Search Results for author: Christoph Brune

Found 29 papers, 11 papers with code

Global Control for Local SO(3)-Equivariant Scale-Invariant Vessel Segmentation

no code implementations22 Mar 2024 Patryk Rygiel, Dieuwertje Alblas, Christoph Brune, Kak Khee Yeung, Jelmer M. Wolterink

To this end, we propose a combination of a global controller leveraging voxel mask segmentations to provide boundary conditions for vessels of interest to a local, iterative vessel segmentation model.

Segmentation

SIRE: scale-invariant, rotation-equivariant estimation of artery orientations using graph neural networks

no code implementations9 Nov 2023 Dieuwertje Alblas, Julian Suk, Christoph Brune, Kak Khee Yeung, Jelmer M. Wolterink

Hence, SIRE can be trained with arbitrarily oriented vessels with varying radii to generalise to vessels with a wide range of calibres and tortuosity.

DFM-X: Augmentation by Leveraging Prior Knowledge of Shortcut Learning

1 code implementation12 Aug 2023 Shunxin Wang, Christoph Brune, Raymond Veldhuis, Nicola Strisciuglio

We propose a data augmentation strategy, named DFM-X, that leverages knowledge about frequency shortcuts, encoded in Dominant Frequencies Maps computed for image classification models.

Data Augmentation Image Classification

Defocus Blur Synthesis and Deblurring via Interpolation and Extrapolation in Latent Space

1 code implementation28 Jul 2023 Ioana Mazilu, Shunxin Wang, Sven Dummer, Raymond Veldhuis, Christoph Brune, Nicola Strisciuglio

We train autoencoders with implicit and explicit regularization techniques to enforce linearity relations among the representations of different blur levels in the latent space.

Data Augmentation Deblurring +1

What do neural networks learn in image classification? A frequency shortcut perspective

1 code implementation ICCV 2023 Shunxin Wang, Raymond Veldhuis, Christoph Brune, Nicola Strisciuglio

Our results demonstrate that NNs tend to find simple solutions for classification, and what they learn first during training depends on the most distinctive frequency characteristics, which can be either low- or high-frequencies.

Data Augmentation Image Classification +1

Embeddings between Barron spaces with higher order activation functions

no code implementations25 May 2023 Tjeerd Jan Heeringa, Len Spek, Felix Schwenninger, Christoph Brune

Moreover, the Barron spaces associated with the $\operatorname{RePU}_s$ have a hierarchical structure similar to the Sobolev spaces $H^m$.

RDA-INR: Riemannian Diffeomorphic Autoencoding via Implicit Neural Representations

no code implementations22 May 2023 Sven Dummer, Nicola Strisciuglio, Christoph Brune

In this work, we focus on a limitation of neural network-based atlas building and statistical latent modeling methods, namely that they either are (i) resolution dependent or (ii) disregard any data/problem-specific geometry needed for proper mean-variance analysis.

Computational Efficiency Dimensionality Reduction

A Survey on the Robustness of Computer Vision Models against Common Corruptions

1 code implementation10 May 2023 Shunxin Wang, Raymond Veldhuis, Christoph Brune, Nicola Strisciuglio

The performance of computer vision models are susceptible to unexpected changes in input images, known as common corruptions (e. g. noise, blur, illumination changes, etc.

Data Augmentation Knowledge Distillation +1

Implicit Neural Representations for Modeling of Abdominal Aortic Aneurysm Progression

no code implementations2 Mar 2023 Dieuwertje Alblas, Marieke Hofman, Christoph Brune, Kak Khee Yeung, Jelmer M. Wolterink

We represent the AAA wall over time as the zero-level set of a signed distance function (SDF), estimated by a multilayer perception that operates on space and time.

SE(3) symmetry lets graph neural networks learn arterial velocity estimation from small datasets

1 code implementation17 Feb 2023 Julian Suk, Christoph Brune, Jelmer M. Wolterink

We demonstrate how to construct an SE(3)-equivariant GNN that is independent of the spatial orientation of the input mesh and show how this reduces the necessary amount of training data compared to a baseline neural network.

Mesh Neural Networks for SE(3)-Equivariant Hemodynamics Estimation on the Artery Wall

1 code implementation9 Dec 2022 Julian Suk, Pim de Haan, Phillip Lippe, Christoph Brune, Jelmer M. Wolterink

Computational fluid dynamics (CFD) is a valuable asset for patient-specific cardiovascular-disease diagnosis and prognosis, but its high computational demands hamper its adoption in practice.

Duality for Neural Networks through Reproducing Kernel Banach Spaces

no code implementations9 Nov 2022 Len Spek, Tjeerd Jan Heeringa, Felix Schwenninger, Christoph Brune

Recently, Barron spaces have been used to prove bounds on the generalisation error for neural networks.

Deep Kernel Learning of Dynamical Models from High-Dimensional Noisy Data

1 code implementation27 Aug 2022 Nicolò Botteghi, Mengwu Guo, Christoph Brune

This work proposes a Stochastic Variational Deep Kernel Learning method for the data-driven discovery of low-dimensional dynamical models from high-dimensional noisy data.

Vocal Bursts Intensity Prediction

Unsupervised Representation Learning in Deep Reinforcement Learning: A Review

1 code implementation27 Aug 2022 Nicolò Botteghi, Mannes Poel, Christoph Brune

This review addresses the problem of learning abstract representations of the measurement data in the context of Deep Reinforcement Learning (DRL).

reinforcement-learning Reinforcement Learning (RL) +1

Going Off-Grid: Continuous Implicit Neural Representations for 3D Vascular Modeling

no code implementations29 Jul 2022 Dieuwertje Alblas, Christoph Brune, Kak Khee Yeung, Jelmer M. Wolterink

This allows us to model complex vascular structures with a representation that is implicit, continuous, light-weight, and easy to integrate with deep learning algorithms.

Super-Resolved Microbubble Localization in Single-Channel Ultrasound RF Signals Using Deep Learning

no code implementations9 Apr 2022 Nathan Blanken, Jelmer M. Wolterink, Hervé Delingette, Christoph Brune, Michel Versluis, Guillaume Lajoinie

The resulting image shows an order-of-magnitude gain in axial resolution compared to a delay-and-sum reconstruction with unprocessed element data.

Super-Resolution

Mesh convolutional neural networks for wall shear stress estimation in 3D artery models

1 code implementation10 Sep 2021 Julian Suk, Pim de Haan, Phillip Lippe, Christoph Brune, Jelmer M. Wolterink

In this work, we propose to instead use mesh convolutional neural networks that directly operate on the same finite-element surface mesh as used in CFD.

Low-Dimensional State and Action Representation Learning with MDP Homomorphism Metrics

no code implementations4 Jul 2021 Nicolò Botteghi, Mannes Poel, Beril Sirmacek, Christoph Brune

Results show that the novel framework can efficiently learn low-dimensional and interpretable state and action representations and the optimal latent policy.

reinforcement-learning Reinforcement Learning (RL) +1

Learning normal form autoencoders for data-driven discovery of universal,parameter-dependent governing equations

1 code implementation9 Jun 2021 Manu Kalia, Steven L. Brunton, Hil G. E. Meijer, Christoph Brune, J. Nathan Kutz

In this work, we introduce deep learning autoencoders to discover coordinate transformations that capture the underlying parametric dependence of a dynamical system in terms of its canonical normal form, allowing for a simple representation of the parametric dependence and bifurcation structure.

Model Discovery

Learned SVD: solving inverse problems via hybrid autoencoding

no code implementations20 Dec 2019 Yoeri E. Boink, Christoph Brune

Our world is full of physics-driven data where effective mappings between data manifolds are desired.

Dimensionality Reduction

Combining Contrast Invariant L1 Data Fidelities with Nonlinear Spectral Image Decomposition

no code implementations16 Mar 2017 Leonie Zeune, Stephan A. van Gils, Leon W. M. M. Terstappen, Christoph Brune

However, for an effective use in image segmentation and shape decomposition, a clear interpretation of the spectral response regarding size and intensity scales is needed but lacking in current approaches.

Image Segmentation Semantic Segmentation

Multiscale Segmentation via Bregman Distances and Nonlinear Spectral Analysis

no code implementations22 Apr 2016 Leonie Zeune, Guus van Dalum, Leon W. M. M. Terstappen, S. A. van Gils, Christoph Brune

For this we generalize a variational segmentation model based on total variation using Bregman distances to construct an inverse scale space.

Medical Diagnosis Segmentation

Optimal Data Collection For Informative Rankings Expose Well-Connected Graphs

no code implementations26 Jul 2012 Braxton Osting, Christoph Brune, Stanley J. Osher

Our approach, based on experimental design, is to view data collection as a bi-level optimization problem where the inner problem is the ranking problem and the outer problem is to identify data which maximizes the informativeness of the ranking.

Clustering Experimental Design +2

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