A theoretical analysis of laser Doppler flowmeters
TL;DR: In this paper, a theoretical analysis of single and dual beam scattering flowmeters is given, taking their Gaussian characteristics into account, and the average power spectrum of the detector signal is derived as a function of the particle concentration.
Abstract: A theoretical analysis is given of single and dual beam scattering flowmeters. All propagating beams are treated rigorously, taking their Gaussian characteristics into account. An exact derivation of the Doppler frequency shows how it depends on the position of the scattering particle within the scattering volume. The spatial and spectral resolutions of both Doppler systems are given. It is shown in what way these depend on the geometry of the optical arrangement. The average power spectrum of the detector signal is derived as a function of the particle concentration. The signal-to-noise ratios of both systems are calculated and compared. Some inherent differences between the two systems will be pointed out.
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TL;DR: This review article presents the theory and practice of these techniques using a tutorial approach and compares the relative merits of the scanning and full-field approaches to velocity map imaging and concludes with a review of reported applications ofThese techniques to blood perfusion mapping and imaging.
Abstract: Laser Doppler velocimetry uses the frequency shift produced by the Doppler effect to measure velocity. It can be used to monitor blood flow or other tissue movement in the body. Laser speckle is a random interference effect that gives a grainy appearance to objects illuminated by laser light. If the object consists of individual moving scatterers (such as blood cells), the speckle pattern fluctuates. These fluctuations provide information about the velocity distribution of the scatterers. It can be shown that the speckle and Doppler approaches are different ways of looking at the same phenomenon. Both these techniques measure at a single point. If a map of the velocity distribution is required, some form of scanning must be introduced. This has been done for both time-varying speckle and laser Doppler. However, with the speckle technique it is also possible to devise a full-field technique that gives an instantaneous map of velocities in real time. This review article presents the theory and practice of these techniques using a tutorial approach and compares the relative merits of the scanning and full-field approaches to velocity map imaging. The article concludes with a review of reported applications of these techniques to blood perfusion mapping and imaging.
706 citations
Cites background from "A theoretical analysis of laser Dop..."
...Eliasson and Dändliker (1974), for example, have given a thorough, but very theoretical, analysis....
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...Eliasson and Dändliker (1974), for example, have given a thorough, but very theoretical, analysis. She and Wall (1975) have compared different experimental techniques applied to the measurement of flow and turbulence....
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...Eliasson and Dändliker (1974), for example, have given a thorough, but very theoretical, analysis....
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TL;DR: In this article, the authors review the status of elastic light scattering, focusing on recent developments, rather than being over-repetitive of earlier reviews, but considerable background is included with the aim of making the paper self-contained.
216 citations
TL;DR: A computer program is available using the Lentz algorithm allowing more extensive calculations, namely, studying of bigger diameters and more important absorption coefficients and emphasis on particle sizing is considered.
Abstract: New progress in Mie theory calculations is reported. A computer program is available using the Lentz algorithm allowing more extensive calculations, namely, studying of bigger diameters and more important absorption coefficients. Emphasis on particle sizing is considered.
86 citations
TL;DR: In this paper, in-plane and out-of-plane displacements and vibrations of objects with diffusely scattering surfaces are measured in real time at a spatial resolution of 35 μm.
Abstract: In-plane as well as out-of-plane displacements and vibrations of objects with diffusely scattering surfaces are measured in real time. Microvibrations with amplitudes down to 1 nm and frequencies up to 5 MHz were analyzed at a spatial resolution of 35 μm.
53 citations
TL;DR: An analysis of Gaussian beam effects in LDA systems in order to quantify their influence on the Doppler signal shows that both axial and lateral frequency gradients can exist in the probe volume of improperly aligned L DA systems.
Abstract: The unique properties of Gaussian beams must be considered when designing and using laser Doppler anemometer systems. This paper presents an analysis of Gaussian beam effects in LDA systems in order to quantify their influence on the Doppler signal. The analytical results, which are verified by experiment, show that both axial and lateral frequency gradients can exist in the probe volume of improperly aligned LDA systems. The effects of lens aberrations and of optical path changes due to the insertion of planar optical elements in the beam are also considered.
45 citations
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46,339 citations
Book•
01 Jan 1943TL;DR: Combinations involving trigonometric and hyperbolic functions and power 5 Indefinite Integrals of Special Functions 6 Definite Integral Integral Functions 7.Associated Legendre Functions 8 Special Functions 9 Hypergeometric Functions 10 Vector Field Theory 11 Algebraic Inequalities 12 Integral Inequality 13 Matrices and related results 14 Determinants 15 Norms 16 Ordinary differential equations 17 Fourier, Laplace, and Mellin Transforms 18 The z-transform
Abstract: 0 Introduction 1 Elementary Functions 2 Indefinite Integrals of Elementary Functions 3 Definite Integrals of Elementary Functions 4.Combinations involving trigonometric and hyperbolic functions and power 5 Indefinite Integrals of Special Functions 6 Definite Integrals of Special Functions 7.Associated Legendre Functions 8 Special Functions 9 Hypergeometric Functions 10 Vector Field Theory 11 Algebraic Inequalities 12 Integral Inequalities 13 Matrices and related results 14 Determinants 15 Norms 16 Ordinary differential equations 17 Fourier, Laplace, and Mellin Transforms 18 The z-transform
27,354 citations
TL;DR: The second edition of this respected text considerably expands the original and reflects the tremendous advances made in the discipline since 1968 as discussed by the authors, with a special emphasis on applications to diffraction, imaging, optical data processing, and holography.
Abstract: The second edition of this respected text considerably expands the original and reflects the tremendous advances made in the discipline since 1968. All material has been thoroughly updated and several new sections explore recent progress in important areas, such as wavelength modulation, analog information processing, and holography. Fourier analysis is a ubiquitous tool with applications in diverse areas of physics and engineering. This book explores these applications in the field of optics with a special emphasis on applications to diffraction, imaging, optical data processing, and holography. This book can be used as a textbook to satisfy the needs of several different types of courses, and it is directed toward both engineers ad physicists. By varying the emphasis on different topics and specific applications, the book can be used successfully in a wide range of basic Fourier Optics or Optical Signal Processing courses.
12,159 citations
Book•
01 Jan 1968
TL;DR: The second edition of this respected text considerably expands the original and reflects the tremendous advances made in the discipline since 1968 as discussed by the authors, with a special emphasis on applications to diffraction, imaging, optical data processing, and holography.
Abstract: The second edition of this respected text considerably expands the original and reflects the tremendous advances made in the discipline since 1968. All material has been thoroughly updated and several new sections explore recent progress in important areas, such as wavelength modulation, analog information processing, and holography. Fourier analysis is a ubiquitous tool with applications in diverse areas of physics and engineering. This book explores these applications in the field of optics with a special emphasis on applications to diffraction, imaging, optical data processing, and holography. This book can be used as a textbook to satisfy the needs of several different types of courses, and it is directed toward both engineers ad physicists. By varying the emphasis on different topics and specific applications, the book can be used successfully in a wide range of basic Fourier Optics or Optical Signal Processing courses.
9,800 citations