• Journal of the Optical Society of Korea
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• 제13권2호
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• pp.251-255
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• 2009

In the non-contact 3-dimensional (3D) shape measurements, the fringe pattern projection method based on the phase-shifting technique has been considered very effective for its high speed and accuracy. The digital fringe projector in particular has great flexibility in generating fringe patterns since the patterns can be controlled easily by the computer program. In this work, we have developed a high-speed digital laser grating projection system using a laser diode and a polygon mirror, and evaluated its performance. It has been demonstrated that all the optical measurements required to find out the profile of a 3D object could be carried out within 31 ms, which confirmed the validity of our 3D measurement system. The result implies the more important fact that the speed in 3D measurement can be enhanced remarkably since, in our novel system, there is no device like a LCD or DMD whose response time limits the measurement speed.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 초전도 자성체
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• pp.25-28
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• 2002

Contact type Ic measurement system is needed to measure Ic continuously for long Bi-2223 tapes. Voltage and current terminals were designed several shapes for 4-probe method Ic measurement. Voltage terminals were made with brass and current terminals were made with Cu. We used 2 kinds of Bi-2223 tapes with different strength. When we measured Ic of Bi-2223 tape with Ag-Mg sheath, The proper weight was 0.3 kg and sharp pin type was better. according to voltage terminal shape and load. In case of Bi-2223 tape with Ag-Mn sheath, the proper terminal weight was 4 kg and sharp pin type was bad. It was possible to make continuous contact type Ic measurement system because We could get proper data - terminal shapes and loads - through these experiments.

• Progress in Superconductivity
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• 제11권2호
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• pp.152-157
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• 2010

We have fabricated the low noise liquid helium(LHe) dewar with a different shape of thermal shield to apply the 64-channel SQUID(Superconducting Quantum Interference Device) gradiometer. The first shape of thermal shield was made of an aluminum plate with a wide width of 100 mm slit and the other shape was modified with a narrow width of 20 mm slit. The two types of dewars were estimated by comparing the thermal noise and the signal-to-noise ratio(SNR) of magnetocardiography(MCG) using the $1^{st}$ order SQUID gradiometer system cooled each dewar. The white noise was different as a point of the dewar. The noise was increased as close as the edge of dewar, and also increased at the thermal shield with the more wide width slit. The white noise of the dewar with thermal shield of 100 mm slit was 6.5 fT/$Hz^{1/2}$ at the center of dewar and 25 fT/$Hz^{1/2}$ at the edge, and the white noise of the other one was 3.5 - 7 fT/$Hz^{1/2}$. We measured the MCG using 64-channel SQUID gradiometer cooled at each LHe dewar and compared the SNR of MCG signal. The SNR was improved of 10 times at the LHe dewar with a modified thermal shield.

• 한국산학기술학회논문지
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• 제10권11호
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• pp.3023-3030
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• 2009

고속 삼차원 형상측정에서는 충분한 위상이송 스텝 수를 적용할 시간을 확보할 수 없기 때문에, 스텝 수를 축소하게 되면서 위상측정에서의 잡음이 증가되게 된다. 본 논문에서는, 다파장 PMP법에 있어서 두 파장의 비례관계를 이용하여 측정된 위상에 포함되어 있는 위상오차를 예측하고, 이를 보정하는 방법을 제안하였으며, 제안된 보정방법의 효용성을 확인하기 위한 실험이 진행되었다. 위상천이법에서 통상적으로 사용되는 스텝 수에 비해 월등히 많은 스텝의 위상 이송으로 측정하였으며, 또한 동일한 대상물을 고속 삼차원측정에서 적용되는 3-3 step의 위상 이송으로 측정하여, 두 경우에서의 측정결과를 비교하여 고속측정에서의 측정잡음을 산출하였다. 그리고, 본 논문에서 제안하고 있는 보정 방법을 측정된 맥놀이 위상과 절대위상에 적용한 결과, 각각에 있어서 90%와 17.2%의 잡음감소가 이루어지는 것으로 확인되었다.

• 한국산업융합학회 논문집
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• 제19권2호
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• pp.62-68
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• 2016

Laser distance measuring systems are used in many fields with high precision. However, when measuring the reflector such as the mirror and the black color, a laser distance measuring system does not guarantee the measurement accuracy. In order to measure the shape of the cargo, this study proposes the radar distance measurement system. The radar distance measuring system is composed of a distance measuring unit with a 24 GHz antenna module, a signal processing and control board and the 1-axis tilting unit. And, this study developed a monitoring program to monitor the measured data. In order to evaluate performance of the developed system, the distance measurement tests are carried out. The distance error was about 6-15 cm. However, considering the size of the cargo, the precision is not a problem. And, cargo shape was measured by using the distance information measured by the 1-axis tilting unit. It could get a 2 dimension shape profile for the cargo stacked in a yard.

• 복식문화연구
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• 제19권3호
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• pp.449-459
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• 2011

The purpose of this study is investigate the feature of the body shape of obese males and to propose a new apparel sizing system considering the body size of obese men through an the analysis of the body measurement of obese men in their twenties as reported in the 'Fifth Korean National Physical Standard Reports'. For this study, a new apparel sizing system for casual wear was proposed for obese men in their twenties after a body measurement of 159 obese men in their 20s with a BMI of 25 and over as reported in the 'Fifth Korean National Physical Standard Reports' conducted by SIZEKOREA. This study sought to investigate the features of obese men's bodies by comparing the body shape between obese men and ordinary men. The result of shows that width, depth and circumference items influencing the width size when producing clothes are larger in the case of an obese body shape than an ordinary body shape, and that the stature, total length, arm length and outside leg length influencing the length size are similar between an obese body shape and an ordinary body shape. Therefore, it was confirmed that an apparel sizing system specializing in clothes for obese customers is required. As a result of this study of the features of body shape, the control dimensions for such an apparel sizing system were determined to be the stature and chest circumference of upper garments and the stature and waist circumference(omphalion) for lower garments. The interval between the sizes was 5cm for the stature and was irregular for the chest and waste circumference. Consequently, 8 sizes were proposed for upper garments and 9 sizes were proposed for lower garments.

• 한국생산제조학회지
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• 제6권4호
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• pp.39-45
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• 1997

Shadow moire topography has been used as a noncontact method for measuring the 3-D shapes of objects. The moire fringes are results from the superposition of a master grating and its shadow projected on the surface of an object. But in case of the classical shadow moire method, in general, the resolution is a few tenths of millimeter. It is difficult to use a phase -shifting method in shadow moire because it is impossible to obtain uniform phase shifts on the whole field. But in this study , We introduce a phase-shifting method to improve the resolution of the classical shadow moire method. This method is based on the fact that if the depth of object is much less than the distance between the observer and the master grating, the phase shifts are almost uniform on the whole field area. Finally, we applied this new phase-shifting method to the measurement of the 3-D shape of a coin.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.271-274
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• 2002

The 3-D measurement using interference pattern projection is very attractive because of its high measuring speed and high sensitivity. When a sinusoidal amplitude grating was projected on an object, the surface-height distribution of the object is translated into a phase distribution of the deformed grating image. The patters was generated by a interferometer, and a PZT was used to shift the fringes on the target surface. The phase-acquisition algorithms are so sufficiently simple that high-resolution phase maps using a CCD camera can be generated in a short time. A working system requires a interferometer, a PZT, and a detector array interfaced to a microcomputer. Results of measurements on the diffused test objects are described.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.96-100
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• 1997

The shadow moire is one of the optical techniques which is able to give contour lines of an object with respect to a master grating plane. The moire patterns are issued from the superposition of a master grating and its shadow projected on the surface of an object. In case of the classical shadow moire method, the sensitivity was a few tenths millimeters. generally, it is difficult to use a phase shift method in shadow moire because it is impossible to obtain uniform phase shifts on the whole field. But in this study we use the fact that if the depth of object is much less than the distance between the observer and the master grating, and the object is displaced perpendicularly to the grating plane, phase shifts are almost uniform. Finally we obtained a better resolution by using a phase shift procedure and applied the phase shifting shadow moire to three dimensional shape measurement.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.220-223
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• 1997

Moire topography method is a well-known non-contacting 3-D measuement method. Recently, the automatic 3-D measurement by moire topography has been required since the method was frequently applied to the engineering and medical fields. 3-D measurement using projection moire topography is very attractive because of it's high measuring speed and high sensitivity. In this paper, using two-wavelength method of projection moire topography tested to measuring object with the 2x-ambiguity problem. Experimental results prove that the proposed scheme is capable of finding absolute fringe orders, so that the 2x-ambiguity problem can be effectively overcome so as to treat large step discontinuities in measured objects.