• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2001년도 Proceedings of 2001 Korea-Japan Joint Seminar on Particle Image Velocimetry
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• pp.23-35
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• 2001

Due to advances in digital image processing, computer and optical hardware, it is possible to extract full flow information from visualized flow images. Recently, the PIV/PTV methods have been accepted as a reliable velocity field measurement technique. In my laboratory, several velocity field measurement techniques have been developed and they were applied to various thermo-fluid flow problems. In this paper, some of the industrial applications will be discussed. As a result, the PIV/PTV technique was proved to be a powerful tool for industrial fluid flow diagnosis.

• 제어로봇시스템학회논문지
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• 제9권3호
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• pp.227-235
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• 2003

We propose an algorithm for the automatic measurement of concentricity and roundness using image processing technique. The proposed measuring method consists of the preprocessing process and the measuring process. In the measuring process, two types of concentricity measurement algorithm and one type of roundness measurement algorithm are proposed. We could measure the concentricity and roundness using input image from CCD camera, without using special measurement equipment. From the experimental results, we could find that the required measurement accuracy specification is sufficiently satisfied using our proposed method.

• 지역사회간호학회지
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• 제17권4호
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• pp.573-582
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• 2006

Purpose: To find out whether the self-care ability measurement used for visiting health care provide an appropriate standard to select service methods using a Delphi survey and to offer basic data that can improve the measurement. Method: A Delphi survey was done with 39 people consisting of theoretical professionals, field managers, and practitioners engaged in visiting health care. Result: It was found that items and weighted points in the currently used self-care ability measurement needed adjustment. Therefore, a modified evaluation standard was presented by domains, items and detailed items. Finally, the self-care ability measurement is composed of 4 domains, 11 items and 19 detailed items. Conclusion: This study is significant in that it presented an evaluation standard applicable directly to business practice by supplementing problems in the existing self-care ability measurement. This study suggests the need to develop various measurements for elderly households based on community.

• Journal of Advanced Marine Engineering and Technology
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• 제31권5호
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• pp.531-542
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• 2007

Simultaneous measurement technique for temperature and velocity fields near a heated solid body has been constructed. The measurement system consists of a 3-late CCD color camera, a color image grabber, a 1ighting system, a host computer and a software for the whole quantification process. Thermo Chromic Liquid Crystals (TCLC) was used as temperature sensors. A neural network was used to get a calibration curve between the temperature and the color change of the TCLC in order to enhance the dynamic range of temperature measurement. The velocity field measurement was attained by the use of the fray-level images taken for the flow field, and by introducing the cross-correlation technique. The temperature and the velocity fields of the forced and the natural convective flows neat the surface of a cartridge heater were measured simultaneously with the constructed measurement system.

• 한국멀티미디어학회논문지
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• 제23권10호
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• pp.1229-1235
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• 2020

A line parallel to the ground is frequently shown in our daily life, which enables us to guess its direction. Especially, such a guess tends to become clear when a vanishing line of the ground is shown together. In this paper, a vision based pallet measurement method is suggested, which uses a technique for estimating three-dimensional direction of a line parallel to the ground. The technique computes actually a vector heading to intersection of a given imaged line parallel to the ground and the ground vanishing line determined previously on calibrating a measurement camera. Through an experiment of measuring a real commercial pallet with various orientation and distance, we found that the technique could measure the orientation of the pallet correctly and accurately. The technique worked well even though an edge line available on the front plane of a pallet was almost parallel to the ground vanishing line.

• 대한기계학회논문집B
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• 제24권1호
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• pp.93-101
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• 2000

The characteristics of spray nozzle have been quantified with the measurement of fluorescence and Mie scattering images. To correct the attenuation of the incident light sheet, a sequential double-pass light sheet system and the geometrical averaging of two images was implemented. Quantitative mass flux distribution of spray was obtained from fluorescence image. 3-D image is reconstructed using 2-D radial images. Sauter mean diameter (SMD) distribution was determined using the ratio of fluorescence signal intensity and Mie scattering signal intensity and the values were quantified with PDP A data. The measurement of mass flux and SMD using planar imaging technique agee with PDP A data fairly well in the low density region. However, in dense region， there are significant errors caused by secondary scattering. It was found that the planar imaging technique provides many advantages over the point measurement technique, such as PDP A, and can be implemented for quantitative measurement, especially in low density region.

• 대한기계학회논문집B
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• 제22권8호
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• pp.1152-1163
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• 1998

In the present work, the image processing technique for measurement of drop sizes has been improved. Firstly, the local processing concept was adopted in addition to the global processing technique to take account of non-uniformity of the illumination intensity ; thereby, basically, the measurement error can be reduced. Also, the unfocussed image of drops can be eliminated more precisely since the elimination process is based on the local normalized contrast. Secondly the algorithms to process the partially detected or overlapped drop images and the non-spherical drop images were developed. Finally, the improved algorithm was tested by using an artificially prepared image-frame, where the partial or overlapped particles and the non-spherical particles are mixed with the normal spherical ones (with their true size-distributions known a priori). The results showed that both the recognition rate of the number of particles and the measurement accuracy were improved prominently.

• 한국연소학회지
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• 제11권3호
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• pp.36-43
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• 2006

The modulated LII technique has been suggested for the measurement of axial velocity profiles of laminar diffusion flames. The theoretical background is explained based on the blackbody radiation and LII signal. Experimentally, soot particles in ethylene diffusion flames are heated by a modulated Ar-ion laser beam. LII signals and their phase angles are measured using a lock-in amplifier at the different flame heights and the axial flow velocities are obtained from the measured phase angle delay informations. The measured velocities are similar to those from LDV measurements under the same operating conditions. The effects of laser power, LII signal wavelength, and modulation frequencies are not sensitive to the velocity measurement. However, the choice of an optical chopper blade type could affect the measurement result. The use of a 6/5 chopper blade showed the better result that is. possibly due to the square shape of modulated laser beam. This study successfully demonstrated that axial flow velocities of laminar diffusion flames can be measured by a new technique utilizing LII signal, which does not need particle seeding unlikely to LDV or PIV techniques.

• Journal of Radiation Protection and Research
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• 제26권3호
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• pp.275-279
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• 2001

In uranium enrichment plants and nuclear fuel fabrication facilities, exact measurement of fissile isotope enrichment of uranium is required for material accounting in international safeguards inspection as well as process quality control. The purpose of this study was to develop a simple measurement system which can portably be used at nuclear fuel fabrication plants especially dealing with low enriched uranium. For this purpose, a small size CZT (CdZnTe) detector was used, and the detector performance in low uranium gamma/X -rays energy range was investigated by use of various enriched uranium oxide samples. New enrichment measurement technique and analysis method for low enriched uranium oxide, so-called, 'semi-peak ratio technique' was developed. The newly developed method was considered as an alternative technique for the low enrichment and would be useful to account nuclear material in safeguarding activity at nuclear fuel fabrication facility.

• 대한전자공학회논문지
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• 제27권2호
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• pp.31-38
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• 1990

외삽기법을 시용하여 실내의 소형 안테나 레이지에서 안테나 이득을 측정할 수 있는 시스템을 개발하였다. 외삽기법은 안테나의 절대이득 측정에 보통 사용되는 2-안테나 방법과 유사한데 가까운거리 구간에서 수신되는 신호의 크기를 거리의 함수로 연속적으로 측정한 후 외삽법을 사용한 신호처리로 무한거리에서 수신되는 신호의 크기를 계산함으로써 안테나의 원역장 이득을 구할 수 있다. 또한 원역장 이득과 근역보정인자를 결합하여 근역장 이득을 안테나로부터의 거리의 함수로 구하는 것도 가능하다. 이 외삽기법을 사용하여 측정한 표준이득 혼 안테나와 OEC 안테나의 이득 측정결과를 고찰하였다.