• 대한기계학회논문집
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• 제18권12호
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• pp.3202-3218
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• 1994

Mode shapes and natural frequencies of vibrating laminated composite plates are taken using real-time and time-average holographic interferometry. Debonds and delamination in the laminated plates are measured nondestructively. During holographic testing of composite plates, it has been found that the conditions for the local resonance in debonds are strongly dependent on the frequency of excitation. A membrane resonance model was proposed to describe this behavior. Relations between characteristic length according to the size, shape of debonds and membrane resonance frequency are presented. Several experiments were performed to verify the membrane resonance model. The agreements between the predicted excitation frequency and the observed resonance frequency are good. The experimental results show that higher stresses and strains due to local resonance lead to the debond detection.

• 한국콘텐츠학회논문지
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• 제6권12호
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• pp.261-268
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• 2006

일반인들이 '3차원업체영상'이라고 알고있는 홀로그램은 1947년 데니스가보 (D.Gabor)가 최초로 발견한 빛의 정보를 기록할 수 있는 특징을 가진 새로운 매체이다. 홀로그램은 물체에서 나오는 두 가지 파장의 간섭결과로서 이룩되는 간섭무늬를 기록하는 것으로 물체의 입체감 표현뿐만 아니라 빛과 공간 조형의 표현이 가능하기 때문에 시각적으로 한층 더 나은 결과를 기대할 수 있다. 홀로그램과 광고의 접목을 가정하여 기존광고매체와 홀로그램광고매체의 시각인지도를 측정 분석하여 홀로그램 광고는 기본방식의 광고보다 시각적 인지도가 높을 것인가에 대하여 알아보고, 하이테크 시대에 부합하는 새로운 광고매체로서, 홀로그램이 소비자에게 시각적으로 주의와 흥미를 유발하는데 우수하여 제3의 시각적 광고매체의 형태로 발전 가능성이 있는지에 대하여 알아본다.

• 대한기계학회논문집B
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• 제26권9호
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• pp.1311-1318
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• 2002

An experimental model is investigated in this paper using the experimental method with a shock tube and the numerical technique. The shock-vortex interaction generated by this model is visualized with various methods: holographic interferometry, shodowgraphy, and numerical computation. In terms of shock dynamics, there are two meaningful physics in the present problem. They are reflective wave from the slip layer at the vortex edge and transmitted shock penetrating the vortex core. The discussion in this study is mainly focused on the two kinds of waves contributing to the quadrupolar pressure distribution around the vortex center during the interaction.

• 조명전기설비학회논문지
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• 제16권1호
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• pp.1-7
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• 2002

변형 삼각간섭계의 공간적인 해상도와 거리계측의 가능성을 이론적으로 유도하였으며 또한, 거리계측의 가능성을 입증하기 위하여 공간적으로 다른 깊이감을 가진 점 광원들에 대한 인코히어런트 홀로그램을 생성하고 이를 수치적으로 복원한 결과를 제시하였다. 그리고 제안된 방법을 이용하여 3차원 영상에 대한 홀로그램을 기록하고 여러 가지 각도에서 영상을 재현함으로써 3차원 영상 디스플레이로서의 가능성도 입증하였다.

• 전자통신동향분석
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• 제31권4호
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• pp.1-12
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• 2016

깊이감, 시점 등의 3차원 영상정보 제공 방법에는 양안 시차에 의한 스테레오 방식, 다시점 기반의 스테레오 방식, 라이트필드 기반의 스테레오 방식, 체적 내에 실제 발광점들을 물리적으로 형성하는 체적형 방식, 빛의 간섭과 회절현상을 이용하여 실제 물체의 파면을 재현하는 홀로그래피 방식 등이 존재한다. 본고에서는, 3차원 영상기술로써 최근 이슈화되고 있는 플렌옵틱 영상기술의 개념을 다시점 영상생성 및 재초점 기능의 관점에서 소개하고, 동시에 관련 국내외 기술개발 동향을 파악하고자 한다. 또한, 플렌옵틱 영상기술의 고도화를 위한 최신 연구개발 이슈 및 응용 가능한 서비스 시나리오에 대해 탐구해 봄으로써, 향후 플렌옵틱 영상처리 기술의 발전 및 활용도를 전망해 보고자 한다.

• 대한기계학회논문집A
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• 제20권10호
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• pp.3211-3223
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• 1996

In this paper, the propagation of elastic wave generated by loading impact to plates made of isotropic of anisotropic material was studied. And the influence of boundary conditions (free or clamped edge) upon the reflection of elastic wave was anlyzed. Also, double exposure holographic interferometer using ruby pulse laser was formed in order to investigate transient waves. Before the elasitc wave was reflected from the edges, the elastic wave of isotropic plate such as aluminum plate showed circular interferometric fringe pattern, whereas that of anisotropic plate such as epoxy composite laminates showed elliptical one. And the transverse displacement curves obtained from experiment and theory for both plates agreed well. Also, the waves reflected from the boundary edges showed much differences according to the boundary condition of edges.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.322-327
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• 2000

Natural convection heat transfer in an enclosure with an opening in the right vertical wall and a heat source at the bottom surface is investigated using a holographic interferometric technique. The effects of the opening length, divider length attached to the top wall, and heater temperature on the temperature distribution are examined. The openging length as well as the divider length greatly affects the degree of inflow and outflow of air. With a small opening, the opening doesn't affect much the upward warm air flow resulting in the symmetric temperature distribution. On the other hand, with the increase of the opening length, the inward cold flow moves the upward flow to the left direction. With the increase of the divider length, temperature in the lower region of enclosure becomes higher for the small opening and lower for the large opening.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.407-410
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• 2002

Triangulation method, conoscopic holography method and interferometry method are analyzed for effective measurement of micro burr geometry, which is formed in micro drilling. To select proper sensor, cylinder with 0.5mm diameter is measured and the result shows that conoscopic holography method is effective for measuring highly inclined surface. Burr with 1.0mm height and 30$\mu\textrm{m}$ height are measured by all methods. The conoscopic holography method is probed to be most proper method for measuring micro burr. A Program for 3D display of measured burr is developed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.418-421
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• 1988

Holographic interferometry is applied in dental research to study the motion of teeth and the deformation of the associated facial structure. We consider double exposure holographic interferometry which has limiting factors such as the stability of fringes, the recording time, the amount of exposure, the localization of fringes and sensitivity. These factors are taken into account to make interferogram. The resulting interferogram gives fringe pattern which is analyzed qualitatively to determine the relative rotation and the deformation of the facial structure.

• 대한기계학회논문집B
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• 제23권7호
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• pp.901-910
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• 1999

Investigated In this paper is the shock reflection from a blunt body, In particular, a circular cylinder of 20 mm diameter, for the weak shock impinging in the range 1<$M_s$ <2. Pressure and shock speed are measured for various shock strengths. Double-pulse holographic interferograms are taken to study the unsteady flow field at $M_s=1.34$. These experimental results are, in overall, well compared with the unstructured adaptive finite volume computation of the Euler equations performed in this study. Correlation of incident and reflected shocks and shock-shock locus obtained by experiment, computation, and theory are presented in parallel.