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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26 citations
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TL;DR: In this paper, a stable and compact speckle interferometer for doing out-of-plane displacement measurements on reflective as well as diffusely scattering object surfaces is demonstrated, which is based on a nearly path length compensated interferometers of the Fizeau type and uses diffuse illumination of the object combined with a speckled reference wave.
26 citations
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TL;DR: A two-dimensional synthetic-aperture-radar phase-correction algorithm is described as a natural extension of a one-dimensional technique developed previously that embodies some similarities of phase-gradient speckle imaging and incorporates improvements in phase estimation.
Abstract: A two-dimensional synthetic-aperture-radar (SAR) phase-correction algorithm is described as a natural extension of a one-dimensional technique developed previously. It embodies some similarities of phase-gradient speckle imaging and incorporates improvements in phase estimation. Diffraction-limited performance has been obtained on actual SAR imagery regardless of scene content or phase-error structure. The algorithm is computationally efficient, robust, and easily implemented on a general-purpose computer or special-purpose hardware.
26 citations
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TL;DR: An iteration algorithm for the analysis of speckle interference patterns is presented and theoretical study shows that the iterated phase converges to a perfect result under ideal conditions.
Abstract: An iteration algorithm for the analysis of speckle interference patterns is presented. First, four digitized phase-shifted patterns are locally averaged. The phase information is then extracted by the usual phase shift algorithm. The wrapped phase is in turn used to reconstruct four new phase-shifted patterns. These three steps form a cycle. Repetition of the three steps has a great effect on suppressing speckle noise. Theoretical study shows that the iterated phase converges to a perfect result under ideal conditions. In general, the iteration causes little error but improves the phase information a great deal. The signal-to-noise ratio rises when additional iterations are performed.
26 citations
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TL;DR: An extended theory for speckle fringe formation on curved surfaces is proposed, which can be applied to the study of curved engineering and technical specimens under various loading conditions such as in-plane, out-of- plane, and out- of-plane shear configurations.
Abstract: Deformation study of curved engineering and technical surfaces, such as pipes and pressure vessels, has gained much importance in the recent past. Speckle interferometric techniques and their electronic and digital analogs, which are whole field techniques, have been effectively applied for practical nondestructive testing applications over the years. However, little work has been done that discusses the speckle fringe formation with a fruitful theoretical formulation to study deformation analysis of curved surfaces. We propose an extended theory for speckle fringe formation on curved surfaces, which can be applied to the study of curved engineering and technical specimens under various loading conditions such as in-plane, out-of-plane, and out-of-plane shear configurations. Simulated contours are generated by use of finite element models with similar loading conditions, and the data are analyzed and compared with the obtained experimental results.
26 citations