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In this paper we consider denoising and inpainting problems for higher dimensional combined cyclic and linear space valued data. These kind of data appear when dealing with nonlinear color spaces such as HSV, and they can be obtained by…

Numerical Analysis · Mathematics 2018-12-10 Ronny Bergmann , Andreas Weinmann

We introduce a new non-smooth variational model for the restoration of manifold-valued data which includes second order differences in the regularization term. While such models were successfully applied for real-valued images, we introduce…

Numerical Analysis · Mathematics 2018-12-10 Miroslav Bačák , Ronny Bergmann , Gabriele Steidl , Andreas Weinmann

The choice of the parameter value for regularized inverse problems is critical to the results and remains a topic of interest. This article explores a criterion for selecting a good parameter value by maximizing the probability of the data,…

Numerical Analysis · Mathematics 2020-02-11 Toby Sanders , Rodrigo B. Platte , Robert D. Skeel

In Multiple-Input Multiple-Output (MIMO) systems, Sphere Decoding (SD) can achieve performance equivalent to full search Maximum Likelihood (ML) decoding, with reduced complexity. Several researchers reported techniques that reduce the…

Information Theory · Computer Science 2015-03-13 Boyu Li , Ender Ayanoglu

1D Total Variation (TV) denoising, considering the data fidelity and the Total Variation (TV) regularization, proposes a good restored signal preserving shape edges. The main issue is how to choose the weight $\lambda$ balancing those two…

Signal Processing · Electrical Eng. & Systems 2020-12-18 Zhanhao Liu , Marion Perrodin , Thomas Chambrion , Radu Stoica

We develop techniques to solve ill-posed inverse problems on the sphere by sparse regularisation, exploiting sparsity in both axisymmetric and directional scale-discretised wavelet space. Denoising, inpainting, and deconvolution problems,…

Information Theory · Computer Science 2017-08-17 Christopher G. R. Wallis , Yves Wiaux , Jason D. McEwen

Graph signal processing is a ubiquitous task in many applications such as sensor, social, transportation and brain networks, point cloud processing, and graph neural networks. Often, graph signals are corrupted in the sensing process, thus…

Signal Processing · Electrical Eng. & Systems 2022-07-27 Masatoshi Nagahama , Koki Yamada , Yuichi Tanaka , Stanley H. Chan , Yonina C. Eldar

Several important classes of images such as text, barcode and pattern images have the property that pixels can only take a distinct subset of values. This knowledge can benefit the restoration of such images, but it has not been widely…

Computer Vision and Pattern Recognition · Computer Science 2015-08-21 Xing Mei , Honggang Qi , Bao-Gang Hu , Siwei Lyu

In this paper, we propose a new technique for two-dimensional phase unwrapping. The unwrapped phase is found as the solution of an inverse problem that consists in the minimization of an energy functional. The latter includes a weighted…

During the past few years, inverse problem formulations of ultrasound beamforming have attracted a growing interest. They usually pose beamforming as a minimization problem of a fidelity term resulting from the measurement model plus a…

Image and Video Processing · Electrical Eng. & Systems 2022-08-12 Sobhan Goudarzi , Adrian Basarab , Hassan Rivaz

Diffusion models have emerged as a key pillar of foundation models in visual domains. One of their critical applications is to universally solve different downstream inverse tasks via a single diffusion prior without re-training for each…

Machine Learning · Computer Science 2023-10-03 Morteza Mardani , Jiaming Song , Jan Kautz , Arash Vahdat

In this paper, we propose an interpretable denoising method for graph signals using regularization by denoising (RED). RED is a technique developed for image restoration that uses an efficient (and sometimes black-box) denoiser in the…

Signal Processing · Electrical Eng. & Systems 2026-05-27 Hayate Kojima , Hiroshi Higashi , Yuichi Tanaka

Non-linear filtering approaches allow to obtain decompositions of images with respect to a non-classical notion of scale, induced by the choice of a convex, absolutely one-homogeneous regularizer. The associated inverse scale space flow can…

Numerical Analysis · Mathematics 2022-03-22 Danielle Bednarski , Jan Lellmann

We construct a structure preserving non-conforming finite element approximation scheme for the bi-harmonic wave maps into spheres equation. It satisfies a discrete energy law and preserves the non-convex sphere constraint of the continuous…

Numerical Analysis · Mathematics 2026-04-09 Ľubomír Baňas , Sebastian Herr

This paper develops a new mathematical framework for denoising in blind two-dimensional (2D) super-resolution upon using the atomic norm. The framework denoises a signal that consists of a weighted sum of an unknown number of time-delayed…

Information Theory · Computer Science 2023-07-19 Mohamed A. Suliman , Wei Dai

We consider variations of the Rudin-Osher-Fatemi functional which are particularly well-suited to denoising and deblurring of 2D bar codes. These functionals consist of an anisotropic total variation favoring rectangles and a fidelity term…

Optimization and Control · Mathematics 2019-07-11 Rustum Choksi , Yves van Gennip , Adam Oberman

In this paper, we study the inverse boundary value problem for the wave equation with a view towards an explicit reconstruction procedure. We consider both the anisotropic problem where the unknown is a general Riemannian metric smoothly…

Analysis of PDEs · Mathematics 2017-10-10 Maarten de Hoop , Paul Kepley , Lauri Oksanen

Numerous total variation (TV) regularizers, engaged in image restoration problem, encode the gradients by means of simple $[-1,1]$ FIR filter. Despite its low computational processing, this filter severely deviates signal's high frequency…

Optimization and Control · Mathematics 2015-06-17 Mahdi S. Hosseini , Konstantinos N. Plataniotis

We study the problem of maximizing the geometric mean of $d$ low-degree non-negative forms on the real or complex sphere in $n$ variables. We show that this highly non-convex problem is NP-hard even when the forms are quadratic and is…

Optimization and Control · Mathematics 2021-03-23 Chenyang Yuan , Pablo A. Parrilo

Denoising of time domain data is a crucial task for many applications such as communication, translation, virtual assistants etc. For this task, a combination of a recurrent neural net (RNNs) with a Denoising Auto-Encoder (DAEs) has shown…

Cosmology and Nongalactic Astrophysics · Physics 2019-05-27 Hongyu Shen , Daniel George , E. A. Huerta , Zhizhen Zhao