• Title/Summary/Keyword: 전자스페클간섭계

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Applications of Speckle Interferometer (스페클 간섭계의 응용)

  • 백성훈;박승규;김철중
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.5
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    • pp.14-18
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    • 2004
  • 스페클 간섭계는 빛을 이용하는 측정 방법이므로 비접촉/원격 측정 방법이며, 빛의 파장의 수십-수백 분의 1 정도의 정밀도로 측정이 가능하고, 레이저가 조사되는 영역 전체의 동시 측정이 가능하다는 장점을 가지고 있다 특히 최근에는 전자, 영상, 컴퓨터 기술의 발달에 힘입어 ESPI(Electronic Speckle Pattern interferometer; 전자 스페클 상관 간섭계) 장치가 많은 발전을 이루었고, 이에 따라 산업 현장에서의 활용도 계속 늘고 있다. (중략)

Principles and Prospect of Speckle Pattern Interferometry (스페클 간섭계의 원리와 전망)

  • 강영준
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.5
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    • pp.7-13
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    • 2004
  • 간섭성 광원인 레이저를 이용한 계측 및 검사기법 중 대표적인 것이 홀로그래피를 이용한 간섭법(Holographic Interferometry, HI)이다. HI는 레이저 파장을 단위로 하기 때문에 물체변형에 대해 측정감도가 좋고 비파괴 비접촉의 계측이 가능하다. 또한 삼차원 정보 추출이 가능해서 주어진 간섭무늬로부터 전 영역의 변형을 구할 수 있다는 커다란 장점을 가지고 있다. 그러나 일반적으로 홀로그래피용 필름은 기록 및 현상방법이 성가시고 그 속도 또한 느릴 뿐만 아니라 간섭무늬 패턴도 매우 복잡해서 산업현장 등 실제의 응용에는 현실적인 어려움이 있다.(중략)

Principles and Applications of Speckle Pattern Interferometry (스페클 패턴 간섭계의 원리 및 응용)

  • 강영준
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.6
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    • pp.32-39
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    • 2000
  • 간섭성 광원인 레이저를 이용한 계측 몇 검사기법 중 대표적인 것이 홀로그래피를 이용한 간섭법(Holographic Interferometry, HI)이다. HI는 레이저파장을 단위로 하기 때문에 물체변형에 대해 측정감도가 좋고 비파괴 비접촉의 계측이 가능하다. 또한 삼차원 정보 추출이 가능해서 주어진 간섭무늬로부터 전 영역의 변형을 구할 수 있다는 커다란 장점을 가지고 있다.(중략)

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Measurement of Temperature Field using Holographic and Speckle Visualization Techniques (홀로그래피/스페클 가시화를 이용한 온도분포 측정)

  • 백성훈;박승규;김철중
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.10a
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    • pp.371-374
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    • 1995
  • The real-time holographic interferometer with a digital high-speed camera is applied to the visualization of transient temperature field. Collimated and diffused laser beams are used to the object beam according to the shape and transmittance of the phase object. Also, ESPI(Electronic Speckle Speckle Pattern Interferometer) technique is used to the visualization and quantitatie measurement of slow-varying temperature field. The experimental results obtained form these two techniques are discussed.

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Vibration Analysis of Loudspeaker by Using Electronic Speckle Pattern interferometry (전자 스페클 간섭계에 의한 스피커 진동 해석)

  • 강영준
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.6 no.1
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    • pp.92-99
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    • 1997
  • 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 interferometry, it has some attractive features, which are rapid recording and reconstruction, satisfiable automation etc. The Time-Average ESPI is used to provide vibration mode shape of an object whose vibration amplitude is given as a fringe pattern. Its merit is rapid and simple measurement for vibrating object. However, it is not possible to determine the direction of motions of a point on the object at any given time, because it does not give any information about the phase of vibration. But, Stroboscopic ESPI can measure the amplitude and phase of vibrating surface. In this paper, loudspeakers were tested by these two methods. As a result, we can assume that these techniques will be applied directly in the loudspeaker industry.

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Vibration Analysis of Loudspeaker by Using Electronic Speckle Pattern Interferometry (전자 스페클 간섭계에 의한 스피커 진동 해석)

  • 김정규;노경완;강영준;김동우
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1996.11a
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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.

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Speckle Interferometric Detection of Defects on the backside of steel plate (스페클 간섭계를 이용한 평판 이면결함의 검출 특성)

  • 김동한;장석원;장경영
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2001.04a
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    • pp.195-198
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    • 2001
  • Backside defect of plate structure may grow due to fatigue or overload to cause critical failure during operation, so it is important to detect this kind of defect in line. For this purpose, nondestructive, non-contact and highly sensitive method is required. ESPI and Shearography are considered as useful method to satisfy these requirements. In this paper, the possibility of application of ESPI and Shearography to detect the backside defect of steel plate and to quantify the defect size was tested. For the experiment, some steel plates with defect on the backside were prepared. Experimental results for these plates showed that location and size of defect could be detected correctly by both of ESPI and Shearography.

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Phase-Shifting System Using Zero-Crossing Detection for use in Fiber-Optic ESPI (영점검출을 이용한 광섬유형 전자 스페클 패턴 간섭계의 위상이동)

  • Park, Hyoung-Jun;Song, Min-Ho;Lee, Jun-Ho
    • Korean Journal of Optics and Photonics
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    • v.16 no.6
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    • pp.516-520
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    • 2005
  • We proposed an efficient phase stepping method for the use in fiber-optic ESPI. To improve phase-stepping accuracy and efficiency, a fiber-optic Michelson interferometer was phase-modulated by a ramp-driven fiber stretcher, resulting in 4$\pi$ phase excursion in the PD interference signal. The zero-crossing points of the signal, which have consecutive $\pi$ phase difference, were carefully detected and used to generate trigger signals for the CCD camera. From the experimental results by using this algorithm, $\pi$/2 phase-stepping errors between the speckle patterns were measured to be less than 0.6 mrad with 100 Hz image capture speed. Also it has been shown that the error from the nonlinear phase modulation and environmental perturbations could be minimized without any feedback algorithm.