Total variation regularization on Riemannian manifolds by iteratively reweighted minimization

P Grohs, M Sprecher - Information and Inference: A Journal of …, 2016 - academic.oup.com
We consider the problem of reconstructing an image from noisy and/or incomplete data. The
values of the pixels lie on a Riemannian manifold $M$ , eg $\mathbb {R}$ for a grayscale …

Projection-based finite elements for nonlinear function spaces

P Grohs, H Hardering, O Sander, M Sprecher - SIAM Journal on Numerical …, 2019 - SIAM
We introduce a novel type of approximation spaces for functions with values in a nonlinear
manifold. The discrete functions are constructed by piecewise polynomial interpolation in a …

[HTML][HTML] Counting unique-sink orientations

J Foniok, B Gärtner, L Klaus, M Sprecher - Discrete Applied Mathematics, 2014 - Elsevier
Unique-sink orientations (USOs) are an abstract class of orientations of the n -cube graph.
We consider some classes of USOs that are of interest in connection with the linear …

[PDF][PDF] Projection-based quasiinterpolation in manifolds

P Grohs, M Sprecher - SAM Report, 2013 - sam.math.ethz.ch
We consider the problem of approximating manifold-valued functions with approximation
spaces spanned by linear combinations of cardinal B-splines with control points constrained to …

Scattered manifold-valued data approximation

P Grohs, M Sprecher, T Yu - Numerische mathematik, 2017 - Springer
We consider the problem of approximating a function f from an Euclidean domain to a manifold
M by scattered samples $$(f(\xi _i))_{i\in \mathcal {I}}$$ ( f ( ξ i ) ) i ∈ I , where the data …

[PDF][PDF] Total variation regularization by iteratively reweighted least squares on Hadamard spaces and the sphere

P Grohs, M Sprecher - preprint, 2014 - sam.math.ethz.ch
We consider the problem of reconstructing an image from noisy and/or incomplete data, where
the image/data take values in a metric space X (eg R for grayscale, S2 for the chromaticity …

[PDF][PDF] Numerical methods for optimization and variational problems with manifold-valued data

M Sprecher - 2016 - research-collection.ethz.ch
In this thesis, we consider optimization and variational problems where the data is constrained
to lie on a Riemannian manifold. Two examples, we will particularly focus on, are the …

A polynomial-time algorithm for the tridiagonal and Hessenberg P-matrix linear complementarity problem

B Gärtner, M Sprecher - Operations research letters, 2012 - Elsevier
We give the first polynomial-time algorithm for solving the linear complementarity problem
with tridiagonal or, more generally, Hessenberg P-matrices.

[PDF][PDF] Why Quasi-Interpolation onto Manifold has Order 4

M Sprecher - 2020 - academia.edu
We consider approximations of functions from samples where the functions take values on a
submanifold of Rn. We generalize a common quasiinterpolation scheme based on cardinal …

A direct Proof for Quadratic Convergence of the Geometric Newton Method

M Sprecher - arXiv preprint arXiv:1607.03869, 2016 - arxiv.org
We consider the problem of numerically computing a critical point of a functional $J\colon M\rightarrow
R$ where $M$ is a Riemannian manifold. Due to local quadratic convergence a …