Paper
29 September 1998 Progress in phase unwrapping
Jonathan Mark Huntley, C. R. Coggrave
Author Affiliations +
Proceedings Volume 3407, International Conference on Applied Optical Metrology; (1998) https://doi.org/10.1117/12.323298
Event: International Conference on Applied Optical Metrology, 1998, Balatonfured, Hungary
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.
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Jonathan Mark Huntley and C. R. Coggrave "Progress in phase unwrapping", Proc. SPIE 3407, International Conference on Applied Optical Metrology, (29 September 1998); https://doi.org/10.1117/12.323298
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Cited by 14 scholarly publications.
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KEYWORDS
Fringe analysis

Phase measurement

Image processing

Projection systems

Modulation

Spatial frequencies

Phase shift keying

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