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Proceedings Paper

Automated regional phase unwrapping by an integrated expert system
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Paper Abstract

Phase unwrapping algorithms used in phase-shift or Fourier transform techniques can be classified typically into two groups: line-based unwrapping and region-based unwrapping. Theoretically, the latter can be less error susceptible than the former. However, the pixel categorization process required in the previous region-based algorithms, utilizing the local information obtained from 3 by 3 pixels, is still error prone in many interferograms contaminated by large- scale noises. In the new approach, the developed expert system intelligently find 2 (pi) jump iso-phase lines that categorize regions having no phase jump based on global/regional information rather than the local information, that is, interferogram-specific knowledge. Then it performs phase unwrapping region by region by adding or subtracting 2 (pi) phase-wrapped band wherever region changes. The regional phase unwrapping isolates noises inherently without propagation, since every pixel's phase is unwrapped independently each other. The new algorithm is also effective especially in handling large-scaled noise- affected phase distributions.

Paper Details

Date Published: 21 November 1997
PDF: 13 pages
Proc. SPIE 3172, Optical Technology in Fluid, Thermal, and Combustion Flow III, (21 November 1997); doi: 10.1117/12.293391
Show Author Affiliations
Wonjong Joo, Seoul National Polytechnic Univ. (United States)
Soyoung Stephen Cha, Univ. of Illinois/Chicago (United States)

Published in SPIE Proceedings Vol. 3172:
Optical Technology in Fluid, Thermal, and Combustion Flow III
Soyoung Stephen Cha; James D. Trolinger; Masaaki Kawahashi, Editor(s)

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