• 대한기계학회논문집A
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• 제29권12권
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• pp.1653-1659
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• 2005

In this study, the performance of a DPRMs is evaluated and the measurement precision for the pile driving is presented. The DPRMs is a visual-measurement system for the pile rebound and the penetration movement using a high speed line-scan camera. The DPRMs generates the measurement deviation. It is caused by the strong impact for the pile driving. To reduce it, the vibration signal analysis about the pile driving is performed. As a result, it is confirmed that the tilting frequency of a camera-tripod structure corresponding to excitation frequency range of the ground is under 40Hz. Through the structure modification, the camera-tripod structure is redesigned to the model being free itself from the excitation frequency range of the ground. By the verification testing about the improvement effects, it is inspected that the tilting and measurement deviation of the redesigned DPRMs are reduced.

• 한국정밀공학회지
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• 제18권8호
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• pp.40-47
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• 2001

Optical measurement methods make it possible to detect object displacements with high resolution and noncontact measurements. Also, they are very robust against EMI noises and have long operation range. An optical triangulation sensor is one of widely used displacement measurement sensors for its sub-micron resolution, fast response, simple structure, and low cost. However. there are several errors caused by inclinations of a surface. speckle effects, power fluctuations of light sources, and noises of detectors. In this paper, in order to minimize error effects, we performed error analysis and proposed a new structure. Then, we setup a new modeling method and verify it through simulations and experiments. Based on the new model. we propose a new sensor structure and establish design criteria. Finally, we design a signal processing system to overcome a resolution-limited problem of light detectors. The resolution of the proposed system is 0.2${\mu}{\textrm}{m}$ in 5mm operating range.

• Journal of Biosystems Engineering
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• 제23권5호
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• pp.481-490
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• 1998

A computer vision system to measure low flow rate of solid particles was developed and tested to examine its performance with various sized 7 kinds of seeds, perilla, mung bean, paddy, small red bean, black soybean, Cuba bean and small potato tuber. The test was performed for two types of particle flow, continuous and discontinuous. For the continuous flow tested with perilla, mung bean and paddy, the tests resulted correlation coefficients for the flow rates measured by the computer vision and direct method about 0.98. Average errors of the computer vision measurement were in a range of 6∼9%. For the discontinuous flow tested with small red bean, black soybean, Cuba bean and small potato tuber, the tests resulted correlation coefficients for the flow rates measured by the computer vision and direct method 0.98∼0.99. Average errors of the computer vision measurement were in a range of 5∼10%. Performance of the computer vision system was compared with that of the conventional optical sensor to count particles in discontinuous flow. The comparison was done with black soybean, Cuba bean and small potato tuber, and resulted that the computer vision has much better performance than the optical sensor in a sense of precision of the measurement.

• 한국항행학회논문지
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• 제13권1호
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• pp.34-40
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• 2009

고정밀 레이저 변위기에서 측정하고자하는 목표물인 표적으로부터 반사되어 돌아오는 반사광의 강도에 따라 애벌런치 포토다이오드(APD: Avalanche Photo Diode) 출력신호의 위상 지연이 발생한다. 이 위상지연에 의한 차이는 측정오차의 주요 원인이 되나 이를 측정하기 위한 적절한 계측기와 측정 방법이 없었다. 본 논문에서는 이들 문제를 해결하기 위하여, APD의 수신회로에 반사광량에 비례하는 출력 DC 전압을 측정하여 실시간으로 반사광의 강도를 측정할 수 있는 광량 측정기법을 제시하고 구현하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1781-1786
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• 2005

In sensor network systems, all the nodes are interconnected and the positional information of each sensor is essential. To measure the temperature, position detection and communication functions are required. Many sensor nodes are distributed to a measurement field, and these sensors have three main functions: they measure the distance to the other nodes, the data of which are used to determine the position of each node; they communicate with other nodes; and they measure the temperature of each node. A novel range measurement method using the difference between light and sound propagation speed is proposed. The experimental results show the temperature distribution as measured with the aid of the determined positions. The positions of every node were calculated with a PC program. Eight nodes were manufactured and their fundamental functions were tested. The results of the range measurement method, which takes relatively accurate measurements, contribute significantly to the accuracy of the position determination. Future studies will focus on 3-D position determination and on the architecture of appropriate sensors and actuators.

• 대한기계학회논문집A
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• 제35권1호
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• pp.53-58
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• 2011

초정밀 소형공작기계는 초정밀가공분야에서 마이크로/메조 스케일 가공품의 정밀제조기술의 핵심으로 개발되어 왔다. 소형초정밀기계의 기하학적 오차는 가공품의 품질에 큰 영향을 미치기 때문에 반드시 분석 및 보정되어야 한다. 기존 소형공작기계의 기하학적 오차는 주로 레이저 간섭계로 측정되었으나 한번의 설치로 모든 기하학적 오차를 측정할 수 없고 까다로운 절차를 따라야 한다. 그 대안으로써 PSD 로 구성된 측정시스템이 개발되었으나 측정가능거리가 PSD 의 유효영역에 한정되었다. 본 논문에서는 측정가능거리를 확장시키고 설치오차를 최소화하여 6-자유도 기하학적 오차를 측정하는 시스템을 제안하고 민감도 해석과 실험을 통하여 이 측정 시스템의 정확도를 증명하였다.

• 조명전기설비학회논문지
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• 제18권5호
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• pp.48-53
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• 2004

광원의 분광복사조도를 250∼1600[nm] 파장 영역에서 정확하게 측정하기 위한 분광복사조도 측정 장치를 개발하였다. 분광복사조도 측정 장치는 광원 장치, 광학계, 분광장치, 광검출장치, 신호 처리 장치 등으로 이루어져 있다. 광검출 장치는 PMT, Si, InGaAs 및 IR enhanced InGaAs 광검출기를 이용함으로써 자외선, 가시광선, 적외선을 포함하는 넓은 파장 범위에서 광원의 스펙트럼을 측정할 수 있다. 개발된 측정 장치를 이용하여 1[kW] quartz-halogen 텅스텐 전구의 분광복사조도를 측정하여 비교하였는데, 측정 결과와 NIST에서 측정된 결과와는 차이는 450∼700[nm] 파장 영역에서 3[%] 이하이며, 700∼1600[m] 파장영역에서는 3.5[%] 이하이며, 250∼400[nm] 파장영역에서는 5[%] 이하로 측정되었다.

• 한국측량학회지
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• 제14권1호
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• pp.17-25
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• 1996

스틸비디오 CCD카메라는 수치영상의 획득과정이 크게 단순화되어 컴퓨터에 직접 연결되지 않고도 독립적으로 수치영상을 획득하여 자체내에 영상을 저장할 수 있는 융통성을 갖추고 있다. 본 연구에서는 각종 산업분야에서 요구되는 품질검사, 구조물의 모니터 링 등에 스틸비디오 카메라를 이용한 수치근접사진측량 시스템의 수행성을 평가하고자 하였다. 수치 영상측정 에서 필수적 인 sub-pixel 측정기 법을 제시하고, 고해상도의 DCS420 스틸비디오 카메라에 대한 기하학적 자체검정 및 구조물에 대한 시험측정을 실시하였다. 자체검정 광속조정의 결과 1:46,000을 초과하는 대상공간 정확도를 얻을 수 있었으며 산업적 음용에 수치영상을 이용한 본 근접사진측량 시스템의 정확도 잠재성과 작업의 효율성을 입증할 수 있었다.

• 전자공학회논문지B
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• 제31B권2호
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• pp.69-79
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• 1994

The conventional machine vision system which has uniform rectangular grid requires tremendous amount of computation for processing and analysing an image especially in 2-D image transfermations such as scaling, rotation and 3-D reconvery problem typical in robot application environment. In this study, the imaging system with nonuiformly distributed image sensors simulating human visual system, referred to as Ploar Exponential Grid(PEG), is compared with the existing conventional uniform rectangular grid system in terms of image resolution and computational complexity. By mimicking the geometric structure of the PEG sensor cell, we obtained PEG-like images using computer simulation. With the images obtained from the simulation, image resolution of the two systems are compared and some basic image processing tasks such as image scaling and rotation are implemented based on the PEG sensor system to examine its performance. Furthermore Fourier transform of PEG image is described and implemented in image analysis point of view. Also, the range and heading-angle measurement errors usually encountered in 3-D coordinates recovery with stereo camera system are claculated based on the PEG sensor system and compared with those obtained from the uniform rectangular grid system. In fact, the PEC imaging system not only reduces the computational requirements but also has scale and rotational invariance property in Fourier spectrum. Hence the PEG system has more suitable image coordinate system for image scaling, rotation, and image recognition problem. The range and heading-angle measurement errors with PEG system are less than those of uniform rectangular rectangular grid system in practical measurement range.

• The Journal of Korean Physical Therapy
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• 제15권4호
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• pp.90-102
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• 2003

Purpose: The purpose of this study is to search effect that GCM joint treatment gets to range of motion of cervical, lumbar, trunk and anke. And cervical gets in ankle joint. Methods: Estimated body deformity using GCM body type assesment chart then measured range of motion of each region. After control group did as act freely after do experiment pre measurement control group did post measurement. After control group did as act freely after do experiment premeasurement, control group did postmeasurement. Each region was measured by measurer who each subject person differs. Experimental group did GCM joint treatment and all measurements each region by measurer who each subject person differs three times measure postmeasurement after premeasurement. When measure with each measurement, measured after leave and walk time interval for 10 minutes. Result: For the analysis of the result of experiment, the results is change amount comparison increased to keep in mind except cervical flexion and both ankle joint's dorsiflexion after experiment of experimental group. In experimental group, cervical, lumber and ankle joint of range of motion was significantly increased(p<.05).