Hybrid phase unwrapping in laser speckle interferometry with overlapping windows by Oliver Schwarz

Cover of: Hybrid phase unwrapping in laser speckle interferometry with overlapping windows | Oliver Schwarz

Published by Shaker in Aachen .

Written in English

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Subjects:

  • Speckle metrology,
  • Laser speckle,
  • Laser interferometers

Edition Notes

Book details

Other titlesHybrid phase unwrapping with overlapping windows
StatementOliver Schwarz.
SeriesBerichte aus der Informatik
Classifications
LC ClassificationsTA1555 .S387 2004
The Physical Object
Paginationvi, 181 p. :
Number of Pages181
ID Numbers
Open LibraryOL23953031M
ISBN 103832224408
ISBN 109783832224400
LC Control Number2007493318

Download Hybrid phase unwrapping in laser speckle interferometry with overlapping windows

Two-dimensional phase unwrapping (PhU) is one of the most important processing steps in optical phase-shifting interferometry. It aims to reconstruct the continuous phase field, but in fact, it becomes very difficult to perform the PhU due to the existence of noise, low modulation, under sampling, discontinuities or other by: 1.

Phase unwrapping in speckle interferometry original one. The Gaussian random noises are uncorrelated at each pixel, in other words, correlation length is one pixel, and the standard deviations are chosen to be o-n=,and times by: 2D phase unwrapping is the key technique in SAR interferometry.

This paper discusses a phase unwrapping algorithm based on fringe line detection. Improvements are presented in order to use this method in areas with intensely fluctuated fringe lines. Results on X-SAR interferometric data are : Yong Zhang, Yirong Wu, Lei Wang, Hailiang Peng.

Experimental laboratory: Introduction to the practical work. Laser dynamic speckle interferometry Schematic diagram of the speckle experimental set‐up. Experimental procedure: • Sample: Ethanol drop. • Capture by the CCD camera. • A sequence of frame‐by‐frame mode in the image Size: 1MB.

J.V. Araújo dos Santos, H. Lopes, "Application of Speckle Interferometry to. is known as phase unwrapping. using speckle pattern interferometry with a double pulse ruby laser and. An approach to two-dimensional (2D) phase unwrapping for synthetic aperture radar (SAR) interferometry is presented, based on separate steps of coarse phase and fine phase.

age speckle but induces a phase change in the grains. As a consequence, the new image intensity uS8(x,y)u2 is made of the same speckle grains as uS(x,y)u2, but such grains are luminous or dark according to the new interference condi-tion. In particular, to make a speckle grain change from lu-minous to dark, a surface displacement D(x,y)5l/4 is re.

Phase unwrapping is the inference of absolute phase from modulo-2π phase. This is a critical step in the InSAR processing chain, yet still one of its most challenging problems; this fact makes of phase unwrapping a crucial problem to InSAR based DEM production.

This thesis introduces a new energy minimization framework for phase unwrapping. cluding errors in the phase measurements, phase unwrapping algorithm, and laser and detector noises. To compensate for these, the displacement values in the AOI were all used to determine the gradient and obtain the corresponding regres- sion plane.

The slope of the edge view, also shown in by: speckle-pattern interferometry, electro-optic inter-ferometry, TV holography, digital speckle interfer-ometry, etc., with many adjunctions such as in-line, shearing or phase-shifting SI, and so on.

‘Digital holography’ (DH) is usually free of misinterpretation, but when an expression like ‘image-plane digital. We propose a hybrid spatiotemporal three-dimensional phase unwrapping algorithm for use in digital speckle pattern interferometry (DSPI).

The feature of the proposed algorithm is the integration of one-dimensional temporal and two-dimensional spatial phase unwrapping algorithms. This is done by applying phase-shifting techniques to speckle interferometry, which will quantitatively determine the phase of double-exposure speckle measurements.

The technique uses computer control to take data and calculate phase without an intermediate recording step. Figure 4. (a) Correlation fringe pattern obtained with the reference window speckle interferometer as a response to a point displacement in the centre of a flat plate.

(b) Wrapped phase map obtained using temporal phase stepping through laser diode current modulation. The field of view of the images is 15mm × 15 mm. Fig. 1 A physical reduction of phase singularities is use-ful. The physical reduction of phase singularities is done by tailoring the spatial coherence of the illu-minating laser light in a Michelson interferometer [4].

As a specific example, deformation measure-ments have been chosen, although the procedure may also be used for form measurements. application of SAR interferometry (INSAR) is unwrapping the interferometric phase. The difficulties arise in attempting to find global optimization procedures with the best possible cost criteria for data phase unwrapping”, Radio Science, Vol.

23,pp. A chapter on computerised optical processes such as electronic speckle interferometry, digital holography and digital speckle photography.

Coverage of digital fringe pattern measurement techniques with special emphasis on phase measurement interferometry and phase unwrapping. Detailed discussion on lasers and laser principles, including an Format: Hardcover.

interferometry, speckle interferometry, technique for generating these frequencies is to split a laser output into two modes by magnetic (Zeeman) splitting. The interferogram oscillates at the frequency of the beat Phase-measuring, Phase-Shifting or Phase-Stepping Interferometry is a technique usedFile Size: KB.

Phase unwrapping is the process of recovering unambigu-ous phase values from phase data that are measured modulo 2!rad (wrapped data). Data of this form are found in many applications, but the advent in the early s of synthetic aperture radar interferometry (In-SAR), in particular, spurred interest in developing reli.

Publications. An Update Algorithm for Fourier Coefficients; Hybrid Phase Unwrapping in Laser Speckle Interferometry with Overlapping Windows; Hybrid phase unwrapping algorithm extended by a minimum-cost-matching strategy.

Sept. 3, Lecture D1Lb4 Interferometry: Phase unwrapping Rocca 10 Example: constant slope We assume a constant range slope (the most common case). We assume the phase rotating counter clockwise. Real parts zero for -π/2 or π/2. Image parts zero for 0 or π. In absence of noise real and imaginary parts never crosses.

However, the steeper the. Multi-wavelength optical phase unwrapping is an easy method that can be used to eliminate 2 π ambiguities in phase maps without such problems. In this chapter we will present quantitative phase images of cells and other microscopic samples, using multi-wavelength optical phase by: Hybrid Phase Unwrapping in Laser Speckle Interferometry with Overlapping Windows.

Veröffentlichungsdatum: Februar Verleger: Shaker Verlag, Aachen. Simone Graf, Tobias Hanning, Robert Wagner: Projektive Rekonstruktion &#x; Möglichkeiten der Stereobildverarbeitung ohne Kalibrierwissen.

The book “Holographic and Speckle Interferometry” by Robert Jones and Catherine Wykes [1] gives a detailed introduction to the field of Speckle interferometry, and a detailed introduction to the light-in-flight technique, which is used with speckle metrology in this thesis can be found in the book.

Matched spatial-phase-shifting for the temporal-phase- unwrapping in electronic speckle pattern interferometry R. Martı´nez-Celorio, A. Da´vila, B. Barrientos, J. Puga, Luis Martı´ Lo´pez Centro de Investigaciones en Optica, AC, ApdoC.P.

Leo´n, Gto, Me´xico Abstract: Asynchronouscombinationspatial-carrierphase- shifting and temporal-phase-unwrapping Cited by: 3. Phase-Shifting Interferometry Phase-shifting techniques Phase-shifting interferometry is a powerful means of analyzing interferograms to recover the phase information.

Traditionally, interferograms were measured by locating the center of a fringe and then tracing along the fringe. Phase-shifting interferometry avoids the need to track. In these techniques, temporal phase unwrapping was applied.

Hence, the measurement errors were also accumulated. InKao et al. applied the phase shifts to the initial status t 0 but not to other instances t. Phase-shifted speckle-correlation fringe patterns can be formed between t 0 and t. This method is very simple but suffers from Cited by: Buy Interferometry in Speckle Light: Theory And Applications on FREE SHIPPING on qualified orders.

Keywords: Phase unwrapping, Least square optimisation, Digital Elevation Model Introduction. Digital Elevation Models can be computed from ERS interferometric products. The phase unwrapping step is the main problem.

We present a robust-to-noise phase-unwrapping algorithm based on a global analysis of the interferogram. ing set of approaches is the final word on phase unwrap-ping procedures, this article serves more as a progress re-port rather than as a review of phase unwrapping procedures.

The advent of interferometric SAR for geophysical studies, in particular, has resulted in the need for accu-rate, efficient methods of two-dimensional phase unwrap-ping.

Here the unwrapping and absolute phase problems as well as the transformation of phase data into displacement values are addressed. Because image processing plays an important role in optical nondestructive testing, finally in Sect.

some modern approaches for automatic fault detection are described. Phase-shifting speckle interferometry Katherine Creath Speckle patterns have high frequency phase data, which make it difficult to find the absolute phase of a sin-gle speckle pattern; however, the phase of the difference between two correlated speckle patterns can be.

broader overlapping deltaic area of Evinos and Acheloos rivers, by implementing a “hybrid INSAR” recent advances in SAR interferometry methods that of differential interferograms, filtering and phase unwrapping.

The data obtained were processed using two different techniques, the Persistent Scatterers. EE/Ge b, Week 3 3 - 10 RADAR INTERFEROMETRY TRIGONOMETRY (continued) • Now let represent the look angle to a point on a “flat earth” as shown in the figure.

Then • In terms of the interferometric phase, it means we can write • The first term represents the phase difference measured for the “flat earth,” i.e. in the.

PHASE UNWRAPPING The wrapped phase comes in the range of [0, 2x1 and the goal of Phase Unwrapping is to get a continuous phase out of it. There are different approaches to the problem, some of them described in [1,2]: region growing, path dependent methods, the recent network programming theory and others.

1. Introduction. Digital Holographic Interferometry (DHI) is a well-established method for the precise measurement of microscopic deformations [1,2].By employing DHI for the retrieval of the out-of-plane deformation component and combining it with Digital Speckle Photography (DSP) [] for the measurement of the in-plane deformation components, 3D Cited by: A resource like no other-the first comprehensive guide to phase unwrapping Phase unwrapping is a mathematical problem-solving technique increasingly used in synthetic aperture radar (SAR) interferometry, optical interferometry, adaptive optics, and medical imaging.

In Two-Dimensional Phase Unwrapping, two internationally recognized experts sort through the 5/5(1). The concept of our laser scanner, which we refer to as the hybrid dispersion laser scanner (HDLS), is shown in Figure 1. Its operation consists of two steps: frequency-to-time conversion and time Cited by: 9.

Quasi Ellipse Method Enabling High Accuracy Phase Reconstruction with Random Phase Steps in Fizeau-Interferometers Michael F.

Küchel. Measurement of Aspheres and Free-Form Surfaces with the Tilted-Wave-Interferometer Goran Bastian Baer, Johannes Schindler, Christof Pruss, Wolfgang Osten.

Abstract. The basic principle of modern optical methods in experimental solid mechanics such as holographic interferometry, speckle metrology, fringe projection and moiré techniques consists either in a specific structuring of the illumination of the object by incoherent projection of fringe patterns onto the surface under test or by coherent superposition (interference) of light fields Cited by: Explore books by Oliver Schwarz with our selection at Click and Collect from your local Waterstones or get FREE UK delivery on orders over £.

The Split-Band Interferometry Approach to Determine the Phase Unwrapping Offset Ludivine Libert1, Dominique Derauw1, Nicolas d’Oreye2,3, François Kervyn4, Anne Orban1 and Christian Barbier1 1Centre Spatial de Liège (CSL), Université de Liège, Avenue du Pré-Aily, Angleur, Belgium 2European Center for Geodynamics and Seismology, Rue Josy Wel L .The phase of the radar echoes may only be measured modulo 2π; however, the whole phase at each point in the image is needed to obtain elevations.

We present here our approach to “unwrapping” the 2π ambiguities in the two‐dimensional data by: of interferometry, large changes in OPL require phase unwrapping. Conversely, small phase changes are limited by the fraction of a fringe that can be measured.

We introduce the phase shifts with an electro-optic modulator (EOM) and use either the Carre or Hariharan algorithms to determine the phase and Size: KB.

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