Paper
18 June 2007 Reaching lambda/100 resolution in static fringes interferometry using linear prediction
Manuel Mestre, Didier Pasquelin, Peter Flug
Author Affiliations +
Abstract
Both in industrial close-to-production quality control and in laboratory metrology, measuring optical components and systems with high precision and resolution (typically lambda/100 ptv) is currently achieved by phase-shifting interferometry devices. The main drawbacks of such devices compared to static fringes systems lie in a higher cost, and a greater the sensitivity to the environment, both vibration and air turbulence; the latter becomes unacceptable for large components and large cavity interferometers. Conversely, static fringes metrology usually lacks precision and resolution. Particularly, the lateral resolution is an issue, due to the sampling theorem. This paper shows how a linear prediction of a random function (with a Bayesian approach) makes it possible to tackle a lambda/100 resolution for the estimated wavefront, being the mathematical expectation of the prediction, i.e. the most probable form with respect to the fringe data. Incidentally, the prediction increases robustness by detecting and correcting aberrant fringe data with a high reliability. Furthermore, a Monte-Carlo simulation performed on the whole conditional probability density of the wavefront, provides a stochastic sub-fringe-spacing interpolation. As a result, confidence intervals for any parameter of interest (such as ptv, rms, ptv of slopes...) can be estimated over the whole aperture, which is novel worldwide. These algorithms have also been adapted to wavefront reconstruction from gradient data for Shack-Hartmann and for moiré devices. Examples of implementing these algorithms to industrial software will be shown.
© (2007) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Manuel Mestre, Didier Pasquelin, and Peter Flug "Reaching lambda/100 resolution in static fringes interferometry using linear prediction", Proc. SPIE 6616, Optical Measurement Systems for Industrial Inspection V, 661610 (18 June 2007); https://doi.org/10.1117/12.726037
Advertisement
Advertisement
RIGHTS & PERMISSIONS
Get copyright permission  Get copyright permission on Copyright Marketplace
KEYWORDS
Wavefronts

Photovoltaics

Reconstruction algorithms

Interferometers

Interferometry

Metrology

Phase shifts

Back to Top