• 한국운동역학회지
• /
• 제14권3호
• /
• pp.49-65
• /
• 2004

The purpose of this study is development of posture evaluation and Range of Motion(ROM) system by using digital vision analysis method. The results of this study are as follows. First, Scoliosis evaluation through this research measurement system represent 3mm error in 7 cervical point and deepest lumbar point, 0.7mm error in other point. This mean this research measurement system have a reliability for scoliosis evaluation. Second, for spine line evaluation on high fat subject, we need reconstrection spine line after measurement for fat thickness in 7 cervical point and deepest lumbar point. Third, In pedioscope error test, it present 0.01848cm in X axis and 0.01757cm in Y axis. This results mean pedioscope have a reliability foot evaluation. Forth, Posture evaluation and Range of Motion measurement system by using digital vision analysis method can fast measure in range of motion and foot evaluation and posture. therefore we can expect this system application in young people posture clinic center and hospital and so on.

• 정보저장시스템학회논문집
• /
• 제8권2호
• /
• pp.44-49
• /
• 2012

We measured the surface flatness of both sides for refractive media using the transmitted digital holography method. To enhance the accuracy of the result, phase-shifting system was used. With two different phase modulation of reference beam, the phase profile of object can be easily obtained. Thus, we proposed the surface measurement method which can measure large area fast, compared with conventional methods. To guarantee the reliability of obtained result, we compared with Zygo measurement system. With the proposed method, the surface flatness of $3.45{\mu}m$ resolution could be obtained.

• 한국위성정보통신학회논문지
• /
• 제10권3호
• /
• pp.84-88
• /
• 2015

본 논문은 극저주파 자계 세기를 무선 모니터링하기 위한 디지털 자계측정기의 설계 및 구현에 대해 기술한다. 우리 실생활에 극 저주파대역의 자기장이 노출되어 있어 인체에 자기장이 얼마나 영향을 미치는가에 대한 연구의 필요성이 있으며 그에 따른 측정 장비의 수요가 증가하고 있다. 본 논문에서는 3-축 코일형 자계센서를 사용하였으며, 자계의 측정 범위는 0.03~10uT, 주파수 범위는 40~180Hz이다. 자계 세기의 측정과 주파수 특성을 보상하는 등화기능은 DSP 기반의 디지털 방식으로 설계하였으며, 측정 값은 와이파이 통신을 이용하여 PC 모니터링 할 수 있도록 설계 및 구현하였고 측정오차는 6% 이내로 실용성을 확인하였다.

• 대한전기학회논문지:시스템및제어부문D
• /
• 제51권5호
• /
• pp.203-211
• /
• 2002

In this paper, the implementation of a new AF(Automatic Focusing) system for a digital still camera is introduced. The proposed system operates in real-time while adjusting focus after the measurement of distance to an object using a passive sensor, which is different from a typical method. In audition, measurement errors were minimized by using the data acquired empirically, and the optimal measuring time was obtained using EV(Exposure Value) which is calculated from CCD luminance signal. Moreover, this system adopted an auxiliary light source for focusing in absolute dark conditions, which is very hard for CCD image Processing. Since this is an open-loop system adjusting focus immediately after the distance measurement, it guarantees real-time operation. The performance of this new AF system was verified by comparing the focusing value curve obtained from AF experiment with the one from the measurement by MF(Manual-Focusing). In both case, edge detector was used for various objects and backgrounds.

• 한국전문물리치료학회지
• /
• 제2권2호
• /
• pp.46-55
• /
• 1995

The purpose of this study was to assess the concurrent validity and reliability of goniometric measurement of joint motion. Subjects were 40 healthy university students. Measurements were performed by 4 inexperienced physical therapy students. Four different instruments were used and three readings were taken with each instrument in random order making a total of 12 readings for flexion of the right elbow of each subject. Goniometers used were 1. universal 2. fluid-based goniometer/inclinometer 3. digital LCD goniometer 4. electronic goniometer/torsiometer. The results were as follows: Concurrent validity was highest (r= .94) with the universal and digital LCD tools. Interrater reliability (Pearson Product Moment Correlation) was good for each tool. Interrater reliability calculated by ICC(2,1) was highest (.96) with the tensiometer and lowest (.78) with the digital LCD goniometer. Intrarater reliability calculated by ICC was excellent (${\geq}.90$) for all instruments. These results show that concurrent validity, intrarater and interrater reliability are very good in the used of all four types of goniometers/inclinometer/tensiometer, even with inexperienced raters. These results confirm the almost universal reliance on hand held goniometers for joint measurement by physical therapists as being a reliable practice. Further research should be done clinically with actual patients.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1997년도 하계학술대회 논문집 C
• /
• pp.1317-1319
• /
• 1997

This paper is to study and develope a measurement apparatus for ferroelectricity. The apparatus consists of wave generation part, high voltage amplifier part, measurement part, data acquisition part and the related controll circuits. Single or double excitation wave is digitalized and sent to the external RAM of wave generation part by personal computer. These datas saved in the RAM are converted to analog excitation wave through D/A converter. The frequency of excitation wave is depend on the read-out speed of the RAM by clock pulse. Such generated wave is applied to high voltage amplifier as a input voltage. The output of high voltage amplifier is applied to ferroelectrics and the response is obtained from the charge amplifier of measurement part. The response is sampled and converted to digital datas through AID converter. These digital datas are automatically saved in the external RAM of acquisition part. The computer takes the digital datas and calculates the electric displacement D, the electric field and the dielectric constant $\varepsilon$. We tested for PZT ceramic sample and could observed the D-E hysteresis lops and ${\varepsilon}_s$-E hysteresis loops with good forms.

• Journal of the Optical Society of Korea
• /
• 제18권5호
• /
• pp.605-610
• /
• 2014

Clouds play an important role in climate change, in the prediction of local weather, and also in aviation safety when instrument assisted flying is unavailable. Presently, various ground-based instruments used for the measurements of the cloud base height or velocity. Lidar techniques are powerful and have many applications in climate studies, including the clouds' temperature measurement, the aerosol particle properties, etc. Otherwise, it is very circumscribed in cloud velocity measurements because there is no Doppler effect if the clouds move in the perpendicular direction to the laser beam path of Doppler lidar. In this paper, we present a method for the measurement of cloud velocity using lidar's range detection and DIC (Digital Image Correlation) system to overcome the disadvantage of Doppler lidar. The lidar system acquires the distance to the cloud, and the cloud images are tracked using the developed fast correlation algorithm of DIC. We acquired the velocities of clouds using the calculated distance and DIC algorithm. The measurement values had a linear distribution.

• 한국생산제조학회지
• /
• 제23권5호
• /
• pp.498-504
• /
• 2014

Displacements and strains are very important for material evaluation as critical factors to a machine's life cycle and safety. Typically, the strain gauge has been employed to measure displacement and strain. However, this contact-type measurement method has disadvantages that are not quantified under the test conditions of a specific object shape, surface roughness, and temperature. In this paper, the measurement of deflection and flexural strain due to the three-point bending test is presented, employing Digital Image Correlation (DIC) methods. In order to ensure measurement reliability, DIC and universal test machine methods were compared by measuring the deflections and flexural strains developed by such bending tests.

• 센서학회지
• /
• 제32권5호
• /
• pp.307-312
• /
• 2023

To measure the flow velocity and direction in the near field of an unmanned underwater vehicle, an optical measurement unit containing an image sensor and a phosphor-integrated pillar that mimics the neuromasts of a fish was constructed. To analyze pillar movement, which changes with fluid flow, fluorescence image analysis was conducted. To analyze the flow velocity, mean force analysis, which could determine the relationship between the light intensity of a fluorescence image and an external force, and length-force analysis, which could determine the distance between the center points of two fluorescence images, were employed. Additionally, angle analysis that can determine the angles at which pixels of a digital image change was selected to analyze the direction of fluid flow. The flow velocity analysis results showed a high correlation of 0.977 between the external force and the light intensity of the fluorescence image, and in the case of direction analysis, omnidirectional movement could be analyzed. Through this study, we confirmed the effectiveness of optical flow sensors equipped with phosphor-integrated pillars.

• 한국정밀공학회지
• /
• 제33권2호
• /
• pp.121-128
• /
• 2016

The mechanical jointing method is very important in the machine parts and structure. They are used by the bolts and rivet because it is very convenient to replace the parts and the structure. However, the mechanical jointing methods using the bolt and rivet needed the open hole. The machine parts life cycle is reduced because this open hole created the stress concentration. Therefore, the measurement methods are needed to evaluate phenomenon of the stress concentration. This paper discusses the development of the measurement algorithm using the digital image correlation methods to measure the strain distribution of the open hole. To implement the measurement algorithm using the DIC, the LabVIEW 2010 programming tool was used. To measure the strain distribution of the open hole, the tensile specimens having an open hole are made by using the aluminum 6061-T6. To secure the reliability of measurement result using the DIC, the DIC measurement results and FEM analysis results were compared.