NEW TECHNIQUES TO DEMODULATE SINGLE IMAGE INTERFEROGRAMS WITH CLOSED FRINGES
"Topics on fringe pattern demodulation, or phase recovery of interferograms, have been studied around the world by several researchers because of their importance in optical metrology areas. In our days, we can find several methods to demodulate fringe patterns, being spatial or temporal. Actua...
| Autor: | |
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| Formato: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2008 |
| País: | México |
| Recursos: | Centro de Investigaciones en Óptica |
| Repositorio: | Repositorio Institucional CIO |
| Idioma: | inglés |
| OAI Identifier: | oai:cio.repositorioinstitucional.mx:1002/679 |
| Acesso em linha: | http://cio.repositorioinstitucional.mx/jspui/handle/1002/679 |
| Access Level: | acceso abierto |
| Palavra-chave: | info:eu-repo/classification/AUTOR/INTERFEROMETRY, FOURIER TRANSFORM, DEMODULATION, INTERFEROGRAMS. info:eu-repo/classification/cti/1 info:eu-repo/classification/cti/22 info:eu-repo/classification/cti/2209 |
| Resumo: | "Topics on fringe pattern demodulation, or phase recovery of interferograms, have been studied around the world by several researchers because of their importance in optical metrology areas. In our days, we can find several methods to demodulate fringe patterns, being spatial or temporal. Actually, the most used methods to recover the phase from fringe pattern images are those whose algorithms are simple and less heavy with the computer resources. For example, methods that work with interferogram images with carrier frequency either spatial or temporal, are very simple compared with methods that work with interferograms without carrier frequency, or closed fringes. Therefore, to have in some way the possibility to introduce carrier frequencies, researchers in the laboratories of optical metrology invest money in faster cameras, more powered (and pulsed) lasers and mechanical components. However, as the computer technology is advancing and is very commercial, we are able to have cheap more robust computers, in such a way that we can invest now less money in computer machines, and throw ourselves to the processing of interferograms without carrier frequency. In this thesis, we present an original work about two new techniques to demodulate interferogram images without carrier frequency or closed fringes. Although this thesis is not a recompilation of the different demodulation methods, we start by introducing the issue of the demodulation with two simple techniques for fringe patterns with carrier frequency. The contribution of this thesis is shown in chapters 2 and 3. In chapter 2, we show an experimental method to recover the phase of interferograms with closed fringes, within a twice differentiable function space C2. This gives a theoretical background to demodulate interferograms with closed fringes by using simple row by row scanning strategies. In chapter 3, we show a more robust method which uses robust quadrature filters. This is a very good noise-tolerant demodulation method. Summing up, we will show how these two ideas are complemented in future works to generate temporal demodulation methods without carrier frequency. We hope forward, with this work, obtain one of the first demodulation techniques for real-time interferograms without temporal carrier frequency." |
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