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Proceedings Paper

Handheld ESPI-speckle interferometer
Author(s): Rene Skov Hansen
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Paper Abstract

A "handheld" speckle interferometer for measuring out-of-plane displacements on reflective as well as diffusely scattering object surfaces is presented. The interferometer is a nearly path length compensated set-up which uses diffuse illumination of the object in combination with a speckled reference. The reference wave is established by reflecting a part of the diffuse object illumination from a glass plate located just in front of the object. The glass plate is mounted on a piezoelectric translator in order to control the phase of the reference wave when using phase stepping algorithms. The coherent light source is a laser diode. A web camera with a Universal Serial Bus (USB) interface is employed as the image-capturing device. Likewise, is the piezoelectric translator controlled through the USB interface. The necessary size of the optical set-up depends on the size of the object. The interferometer presented here is a compact version of the set-up, which is capable of measuring displacments of small objects, having either a specularly reflecting- or a diffusely scattering surface. The small optical set-up together with the use of the popular USB-communication for acquiring the images and controlling the phase of the reference wave constitutes a compact "handheld" instrument and eliminates the need for installing extra hardware, such as frame grabber and Digital to Analog converter, in the host computer.

Paper Details

Date Published: 27 May 2003
PDF: 4 pages
Proc. SPIE 4933, Speckle Metrology 2003, (27 May 2003); doi: 10.1117/12.516645
Show Author Affiliations
Rene Skov Hansen, Riso National Lab. (Denmark)

Published in SPIE Proceedings Vol. 4933:
Speckle Metrology 2003
Kay Gastinger; Ole Johan Lokberg; Svein Winther, Editor(s)

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