One-step differentiation of iterative algorithms

J Bolte, E Pauwels, S Vaiter - Advances in Neural …, 2023 - proceedings.neurips.cc
In appropriate frameworks, automatic differentiation is transparent to the user, at the cost of
being a significant computational burden when the number of operations is large. For …

Learning regularization parameter-maps for variational image reconstruction using deep neural networks and algorithm unrolling

A Kofler, F Altekrüger, F Antarou Ba, C Kolbitsch… - SIAM Journal on Imaging …, 2023 - SIAM
We introduce a method for the fast estimation of data-adapted, spatially and temporally
dependent regularization parameter-maps for variational image reconstruction, focusing on …

On optimal regularization parameters via bilevel learning

MJ Ehrhardt, S Gazzola, SJ Scott - 2023 - books.google.com
Variational regularization is commonly used to solve linear inverse problems, and involves
augmenting a data fidelity by a regularizer. The regularizer is used to promote a priori …

Optimising seismic imaging design parameters via bilevel learning

S Downing, S Gazzola, IG Graham… - Inverse Problems, 2024 - iopscience.iop.org
Full waveform inversion (FWI) is a standard algorithm in seismic imaging. It solves the
inverse problem of computing a model of the physical properties of the earth's subsurface by …

An Adaptively Inexact Method for Bilevel Learning Using Primal-Dual Style Differentiation

L Bogensperger, MJ Ehrhardt, T Pock… - arxiv preprint arxiv …, 2024 - arxiv.org
We consider a bilevel learning framework for learning linear operators. In this framework, the
learnable parameters are optimized via a loss function that also depends on the minimizer of …

Efficient gradient-based methods for bilevel learning via recycling Krylov subspaces

MJ Ehrhardt, S Gazzola, SJ Scott - arxiv preprint arxiv:2412.08264, 2024 - arxiv.org
Many optimization problems require hyperparameters, ie, parameters that must be pre-
specified in advance, such as regularization parameters and parametric regularizers in …

Optimising seismic imaging design parameters via bilevel learning

S Downing, S Gazzola, IG Graham… - arxiv preprint arxiv …, 2023 - arxiv.org
Full Waveform Inversion (FWI) is a standard algorithm in seismic imaging. Its implementation
requires the a priori choice of a number of" design parameters", such as the positions of …

Bilevel Learning with Inexact Stochastic Gradients

MS Salehi, S Mukherjee, L Roberts… - arxiv preprint arxiv …, 2024 - arxiv.org
Bilevel learning has gained prominence in machine learning, inverse problems, and
imaging applications, including hyperparameter optimization, learning data-adaptive …

Derivative-free stochastic bilevel optimization for inverse problems

M Staudigl, S Weissmann, T van Leeuwen - arxiv preprint arxiv …, 2024 - arxiv.org
Inverse problems are key issues in several scientific areas, including signal processing and
medical imaging. Data-driven approaches for inverse problems aim for learning model and …

An adaptively inexact first-order method for bilevel optimization with application to hyperparameter learning

MS Salehi, S Mukherjee, L Roberts… - arxiv preprint arxiv …, 2023 - arxiv.org
Various tasks in data science are modeled utilizing the variational regularization approach,
where manually selecting regularization parameters presents a challenge. The difficulty gets …