Topic
Speckle imaging
About: Speckle imaging is a research topic. Over the lifetime, 3730 publications have been published within this topic receiving 62354 citations.
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01 Apr 2015
TL;DR: In this paper, a single-slit spatial carrier shearing speckle interferometry measuring system and a measuring method are described, in which a laser shot by a laser device passes through a beam expander and then irradiates a measured object in the form of diffusion light, diffuse reflection light on the surface of the measured object sequentially passes through an imaging lens, a slit diaphragm, a 4f system, and a Michelson type device to be projected onto a target surface of an CCD camera.
Abstract: The invention discloses a single-slit spatial carrier shearing speckle interferometry measuring system and a measuring method. The measuring system and the measuring method are characterized in that laser shot by a laser device passes through a beam expander and then irradiate a measured object in the form of diffusion light, diffuse reflection light on the surface of the measured object sequentially passes through an imaging lens, a slit diaphragm, a 4f system and a Michelson type device to be projected onto a target surface of an CCD camera. The measuring system and the measuring method can carry out nondestructive, full-field, rapid and dynamic measurement for the defects and stress deformation of the surface of the measured object and is convenient for field measurement.
19 citations
TL;DR: Wang et al. as discussed by the authors proposed a color imaging method through scattering media based on phase retrieval with triple correlation, which theoretically proved that the spatial averaging of the triple correlation technique can be used to retrieve the Fourier phase of object and experimentally demonstrate that it can be applied in color imaging through scattering medium.
19 citations
25 Nov 1985
TL;DR: In this article, the phase of the difference between two correlated speckle patterns can be determined by applying phase-shifting techniques to the interferometry, which will quantitatively determine the phase.
Abstract: Speckle patterns have high-frequency phase data, which make finding the absolute phase of a single speckle pattern difficult. However, the phase of the difference between two correlated speckle patterns can be determined 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. The randomness of the speckle causes noisy data points that are removed by data processing routines. A study of the phase errors attributable to decorrelation of the speckle patterns shows a 33° rms error for 10 waves of tilt. One application of this technique is finding the phase of deformations, where up to 10 waves of wavefront deformation can easily be measured. Results of deformations caused by tilt of a metal plate and a disbond in a honeycomb structure brazed to an aluminum plate are shown.
19 citations
TL;DR: The MicroStar as discussed by the authors is a laser-optical measuring device that can be used for quantitative strain-stress measurement on nearly any industrial component, including car bodies, gear boxes, engines, and suspensions.
Abstract: Laser speckle interferometry as a full-field noncontact measuring technique offers interesting opportunities for strain-stress analysis on components. While its application in material testing and material research has already achieved some acceptance in research and industry, its application to complex industrial components like car bodies, gear boxes, engines, and suspensions has been limited. Basic difficulties have arisen from the relatively large rigid-body movements of components under test, harsh environmental conditions in the real test world, and the often complex shape of the analyzed component, especially in the most interesting areas. The commercial availability of a radically miniaturized 3-D speckle interferometer has led to the new laser-optical measuring device, the MicroStarâ„¢, which can be used for quantitative strain-stress measurement on nearly any industrial component. The device uses 3-D speckle interferometry to measure the shape and the 3-D deformation in the area of interest. The combination of shape and deformation provides all necessary data for quantitative 3-D strain analysis. The principal stresses as well as the bending and tensile components of the strains can be easily determined. In this paper, the principle and applications of this new system are presented.
19 citations
TL;DR: Experimental results are presented that demonstrate the validity and the advantage of the proposed signal-domain phase-only correlation technique over both the conventional intensity correlation technique and the spatial-frequency- domain phase- only correlation technique.
Abstract: As an alternative to the intensity correlation used in conventional speckle metrology, we propose a new technique for displacement observation that is based on spatial-signal-domain phase-only correlation and that makes use of the pseudophase of the complex analytic signal generated from a Hilbert-filtered speckle pattern. Experimental results are presented that demonstrate the validity and the advantage of the proposed signal-domain phase-only correlation technique over both the conventional intensity correlation technique and the spatial-frequency-domain phase-only correlation technique.
19 citations