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Proceedings Paper

Progress in phase unwrapping
Author(s): Jonathan Mark Huntley; C. R. Coggrave
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Paper Abstract

This paper reviews some of the main developments in numerical phase unwrapping techniques that have been introduced over the past five years. In quality control applications of wholefield optical techniques it is often necessary for the phase unwrapping to be both robust and performed within a guaranteed time period of a few seconds or less. Deterministic algorithms that have data-independent run times are therefore desirable. The temporal phase unwrapping algorithm has been implemented on a pipeline image processor which is able to calculate phase maps from phase-shifted fringe patterns acquired at 30 frames s-1, and to unwrap the resulting phase maps in real time. One application of the system is measurement of surface profile. The fringe patterns are projected at 30 frames s-1 using a high resolution data projector. The spatial frequency is reduced exponentially from the maximum value. The sequence of phase values at a given pixel is then unwrapped independently of the other image pixels, and all the intermediate phase values contribute in a least squares sense to the final range estimate for the pixel. A total acquisition and processing time of 0.7 s has been achieved for a maximum spatial frequency of 16 fringes across the field of view.

Paper Details

Date Published: 29 September 1998
PDF: 8 pages
Proc. SPIE 3407, International Conference on Applied Optical Metrology, (29 September 1998); doi: 10.1117/12.323298
Show Author Affiliations
Jonathan Mark Huntley, Loughborough Univ. (United Kingdom)
C. R. Coggrave, Loughborough Univ. (United Kingdom)

Published in SPIE Proceedings Vol. 3407:
International Conference on Applied Optical Metrology
Pramod Kumar Rastogi; Ferenc Gyimesi, Editor(s)

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