Dual-beam symmetric illumination-observation TV holography system for measurements
01 Dec 2001-Optical Engineering (International Society for Optics and Photonics)-Vol. 40, Iss: 12, pp 2780-2787
TL;DR: In this article, instead of observing along the optical axis, the scattered light along the direction of the illumination beams, and imaged it as two separate images onto the photo sensor of a CCD camera, was used for real-time evaluation of in-plane displacement components as well as surface shape.
Abstract: The Leendertz dual-beam symmetric illumination-normal ob- servation arrangement is widely employed for real time evaluation of in-plane displacement components as well as surface shape. Instead of observing along the optical axis, we have examined the Leendertz ar- rangement by observing the scattered light along the direction of the illumination beams, and imaged it as two separate images onto the photo sensor of a CCD camera. The interferometer is a combination of two channels, each of which measures independently and simulta- neously the information pertaining to either the in-plane displacement component of a deformation vector, or the surface relief variation of a three-dimensional object. In addition, a summary of possible measure- ments that can be carried out from the present arrangement is also high- lighted. Experimental results using a four-frame phase shifting technique are illustrated. © 2001 Society of Photo-Optical Instrumentation Engineers.
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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.
40 citations
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...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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TL;DR: In this paper, a reference beam is added to a dual-beam symmetric illumination electronic speckle pattern interferometry (ESPI) system and shared by the two illuminations.
Abstract: A method for three-dimensional (3D) displacement measurement by separating out-of-plane displacement from in-plane displacement is presented. A reference beam is added to a dual-beam symmetric illumination electronic speckle pattern interferometry (ESPI) system and shared by the two illuminations. The test object is illuminated by the two object beams, respectively. Two phase maps, which include out-of-plane and in-plane displacement, can be obtained by phase-shifting techniques. In order to decrease electronic noises in the phase maps, one of the phase maps is calculated by the reversed phase-shifting method presented. By using inverse phase distribution, out-of-plane displacement can be easily separated from in-plane displacement by subtraction and can greatly decrease electronic noises. The principle of the method is presented and proved by a typical three-point bending experiment. Experimental results are offered.
11 citations
28 Jul 2017
TL;DR: In this paper, a three-dimensional interference pattern formed by the interference of secondary, dephased wavelets scattered by an optical rough surface or transmitted through a scattered medium that imposes random phases of the wave.
Abstract: Speckle pattern is a three-dimensional (3D) interference pattern formed by the interference of secondary, dephased wavelets scattered by an optical rough surface or transmitted through a scattered medium that imposes random phases of the wave. The randomly coded pattern that carries the information about the object deformation provided to develop a wide range of methods, which can be classified into three broad categories: speckle photography, speckle interferometry, and speckle shear interferometry. Speckle photography is based on recording of objective or subjective speckle patterns, before and after the object is subjected to load. Digital speckle shear interferometry or digital shearography (DS) has been widely used for the measurement of the spatial derivatives of object deformation. The DS system has found a prominent application in aerospace industry for nondestructive testing of spacecraft structures. Microsystems such as micro-electro-mechanical systems and micro-opto-electromechanical systems combining micro-size electrical and mechanical mechanism are finding increasing applications in various fields.
3 citations
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TL;DR: A fringe-formation theory for a dual-beam illumination configuration that leads to a twofold increase in sensitivity for the measurement of in-plane displacement and it is shown that the sensitivity obtainable is the usual interferometric sensitivity.
Abstract: A fringe-formation theory for a dual-beam illumination configuration that leads to a twofold increase in sensitivity for the measurement of in-plane displacement is described. Here we have taken into account all four beams simultaneously that are generated at the image plane owing to two-beam illumination and their cross-interference terms for fringe formation. We show that the sensitivity obtainable is the usual interferometric sensitivity when we take into account all four beams simultaneously and doubles only when the retroreflected beams are observed. A detailed theory and an experimental demonstration of the method are presented.
5 citations
Additional excerpts
...40(12) 2780–2787 (December 2001) 0091-3286/2001/ r d...
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