• Journal of the Optical Society of Korea
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• 제14권1호
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• pp.33-37
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• 2010

The joint transform correlator (JTC) has been the best known technique for pattern recognition and identification. The JTC optically compares the reference image with the sample image then examines match or non-match by acquiring a correlation peak. However, the JTC technique has some problems such as weak correlation discrimination and noise which originates from the interference fringes in the Fourier transform plane. In order to solve these problems, this paper proposes a new technique of modifications of the interference fringes by adopting special iterative filters. Experimental results are presented to show that the proposed technique can successfully improve the correlation peaks and the level of discrimination.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2010년도 추계학술발표대회
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• pp.629-632
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• 2010

본 논문에서는 Fringe Pattern profilometry(FPP)을 이용한 높이 측정 시스템을 구현하고, R, G, B 각 컬러 채널별로 위상이 다른 파형을 인가함으로써 Phase shifting 방법을 이용한 실시간 위상 정보를 획득할 수 있게 한다. 디지털 프로젝터의 비선형성으로 인해 필연적으로 발생하는 하모닉스 성분을 근사화된 정현파를 인가함으로써 높이 정보에서 가장 큰 문제를 발생하는 2차 하모닉스 성분을 줄인다. 이렇게 구한 위상 값을 Digital Phase Loop Lock(DPLL)회로에 인가함으로써 3차원 모양 정보를 실시간으로 획득 가능하게 한다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.356-361
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• 1996

Nowadays, Electronic Speckle Pattern Interferometry is a well established measuring technique with a wide range of industrial applications, particularly in the fields of deformation measurement and vibration analysis. Comparing with holographic inteferometry, it has some attractive features, which are rapid recording and reconstruction, satisfiable automation etc. Time-average ESPI was used to provide vibration mode shape of an object whose vibration amplitude is given as a fringe pattern. However, it is not possible to determine the direction of motions of a point on the object at any given time, because time-average method does not give any information about the phase of vibration. A better technique is stroboscopic method which can measure the amplitude and phase of vibrating surface. In this paper, loudspeakers were tested by these two methods and the mode shape and amplitude of vibration were visualized. As measured results, we can assume that these techniques will be applied directly in the loudspeaker industry.

• 한국진공학회지
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• 제17권1호
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• pp.46-50
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• 2008

Febry-Perot 프린지 패턴의 광 반사성을 가지고 있는 다공성 실리콘을 이용하여 암호화된 광학 이미지를 제작하였다. 암호화된 광학이미지 다공성 실리콘 샘플은 p-type 실리콘 웨이퍼 (boron-doped,<100> orientation, resistivity $0.8{\sim}1.2m{\Omega}-cm$)를 이용하여 빔 프로젝트의 광원과 전기화학적 식각을 통하여 만들어 졌다. 광학 이미지 다공성 실리콘 샘플은 전기화학적 식각과정에 빔 프로젝트의 광원에 의하여 톡특한 Febry-Perot 프린지 패턴을 나타낸다. 실리콘 웨이퍼의 광 반사성의 프린지 패턴을 퓨리에 변환을 통하여 유효광학두께를 측정하고 실리콘웨이퍼에 암호화 시킨 광학이미지를 제작하였다.

• 한국광학회:학술대회논문집
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• 한국광학회 1990년도 제5회 파동 및 레이저 학술발표회 5th Conference on Waves and lasers 논문집 - 한국광학회
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• pp.131-135
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• 1990

The combined technique of holographic interferometry and speckle photography, so called holospeckle interferometry, has been attention for the measurement of 3-D displacements. This new technique enables the researcher to obtain information of in plane and out-of plane displacements from one photographic plate. There is room for further development of special optical arrangement in order to apply holospeckle interferometry in specific field. In this study, the enlarged fringe pattern was obtained by specifical optical arrangement.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
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• pp.203-206
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• 2003

This study is focused on proposing a creative system that can display 3D hologram on the real-time basis. This method applies 3D display on volume hologram based on CGH. The process of implementing the system consists of two stages of fringe pattern recording for passive component that includes information on hologram, and irradiating object beam. Distinguished from an existing electronic holographic display system, this system is free from the process of a huge calculation that is necessary to compose CGH for a real-time 3D display.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 춘계학술대회 논문집
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• pp.309-310
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• 2007

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.400-403
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• 2002

This paper presents a shearographic technique for measuring in-plane strains. During the measurement, the test object is illuminated alternately with two laser beams, symmetrically with respect to the viewing direction. Employing a phase shift technique, the phase distributions due to object deformation for each beam are obtained separately. The difference of the two phase distributions depicts the derivative of in-plane surface displacements. The technique is equivalent to a system of many strain gages.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.413-414
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• 2006

In this paper, we propose an efficient coding method of digital hologram (or fringe pattern) using multi-view prediction technique based on video and image coding standard such as MPEG. The proposed algorithm illustrates that it has better properties for reconstruction and higher compression rate than the previous researches.

• 한국세라믹학회지
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• 제30권11호
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• pp.919-924
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• 1993

Domain structure and the spatial arrangement of tetragonal and rhombohedral phases in PZT ceramics at MPB composition were investigated with a transmission electron microscope. Fringe Contrast and doublet spot splitting were observed in the image mode and the selected area diffraction pattern, respectively. Besides, triplet spot splitting was also observed in the other part of the specimen. These observations indicate that both the single phase regions and the regions which are comosed of alternatively arranged tetragonal and rhombohedral domains coexist in a PZT ceramics at the MPB composition.