Journal ArticleDOI
Some fundamental properties of speckle
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In this paper, the distribution of scale sizes in a speckle pattern (i.e., the Wiener spectrum) is investigated from a physical point of view, and it is shown that adding M uncorrelated speckles on an intensity basis can reduce the contrast by 1/√M.Abstract:
A speckle pattern formed in polarized monochromatic light may be regarded as resulting from a classical random walk in the complex plane. The resulting irradiance fluctuations obey negative exponential statistics, with ratio of standard deviation to mean (i.e., contrast) of unity. Reduction of this contrast, or smoothing of the speckle, requires diversity in polarization, space, frequency, or time. Addition of M uncorrelated speckle patterns on an intensity basis can reduce the contrast by 1/√M. However, addition of speckle patterns on a complex amplitude basis provides no reduction of contrast. The distribution of scale sizes in a speckle pattern (i.e., the Wiener spectrum) is investigated from a physical point of view.read more
Citations
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A motion artefact in real-time ultrasound scanners.
TL;DR: The physical origin of this anomaly is described and the speckle pattern in images of soft tissue is an artefact and it may move in a way which bears no simple relationship to the motion of the tissues.
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Local activity indicators for hard-switching adaptive filtering of images with mixed noise
TL;DR: It is illustrated that the considered local activity indicators can be applied as adaptation parameters to locally adaptive hard-switching processing (filtering) of images by presenting a quantitative analysis of several local activity indicator properties and providing comparisons between them.
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Adjustment of geodetic measurements with mixed multiplicative and additive random errors
TL;DR: In this paper, the bias-corrected weighted least squares (LS) method was extended to the case of mixed multiplicative and additive random errors, and the first order approximation of accuracy for all three methods was derived.
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Multiple mode x-ray ptychography using a lens and a fixed diffuser optic
TL;DR: In this paper, a combination of a Fresnel lens and a diffuser for x-ray ptychography is employed, which uses increased flux by enlarging the width of the coherence-defining slits upstream of the experimental station.
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A Fast High-Order Total Variation Minimization Method for Multiplicative Noise Removal
TL;DR: In this paper, the authors proposed a high-order total variation minimization method to restore multiplicative noisy images, which is able to preserve edges and at the same time avoid the staircase effect in the smooth regions.
References
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ReportDOI
Statistical properties of laser sparkle patterns
TL;DR: In this article, the first order statistics of the observed electric-field strength, the observed light intensity, and observed light phase are examined, and the autocorrelation functions of the complex field and intensity processes are investigated, and that of the electric field is found to be proportional to the Fourier transform of the light intensity distribution incident on the scattering surface.
Book ChapterDOI
Statistical Properties of Laser Speckle Patterns
TL;DR: In this article, the first-order statistics of the complex amplitude, intensity and phase of speckle are derived for a free-space propagation geometry and for an imaging geometry.
Journal ArticleDOI
Some Aspects of Diffraction Theory and their Application to the Ionosphere
TL;DR: In this paper, the Fourier approach is extended to deal with problems of ''random'' diffraction, for which purpose the use of auto-correlation functions is introduced and explained in physical terms.
Investigation of molecular motions in supercooled liquids by Mossbauer scattering D C Champeney and F W D Woodhams Some Aspects of Diffraction Theory and their Application to the Ionosphere
J A Ratcliffe,D C Champeney +1 more
TL;DR: In this article, the Fourier approach is extended to deal with problems of ''random'' diffraction, for which purpose the use of auto-correlation functions is introduced and explained in physical terms.
Journal ArticleDOI
XII. On the resultant of a large number of vibrations of the same pitch and of arbitrary phase
TL;DR: In this article, the resultant of a large number of vibrations of the same pitch and of arbitrary phase is discussed. But the authors focus on the effect of the phase of the vibrations.