Comparison between temporal and spatial phase unwrapping for damage detection using shearography

2006 ◽  
Author(s):  
A. V. Fantin ◽  
A. Dal Pont ◽  
D. P. Willemann ◽  
A. Albertazzi
Keyword(s):  
Damage Detection ◽  
Phase Unwrapping ◽  
Spatial Phase ◽  
Temporal And Spatial

scholarly journals One-Step Three-Dimensional Phase Unwrapping Approach Based on Small Baseline Subset Interferograms

2020 ◽  
Vol 12 (9) ◽  
pp. 1473 ◽  
Author(s):  
Christina Esch ◽  
Joël Köhler ◽  
Karlheinz Gutjahr ◽  
Wolf-Dieter Schuh
Keyword(s):  
Spatial Information ◽  
Real Data ◽  
Single Step ◽  
Phase Unwrapping ◽  
Motion Model ◽  
Phase Gradient ◽  
Spatial Phase ◽  
Small Baseline Subset ◽  
Temporal And Spatial ◽  
Small Baseline

One of the most critical steps in a multitemporal D-InSAR analysis is the resolution of the phase ambiguities in the context of phase unwrapping. The Extended Minimum Cost Flow approach is one of the potential phase unwrapping algorithms used in the Small Baseline Subset analysis. In a first step, each phase gradient is unwrapped in time using a linear motion model and, in a second step, the spatial phase unwrapping is individually performed for each interferogram. Exploiting the temporal and spatial information is a proven method, but the two-step procedure is not optimal. In this paper, a method is presented which solves both the temporal and spatial phase unwrapping in one single step. This requires some modifications regarding the estimation of the motion model and the choice of the weights. Furthermore, the problem of temporal inconsistency of the data, which occurs with spatially filtered interferograms, must be considered. For this purpose, so called slack variables are inserted. To verify the method, both simulated and real data are used. The test region is the Lower-Rhine-Embayment in the southwest of North Rhine-Westphalia, a very rural region with noisy data. The studies show that the new approach leads to more consistent results, so that the deformation time series of the analyzed pixels can be improved.

Robust Spatial Phase Unwrapping for On-Line MR-Temperature Monitoring

2007 ◽  
Author(s):  
B. Denis de Senneville ◽  
G. Maclair ◽  
M. Ries ◽  
P. Desbarats ◽  
B. Quesson ◽  
...  
Keyword(s):  
Phase Unwrapping ◽  
Temperature Monitoring ◽  
Spatial Phase ◽  
On Line

Automated fringe pattern analysis in experimental mechanics: A review

1998 ◽  
Vol 33 (2) ◽  
pp. 105-125 ◽  
Author(s):  
J M Huntley
Keyword(s):  
Solid Mechanics ◽  
Automated Analysis ◽  
Random Errors ◽  
Orthotropic Plates ◽  
Fine Grid ◽  
Ball Impact ◽  
Spatial Phase ◽  
Bending Waves ◽  
Fringe Pattern Analysis ◽  
Temporal And Spatial

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 dual-reference wave holography) and finite strains in propellant grains (fine grid technique).

scholarly journals PSInSAR Study of Lyngenfjord Norway, using TerraSAR-X Data

2018 ◽  
Vol IV-5 ◽  
pp. 245-251
Author(s):  
U. Asopa ◽  
S. Kumar ◽  
P. K. Thakur
Keyword(s):  
Phase Shift ◽  
Temporal Analysis ◽  
Phase Unwrapping ◽  
Synthetic Aperture ◽  
Interferometric Synthetic Aperture Radar ◽  
Point Distribution ◽  
Subpixel Accuracy ◽  
Persistent Scatterer ◽  
Temporal And Spatial ◽  
Temporal Basis

<p><strong>Abstract.</strong> In this research paper, focus is given on exploring the potential of Persistent Scatterer Interferometric Synthetic Aperture Radar (PSInSAR) technique for the measurement of landslide, which is the extension of existing DInSAR technique. In PSInSAR technique, the movement is measured by finding the phase shift in the scatterers present in the study area through the course of time. The backscattering of such a scatterer does not change during the study. By using this technique, 32 datasets acquired over a period of time i.e. from 2009 to 2011 over the area of Troms County of Lyngen Fjord, Norway are analysed. The dataset utilised are acquired with TerraSAR-X and TanDEM-X pair, in Stripmap mode of acquisition. Coregistration of dataset with subpixel accuracy is done with master images is done to align all the dataset correctly. APS estimation is done in order to remove the phase decorrelation caused by the atmosphere, movement, etc. using algorithms for phase unwrapping which allowed the processing of sparse data and the effect of atmosphere is reduced by doing analysis on temporal basis of the phase shift in interferograms of successive datasets. By this study it has been tried to show the estimation of shift can be done by the temporal analysis of the data acquired by TerraSAR-X. The velocity output is displayed in a map reflecting the velocity of movement. Apart from this, the data properties such as baseline distribution both temporal and spatial are displayed in a chart. Other outputs obtained are the atmospheric Phase Screen, sparse point distribution, reflectivity map of the study area etc. are displayed using a map of terrain. The output velocity obtained of the terrain movement is found to be in the range of &amp;minus;40<span class="thinspace"></span>mm/yr to &amp;minus;70<span class="thinspace"></span>mm/yr.</p>

Matched spatial-phase-shifting for the temporal-phase-unwrapping in electronic speckle pattern interferometry

Optik ◽  
2001 ◽  
Vol 112 (11) ◽  
pp. 515-520 ◽  
Author(s):  
R.A. Martínez-Celorio ◽  
A. Dávila ◽  
B. Barrientos ◽  
J.H. Puga ◽  
Luis Martí López
Keyword(s):  
Speckle Pattern ◽  
Phase Unwrapping ◽  
Phase Shifting ◽  
Electronic Speckle Pattern Interferometry ◽  
Spatial Phase ◽  
Temporal Phase

scholarly journals Multi-anchor spatial phase unwrapping for fringe projection profilometry

2019 ◽  
Vol 27 (23) ◽  
pp. 33488 ◽  
Author(s):  
Sen Xiang ◽  
You Yang ◽  
Huiping Deng ◽  
Jin Wu ◽  
Li Yu
Keyword(s):  
Phase Unwrapping ◽  
Fringe Projection ◽  
Spatial Phase ◽  
Fringe Projection Profilometry
Sign in / Sign up

Export Citation Format

Share Document