• 제목/요약/키워드: Phase Shifting

검색결과 391건 처리시간 0.049초

DMD를 이용한 위상천이 모아레 3차원 형상 측정 (Application of DMD for Phase Shifting in Moire Topology)

  • 정경석;정용상
    • 한국산학기술학회논문지
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    • 제12권6호
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    • pp.2457-2462
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    • 2011
  • 생산방식의 변화에 따라 3차원 형상을 신속하고 정확하게 측정하는 것이 중요해졌다. 가장 훌륭한 비접촉 3차원 측정방법인 모아레 방법 중 잡음신호를 효과적으로 제거할 수 있는 위상천이 방법을 구현함에 있어 DMD를 이용하여 격자를 생성하고 이송하는 효과를 발생하도록 하였다. 컴퓨터에서 격자를 이송하고 위상천이를 발생하므로 기계적 이송으로 인한 잡음신호의 발생 가능성을 배제할 수 있으며 광학렌즈와의 적절한 조합을 통해 쉽게 분해능을 변화하며 3차원 정보 획득이 가능하다. 근본적인 $2\pi$ 모호성문제를 극복하기 위하여 2차원 위상정력을 실시하였다. 이 방법을 적용하여 3차원 형상의 측정을 수행하였다.

광탄성 프린지 위상 이동법을 이용한 곡선보평판의 응력 해석 (Stress Analysis of a Curved Beam Plate by using Photoelastic Fringe Phase Shifing Technique)

  • 백태현;김명수;김수일
    • 대한기계학회논문집A
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    • 제24권9호
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    • pp.2313-2318
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    • 2000
  • The method of photoelasticity allows one to obtain principal stress differences and principal stress directions in a photoelastic model. In the classical approach, the photoelastic parameters are measured manually point by point. This is time consuming and requires skill in the identification and measurement of photoelastic data. Fringe phase shifting method has been recently developed and widely used to measure and analyze fringe data in photo-mechanics. This paper presents the test results of photoelastic fringe phase shifting method for the stress analysis of a curved beam plate. The technique used here requires four phase stepped photoelastic images obtained from a circular polariscope by rotating the analyzer at 0˚, 45˚, 90˚ and 135˚. Experimental results are compared with those of ANSYS and calculated by the simple beam theory. Good agreement among the results can be observed.

광학적 비접촉 측정에 의한 구조물 해석의 화상처리 계측 시스템 개발에 관한 연구 (A Study on the Development of Image Processing Measurement System for Structural Analysis by Optical Non-contact Measurement)

  • 장순석;김경석;홍진후;최지은;강기수;김달우
    • 한국정밀공학회지
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    • 제18권7호
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    • pp.149-154
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    • 2001
  • This study discusses a non-contact optical technique, electronic speckle pattern interferometry(ESPI), that is well suited for a deformation measurement of structure. Phase shifting method and unwrapping method have used to make deformation quantitative widely. In this paper, a previous numerical formula for phase shifting method is reconstructed in addition to least square fitting method to improve sensitivity and phase unwrapping based on vertical-horizontal scanning method is applied to analyze in-plane and out-of-plane deformation quantitatively.

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광 간섭계의 측정 정밀도와 구동 정밀도의 관계 (The effects of moving accuracy on inteferometric 3D shape measurement)

  • 박민철;엄창용;김승우
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2001년도 춘계학술대회 논문집
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    • pp.110-113
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    • 2001
  • We present an interferometer system, which is able to perform both the phase shifting interferometry and white light interferometry. The interferometer system uses a d.c. motor to control the probe position with an accuracy of 10nm, which shows an outstanding performance on white light interferometry. However, the moving mechanism of d.c. motor is not accurate enough for the phase shifting interferometry that requires a moving precision less than 1 nm. We therefore propose a Fourier transform technique to calculate the phase of interferograms, which is strongly resistant to calibration errors and external vibration. Experimental results show that the Fourier transform technique is capable of reducing the measurement error caused by inaccurate movement within 0.1nm.

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백색광 간섭계의 위상 정점 알고리즘에서 조명에 따른 위상 정점 모호성에 관한 연구 (Phase Peak Ambiguity According to Illumination in White-Light Phase-Shifting Interferometry)

  • 김기홍;이형석
    • 한국정밀공학회지
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    • 제25권1호
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    • pp.85-91
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    • 2008
  • White light scanning interferometry has gotten a firm position in 3D surface profile measuring field. Recently, the LCD industry gave a chance for this technology to enter into real industry fields. It is known that white-light phase-shifting algorithm give a best resolution compare to other algorithms, but there are some problems to be resolved. One of them is 300nm jump in height profile, called bat-wing effect. The main reason of this problem is an ambiguity of phase-peak detection algorithm, and some solution has been proposed, but it didn't work perfectly. In this paper, I will show the cases when these effects are occurred, and these height discrepancies will be almost disappeared when broad-band illuminators are used.