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An ill-posed inverse problem of autoconvolution type is investigated. This inverse problem occurs in nonlinear optics in the context of ultrashort laser pulse characterization. The novelty of the mathematical model consists in a physically…

Mathematical Physics · Physics 2013-01-28 Daniel Gerth , Bernd Hofmann , Simon Birkholz , Sebastian Koke , Günter Steinmeyer

A main drawback of classical Tikhonov regularization is that often the parameters required to apply theoretical results, e.g., the smoothness of the sought-after solution and the noise level, are unknown in practice. In this paper we…

Numerical Analysis · Mathematics 2021-01-01 Daniel Gerth , Ronny Ramlau

We consider efficient methods for computing solutions to dynamic inverse problems, where both the quantities of interest and the forward operator (measurement process) may change at different time instances but we want to solve for all the…

Numerical Analysis · Mathematics 2021-07-14 Mirjeta Pasha , Arvind K. Saibaba , Silvia Gazzola , Malena I. Espanol , Eric de Sturler

The success of deep neural networks is mostly due their ability to learn meaningful features from the data. Features learned in the hidden layers of deep neural networks trained in computer vision tasks have been shown to be similar to…

Machine Learning · Computer Science 2017-01-04 Biswajit Paria , Vikas Reddy , Anirban Santara , Pabitra Mitra

We propose a variational regularisation approach for the problem of template-based image reconstruction from indirect, noisy measurements as given, for instance, in X-ray computed tomography. An image is reconstructed from such measurements…

Optimization and Control · Mathematics 2019-04-02 Lukas F. Lang , Sebastian Neumayer , Ozan Öktem , Carola-Bibiane Schönlieb

Improved estimation of hydrometeorological states from down-sampled observations and background model forecasts in a noisy environment, has been a subject of growing research in the past decades. Here, we introduce a unified framework that…

Data Analysis, Statistics and Probability · Physics 2014-09-15 Ardeshir Mohammad Ebtehaj , Efi Foufoula-Georgiou

We present a new inner-outer iterative algorithm for edge enhancement in imaging problems. At each outer iteration, we formulate a Tikhonov-regularized problem where the penalization is expressed in the 2-norm and involves a regularization…

Numerical Analysis · Mathematics 2020-12-30 Silvia Gazzola , Misha E. Kilmer , James G. Nagy , Oguz Semerici , Eric L. Miller

This paper deals with Tikhonov regularization for linear and nonlinear ill-posed operator equations with wavelet Besov norm penalties. We focus on $B^0_{p,1}$ penalty terms which yield estimators that are sparse with respect to a wavelet…

Numerical Analysis · Mathematics 2019-09-04 Thorsten Hohage , Philip Miller

In the framework of real Hilbert spaces, we investigate first-order dynamical systems governed by monotone and continuous operators. We demonstrate that when the monotone operator flow is augmented with a Tikhonov regularization term, the…

Optimization and Control · Mathematics 2025-04-29 Radu Ioan Bot , Dang-Khoa Nguyen

Conditional stability estimates are a popular tool for the regularization of ill-posed problems. A drawback in particular under nonlinear operators is that additional regularization is needed for obtaining stable approximate solutions if…

Numerical Analysis · Mathematics 2019-05-29 Daniel Gerth , Bernd Hofmann , Christopher Hofmann

Seismic travel time tomography is a geophysical imaging method to infer the 3-D interior structure of the solid Earth. Most commonly formulated as a linear(ized) inverse problem, it maps differences between observed and expected wave travel…

Numerical Analysis · Mathematics 2024-10-15 Naomi Schneider , Volker Michel , Karin Sigloch , Eoghan J. Totten

This study aimed to develop a virtual sensing algorithm of structural vibration for the real-time identification of unmeasured information. First, certain local point vibration responses (such as displacement and acceleration) are measured…

Computational Engineering, Finance, and Science · Computer Science 2022-11-24 Seungin Oh , Hanmin Lee , Jai-Kyung Lee , Hyungchul Yoon , Jin-Gyun Kim

The parameter selection is crucial to regularization based image restoration methods. Generally speaking, a spatially fixed parameter for regularization item in the whole image does not perform well for both edge and smooth areas. A larger…

Image and Video Processing · Electrical Eng. & Systems 2021-04-07 Tingting Zhang , Jie Chen , Caiying Wu , Zhifei He , Tieyong Zeng , Qiyu Jin

We propose a regularization-based image restoration scheme for 2D images recorded over time (2D+t). We design an infimal convolution-based regularization function which we call spatio-temporal Adaptive Infimal Convolution (STAIC)…

Image and Video Processing · Electrical Eng. & Systems 2024-04-09 Deepak G Skariah , Muthuvel Arigovindan

Solving inverse problems is central to a variety of important applications, such as biomedical image reconstruction and non-destructive testing. These problems are characterized by the sensitivity of direct solution methods with respect to…

Numerical Analysis · Mathematics 2023-05-17 Simon Göppel , Jürgen Frikel , Markus Haltmeier

In this paper, we study the Tikhonov regularization scheme in Hilbert scales for the nonlinear statistical inverse problem with a general noise. The regularizing norm in this scheme is stronger than the norm in Hilbert space. We focus on…

Statistics Theory · Mathematics 2024-04-09 Abhishake Rastogi

We propose a sparse regularization model for inversion of incomplete Fourier transforms and apply it to seismic wavefield modeling. The objective function of the proposed model employs the Moreau envelope of the $\ell_0$ norm under a tight…

Numerical Analysis · Mathematics 2022-06-13 Tingting Wu , Yuesheng Xu

We investigate the strong convergence properties of a proximal-gradient inertial algorithm with two Tikhonov regularization terms in connection to the minimization problem of the sum of a convex lower semi-continuous function $f$ and a…

Optimization and Control · Mathematics 2024-07-16 Szilárd Csaba László

Tomography can be used to reveal internal properties of a 3D object using any penetrating wave. Advanced tomographic imaging techniques, however, are vulnerable to both systematic and random errors associated with the experimental…

Numerical Analysis · Mathematics 2019-02-08 Anthony P. Austin , Zichao Wendy Di , Sven Leyffer , Stefan M. Wild

We introduce an adaptive regularization approach. In contrast to conventional Tikhonov regularization, which specifies a fixed regularization operator, we estimate it simultaneously with parameters. From a Bayesian perspective we estimate…

Computer Vision and Pattern Recognition · Computer Science 2009-06-19 Andriy Myronenko , Xubo Song