Phase Estimation in Optical Interferometry

Phase Estimation in Optical Interferometry
Author: Pramod Rastogi
Publisher: CRC Press
Total Pages: 364
Release: 2014-11-21
Genre: Science
ISBN: 1466598328

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This book covers the essentials of phase-stepping algorithms used in interferometry and pseudointerferometric techniques. It presents the basic concepts and mathematics needed for understanding modern phase estimation methods. The book first focuses on phase retrieval from image transforms using a single frame. It then examines the local environment of a fringe pattern, the phase estimation approach based on local polynomial phase modeling, temporal high-resolution phase evaluation methods, and methods of phase unwrapping. It also discusses experimental imperfections liable to adversely influence the accuracy of phase measurements.

Handbook of Holographic Interferometry

Handbook of Holographic Interferometry
Author: Thomas Kreis
Publisher: John Wiley & Sons
Total Pages: 554
Release: 2006-04-20
Genre: Science
ISBN: 3527604928

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The book presents the principles and methods of holographic interferometry - a coherent-optical measurement technique for deformation and stress analysis, for the determination of refractive-index distributions, or applied to non-destructive testing. Emphasis of the book is on the quantitative computer-aided evaluation of the holographic interferograms. Based upon wave-optics the evaluation methods, their implementation in computer-algorithms, and their applications in engineering are described.

Holographic Interferometry

Holographic Interferometry
Author: Thomas Kreis
Publisher: Wiley-VCH
Total Pages: 362
Release: 1996-04-11
Genre: Language Arts & Disciplines
ISBN:

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The book presents the principles and methods of holographic interferometry, a coherent-optical measurement technique for deformation and stress analysis, for the determination of refractive-index distributions, or applied to non-destructive testing. Emphasis of the book is on the quantitative computer-aided evaluation of the holographic interferograms. Based upon wave-optics the evaluation methods, their implementation in computer-algorithms, and their applications in engineering are described.

Holographic Interferometry

Holographic Interferometry
Author: Pramod K. Rastogi
Publisher: Springer
Total Pages: 343
Release: 2013-04-17
Genre: Science
ISBN: 3540480781

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Holographic Interferometry provides a valuable and up-to-date source of information in the rapidly expanding field. The eight specialists` contributions cover the principles and methods currently in use. The scope of the book has been limited to the study of opaque object and ample space has been devoted to a comprehensive treatment of the phenomena of fringe formation, with a particular emphasis on the quantitative evaluation of the holographic interference fringe patterns. The emergence of computer-aided fringe analysis and phase-shifting techniques have simplified considerably the quantative real-time measurements of object shapes and deformations. The last two chapters provide a reasonably detailedoverview of full-field holographic methods for the measurement of shapes, displacements, dervatives, difference displacements and vibrations.

Digital Holography

Digital Holography
Author: Ulf Schnars
Publisher: Springer Science & Business Media
Total Pages: 165
Release: 2005-12-08
Genre: Science
ISBN: 3540269118

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This highly practical and self-contained guidebook explains the principles and major applications of digital hologram recording and numerical reconstruction (Digital Holography). A special chapter is designated to digital holographic interferometry with applications in deformation and shape measurement and refractive index determination. Applications in imaging and microscopy are also described. Spcial techniques such as digital light-in-flight holography, holographic endoscopy, information encrypting, comparative holography, and related techniques of speckle metrology are also treated

Iterative Phase Estimation Algorithms in Interferometric Systems

Iterative Phase Estimation Algorithms in Interferometric Systems
Author: Wesley E. Farriss
Publisher:
Total Pages: 191
Release: 2021
Genre:
ISBN:

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"Coherent optical interferometry has a long history of enabling extremely precise measurements at length scales of less than the wavelength of light used in the interferometer. It is the ability of these systems to measure both the relative phase and amplitude information of the optical field that makes them so useful. As the name would imply, measuring phase and amplitude is accomplished by interfering two or more beams of light. Interferometric techniques have been adopted for use in both imaging/sensing technologies. For imaging systems under ideal conditions, the ability to measure both phase and amplitude information in one transverse plane allows for the calculation of that field's phase and amplitude distribution in any other transverse plane. However, the presence of atmospheric turbulence unpredictably alters the index of refraction in the propagation medium thereby adversely affecting the reliability of calculation of phase and amplitude in other transverse planes. To address this problem, we demonstrate iterative sharpness maximization (ISM) correction of anisoplanatic turbulence effects in simulated range-compressed holography (RCH) fields and their corresponding range images. Our turbulence correction estimated four phase screens placed along the path of optical propagation using nonlinear optimizations aided by the method of sieves technique. We conducted a study of range images created from simulated single speckle realization 3D RCH fields subjected to twenty different turbulence profiles at five different strengths of turbulence, D/r0 = 7, 14, 21, 28, and 36. Range images showed significant improvement for all strengths of turbulence. To assist in correction, we introduced a novel constraint limiting the spread of energy in the corrected pupil. Corrected range images were qualitatively very similar to unaberrated range images in all but the most severe turbulence case, D/r0 = 36. Additionally, our algorithm was tested for fields affected by shot noise. Mean target photons per speckle ranged from 10 -2 to 10 2 in these simulations. For an effective D/r0 = 36, range images corrected from fields with 102 mean photons per speckle had very similar RMSE when compared to corrected noiseless range images. On average, corrected range images created from fields with 1 mean target photon per speckle differed by less than 5% RMSE from noiseless corrected range images. We went on to construct a RCH system in a laboratory setting using a linear frequency modulated CW laser and a high frame rate camera which allowed us to create 3D images of laboratory targets. Data was collected both with and without the effects of turbulence. In the former, multiple Lexitek turbulence screens were used to aberrate the image fields of our lab target at two different effective strengths of anisoplanatic turbulence, D/r0 = 7 and D/r0 = 16, respectively. Both of these sets of real aberrated image fields showed profound improvement in quality after correction with our phase ISM turbulence mitigation algorithm. Novel interferometric systems are also being developed which enable modal analysis of an optical field. This generalized optical interferometry (GOI) treats coherent optical fields as a linear superposition of transverse modes and recovers the amplitudes of modal weighting coefficients. In order to maximize the utility of these systems, we used phase retrieval by nonlinear optimization to recover the phase of these modal weighting coefficients. Algorithms were developed both for use with an array detector and for use with a bucket detector. Information diversity increased the robustness of both algorithms by better constraining the solutions. In our array detection phase retrieval, the algorithm was able to recover nearly all coefficient phases for simulated fields consisting of up to 21 superpositioned Hermite Gaussian modes from simulated data and proved to be resilient to shot noise. Similarly, the algorithm we developed using data from a simulated bucket detector was able to consistently recover better than 95% of coefficient phases for simulated random fields consisting of up to 21 superpositioned Hermite Gaussian modes using between three and seven measurements per unknown phase coefficient. With shot noise, the algorithm achieved performance on par with noiseless simulations with 106 mean signal photons per measurement. The role played by number of measurements per unknown (mpu), photons per unknown per measurement (ppu), and order of superposition in the bucket detection algorithm's performance was also explored"--Pages xvi-xix

Digital Optical Measurement Techniques and Applications

Digital Optical Measurement Techniques and Applications
Author: Pramod Rastogi
Publisher: Artech House
Total Pages: 473
Release: 2015-05-01
Genre: Technology & Engineering
ISBN: 1608078078

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This new resource explains the principles and applications of today’s digital optical measurement techniques. From start to finish, each chapter provides a concise introduction to the concepts and principles of digital optical metrology, followed by a detailed presentation of their applications. The development of all these topics, including their numerous methods, principles, and applications, has been illustrated using a large number of easy-to-understand figures. This book aims to not only help the reader identify the appropriate techniques in function of the measurement requirements, but also assess modern digital measurement systems.

Single and Multicomponent Digital Optical Signal Analysis

Single and Multicomponent Digital Optical Signal Analysis
Author: Rishikesh Kulkarni
Publisher: IOP Publishing Limited
Total Pages: 0
Release: 2017
Genre: Science
ISBN: 9780750314671

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Optical techniques such as electronic speckle pattern interferometry, holographic interferometry, and fringe projection have emerged as the prominent tools for non-contact measurements, with applications ranging from biology to materials science. In these processes, information about the measured physical quantity is stored in the phase or associated derivatives of an interference fringe pattern. Consequently, a reliable estimation of phase and its derivatives, commonly referred to as fringe analysis becomes a primary requirement for the application and interpretation of these optical techniques. Here, leading researchers in fringe analysis methods present a review of the tools and methods of multicomponent fringe analysis and interferometric data, and outline a wide range of digital signal-processing-based interferometric data-processing techniques.