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Journal ArticleDOI

Recent developments in digital speckle pattern interferometry

TL;DR: This poster presents a poster presenting a probabilistic procedure to constrain the response of the immune system to chemotherapy-like injuries in mice.
About: This article is published in Optics and Lasers in Engineering.The article was published on 2003-11-01. It has received 40 citations till now. The article focuses on the topics: Electronic speckle pattern interferometry & Speckle pattern.
Citations
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Journal ArticleDOI
TL;DR: In this paper, 3D electronic speckle pattern interferometry (ESPI) measurements were used during tensile shear experiments to observe full-field in-plane and out-of-plane deformation of lap joint samples and to detect strain concentrations in the vicinity of glue lines.
Abstract: Phenol-resorcinol-formaldehyde (PRF) and one-component polyurethane (PUR) resins were used to manufacture single lap joint samples corresponding to EN 302-1. 3D electronic speckle pattern interferometry (ESPI), which enables measurement of spatial displacement of less than 0.1 μm, was used during tensile shear experiments to observe full-field in-plane and out-of-plane deformation of the lap joint samples and to detect strain concentrations in the vicinity of glue lines. Finite element analysis was performed to validate ESPI measurements. In general, ESPI measurements showed that in a lap joint experiment a very small volume of material close to the ends of the overlapping area is highly strained. ESPI and finite element analysis pointed out that PUR glue lines are characterised by much higher shear deformations than PRF glue lines, especially at the ends of the overlapping area. However, due to the lower Young's modulus of PUR resin compared to PRF, higher shear strains but lower shear stress concentrations can be expected in PUR, which was confirmed by the FE model.

49 citations


Cites methods from "Recent developments in digital spec..."

  • ...A more detailed description of the ESPI technique is given by several authors (Rastogi 2001; Eberhardsteiner 2002; Siebert et al. 2002; Mohan and Rastogi 2003)....

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  • ...Du1 ´ s (2)11 Dx1 Du2 ´ s (3)22 Dx2 1 Du Du1 2 ´ s q (4)12 ≥ ¥2 Dx Dx2 1 A more detailed description of the ESPI technique is given by several authors (Rastogi 2001; Eberhardsteiner 2002; Siebert et al. 2002; Mohan and Rastogi 2003)....

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Journal ArticleDOI
TL;DR: In this article, the authors measured the strain field in a mechanically loaded Norway spruce branch-stem junction by means of electronic speckle pattern analysis and compared the results with strain distribution in a polyester cast of identical shape as the branch and a simplified polyester model consisting of two halfcylinders.
Abstract: Direct measurement of strain field in a mechanically loaded Norway spruce branch–stem junction was performed by means of electronic speckle pattern analysis. Results were compared with strain distribution in a polyester cast of identical shape as the branch–stem junction, and a simplified polyester model consisting of two half-cylinders. Compared to polyester models, the branch–stem junction was characterised by a very homogeneous distribution of strain, which can be interpreted as a homogeneous distribution of stress in terms of fraction of material strength. This optimised transfer of mechanical load from the branch to the stem is achieved by a combination of naturally optimised shape with, additionally, optimised mechanical wood properties in the junction area.

44 citations


Cites methods from "Recent developments in digital spec..."

  • ...A more detailed description of the ESPI technique and its application to wood surfaces is given by several authors (Eberhardsteiner 1995; Dumail et al. 2000; Rastogi 2001; Eberhardsteiner 2002; Siebert et al. 2002; Mohan and Rastogi 2003; Gindl et al. 2005; Müller et al. 2005)....

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Journal ArticleDOI
TL;DR: In this article, the distribution of shear strains at the interface along the fibre length measured by ESPI corresponds well to classical shear-lag theory, and it is concluded that ESPI is a powerful tool for the unravelling of composite micromechanics.
Abstract: The distribution of strain in a single wood fibre-reinforced-low density polyethylene (LDPE) composite was measured by means of electronic laser speckle interferometry (ESPI). Finite element analysis and analytical analysis of strain distribution in the model composite was performed for validation and confirmed the experimental results. Low strain in the fibre and a concentration of high axial strain in the matrix region close to both fibre ends was measured. The regions of high strain next to the fibre ends indicate a significant transfer of stress from the matrix to the fibre via fibre ends. The distribution of shear strains at the interface along the fibre length measured by ESPI corresponds well to classical shear-lag theory. It is concluded that ESPI is a powerful tool for the unravelling of composite micromechanics.

37 citations

Journal ArticleDOI
TL;DR: In this paper, a dual-function ESPI system is developed for the measurement of out-of-plane displacement and its slope change and a difference-ofphase method with a five-step algorithm is used for speckle fringe analysis.

33 citations

Journal ArticleDOI
TL;DR: An effective method for speckle noise removal in digital Speckle pattern interferometry is presented, which is based on a wave-atom thresholding technique that improves the sparse representation of fringe patterns when compared with traditional expansions.
Abstract: We present an effective method for speckle noise removal in digital speckle pattern interferometry, which is based on a wave-atom thresholding technique. Wave atoms are a variant of 2D wavelet packets with a parabolic scaling relation and improve the sparse representation of fringe patterns when compared with traditional expansions. The performance of the denoising method is analyzed by using computer-simulated fringes, and the results are compared with those produced by wavelet and curvelet thresholding techniques. An application of the proposed method to reduce speckle noise in experimental data is also presented.

32 citations

References
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Journal ArticleDOI
TL;DR: In this paper, a fringe system is obtained showing contours of constant slope resolved in the direction of image displacement, which is a comparison with result obtained by holographic interferometry.
Abstract: The surface to be studied is illuminated with laser light and two images are formed, displaced relative to one another in the image. Speckle pattern interferometry is used to measure phase changes between the two images resulting from deformation of the surface. A fringe system is obtained showing contours of constant slope resolved in the direction of image displacement. A comparison is made with result obtained by holographic interferometry.

298 citations


"Recent developments in digital spec..." refers methods in this paper

  • ...A Michelson type of shear interferometer [30] is generally employed to introduce lateral shear in an optical configuration [31–33]....

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Journal ArticleDOI
TL;DR: In this article, the authors present a coherent optical metrology approach based on speckle pattern interferometry with optical to electronic interfacing by means of a modified closed-circuit television arrangement.
Abstract: In a brief period, lasers have developed from curiosities of the physics laboratory to tools suited to incorporation in complex instrumentation systems. One line of progress has been through the applications of holography and holographic interferometry to engineering metrology where the potential of a precision comparator is realized without a convenient means of using it. The process, however, has formed a basis for development and the progress of holographic metrology is reviewed leading to more general concepts better described as “Coherent Optical Metrology”.The authors' latest developments in this area are described where, by means of a coherent optical sampling technique, three dimensional data is coded onto an electronic video waveform. The method is based on speckle pattern interferometry with optical to electronic interfacing by means of a modified closed-circuit television arrangement. With this instrumentation, most of the measurement facilities of holography are retained without many of the in...

213 citations


"Recent developments in digital spec..." refers methods in this paper

  • ...While the arrangement [14] senses the in-plane displacement with sensitivity proposed by Leendertz [2], the one described in [11,12] yields two-fold increase in sensitivity....

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  • ...DSPI is an optical measurement technique [2] that combines speckle pattern interferometry with electronic detection and processing, and is widely used in the investigation of a wide range of physical parameters such as displacements, vibrations, strains and surface profiles of engineering structures....

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  • ...illumination—normal observation [2], (ii) oblique illumination—observation [9], (iii) normal illumination—dual direction observation [10] and (iv) dual-beam symmetric illumination—observation [11–14]....

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Book
01 Jan 1997
TL;DR: In this article, Krishnaswamy et al. presented a survey of the optical metrology of engineering surfaces, focusing on the use of Holographic Interferometry in Nondestructive Measurement and Testing.
Abstract: Introduction (P.K. Rastogi). Optical Metrology of Engineering Surfaces -- Scope and Trends (H.J. Tiziani). Digital Processing of Fringe Patterns in Optical Metrology (W. Osten, W. J?ptner). Interferometric Optical Testing (D. Briers). Holographic Interferometry -- An Important Tool in Nondestructive Measurement and Testing (P.K. Rastogi). Speckle Photography, Shearography, and ESPI (C. Joenathan). Photoelasticity and Moire (A. Asundi). Optical Fiber Sensors (A.D. Kersey). Fiber Optic Smart Sensing (D. Inaudi). Holographic Metrology of Micro-Objects in a Dynamic Volume (C.S. Vikram). Particle Image Velocimetry (I. Grant). Surface Roughness Measurement (J.M. Bennet). Lidar for Atmospheric Remote Sensing (U.N. Singh). Some Other Methods in Optical Metrology (S. Krishnaswamy, T.C. Philip Chu, I. Saxena, H.G. Maas).

177 citations