Journal ArticleDOI
Some fundamental properties of speckle
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TLDR
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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Nonlocal Filtering Applied to 3-D Reconstruction of Tomographic SAR Data
TL;DR: Two spatially adaptive filtering methods to improve the estimation of the covariance matrix (CM), which is required for the processing of tomographic SAR data, are introduced and their effect on scatterer separation and height estimation is evaluated.
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Speckle reduction by adaptive window anisotropic diffusion
TL;DR: To smooth out speckle noise and preserve edge information in noisy images, a novel algorithm called Speckle reduction by adaptive window anisotropic diffusion is proposed, which can adaptively modulate its window size and orientation.
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A hybrid algorithm for speckle noise reduction of ultrasound images
TL;DR: The results of various quantitative, qualitative measures and by visual inspection of denoise synthetic and real ultrasound images demonstrate that the proposed hybrid algorithm have strong denoising capability and able to preserve the fine image details such as edge of a lesion better than previously developed methods for speckle noise reduction.
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Anisotropic shear behavior of rock joint replicas
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TL;DR: In this article, an anisotropic peak shear strength model is proposed incorporating actual peak dilation angle and shear component of asperities, which is modified with mean plane to find out actual dilation angles and back calculated from experimental results.
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Unsupervised segmentation using a self-organizing map and a noise model estimation in sonar imagery
TL;DR: A new estimation and segmentation procedure on images provided by a high-resolution sonar, which has been successfully applied to real sonar images, and is compatible with an automatic processing of massive amounts of data.
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.