• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.11
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• pp.1136-1143
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• 2010

One-way laser ranging technology is applied for the precise orbit determination of LRO, which is the first trial for supporting the missions of lunar or planetary spacecraft. In this paper, LRO payload and ground system are discussed for LRO laser ranging, and some errors effecting on time of flight and tracking mount accuracy are analyzed. Additionally several technologies are also analyzed to make laser pulses shot from ground stations to arrive in the LRO earth window. Measurement data of LRO laser ranging verified that these technologies could be implemented for one-way laser ranging of lunar spacecraft.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.6
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• pp.1300-1305
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• 2012

In this research, we propose a momentum measurement system using the accelerometer sensor, MCU, and Bluetooth to measure the exact momentum. The proposed system can figure out information for the real time travel distance. We performed various experiments, and analyzed the results using the proposed momentum measurement system. In the simulation experiments, we compared the reliability and accuracy for the existing momentum measurement systems from the analyzed results. The proposed system showed travel distance error of less than 8% as compared to the existing system with the error of approximately 13%. We expect that the proposed system apply to the commercial products.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3227-3229
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• 1999

수신된 초음파 파형이 표준 파형과 정합되는 시간을 수신 시점으로 사용함으로써 정확한 거리측정을 가능하게 하는 초음파 센서 거리계의 성능 개선을 제안하였다. 근거리 측정용으로 많이 사용되는 초음파센서는 다른 거리측정 시스템에 비해 하드웨어 구현이 용이하고 가격이 저렴한 장점이 있으나 센서 수신부측 Limit 회로의 threshold level의 선택 문제에 따른 거리 측정의 오차와 소음에 의한 거리 측정 오차가 매우 큰 문제가 되고 있다. 본 논문에서는 수신된 초음파 파형에 표준 파형을 정합하여 최대의 정합값을 가지는 시점을 수신 시간으로 간주하여, 소음환경비서도 거리 측정이 가능한 파형 정합 방법을 제한하였다. 본 논문의 실험을 통하여, 잡음이 심한 소음환경에서도 제안한 파형 정합 방법이 Threshold 방법 보다 초음파센서 거리 측정 성능이 개선됨을 확인할 수 있었다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.329-336
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• 2008

Nowadays with advancement in technology and aging society, the number of disabled citizens is increasing. The disabled citizens always need a caretaker for daily life routines especially for mobility. In future, the need is considered to increase more. To reduce the burden from the disabled, various devices for healthcare are introduced using computer technology. The power wheelchair is an important and convenient mobility device. The demand of power wheelchair is increasing for assistance in mobility. In this paper we proposed a robotic wheelchair for mobility aid to reduce the burden from the disabled. The main issue in an autonomous wheelchair is the automatic detection and avoidance of obstacles and going to the pre-designated place. The proposed algorithm detects the obstacles and avoids them to drive the wheelchair to the desired place safely. By this way, the disabled will not always have to worry about paying deep attention to the surroundings and his path.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2001.06a
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• pp.85-88
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• 2001

레이저 거리측정기는 레이저를 이용한 거리측정 방법으로 레이저송수신펄스의 시간차로부터 거리를 측정하는 방법이다. 본 연구에서는 송광부, 수광부, 제어모듈 통의 하드웨어로 시스템을 구성하고, 거리측정의 오차를 보정 알고리즘을 사용하여 거리를 계측하는 80196 기반의 거리측정기를 개발하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.04a
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• pp.330-333
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• 2010

본 논문은 인간의 시각체계를 모방한 스테레오 비전 시스템을 이용해 물체까지의 거리를 측정하는 방법을 제안한다. 기존 연구에서의 거리 측정 방법은 스테레오 카메라의 중복 영역 중에서 광축 내부에 물체가 위치했을 경우에만 측정 가능하다는 단점이 있다. 그래서 본 논문에서는 두 카메라의 중복영역 중에서 광축 외부에 물체가 위치했을 경우에 그 물체까지의 거리를 측정하는 방법을 제안 한다. 본 논문에서 제안한 거리 측정 방법을 확인하기 위해 시뮬레이션을 실행하였다. 시뮬레이션 실험 결과 제안된 거리 측정 방법의 정확성을 확인하였다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.4
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• pp.106-115
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• 2003

In crossing stereo camera system as a security equipment system, a new algorithm for the tracking method of the moving object and the measurement method of distance of the object from cameras to moving object is proposed. The stereo input images are matched by a pixel for the moving object extraction, then the moving elements obtained from an adaptive threshold's value for an error correction and the moving object area extracted by noise eliminative algorithm. In addition to, the moving object traced by control pan/tilt of cameras using a coordinate value of the moving object, and the measurement method of distance to moving object by using special features of the crossing stereo camera system is proposed. From the experimental results, the proposed algorithm was found to be able to measure of the distance and trace for moving object in a stereo security camera system. The error rate of a distance measurement be existed within 6%. Moreover in implementation the proposed algorithm, the stereo security system, the automatic moving robot system and the stereo remote control system will be applied practical application.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.5
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• pp.422-428
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• 2013

Recently, many unmanned aerial vehicle (UAV) studies have focused on small UAVs, because they are cost effective and suitable in dangerous indoor environments where human entry is limited. Map building through distance measurement is a key technology for the autonomous flight of small UAVs. In many researches for unmanned systems, distance could be measured by using laser range finders or stereo vision sensors. Even though a laser range finder provides accurate distance measurements, it has a disadvantage of high cost. Calculating the distance using a stereo vision sensor is straightforward. However, the sensor is large and heavy, which is not suitable for small UAVs with limited payload. This paper suggests a low-cost distance measurement system using a laser pointer and a monocular vision sensor. A method to measure distance using the suggested system is explained and some experiments on map building are conducted with these distance measurements. The experimental results are compared to the actual data and the reliability of the suggested system is verified.

• Journal of the Korea Society of Computer and Information
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• v.15 no.6
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• pp.73-80
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• 2010

Vocabulary recognition system is providing inaccurate vocabulary and similar phoneme recognition due to reduce recognition rate. It's require method of similar phoneme recognition unrecognized and efficient feature extraction process. Therefore in this paper propose phoneme likelihood error correction improvement system using based on phoneme feature Bhattacharyya distance measurement. Phoneme likelihood is monophone training data phoneme using HMM feature extraction method, similar phoneme is induced recognition able to accurate phoneme using Bhattacharyya distance measurement. They are effective recognition rate improvement. System performance comparison as a result of recognition improve represent 1.2%, 97.91% by Euclidean distance measurement and dynamic time warping(DTW) system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.220-223
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• 2018

스마트폰의 GPS 기능으로 위치 정보를 수집하여 사용자에게 서비스를 제공하는 시스템이 많아지고 있다. 이러한 GPS 기능은 위성에서 송신된 신호로 위도와 경도를 측정하여 위치를 계산한다. 하지만, 이러한 기능은 사용자가 실외에 있을 경우에만 사용이 가능한 것으로, 실내에서는 사용이 불가능하다는 단점이 있다. 최근 상용화 되고 있는 UWB 레이더 센서는 실내외에서 사용이 가능하고, 객체 탐지 및 거리측정이 간단함과 동시에 저렴하다는 장점이 있다. 본 논문에서는 UWB 레이더 센서와 표준편차를 이용하여 거리 측정 방법을 제시하고자 한다. 제시하고 있는 방법은 레이더 센서에서 나오는 raw data를 그래프화 하여 최대 탐지 거리가 몇 m 인지 파악하고, 파악된 최대 감지 거리를 일정 구간으로 나누어 구간별 거리를 측정한다. 그 후 표준편차 공식을 이용하여 객체의 유무를 판단한다. 실험 결과에서는 제시하는 방법으로 최대 거리 9.7m에서 최대 오차 0.27m 이내로 측정되는 것을 확인하였다.