• 한국정밀공학회지
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• 제24권12호
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• pp.104-110
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• 2007

Internal defects are mainly caused by a corrosive action and degradation in the pipe used in a nuclear power plant or factory. The ESPI method have the many advantages when compared with conventional method. The advantage are the area measurement ability at one time and non-contact measurement ability in the real-time. In this paper, we studied on the measurement of a internal defect by using out of plane ESPI technique. Here, we compared the experimental results using out of plane ESPI with the FEM results.

• 대한기계학회논문집
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• 제19권6호
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• pp.1382-1390
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• 1995

Electronic Speckle Pattern Interferometry (ESPI) with a CW laser, a video system and an image processor was utilized to measure the in-plane displacement. Unlike traditional strain gauges or Moire method. ESPI method measure the in-plane displacement on real time with out any surface preparation on surface attachment. The specimen has a crack of 10*0.1 mm in the middle of plate and strain gauge was also attached on that surface to compare with ESPI method. This study reveled the ESPI method to measure the displacement and distribution of strain in the specimen. It was shown in tensile tests that the measurement by ESPI method was comparable with strain gauge.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 추계학술대회 논문집
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• pp.319-320
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• 2006

• 융합신호처리학회논문지
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• 제4권4호
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• pp.40-46
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• 2003

본 연구에서는 광학식 계측 기술인 ESPI에서 면외변위인 물체의 진동에 대한 분석을 수행하였다. 진동하는 물체는 고유한 노달 라인을 가지게 된다. 따라서 이를 분석함으로써 진동하는 물체에 대한 정보를 얻을 수 있다. 측정 물체로 스피커와 외팔보 평판을 사용하였으며, 이를 시간 평균 ESPI로 정성적으로 분석하였다. 본 연구의 실험 결과로 스피커에서는 진동 주파수 550Hz와 진폭 570mV에서 저차 모드 간섭무늬가 나타났으며, 진동 주파수 950Hz와 진폭 570mV에서 고차 모드 간섭무늬가 나타났다. 이러한 ESPI는 측정에 레이저를 이용하기 때문에 비파괴, 비접촉 검사이며, 높은 분해능을 가진다. 또한 레이저가 조사되는 영역이 측정 영역이 되므로 측정 물체의 크기에 제한되지 않는다.

• 한국정밀공학회지
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• 제19권3호
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• pp.66-72
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• 2002

Electronic Speckle Pattern Interferometry (ESPI) has been recently developed and widely used because it has advantage to be able to measure surface deformations of engineering components and materials in industrial areas with non-contact. The speckle patterns to be formed with interference and scattering phenomena can measure not only out-of-plane but also in-plane deformations, together with the use of digital image equipment to process the informations included in the speckle patterns and to display consequent interferogram on a computer monitor. In this study, the experimental results of a canti-levered plate using ESPI were compared with those obtained from the simple beam theory. The ESPI results of the canti-levered plate analyzed by 4-step phase shifting method are close to the theoretical expectation. Also, out-of-plane displacements of a spot welded cacti-levered plate were measured by ESPI with 4-step phase shifting technique. The phase map of the spot welded cacti-levered plate is quite different from that of the canti-levered plate without spot welding.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.239-242
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• 2001

Electronic Speckle Pattern Interferometry(ESPI) was proposed in the 1970's as a method of producing the interferogram without using traditional holographic technique. ESPI is more faster than Holography method, because the interferometric image is recorded and updated by the video camera every 1/30 second and whold-field inspection possibly. In this study using a non-contact optical technique that is suited for in-plane and out-of-plane deformation measurement. Thin plate with crack was analyzed by ESPI to determine the characteristics of vibration mode shape and natural frequency. Also, results of the experiment were compared with Finite Element Method(FEM).

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 추계학술대회 논문집 - 한국공작기계학회
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• pp.69-73
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• 1999

This study discusses a non-contact optical technique, electronic speckle pattern interferometry(ESPI), that is well suited for in-plane and out-of-plane deformation measurement. AS4/PEEK[30/-30/90]s, composite laminate plate was analyzed by ESPI to determine the vibration characteristics with tensile loading and without it. vibration mode shapes are quantitatively compared with the result of numerical analysis. The experimental results agree well with those of numerical analysis. we found that when the composite laminate plate is under the tensile loading, vibration modes can be measured with high accuracy by ESPI.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.1043-1044
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• 2010

• 한국정밀공학회지
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• 제30권1호
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• pp.59-66
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• 2013

The measuring of internal defects of objects using the shearography has many advantages. It is a non-contact and non-destructive method and It has a real time measurement speed and no constraints of object shape. Compared to ESPI(Electronic Speckle Pattern Interferometry), Shearography has a very low error rate by vibration and air turbulence. So shearography provides possibilities of industrial application. In this paper, Image processing algorithm that is measurement of out-of-plane deformation using the shearography is proposed by developed using the LabVIEW 2010 and measurement result of out-of-plane ESPI and Shearography are compared quantitatively.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.241-244
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• 1997

This paper proposes Electronic Speckle Pattern Interferometry(ESPI) for the quantitative buckling analysis of square tube, which is unable to be measured with previous methods. The quantitative buckling analysis in elasticity is important part to study strain-stress analysis of thick-plated tube and fatigue analysis. However, it is unsolved problem with theory and previous experimental method. The merits of ESPI, Whole-filed measurement and high accurate 3D-displacement measurement make it possible to determinate the buckling analysis in elasticity quantitatively.