Journal ArticleDOI
Computerized optical fringe pattern analysis in photomechanics: a review
TLDR
This work reviews several automatic and semiautomatic image processing algorithms that enable the reduction of both speckle and full-field fringe patterns to quantitative data and presents examples of digital image processing based data reduction.Abstract:
Computerized analysis of optical fringe patterns has become an accepted method of reducing the time and tedium associated with extracting quantitative data from phase encoded intensity distributions. The computing power of today's personal computers makes digital image processing of moire, holographic, photoelastic, and speckle interferometric fringe patterns both economical and efficient. We review several automatic and semiautomatic image processing algorithms that enable the reduction of both speckle and full-field fringe patterns to quantitative data. The speckle patterns are analyzed using morphological properties, while the full-field fringe patterns are analyzed using standard thinning and fringe order seeding, sinusoidal fitting, Fourier transform, and phasestepping techniques. The mapping that each fringe pattern experiences when being digitized is also discussed so that proper system calibration can be developed. Analysis of geometric moire, moire interferometric, photoelastic, and speckle interferometric fringe patterns are presented as examples of digital image processing based data reduction.read more
Citations
More filters
Journal ArticleDOI
Phase-evaluation methods in whole-field optical measurement techniques
TL;DR: The phase-evaluation methods as discussed by the authors use a combination of phase-shifted intensity values, provided by the modulation of one or several fringe patterns, to calculate the principal value of the optical phase.
Journal ArticleDOI
Automated fringe pattern analysis in experimental mechanics: A review
TL;DR: The main numerical techniques that have been developed to carry out fully automated analysis of fringe patterns resulting from solid mechanics experiments are reviewed, and a unified treatment for both speckle and smooth-wavefront interferograms is presented.
Journal ArticleDOI
Fringe pattern analysis by a phase-shifting method using Fourier transform
TL;DR: The interference fringes obtained by optical methods such as holographic interterometry and Twyman-Green interferometry are analyzed using image processing and a new phase analysis method is proposed to erase errors.
Journal ArticleDOI
Photoelasticity stress analysis using carrier fringe and FFT techniques
TL;DR: In this paper, a carrier fringe technique for photoelasticity stress analysis is described and verified experimentally, where linear carrier fringes generated by using a quartz wedge are superimposed on fringes formed by the stressed model and the resultant fringe pattern is captured using a charge coupled device camera and stored in a digital frame buffer.
Patent
Full field photoelastic stress analysis
TL;DR: In this paper, a simple polariscope was constructed having two polarizing filters with a single one-quarter waveplate placed between the polarizing filter and the waveplate and reflected from a sub-fringe birefringent coating on a structure under load.