Derivatives of displacement obtained by direct manipulation of phase-shifted interferograms

Facchini, M.; Zanetta, P.

doi:10.1364/ao.34.007202

Cited by 13 publications

(7 citation statements)

References 8 publications

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“…It is now necessary to discuss how the gradient measurements ∇φ k can be estimated from the complex interferograms. The interferogram is a complex number z(r, a) = A(r, a) exp jφ(r, a) where A is the product of master and slave reflectivity, (r, a) are the range and azimuth coordinates in radar geometry and φ is the interferometric phase as in Equation (1). Since in the case of glacier flow the interferometric phase varies by several wavelengths within the scale of the deformation pattern, it is possible to perform a local linear approximation of the deformation phase.…”

Section: Phase Gradients Estimation Avoiding Phase Unwrappingmentioning

confidence: 99%

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Estimating Strain and Rotation From Wrapped SAR Interferograms

Parizzi

Jaber

2018

IEEE Geosci. Remote Sensing Lett.

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This letter aims to discuss a general framework that allows the direct interpretation of the wrapped DInSAR phase in terms of surface strain S and rotation R components. The methodology is demonstrated showing the estimation of strain and rotation components of a glacier flow using three TerraSAR-X interferometric geometries (ascending right-looking, descending right-looking and descending left-looking. Finally since the left looking geometry can be difficult to obtain on a regular basis, the surface parallel flow assumption is extended to the phase gradients inversion in order to reduce the amount of necessary geometries from three to two.

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Section: Phase Gradients Estimation Avoiding Phase Unwrappingmentioning

confidence: 99%

“…Interferometric measurements can be directly related to the spatial gradients of the motion [1] [2] [3] [4]. This work exploits this property to resolve between strains and rotation components without the need to unwrap the interferometric phase.…”

Section: Introductionmentioning

confidence: 99%

Estimating Strain and Rotation From Wrapped SAR Interferograms

Parizzi

Jaber

2018

IEEE Geosci. Remote Sensing Lett.

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“…Recent reviews on the subject are given in references (8) and (68). It is worth noting that phase unwrapping is unnecessary when calculating strains: the sin DF and cos DF fringes can be differentiated to give the phase gradients directly (69,70) or the differentiation can be carried out in the Fourier domain (71). Figure 9 shows a simple one-dimensional example of phase unwrapping.…”

Section: Phase Unwrappingmentioning

confidence: 99%

Automated fringe pattern analysis in experimental mechanics: A review

Huntley

1998

The Journal of Strain Analysis for Engineering Design

108

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The paper reviews the main numerical techniques that have been developed to carry out fully automated analysis of fringe patterns resulting from solid mechanics experiments. These include temporal and spatial phase shifting interferometry, temporal and spatial phase unwrapping, and calculation of strain fields from the phase maps. Systematic and random errors associated with the various procedures are also analysed. A unified treatment for both speckle and smooth-wavefront interferograms is presented, and the common features underlying many of the algorithms are emphasized. The paper is illustrated with applications that include ball impact (moiré photography), bending waves in orthotropic plates (double-pulsed dualreference wave holography) and finite strains in propellant grains (fine grid technique).

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“…Since the phase derivative is proportional to the strain developed on the object surface, its accurate estimation becomes an absolute necessity. Various methods have been proposed for the direct estimation of phase derivative based on shearography [6], direct manipulation of phase-shifted interferograms [7], Fourier transform technique [8], and space-frequency representations of fringe patterns [9,10]. Shearing based phase derivative estimation requires an image shearing camera to capture two sheared images.…”

Section: Introductionmentioning

confidence: 99%

Direct phase derivative estimation using difference equation modeling in holographic interferometry

Kulkarni

Rastogi

2014

J. Opt.

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A new method is proposed for the direct phase derivative estimation from a single spatial frequency modulated carrier fringe pattern in holographic interferometry. The fringe intensity in a given row/column is modeled as a difference equation of intensity with spatially varying coefficients. These coefficients carry the information on the phase derivative. Consequently, the accurate estimation of the coefficients is obtained by approximating the coefficients as a linear combination of the predefined linearly independent basis functions. Unlike Fourier transform based fringe analysis, the method does not call for performing the filtering of the Fourier spectrum of fringe intensity. Moreover, the estimation of the carrier frequency is performed by applying the proposed method to a reference interferogram. The performance of the proposed method is insensitive to the fringe amplitude modulation and is validated with the simulation results.

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Derivatives of displacement obtained by direct manipulation of phase-shifted interferograms

Cited by 13 publications

References 8 publications

Estimating Strain and Rotation From Wrapped SAR Interferograms

Estimating Strain and Rotation From Wrapped SAR Interferograms

Automated fringe pattern analysis in experimental mechanics: A review

Direct phase derivative estimation using difference equation modeling in holographic interferometry

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