41 citations · 146 across the 38 of their papers we have counts for
40 papers
Reconstruction of shear modulus inclusions in elastostatics via divergence-free localization
Henrik Garde, Nuutti Hyvönen, Valter Pohjola
We formulate an improved version of the monotonicity method for shape reconstruction in the inverse problem of linear elastostatics. We show that this method can reconstruct inclus…
Direct reconstruction for acoustic inverse Born scattering
Nuutti Hyvönen, Lisa Schätzle
We consider the inverse medium scattering problem for the Helmholtz equation in two dimensions, i.e., the task to recover a compactly supported penetrable two-dimensional scatterer…
Möbius-transformed trapezoidal rule for polynomial weights
Nuutti Hyvönen, Yuya Suzuki
This work studies numerical integration by the Möbius-transformed trapezoidal rule, which combines the classical trapezoidal rule with a change of variables induced by a Möbius tra…
A bilinear inverse problem with forward operator inaccuracy applied to neonatal atlas-based diffuse optical tomography
Aada Hakula, Pauliina Hirvi, Nuutti Hyvönen
In this work, we assume to have a set of candidate forward operator matrices and suggest principal component analysis for modeling their variation from the mean. We use this princi…
Total variation regularization with reduced basis in electrical impedance tomography
A. Hannukainen, N. Hyvönen, V. Toresen
This work considers using reduced basis techniques in connection to (smoothened) total variation regularization in electrical impedance tomography, but analogous ideas can also be…
Approximation of differential entropy in Bayesian optimal experimental design
Chuntao Chen, Tapio Helin, Nuutti Hyvönen +1
Bayesian optimal experimental design provides a principled framework for selecting experimental configurations that maximize obtained information. In this work, we consider setting…
Projection-based preprocessing for electrical impedance tomography to reduce the effect of electrode contacts
Altti Jääskeläinen, Jussi Toivanen, Asko Hänninen +2
This work introduces a method for preprocessing measurements of electrical impedance tomography to considerably reduce the effect uncertainties in the electrode contacts have on th…
Continuity of the linearized forward map of electrical impedance tomography from square-integrable perturbations to Hilbert-Schmidt operators
Joanna Bisch, Markus Hirvensalo, Nuutti Hyvönen
This work considers the Fréchet derivative of the idealized forward map of two-dimensional electrical impedance tomography, i.e., the linear operator that maps a perturbation of th…
Möbius-Transformed Trapezoidal Rule
Yuya Suzuki, Nuutti Hyvönen, Toni Karvonen
We study numerical integration by combining the trapezoidal rule with a Möbius transformation that maps the unit circle onto the real line. We prove that the resulting transformed…
Linearization-based direct reconstruction for EIT using triangular Zernike decompositions
Antti Autio, Henrik Garde, Markus Hirvensalo +1
This work implements and numerically tests the direct reconstruction algorithm introduced in [Garde & Hyvönen, SIAM J. Math. Anal., 2024] for two-dimensional linearized electrical…
Bayesian experimental design for head imaging by electrical impedance tomography
N. Hyvönen, A. Jääskeläinen, R. Maity +1
This work considers the optimization of electrode positions in head imaging by electrical impedance tomography. The study is motivated by maximizing the sensitivity of electrode me…
Bayesian experimental design for linear elasticity
Sarah Eberle-Blick, Nuutti Hyvönen
This work considers Bayesian experimental design for the inverse boundary value problem of linear elasticity in a two-dimensional setting. The aim is to optimize the positions of c…
Bayesian design of measurements for magnetorelaxometry imaging
Tapio Helin, Nuutti Hyvönen, Jarno Maaninen +1
The aim of magnetorelaxometry imaging is to determine the distribution of magnetic nanoparticles inside a subject by measuring the relaxation of the superposition magnetic field ge…
Linearised Calderón problem: Reconstruction and Lipschitz stability for infinite-dimensional spaces of unbounded perturbations
Henrik Garde, Nuutti Hyvönen
We investigate a linearised Calderón problem in a two-dimensional bounded simply connected domain . After extending the linearised problem for perturbations,…
Approximation error method for imaging the human head by electrical impedance tomography
Valentina Candiani, Nuutti Hyvönen, Jari P. Kaipio +1
This work considers electrical impedance tomography imaging of the human head, with the ultimate goal of locating and classifying a stroke in emergency care. One of the main diffic…
Series reversion in Calderón's problem
Henrik Garde, Nuutti Hyvönen
This work derives explicit series reversions for the solution of Calderón's problem. The governing elliptic partial differential equation is in a bounded…
Edge-promoting adaptive Bayesian experimental design for X-ray imaging
Tapio Helin, Nuutti Hyvönen, Juha-Pekka Puska
This work considers sequential edge-promoting Bayesian experimental design for (discretized) linear inverse problems, exemplified by X-ray tomography. The process of computing a to…
Electrodeless electrode model for electrical impedance tomography
J. Dardé, N. Hyvönen, T. Kuutela +1
Electrical impedance tomography is an imaging modality for extracting information on the interior structure of a physical body from boundary measurements of current and voltage. Th…
Sequentially optimized projections in X-ray imaging
Martin Burger, Andreas Hauptmann, Tapio Helin +2
This work applies Bayesian experimental design to selecting optimal projection geometries in (discretized) parallel beam X-ray tomography assuming the prior and the additive noise…
Inverse heat source problem and experimental design for determining iron loss distribution
Antti Hannukainen, Nuutti Hyvönen, Lauri Perkkiö
Iron loss determination in the magnetic core of an electrical machine, such as a motor or a transformer, is formulated as an inverse heat source problem. The sensor positions insid…
Mimicking relative continuum measurements by electrode data in two-dimensional electrical impedance tomography
Henrik Garde, Nuutti Hyvönen
This paper introduces a constructive method for approximating relative continuum measurements in two-dimensional electrical impedance tomography based on data originating from eith…
Optimal depth-dependent distinguishability bounds for electrical impedance tomography in arbitrary dimension
Henrik Garde, Nuutti Hyvönen
The inverse problem of electrical impedance tomography is severely ill-posed. In particular, the resolution of images produced by impedance tomography deteriorates as the distance…
On regularity of the logarithmic forward map of electrical impedance tomography
Henrik Garde, Nuutti Hyvönen, Topi Kuutela
This work considers properties of the logarithm of the Neumann-to-Dirichlet boundary map for the conductivity equation in a Lipschitz domain. It is shown that the mapping from the…
Computational framework for applying electrical impedance tomography to head imaging
Valentina Candiani, Antti Hannukainen, Nuutti Hyvönen
This work introduces a computational framework for applying absolute electrical impedance tomography to head imaging without accurate information on the head shape or the electrode…