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This paper introduces an expectation-maximization (EM) algorithm within a wavelet domain Bayesian framework for semi-blind channel estimation of multiband OFDM based UWB communications. A prior distribution is chosen for the wavelet…

Networking and Internet Architecture · Computer Science 2007-08-13 Sajad Sadough , Mahieddine Ichir , Emmanuel Jaffrot , Pierre Duhamel

Tomographic reconstruction is an ill-posed inverse problem that calls for regularization. One possibility is to require sparsity of the unknown in an orthonormal wavelet basis. This in turn can be achieved by variational regularization…

Numerical Analysis · Mathematics 2018-01-17 Zenith Purisha , Juho Rimpeläinen , Tatiana Bubba , Samuli Siltanen

In this paper, we study a newly developed shearlet system on bounded domains which yields frames for $H^s(\Omega)$ for some $s\in \mathbb{N}$, $\Omega \subset \mathbb{R}^2$. We will derive approximation rates with respect to $H^s(\Omega)$…

Functional Analysis · Mathematics 2019-03-04 Philipp Petersen , Mones Raslan

In this paper, a new probability density function (pdf) is proposed to model the statistics of wavelet coefficients, and a simple Kalman's filter is derived from the new pdf using Bayesian estimation theory. Specifically, we decompose the…

Computer Vision and Pattern Recognition · Computer Science 2016-08-03 Mario Mastriani , Alberto E. Giraldez

Accurate reconstruction of arbitrary-shaped long slender continuum bodies, such as guidewires, catheters and other soft continuum manipulators, is essential for accurate mechanical simulation. However, existing image-based reconstruction…

Robotics · Computer Science 2026-03-25 Yaozhi Zhang , Shun Yu , Yugang Zhang , Yang Liu

Depth estimation is an essential component in understanding the 3D geometry of a scene, with numerous applications in urban and indoor settings. These scenes are characterized by a prevalence of human made structures, which in most of the…

Computer Vision and Pattern Recognition · Computer Science 2020-09-03 Mattia Rossi , Mireille El Gheche , Andreas Kuhn , Pascal Frossard

We address the problem of image reconstruction from incomplete measurements, encompassing both upsampling and inpainting, within a learning-based framework. Conventional supervised approaches require fully sampled ground truth data, while…

Computer Vision and Pattern Recognition · Computer Science 2026-03-23 Benjamin Walder , Daniel Toader , Robert Nuster , Günther Paltauf , Peter Burgholzer , Gregor Langer , Lukas Krainer , Markus Haltmeier

Inverse problems are fundamental in fields like medical imaging, geophysics, and computerized tomography, aiming to recover unknown quantities from observed data. However, these problems often lack stability due to noise and…

Numerical Analysis · Mathematics 2024-06-26 Andrea Ebner , Matthias Schwab , Markus Haltmeier

The reconstruction of images from measured data is an increasing field of research. For highly under-determined problems, template-based image reconstruction provides a way of compensating for the lack of sufficient data. A caveat of this…

Optimization and Control · Mathematics 2023-05-29 Sebastian Neumayer , Antonia Topalovic

Background: Underwater images, in general, suffer from low contrast and high color distortions due to the non-uniform attenuation of the light as it propagates through the water. In addition, the degree of attenuation varies with the…

Image and Video Processing · Electrical Eng. & Systems 2022-01-20 Prasen Kumar Sharma , Ira Bisht , Arijit Sur

Super-resolution is generally referred to as the task of recovering fine details from coarse information. Motivated by applications such as single-molecule imaging, radar imaging, etc., we consider parameter estimation of complex…

Information Theory · Computer Science 2016-08-10 Dehui Yang , Gongguo Tang , Michael B. Wakin

One of the challenges in phase measuring deflectometry is to retrieve the wavefront from objects that present discontinuities or non-differentiable gradient fields. Here, we propose the integration of such gradients fields based on an…

Numerical Analysis · Mathematics 2023-06-02 Ricardo Legarda-Saenz , Jorge L. Flores , Manuel Servin , Anabel Martin-Gonzalez

This paper presents a new method for the reconstruction of weak lensing mass maps. It uses the multiscale entropy concept, which is based on wavelets, and the False Discovery Rate which allows us to derive robust detection levels in wavelet…

Astrophysics · Physics 2009-11-10 Jean-Luc Starck , Sandrine Pires , Alexandre Refregier

We consider the recovery of a continuous domain piecewise constant image from its non-uniform Fourier samples using a convex matrix completion algorithm. We assume the discontinuities/edges of the image are localized to the zero levelset of…

Information Theory · Computer Science 2018-02-14 Greg Ongie , Sampurna Biswas , Mathews Jacob

Sampling-based alpha matting methods have traditionally followed the compositing equation to estimate the alpha value at a pixel from a pair of foreground (F) and background (B) samples. The (F,B) pair that produces the least reconstruction…

Computer Vision and Pattern Recognition · Computer Science 2017-04-05 Jubin Johnson , Hisham Cholakkal , Deepu Rajan

Wavelet estimators for a probability density f enjoy many good properties, however they are not "shape-preserving" in the sense that the final estimate may not be non-negative or integrate to unity. A solution to negativity issues may be to…

Methodology · Statistics 2017-08-29 Carlos Aya Moreno , Gery Geenens , Spiridon Penev

In this paper, we propose a new framework to remove parts of the systematic errors affecting popular restoration algorithms, with a special focus for image processing tasks. Generalizing ideas that emerged for $\ell_1$ regularization, we…

Statistics Theory · Mathematics 2016-09-16 C-A. Deledalle , N. Papadakis , J. Salmon , S. Vaiter

We present a novel method for predicting accurate depths from monocular images with high efficiency. This optimal efficiency is achieved by exploiting wavelet decomposition, which is integrated in a fully differentiable encoder-decoder…

Computer Vision and Pattern Recognition · Computer Science 2021-08-17 Michaël Ramamonjisoa , Michael Firman , Jamie Watson , Vincent Lepetit , Daniyar Turmukhambetov

Common approach to radial distortion is by the means of polynomial approximation, which introduces distortion-specific parameters into the camera model and requires estimation of these distortion parameters. The task of estimating radial…

Computer Vision and Pattern Recognition · Computer Science 2007-05-23 Lili Ma , YangQuan Chen , Kevin L. Moore

Image de-blurring is important in many cases of imaging a real scene or object by a camera. This project focuses on de-blurring an image distorted by an out-of-focus blur through a simulation study. A pseudo-inverse filter is first explored…

Computer Vision and Pattern Recognition · Computer Science 2017-11-03 Yuzhen Lu