Search Results for author: Andreas Hauptmann

Found 27 papers, 6 papers with code

Inverse Problems with Learned Forward Operators

no code implementations21 Nov 2023 Simon Arridge, Andreas Hauptmann, Yury Korolev

The first one is completely agnostic to the forward operator and learns its restriction to the subspace spanned by the training data.

Convergent regularization in inverse problems and linear plug-and-play denoisers

no code implementations18 Jul 2023 Andreas Hauptmann, Subhadip Mukherjee, Carola-Bibiane Schönlieb, Ferdia Sherry

While a significant amount of research has gone into establishing the convergence of the PnP iteration for different regularity conditions on the denoisers, not much is known about the asymptotic properties of the converged solution as the noise level in the measurement tends to zero, i. e., whether PnP methods are provably convergent regularization schemes under reasonable assumptions on the denoiser.

Denoising Image Reconstruction

Domain independent post-processing with graph U-nets: Applications to Electrical Impedance Tomographic Imaging

no code implementations8 May 2023 William Herzberg, Andreas Hauptmann, Sarah J. Hamilton

We demonstrate effectiveness and flexibility of the graph U-Net for improving reconstructions from electrical impedance tomographic (EIT) measurements, a nonlinear and highly ill-posed inverse problem.

Joint Activity Detection and Channel Estimation for Clustered Massive Machine Type Communications

no code implementations4 May 2023 Leatile Marata, Onel Luis Alcaraz López, Andreas Hauptmann, Hamza Djelouat, Hirley Alves

Compressed sensing multi-user detection (CS-MUD) algorithms play a key role in optimizing grant-free (GF) non-orthogonal multiple access (NOMA) for massive machine-type communications (mMTC).

Action Detection Activity Detection

Model-corrected learned primal-dual models for fast limited-view photoacoustic tomography

no code implementations4 Apr 2023 Andreas Hauptmann, Jenni Poimala

In this work we advance the methodological and theoretical basis for model corrections in learned image reconstructions by embedding the model correction in a learned primal-dual framework.

Unsupervised denoising for sparse multi-spectral computed tomography

no code implementations2 Nov 2022 Satu I. Inkinen, Mikael A. K. Brix, Miika T. Nieminen, Simon Arridge, Andreas Hauptmann

However, these issues are especially exacerbated when sparse imaging scenarios are encountered due to a significant reduction in photon counts.}

Computed Tomography (CT) Denoising

Reconstruction and segmentation from sparse sequential X-ray measurements of wood logs

no code implementations20 Jun 2022 Sebastian Springer, Aldo Glielmo, Angelina Senchukova, Tomi Kauppi, Jarkko Suuronen, Lassi Roininen, Heikki Haario, Andreas Hauptmann

Thus, here we propose the use of a Dimension reduced Kalman Filter to accumulate information between slices and allow for sufficiently accurate reconstructions for further assessment of the object.

Computed Tomography (CT)

Unsupervised Knowledge-Transfer for Learned Image Reconstruction

no code implementations6 Jul 2021 Riccardo Barbano, Zeljko Kereta, Andreas Hauptmann, Simon R. Arridge, Bangti Jin

Deep learning-based image reconstruction approaches have demonstrated impressive empirical performance in many imaging modalities.

Image Reconstruction SSIM +1

Graph Convolutional Networks for Model-Based Learning in Nonlinear Inverse Problems

1 code implementation28 Mar 2021 William Herzberg, Daniel B. Rowe, Andreas Hauptmann, Sarah J. Hamilton

This gives rise to the proposed iterative Graph Convolutional Newton-type Method (GCNM), which includes the forward model in the solution of the inverse problem, while all updates are directly computed by the network on the problem specific mesh.

Image Reconstruction

An efficient Quasi-Newton method for nonlinear inverse problems via learned singular values

no code implementations14 Dec 2020 Danny Smyl, Tyler N. Tallman, Dong Liu, Andreas Hauptmann

Here we present a highly efficient data-driven Quasi-Newton method applicable to nonlinear inverse problems.

Machine Learning in Magnetic Resonance Imaging: Image Reconstruction

no code implementations9 Dec 2020 Javier Montalt-Tordera, Vivek Muthurangu, Andreas Hauptmann, Jennifer Anne Steeden

Following the success of machine learning in a wide range of imaging tasks, there has been a recent explosion in the use of machine learning in the field of MRI image reconstruction.

BIG-bench Machine Learning Management +1

Quantifying Sources of Uncertainty in Deep Learning-Based Image Reconstruction

no code implementations17 Nov 2020 Riccardo Barbano, Željko Kereta, Chen Zhang, Andreas Hauptmann, Simon Arridge, Bangti Jin

Image reconstruction methods based on deep neural networks have shown outstanding performance, equalling or exceeding the state-of-the-art results of conventional approaches, but often do not provide uncertainty information about the reconstruction.

Image Reconstruction

Deep Learning in Photoacoustic Tomography: Current approaches and future directions

1 code implementation16 Sep 2020 Andreas Hauptmann, Ben Cox

The need for rapid image formation and the practical restrictions on data acquisition that arise from the constraints of a clinical workflow are presenting new image reconstruction challenges.

Image Reconstruction

On the unreasonable effectiveness of CNNs

no code implementations29 Jul 2020 Andreas Hauptmann, Jonas Adler

Deep learning methods using convolutional neural networks (CNN) have been successfully applied to virtually all imaging problems, and particularly in image reconstruction tasks with ill-posed and complicated imaging models.

Image Reconstruction

Blind hierarchical deconvolution

no code implementations22 Jul 2020 Arttu Arjas, Lassi Roininen, Mikko J. Sillanpää, Andreas Hauptmann

Deconvolution is a fundamental inverse problem in signal processing and the prototypical model for recovering a signal from its noisy measurement.

On Learned Operator Correction in Inverse Problems

1 code implementation14 May 2020 Sebastian Lunz, Andreas Hauptmann, Tanja Tarvainen, Carola-Bibiane Schönlieb, Simon Arridge

We discuss the possibility to learn a data-driven explicit model correction for inverse problems and whether such a model correction can be used within a variational framework to obtain regularised reconstructions.

Rapid Whole-Heart CMR with Single Volume Super-resolution

no code implementations22 Dec 2019 Jennifer A. Steeden, Michael Quail, Alexander Gotschy, Andreas Hauptmann, Simon Arridge, Rodney Jones, Vivek Muthurangu

Conclusion: This paper demonstrates the potential of using a residual U-Net for super-resolution reconstruction of rapidly acquired low-resolution whole heart bSSFP data within a clinical setting.

Anatomy Super-Resolution

Multi-Scale Learned Iterative Reconstruction

1 code implementation1 Aug 2019 Andreas Hauptmann, Jonas Adler, Simon Arridge, Ozan Öktem

Applicability of these methods to large scale inverse problems is however limited by the available memory for training and extensive training times, the latter due to computationally expensive forward models.

Computed Tomography (CT)

Networks for Nonlinear Diffusion Problems in Imaging

no code implementations29 Nov 2018 Simon Arridge, Andreas Hauptmann

By design, we obtain a nonlinear network architecture that is well suited for diffusion related problems in imaging.

Approximate k-space models and Deep Learning for fast photoacoustic reconstruction

no code implementations9 Jul 2018 Andreas Hauptmann, Ben Cox, Felix Lucka, Nam Huynh, Marta Betcke, Paul Beard, Simon Arridge

We present a framework for accelerated iterative reconstructions using a fast and approximate forward model that is based on k-space methods for photoacoustic tomography.

Deep D-bar: Real time Electrical Impedance Tomography Imaging with Deep Neural Networks

no code implementations8 Nov 2017 Sarah Jane Hamilton, Andreas Hauptmann

The mathematical problem for Electrical Impedance Tomography (EIT) is a highly nonlinear ill-posed inverse problem requiring carefully designed reconstruction procedures to ensure reliable image generation.

Image Generation

Model based learning for accelerated, limited-view 3D photoacoustic tomography

no code implementations31 Aug 2017 Andreas Hauptmann, Felix Lucka, Marta Betcke, Nam Huynh, Jonas Adler, Ben Cox, Paul Beard, Sebastien Ourselin, Simon Arridge

Recent advances in deep learning for tomographic reconstructions have shown great potential to create accurate and high quality images with a considerable speed-up.

Tomographic Reconstructions

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