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Proceedings Paper

Algorithm for surface contouring using two-source phase-stepping digital shearography
Author(s): Antonio Fernandez; Abundio Davila; Carlos Perez-Lopez; Gabriel Mendiola; Jesus Blanco-Garcia
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Paper Abstract

A novel approach to surface contouring using two-source phase-stepping digital shearography is proposed. In this technique, the illumination source is displaced in a prescribed manner to produce a phase difference increment. For a particular experimental arrangement, this phase change is a function of the height coordinates of two sheared points of the object. Therefore, if the height of the sheared point is known, the phase change in each pixel only depends on the height in the same pixel. This requitement is fulfilled by placing a reference plan of suitable dimensions inside the field of view. To measure the shape of a 3D object, first we calculate the phase change using the well- known five-bucket algorithm of phase stepping, and then we use iteration and interpolation routines to find a height value, for which the difference between the phase change calculated by phase stepping and the theoretical value obtained for this height is smaller than a given tolerance. Results obtained with computer-generated shearing speckle interferograms are significantly more accurate than if a linear relationship between phase change and 3D shape is assumed. Finally, we discuss the performance of the suggested approach.

Paper Details

Date Published: 14 August 2001
PDF: 4 pages
Proc. SPIE 4419, 4th Iberoamerican Meeting on Optics and 7th Latin American Meeting on Optics, Lasers, and Their Applications, (14 August 2001); doi: 10.1117/12.437103
Show Author Affiliations
Antonio Fernandez, Univ. de Vigo (Spain)
Abundio Davila, Ctr. de Investigaciones en Optica, AC (Mexico)
Carlos Perez-Lopez, Ctr. de Investigaciones en Optica, AC (Mexico)
Gabriel Mendiola, Ctr. de Investigaciones en Optica, AC (Mexico)
Jesus Blanco-Garcia, Univ. de Vigo (Spain)


Published in SPIE Proceedings Vol. 4419:
4th Iberoamerican Meeting on Optics and 7th Latin American Meeting on Optics, Lasers, and Their Applications

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