眞測量)의 정확도(正確度)를 향상시키기 위해 DLT프로그램을 수정하였다. 수정된 프로그램에는 과대오차(過大誤差)의 검출(檢出) 및 외부표정요소(外部標定要素)의 계산과정을 포함시켰으며, 반복계산수를 증가시켰다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1996년도 춘계학술대회
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• pp.31-35
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• 1996

This paper presents a real time algorithm for monitoring of the arrythmia of ECG signal. A real time monitoring, following by detecting a QRS complex, is the most important. Using 2-dimensional time-delay coordinates which are reconstructed by the phase portrait plotting special trajectory, we detect QRS complexes. In this study, arrythmias are detected by matching the past standard template with tile present pattern when changing abruptly In order to matching with each other, we propose modified chain coding algorithm which applies vetor table consisting of eight orthonormal code(=binary code) to the phase portraits. This algorithm using logical function increases the weight if exceeding to the threshold determinded by correlation value and the distance from a straight line(y=x). Evaluating the performance of the proposed algorithm, we use standard MIT/BIH database. The results are fellowing, 1) Improve the speed of matching template than that of cross-correlation ever has been used. 2) Because the proposed algorithm is robust to varing fiducial point, it is possible to monitor the ECG signal with irregular RR interval. 3) In spite of baseline wandering owing to the low frequency noise, monitoring performance is not reduced.

• 전기학회논문지
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• 제65권7호
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• pp.1252-1256
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• 2016

Internet of Things(IoT)-devices are now expanding inter-connecting networking technologies to invent healthcare monitoring system especially for assessing physiological conditions of the chronically-ill patients those with cardiovascular diseases. Hence, IoT system is expected to be utilized for home healthcare by dedicating the original usage of IoT devices to collect the biomedical data such as electrocardiogram(ECG) and photoplethysmography(PPG) signal. The aim of this work is to implement health monitoring system by integrating IoT devices with Raspberry-pi components to measure and analyze ECG and the multi-channel PPG signals. The acquired data and fiducial features from our system can be transmitted to mobile devices via wireless networking technology to support the concept of tele-monitoring services based on IoT devices.

• Journal of Information Processing Systems
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• 제18권1호
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• pp.97-114
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• 2022

Interest is increasing in electrocardiogram (ECG) signal analysis for embedded devices, creating the need to develop an algorithm suitable for a low-power, low-memory embedded device. Linear approximation of the ECG signal facilitates the detection of fiducial points by expressing the signal as a small number of vertices. However, dynamic programming, a global optimization method used for linear approximation, has the disadvantage of high complexity using memoization. In this paper, the calculation area and memory usage are improved using a linear approximated template. The proposed algorithm reduces the calculation area required for dynamic programming through local optimization around the vertices of the template. In addition, it minimizes the storage space required by expressing the time information using the error from the vertices of the template, which is more compact than the time difference between vertices. When the length of the signal is L, the number of vertices is N, and the margin tolerance is M, the spatial complexity improves from O(NL) to O(NM). In our experiment, the linear approximation processing time was 12.45 times faster, from 18.18 ms to 1.46 ms on average, for each beat. The quality distribution of the percentage root mean square difference confirms that the proposed algorithm is a stable approximation.

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2009년도 학술대회
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• pp.558-561
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• 2009

본 논문에서는 증강현실에서 마커에 포함된 이미지뿐만 아니라 문자 인식을 지원하기 위한 심플 프레임 마커를 제안한다. 마커 내부에 임의의 패턴 대신에 문자를 삽입하고 문자 인식 알고리즘(Optical Character Recognition)을 사용하여 인식하면 실행 전 학습과정이 필요 없을 뿐만 아니라 문자의 친숙함 때문에 시각적 장애요인도 줄일 수 있다. 따라서 기존의 마커 방식인 이미지뿐만 아니라 문자도 인식하기 위해서 제안된 심플 프레임 마커는 정의된 마커의 가로세로 비율에 따라 이미지타입의 마커(Square SFMarker)인지 문자타입의 마커(Rectangle SFMarker)인지를 구별하고 각기 다른 인식 알고리즘을 적용한다. 또한 문자 인식을 위한 전처리 과정을 줄이기 위해 디자인 단계에서 마커 테두리에 방향정보를 삽입하고, 인식 단계에서는 이 방향 정보를 추출하여 문자 인식을 빠르고 정확하게 수행한다. 마지막으로 매 프레임 문자를 인식하는 알고리즘을 수행 시 추적 속도가 저하되므로, 프레임간 변화량이 적을 때는 이전 프레임의 인식 결과 정보를 사용하여 수행 속도를 높인다.