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Related papers: Assessing cloudiness in nonwovens

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Cloudiness or formation is a concept routinely used in industry to address deviations from homogeneity in nonwovens and papers. Measuring a cloudiness index based on image data is a common task in industrial quality assurance. The two most…

Computer Vision and Pattern Recognition · Computer Science 2022-04-12 Michael Godehardt , Ali Moghiseh , Christine Oetjen , Joachim Ohser , Katja Schladitz

We show how to estimate the covariance of the power spectrum of a statistically homogeneous and isotropic density field from a single periodic simulation, by applying a set of weightings to the density field, and by measuring the scatter in…

Astrophysics · Physics 2009-11-11 A. J. S. Hamilton , C. D. Rimes , R. Scoccimarro

Wave propagation in architectured materials, or materials with microstructure, is known to be dependent on the ratio between the wavelength and a characteristic size of the microstructure. Indeed, when this ratio decreases (i.e. when the…

Classical Physics · Physics 2017-07-24 Rosi Giuseppe , Placidi Luca , Auffray Nicolas

Power system coherency refers to the phenomenon that machines in a power network exhibit similar frequency responses after disturbances, and is foundational for model reduction and control design. Despite abundant empirical observations,…

Systems and Control · Electrical Eng. & Systems 2025-11-11 Yixuan Liu , Yingzhu Liu , Pengcheng You

The power density spectrum of a light curve is often calculated as the average of a number of spectra derived on individual time intervals the light curve is divided into. This procedure implicitly assumes that each time interval is a…

Instrumentation and Methods for Astrophysics · Physics 2011-08-25 Cristiano Guidorzi

This paper proposes a novel feature called spectrum congruency for describing edges in images. The spectrum congruency is a generalization of the phase congruency, which depicts how much each Fourier components of the image are congruent in…

Image and Video Processing · Electrical Eng. & Systems 2021-03-11 Fang Yang , Xin Su , Li Chai

We measure the covariance of the non-linear matter power spectrum from N-body simulations using two methods. In the first case, the covariance of power is estimated from the scatter over many random realizations of the density field. In the…

Astrophysics · Physics 2009-11-11 C. D. Rimes , A. J. S. Hamilton

Natural images are characterized by the multiscaling properties of their contrast gradient, in addition to their power spectrum. In this work we show that those properties uniquely define an {\em intrinsic wavelet} and present a suitable…

Statistical Mechanics · Physics 2009-11-07 A. Turiel , N. Parga

Hyperspectral imaging is a powerful technology that is plagued by large dimensionality. Herein, we explore a way to combat that hindrance via non-contiguous and contiguous (simpler to realize sensor) band grouping for dimensionality…

Image and Video Processing · Electrical Eng. & Systems 2019-05-31 Muhammad Aminul Islam , Derek T. Anderson , John E. Ball , Nicolas H. Younan

A theory is presented for the frequency dependence of the power spectrum of photon current fluctuations originating from a disordered medium. Both the cases of an absorbing medium (``grey body'') and of an amplifying medium (``random…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 E. G. Mishchenko , M. Patra , C. W. J. Beenakker

Singular spectrum analysis is developed as a nonparametric spectral decomposition of a time series. It can be easily extended to the decomposition of multidimensional lattice-like data through the filtering interpretation. In this…

Computer Vision and Pattern Recognition · Computer Science 2015-05-08 Kenji Kume , Naoko Nose-Togawa

Probabilistic amplitude shaping (PAS) is a practical means to achieve a shaping gain in optical fiber communication. However, PAS and shaping in general also affect the signal-dependent generation of nonlinear interference. This provides an…

Information Theory · Computer Science 2023-04-18 Mohammad Taha Askari , Lutz Lampe , Jeebak Mitra

A crucial issue in cosmology is the determination of the fluctuation power spectrum.The standard picture of the matter clustering, the Cold Dark Matter model (and its variant), assumes that,on scales smaller than a certain ``flattening…

Astrophysics · Physics 2009-10-28 Francesco Sylos Labini , Luca Amendola

Herschel observations of interstellar clouds support a paradigm for star formation in which filaments play a central role. One of the foundations of this paradigm is the finding, based on studies of the radial column density profiles, that…

We consider the waveguiding by thin patterned slabs embedded in a homogeneous medium. In the longwave limit, the wave spectra of slabs are found to be well described by a single frequency-independent parameter, which we call the "guiding…

Optics · Physics 2007-09-28 Serge Luryi , Arsen V. Subashiev

While robust divergence such as density power divergence and $\gamma$-divergence is helpful for robust statistical inference in the presence of outliers, the tuning parameter that controls the degree of robustness is chosen in a…

Methodology · Statistics 2021-09-15 Shonosuke Sugasawa , Shouto Yonekura

A weakly nonlinear spectrum and a strongly nonlinear spectrum coexist in a statistically steady state of elastic wave turbulence. The analytical representation of the nonlinear frequency is obtained by evaluating the extended self-nonlinear…

Chaotic Dynamics · Physics 2014-01-15 Naoto Yokoyama , Masanori Takaoka

A method for constructing non-uniform filter banks is presented. Starting from a uniform system of translates, generated by a prototype filter, a non-uniform covering of the frequency axis is obtained by composition with a warping function.…

Functional Analysis · Mathematics 2019-12-23 Nicki Holighaus , Christoph Wiesmeyr , Zdeněk Průša

We demonstrate that for gapped bilayer graphene, the nonlinear nature of the screening of an external disorder potential and the resulting inhomogeneity of the electron liquid are crucial for describing the electronic compressibility. In…

Mesoscale and Nanoscale Physics · Physics 2012-11-06 D. S. L. Abergel , E. Rossi , S. Das Sarma

Turbulence is a dominant feature operating in gaseous flows across nearly all scales in astrophysical environments. Accordingly, accurately estimating the statistical properties of such flows is necessary for developing a comprehensive…

Solar and Stellar Astrophysics · Physics 2014-11-27 Lukas Konstandin , Rahul Shetty , Philipp Girichidis , Ralf S. Klessen
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