Speckle imaging

About: Speckle imaging is a research topic. Over the lifetime, 3730 publications have been published within this topic receiving 62354 citations.

Coherence-Domain Methods in Tissue and Cell Optics

Abstract: Effects that accompany the propagation of laser radiation in tissues and interaction of laser radiation with cell flows are considered. These effects include diffraction, formation of speckle structures, interference of speckle fields, scattering from moving particles, etc. We discuss coherent optical methods that hold much promise for applications in biomedicine, such as photon-correlation spectroscopy; speckle interferometry; coherent topography and tomography; diffusion wave spectroscopy; phase, confocal, and Doppler microscopy; and low-coherence interferometry and tomography.

In situ and real-time tensile testing of thin films using double-field-of-view electronic speckle pattern interferometry

Abstract: It is very difficult to accurately measure the mechanical properties of low-dimensional film whose thickness is at the level of a micrometre or below. In this paper, we present an experimental method to measure the mechanical properties of thin films. An integrated deformation and load measurement system is also developed, which consists of an electronic speckle interferometry unit, a uniaxial tensile unit and a spring beam deflection unit. The electronic speckle interferometry unit is a double-field-of-view electronic speckle pattern interferometry system, one sensitive to the in-plane displacement to measure the film deformations and the other to the out-of-plane displacement and to measure the spring beam deflections (converted to microloads). The new system allows in situ and real-time measurements of the deformations of the thin films and microforces under uniaxial tensile testing. The tested thin films can be metals, oxide ceramics, and multi-layer composites of thickness from several tens of micrometres to less than a micrometre, and the tensile load from 88 µN to 15 N. We present the underlying principle of the method and the experimental set-up. Experiments were carried out by testing the deformations of pure Ni, Au, and Au/Cr multi-layer films. The measured performance of the method and testing system is also discussed.

Digital speckle-pattern interferometry as a full-field fluid-velocimetry technique.

Abstract: We present a novel fluid-velocimetry technique based on speckle interferometry. The light scattered from an illuminated plane is recorded with a CCD camera at the same time as a speckled reference beam. Substraction of two nonsimultaneous frames provides information about the velocity field for an out-of-plane component. An application to a Rayleigh-Benard convective flow is given.

A simplified system for digital speckle interferometry

Abstract: A video speckle interferometer has been demonstrated which uses a spherical surface of small radius at the centre of the camera aperture to simplify the alignment of the reference beam. In combination with a fast microcomputer, this gives a compact and relatively inexpensive system which is able to display phase-stepped interferograms of good quality with a repetition rate approaching one second. The software for phase stepping and unwrapping has novel features and can be applied to other types of interferometer.

Speckle Interferometry at the US Naval Observatory. IV.

Abstract: The results of 1314 speckle interferometric observations of 625 binary stars, ranging in separation from 02 to 52 with a limiting secondary magnitude of V = 11, are tabulated. These observations were obtained using the 66 cm refractor at the US Naval Observatory in Washington, DC, with an intensified CCD detector. This is the fourth in a series of papers presenting measures obtained with this equipment and covers the period 1997 January 1 through December 31. Random errors for all measures are estimated to be 18 mas in separation and 057/ρ in position angle, where ρ is the separation in arcseconds.