• Title/Summary/Keyword: Precise measurement

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Precise Measurement of High Current Shunt Resistance (대전류 분류기 저항의 정밀측정)

  • Kim K.-T.;Han K.-S.;Kwon S.-W.;Kim M.-S.;Jeong J.Y.;Kim I.S.
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.54 no.9
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    • pp.403-406
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    • 2005
  • Precise measurement of extremely low resistance shunt is important for characterization and calibration of high current instruments. We tested resistance measurement method for extremely high current shunt (up to 140 kA), where resistance is determined by precise measurement of voltage drop at 10 A test current in the frequency range of 40 Hz to 10 kHz. For the extremely low ac voltage to be precisely measured, a verification of the measurement method was also carried, where the inherent noise is systematically evaluated. The measurement uncertainty was estimated to be $1\;\%\;at\;95\;\%$ confidence level (k=2) for about 50 $\mu\Omega$.

Precise Edge Detection Method Using Sigmoid Function in Blurry and Noisy Image for TFT-LCD 2D Critical Dimension Measurement

  • Lee, Seung Woo;Lee, Sin Yong;Pahk, Heui Jae
    • Current Optics and Photonics
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    • v.2 no.1
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    • pp.69-78
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    • 2018
  • This paper presents a precise edge detection algorithm for the critical dimension (CD) measurement of a Thin-Film Transistor Liquid-Crystal Display (TFT-LCD) pattern. The sigmoid surface function is proposed to model the blurred step edge. This model can simultaneously find the position and geometry of the edge precisely. The nonlinear least squares fitting method (Levenberg-Marquardt method) is used to model the image intensity distribution into the proposed sigmoid blurred edge model. The suggested algorithm is verified by comparing the CD measurement repeatability from high-magnified blurry and noisy TFT-LCD images with those from the previous Laplacian of Gaussian (LoG) based sub-pixel edge detection algorithm and error function fitting method. The proposed fitting-based edge detection algorithm produces more precise results than the previous method. The suggested algorithm can be applied to in-line precision CD measurement for high-resolution display devices.

Precise Measurement of Dielectric Constant Using Cross Capacitance Measurement Method (Cross Capacitance 측정법을 이용한 유전상수 정밀측정)

  • Kim, Han-Jun;Kang, Jeon-Hong;Yu, Kwang-Min;Lee, Sei-Hyun;Koo, Kyung-Wan;Han, Sang-Ok
    • Proceedings of the KIEE Conference
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    • 2007.07a
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    • pp.1287-1288
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    • 2007
  • The cross capacitor electrode system applied Thompson-Lampard theorem for precise and accurate measurement of dielectric constants is studied in this study. The capacitance derived from cross capacitor is calculated by the equation of ($C=\frac{{\epsilon}ln2}{\pi}{\cdot}$ effectivelength of electrode) which is very different from the equation of capacitance derived from parallel plate capacitor. From above mentioned reason, the capacitance measurement uncertainty of cross capacitor can be reduced then that of the parallel plate capacitor. the measurement dielectric constant measured by cross capacitor electrode method is one order more accurate and precise than that of 3-electrode method.

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Precision control of a mobile/task robot using visual information (비젼 정보를 이용한 이동/작업용 로봇의 정밀제어)

  • 한만용;이장명
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.34S no.10
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    • pp.71-79
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    • 1997
  • This paper introduces a methodology of the precise control of a mobile/task robot using visual information captured bythe camera attached at the hand of the task robot. The major problem residing in the precise control of mobile/task robot is providing an accurate and stable base for the task robot through the precise control of mobile robot. On account of uncertainties on the surface, the precise control of mobile robot is not feasible without using external position sensor. In this paper, the methodology for the precise control of mobile robot is proposed, which recognizes the position of mobile robot using the camera attached at the hand of the task robot. While the task robot is approaching to an assembly part, the position of mobile robot is measured using the line correspondence between the image capturesd by the camera and the real assembly part, and using the kinematic transformation from the hand of the task robot to the mobile robot. To verify the solidness of this method, experimental data for the measurement of camera position/orientation and for the precise control of mobile robot using measurement are shown.

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Precise response time measurement and analysis of liquid crystal displays

  • Glinel, David;Boher, Pierre;Leroux, Thierry
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.723-728
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    • 2006
  • In this paper, we present a new system, OPTISCOPE SA, especially designed for precise measurement of temporal behavior of LCD displays. We show that gray to gray level response time measurement requires a very sensitive and precise instrument and also that the capacity to measure luminance levels and gamma curve can be useful. Quite often, precise evaluation of LCD response time needs also use of low pass and stop band filters to suppress noise and flicker. Low pass filters affect the results but can be corrected for simple temporal behaviors. For complex temporal behaviors like those observed for overdriven LCDs, we show that direct adjustment of theoretical responses is much more efficient to get a complete picture of the temporal behavior of such displays.

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Implementation of Synchronized Phasor Measurement Unit Using GPS (GPS를 이용한 동기페이저측정장치의 EMTP모델 구현)

  • Cho, Ki-Seon;Heo, Mun-Jun;Choi, Myung-Seok;Shin, Joong-Rin
    • Proceedings of the KIEE Conference
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    • 1999.07c
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    • pp.1262-1266
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    • 1999
  • More precise operation and control is required to ensure the stability and security of modern large power systems that is a complicated and widely dispersed structure. To ensure the precise operation and control of modern power system, most of all, precise monitoring and measurement of the various state values of power system is required. This paper discusses phasor measurement unit using synchronization signals from the GPS satellite system- Synchronized Phasor Measurement Unit. Considering the power system operation state, the transmitting data format over modems is defined. To provide all available information, PMU process the measurements to generate three phase symmetrical component. This paper proposes the transmitted data format and implements the PMU model using EMTP/Models. The validity of proposed model is confirmed through several contingency on the simple power system.

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A Study on the Precise Measurement of the Performance in the Heating System (발열시스템 열적 성능의 정밀측정에 관한 연구)

  • 최창용;김홍건
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.11 no.6
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    • pp.60-67
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    • 2002
  • A precise measurement of field test was performed to estimate the thermal performance of the forced convection electric air heater by experiment. Air temperature, flow rate and electrical power input were measured with the related measurement sensors, and acquisition methods for the measured data were studied to estimate the thermal performance of the tested air heater effectively. To determine the mean air temperature at the flow cross-section, measuring positions were chosen by considering the flow velocity profile and the equally divided cross-sectional area. From the experimental results, thermal efficiency was obtained accurately as an indication of the tested heating system performance.

Rock Displacement Measurement System by Precise Vision Metrology (정밀 화상계측법을 이용한 암반변위 계측시스템)

  • Hwang, Jae-Yun
    • Tunnel and Underground Space
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    • v.21 no.6
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    • pp.450-459
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    • 2011
  • For the purpose of evaluating the safety of rock structures such as underground caverns, tunnels and slopes, rock displacement measurement is carried out to identify the behavior of rock masses. Tapes, levels, and total stations are usually applied to the displacement measurement. These tools, however, are weighed down by many disadvantages. In this study, a new displacement measurement system by precise vision metrology was proposed for the observational design and construction method of rock structures, and then applied to a tunnel under construction. Comparisons and investigations of the measurement of the tunnel have confirmed the effectiveness and applicability of the developed measurement system.

A Study on the Precise Distance Measurement for Radar Level Transmitter of FMCW Type using Correlation Anaysis Method (상관분석법을 이용한 FMCW 타입 레이더 레벨 트랜스미터의 정밀 거리 측정에 관한 연구)

  • Ji, Suk-Joon;Lee, John-Tark
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.61 no.7
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    • pp.1024-1031
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    • 2012
  • In this paper, FMCW type radar level transmitter using correlation analysis method is implemented for precise distance measurement of cargo tank. FMCW type radar level transmitter is the device for distance measurement which calculates the distance by analyzing the beat frequency, that is, the frequency difference between Tx and RX signal from radar antenna using Fast Fourier Transform(FFT), but compensated algorithm like Zoom FFT is needed for the improvement of the frequency precision because the frequency precision of FFT is limited depending on sampling frequency and the number of sampling data. In case of Zoom FFT, the number of sampling data and noisy signal are the main factor influencing the measurement accuracy of Zoom FFT like FFT. Therefore, in order to overcome the limited environment and achieve the precise measurement, correlation coefficient is used for the distance measurement and the errors of measurement are verified to be in the range of ${\pm}1mm$.