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Journal ArticleDOI

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.
Citations
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Journal ArticleDOI
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


Additional excerpts

  • ...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....

    [...]

Journal ArticleDOI
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

Book ChapterDOI
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

References
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Journal ArticleDOI
TL;DR: A dual in-plane electronic speckle pattern interferometry system has been developed for in situ measurements, and the overall system is controlled by advanced software, which allows switching between the two perpendicular planes in quasi real time.
Abstract: A dual in-plane electronic speckle pattern interferometry (ESPI) system has been developed for in situ measurements. The optical setup is described here. The system uses an electro-optical switch to change between the illumination directions for x and y sensitivity. The ability of the electro-optic device to change the polarization of the laser light forms the basis of this switch. The electro-optic device is a liquid-crystal layer cemented between two optically flat glass plates. An electric field can be set up across the layer by application of a voltage to electrodes. The speckle interferometry system incorporates two additional liquid-crystal devices to facilitate phase shifting, and the overall system is controlled by advanced software, which allows switching between the two perpendicular planes in quasi real time. The fact that there are no moving parts is an advantage in any ESPI system for which mechanical stability is vital.

22 citations

Journal ArticleDOI
TL;DR: An optical configuration is suggested that will achieve a twofold increase in sensitivity when one measures an in-plane displacement component of a deformation vector compared with the Leendertz two-beam illumination method.
Abstract: An optical configuration is suggested that will achieve a twofold increase in sensitivity when one measures an in-plane displacement component of a deformation vector compared with the Leendertz two-beam illumination method. A theory and experimental demonstration of the method are presented.

22 citations

Proceedings ArticleDOI
16 Jan 1989
TL;DR: A new method of contouring 3-D objects in real-time by making use of Digital Speckle Pattern Interferometry (DSPI) alongwith an in-plane sensitive optical configuration is suggested.
Abstract: A new method of contouring 3-D objects in real-time is suggested. The technique makes use of Digital Speckle Pattern Interferometry (DSPI) alongwith an in-plane sensitive optical configuration. The contour interval can be varied in real-time by varying the tilt applied to the object. The variation of the contour interval with the tilt angle and the angle between the illumination beams is discussed. The decorrelation of speckle pattern due to tilt and consequently the disappearance of the fringes is also discussed. Experimental results have been presented for a variety of objects.© (1989) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

20 citations

Journal ArticleDOI
TL;DR: A modification of a dual-beam illumination arrangement for electronic speckle pattern interferometry (ESPI) that leads to a twofold increase in the sensitivity to in-plane displacements is described in this paper.
Abstract: A modification of a dual-beam illumination arrangement for electronic speckle pattern interferometry (ESPI) that leads to a twofold increase in the sensitivity to in-plane displacements is described. For each of the two illumination beams, the scattered light is observed along the direction of illumination, and these two components of the scattered light are then combined. The error in perspective caused by oblique observation can be almost corrected for by using two right-angle prisms in front of the object being studied. Experimental results including phasestepping are presented and compared with the results predicted by theory.

17 citations

Journal ArticleDOI
TL;DR: In this paper, a comparative time-averaged TV holographic technique that allows fringe compensation is presented, which employs two identical objects, the test and the master, that are subjected to sinusoidal vibration to detect the difference in either out-of-plane vibration amplitude or phase distributions.
Abstract: A comparative time-averaged TV holographic technique that allows fringe compensation is presented. The technique employs two identical objects, the test and the master, that are subjected to sinusoidal vibration to detect the difference in either out-of-plane vibration amplitude or phase distributions. In addition, the present optical configuration offers simultaneous visualization of vibration amplitudes of the test object. Detailed theoretical and experimental results are presented.

16 citations