Journal ArticleDOI
Nondestructive testing by use of TV holography and deformation phase gradient calculation
TLDR
A technique for nondestructive testing based on phase shifting TV holography and digital image processing is presented, which calculates the phase modulation of the object light caused by object deformation and smoothed the resulting deformation phase image to obtain a better signal-to-noise ratio.Abstract:
We present a technique for nondestructive testing based on phase shifting TV holography and digital image processing With this technique we calculate the phase modulation of the object light caused by object deformation The resulting deformation phase image is smoothed to obtain a better signal-to-noise ratio Smoothing is done by a new low pass filtering procedure we call phase shifting convolution This procedure is based on smoothing of two phase images: the original phase image and a second image obtained by spatial phase shift of the original phase image By combining the two smoothed images we obtain an image without smoothing errors close to the 2π phase ambiguities in the deformation phase image To detect surface areas with local inhomogeneous deformations indicating material defects, we calculate and display the deformation phase gradients Examples with testing of composite materials are shownread more
Citations
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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
A systematic approach to TV holography
TL;DR: In this paper, the authors proposed an original scheme for the systematic treatment of TVH and to review the existing techniques according to it, and split the measurement process into four highly independent stages (illumination and observation geometry, temporal treatment, secondary-correlogram generation and fringe-pattern analysis) and establish a common notation to formulate the corresponding techniques.
Book ChapterDOI
Phase-Shifting Holographic Interferometry
TL;DR: Quantitative data can be extracted from holographic interference fringes using Phase-Measurement Interferometry (PMI) techniques using spatial and temporal techniques, which process the data analytically on a point-by-point basis.
Journal ArticleDOI
On the performance of some unwrapping algorithms
TL;DR: This work attempts an objective comparison in terms of performance and execution speed of some of the best known phase unwrapping algorithms.
Journal ArticleDOI
The application of interferometric techniques to the nondestructive inspection of fiber-reinforced materials
J. P. Nokes,Gary Cloud +1 more
TL;DR: In this paper, a method for increasing the sensitivity of dynamic materials evaluation (DME) to localized damage in fiber-reinforced composites was examined, which included an increase in the frequency used to evaluate the dynamic properties, utilization of mode-shape information and different procedures for evaluating the experimental data.
References
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Journal ArticleDOI
Phase-shifting speckle interferometry
TL;DR: One application of phase-shifting techniques to speckle interferometry is finding the phase of deformations, where up to ten waves of wavefront deformation can easily be measured.
Journal ArticleDOI
Fringe scanning speckle-pattern interferometry.
Suezou Nakadate,Hiroyoshi Saito +1 more
TL;DR: Digital speckle-pattern interferometry systems for automatic measurement of deformations of a diffuse object are presented, which are based on a fringe scanning method with phase-shifted Speckle interferograms.
Journal ArticleDOI
Automatic fringe pattern analysis: A review
TL;DR: A cross-section of techniques and applications of automatic and interactive fringe pattern analysis and some of the ways in which prior knowledge of the fringe pattern characteristics can be used to simplify the analysis procedure are described.
Journal ArticleDOI
Automatic fringe analysis with a computer image-processing system
TL;DR: The application of a general-purpose image-processing computer system to automatic fringe analysis is presented and three areas of application have been examined where the use of a system based on a random access frame store has enabled a processing algorithm to be developed to suit a specific problem.