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Related papers: Multiscale Optimal Filtering on the Sphere

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In this paper, we present an optimal filter for the enhancement or estimation of signals on the 2-sphere corrupted by noise, when both the signal and noise are realizations of anisotropic processes on the 2-sphere. The estimation of such a…

Instrumentation and Methods for Astrophysics · Physics 2015-06-17 Zubair Khalid , Rodney A. Kennedy , Parastoo Sadeghi , Salman Durrani

We present a joint SO(3)-spectral domain filtering framework using directional spatially localized spherical harmonic transform (DSLSHT), for the estimation and enhancement of random anisotropic signals on the sphere contaminated by random…

Signal Processing · Electrical Eng. & Systems 2021-02-03 Adeem Aslam , Zubair Khalid

We derive optimal filters on the sphere in the context of detecting compact objects embedded in a stochastic background process. The matched filter and the scale adaptive filter are derived on the sphere in the most general setting,…

Astrophysics · Physics 2011-10-28 J. D. McEwen , M. P. Hobson , A. N. Lasenby

The bilateral filter is a useful nonlinear filter which without smoothing edges, it does spatial averaging. In the literature, the effectiveness of this method for image denoising is shown. In this paper, an extension of this method is…

Computer Vision and Pattern Recognition · Computer Science 2017-02-07 Seyede Mahya Hazavei , Hamid Reza Shahdoosti

A new image denoising algorithm to deal with the additive Gaussian white noise model is given. Like the non-local means method, the filter is based on the weighted average of the observations in a neighborhood, with weights depending on the…

Other Statistics · Statistics 2011-11-04 Qiyu Jin , Ion Grama , Quansheng Liu

We construct a directional spin wavelet framework on the sphere by generalising the scalar scale-discretised wavelet transform to signals of arbitrary spin. The resulting framework is the only wavelet framework defined natively on the…

Information Theory · Computer Science 2017-06-06 Jason D. McEwen , Boris Leistedt , Martin Büttner , Hiranya V. Peiris , Yves Wiaux

A new technique for reliably identifying point sources in millimeter/sub-millimeter wavelength maps is presented. This method accounts for the frequency dependence of noise in the Fourier domain as well as non-uniformities in the coverage…

Instrumentation and Methods for Astrophysics · Physics 2015-06-15 T. A. Perera , G. W. Wilson , K. S. Scott , J. E. Austermann , J. R. Schaar , A. Mancera

The details of an image with noise may be restored by removing noise through a suitable image de-noising method. In this research, a new method of image de-noising based on using median filter (MF) in the wavelet domain is proposed and…

Multimedia · Computer Science 2017-03-21 Afrah Ramadhan , Firas Mahmood , Atilla Elci

Spherical radial-basis-based kernel interpolation abounds in image sciences including geophysical image reconstruction, climate trends description and image rendering due to its excellent spatial localization property and perfect…

Machine Learning · Computer Science 2024-01-17 Xiaotong Liu , Jinxin Wang , Di Wang , Shao-Bo Lin

I discuss approaches to optimally remove noise from images. A generalization of Wiener filtering to Non-Gaussian distributions and wavelets is described, as well as an approach to measure the errors in the reconstructed images. We argue…

Astrophysics · Physics 2009-10-31 Ue-Li Pen

We propose a new image denoising algorithm when the data is contaminated by a Poisson noise. As in the Non-Local Means filter, the proposed algorithm is based on a weighted linear combination of the bserved image. But in contract to the…

Applications · Statistics 2012-01-31 Qiyu Jin , Ion Grama , Quansheng Liu

We propose a sampling scheme that can perfectly reconstruct a collection of spikes on the sphere from samples of their lowpass-filtered observations. Central to our algorithm is a generalization of the annihilating filter method, a tool…

Information Theory · Computer Science 2016-01-20 Ivan Dokmanic , Yue M. Lu

This paper presents a novel Bayesian strategy for the estimation of smooth signals corrupted by Gaussian noise. The method assumes a smooth evolution of a succession of continuous signals that can have a numerical or an analytical…

Applications · Statistics 2016-02-12 Abderrahim Halimi , Gerald S. Buller , Steve McLaughlin , Paul Honeine

Satellites mapping the spatial variations of the gravitational or magnetic fields of the Earth or other planets ideally fly on polar orbits, uniformly covering the entire globe. Thus, potential fields on the sphere are usually expressed in…

Data Analysis, Statistics and Probability · Physics 2013-06-17 Frederik J. Simons , F. A. Dahlen

During the acquisition of an image from its source, noise always becomes an integral part of it. Various algorithms have been used in past to denoise the images. Image denoising still has scope for improvement. Visual information…

Image and Video Processing · Electrical Eng. & Systems 2019-09-17 Santosh Paudel , Ajay Kumar Shrestha , Pradip Singh Maharjan , Rameshwar Rijal

We develop a sampling scheme on the sphere that permits accurate computation of the spherical harmonic transform and its inverse for signals band-limited at $L$ using only $L^2$ samples. We obtain the optimal number of samples given by the…

Information Theory · Computer Science 2014-07-25 Zubair Khalid , Rodney A. Kennedy , Jason D. McEwen

The localized nature of curvelet functions, together with their frequency and dip characteristics, makes the curvelet transform an excellent choice for processing seismic data. In this work, a denoising method is proposed based on a…

Geophysics · Physics 2023-04-14 Naveed Iqbal , Mohamed Deriche , Ghassan AlRegib , Sikandar Khan

The problem of known signal detection in Additive White Gaussian Noise is considered. In this paper a new detection algorithm based on Discrete Wavelet Transform pre-processing and threshold comparison is introduced. Current approaches…

Information Theory · Computer Science 2007-07-16 Ignacio Melgar , Jaime Gomez , Juan Seijas

We introduce WaveSim, a multi-scale similarity metric for the evaluation of spatial fields in weather and climate applications. WaveSim exploits wavelet transforms to decompose input fields into scale-specific wavelet coefficients. The…

Atmospheric and Oceanic Physics · Physics 2025-12-17 Gabriele Accarino , Viviana Acquaviva , Sara Shamekh , Duncan Watson-Parris , David Lawrence

This paper introduces the use of pseudo-filters that optimize the detection/extraction of sources on a background. We assume as a first approach that such sources are described by a spherical (central) profile and that the background is…

Astrophysics · Physics 2009-11-06 J. L. Sanz , D. Herranz , E. Martinez-Gonzalez
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