Search Results for author: Joachim Weickert

Found 34 papers, 1 papers with code

Efficient Parallel Algorithms for Inpainting-Based Representations of 4K Images -- Part II: Spatial and Tonal Data Optimization

no code implementations12 Jan 2024 Niklas Kämper, Vassillen Chizhov, Joachim Weickert

Homogeneous diffusion inpainting can reconstruct missing image areas with high quality from a sparse subset of known pixels, provided that their location as well as their gray or color values are well optimized.

4k Image Compression

Efficient Parallel Algorithms for Inpainting-Based Representations of 4K Images -- Part I: Homogeneous Diffusion Inpainting

no code implementations12 Jan 2024 Niklas Kämper, Vassillen Chizhov, Joachim Weickert

However, a major challenge has been to design fast solvers for homogeneous diffusion inpainting that scale to 4K image resolution ($3840 \times 2160$ pixels) and are real-time capable.

4k Image Reconstruction

Gaining Insights into Denoising by Inpainting

no code implementations23 Sep 2023 Daniel Gaa, Vassillen Chizhov, Pascal Peter, Joachim Weickert, Robin Dirk Adam

In contrast to traditional denoising methods that adapt the operator to the data, our approach adapts the data to the operator.

Denoising Image Compression

Regularised Diffusion-Shock Inpainting

no code implementations15 Sep 2023 Kristina Schaefer, Joachim Weickert

We introduce regularised diffusion--shock (RDS) inpainting as a modification of diffusion--shock inpainting from our SSVM 2023 conference paper.

Anisotropic Diffusion Stencils: From Simple Derivations over Stability Estimates to ResNet Implementations

no code implementations11 Sep 2023 Karl Schrader, Joachim Weickert, Michael Krause

Our directional splitting also allows a very natural translation of the explicit scheme into ResNet blocks.

Diffusion-Shock Inpainting

no code implementations16 Mar 2023 Kristina Schaefer, Joachim Weickert

Moreover, it benefits from the sharp edge structure generated by the shock filter, and it exploits the efficient filling-in effect of homogeneous diffusion.

Image Blending with Osmosis

no code implementations14 Mar 2023 Paul Bungert, Pascal Peter, Joachim Weickert

For our blending purposes, we explore several ways to compose drift vector fields based on the derivatives of our input images.

Optimising Different Feature Types for Inpainting-based Image Representations

no code implementations26 Oct 2022 Ferdinand Jost, Vassillen Chizhov, Joachim Weickert

Its performance is demonstrated with a novel set of features that also includes local averages.

Image Compression

CNN-based Euler's Elastica Inpainting with Deep Energy and Deep Image Prior

no code implementations16 Jul 2022 Karl Schrader, Tobias Alt, Joachim Weickert, Michael Ertel

As a remedy, we design the first neural algorithm that simulates inpainting with Euler's Elastica.

Image Inpainting

Domain Decomposition Algorithms for Real-time Homogeneous Diffusion Inpainting in 4K

no code implementations8 Oct 2021 Niklas Kämper, Joachim Weickert

Inpainting-based compression methods are qualitatively promising alternatives to transform-based codecs, but they suffer from the high computational cost of the inpainting step.

4k

Learning Sparse Masks for Diffusion-based Image Inpainting

no code implementations6 Oct 2021 Tobias Alt, Pascal Peter, Joachim Weickert

Diffusion-based inpainting is a powerful tool for the reconstruction of images from sparse data.

Image Compression Image Inpainting

Designing Rotationally Invariant Neural Networks from PDEs and Variational Methods

no code implementations31 Aug 2021 Tobias Alt, Karl Schrader, Joachim Weickert, Pascal Peter, Matthias Augustin

With only a few small filters, they can achieve the same invariance as existing techniques which require a fine-grained sampling of orientations.

Novel Concepts

Connections between Numerical Algorithms for PDEs and Neural Networks

no code implementations30 Jul 2021 Tobias Alt, Karl Schrader, Matthias Augustin, Pascal Peter, Joachim Weickert

We connect these concepts to residual networks, recurrent neural networks, and U-net architectures.

Efficient Data Optimisation for Harmonic Inpainting with Finite Elements

no code implementations4 May 2021 Vassillen Chizhov, Joachim Weickert

Harmonic inpainting with optimised data is very popular for inpainting-based image compression.

Image Compression

Translating Numerical Concepts for PDEs into Neural Architectures

no code implementations29 Mar 2021 Tobias Alt, Pascal Peter, Joachim Weickert, Karl Schrader

We investigate what can be learned from translating numerical algorithms into neural networks.

Multi-frame Super-resolution from Noisy Data

no code implementations25 Mar 2021 Kireeti Bodduna, Joachim Weickert

Obtaining high resolution images from low resolution data with clipped noise is algorithmically challenging due to the ill-posed nature of the problem.

Multi-Frame Super-Resolution

JPEG Meets PDE-based Image Compression

no code implementations1 Feb 2021 Sarah Andris, Joachim Weickert, Tobias Alt, Pascal Peter

Our codec consistently outperforms JPEG and gives useful indications for successfully developing hybrid codecs further.

Image Compression

Sparse Inpainting with Smoothed Particle Hydrodynamics

no code implementations23 Nov 2020 Viktor Daropoulos, Matthias Augustin, Joachim Weickert

Furthermore, we examine the use of Voronoi tessellation for defining the necessary parameters in the SPH method as well as selecting optimally located image samples.

Image Inpainting

Learning Integrodifferential Models for Image Denoising

no code implementations21 Oct 2020 Tobias Alt, Joachim Weickert

We show that both multiscale information and anisotropy are crucial for its success.

Image Denoising Philosophy

Inpainting-based Video Compression in FullHD

no code implementations24 Aug 2020 Sarah Andris, Pascal Peter, Rahul Mohideen Kaja Mohideen, Joachim Weickert, Sebastian Hoffmann

Compression methods based on inpainting are an evolving alternative to classical transform-based codecs for still images.

Video Compression

Translating Diffusion, Wavelets, and Regularisation into Residual Networks

no code implementations7 Feb 2020 Tobias Alt, Joachim Weickert, Pascal Peter

Convolutional neural networks (CNNs) often perform well, but their stability is poorly understood.

Denoising

Removing Multi-frame Gaussian Noise by Combining Patch-based Filters with Optical Flow

no code implementations22 Jan 2020 Kireeti Bodduna, Joachim Weickert

Patch-based approaches such as 3D block matching (BM3D) and non-local Bayes (NLB) are widely accepted filters for removing Gaussian noise from single-frame images.

Optical Flow Estimation

Robustness of Brain Tumor Segmentation

no code implementations24 Dec 2019 Sabine Müller, Joachim Weickert, Norbert Graf

In our work we investigate the generalization behavior of deep neural networks in this scenario.

Brain Tumor Segmentation Segmentation +1

Variational Coupling Revisited: Simpler Models, Theoretical Connections, and Novel Applications

no code implementations12 Dec 2019 Aaron Wewior, Joachim Weickert

As a specific example, we present a first order coupling model that outperforms classical TV regularisation.

Denoising

Learning a Generic Adaptive Wavelet Shrinkage Function for Denoising

no code implementations21 Oct 2019 Tobias Alt, Joachim Weickert

In contrast to many existing shrinkage functions, it is able to enhance image structures by amplifying wavelet coefficients.

Denoising

Object Segmentation Tracking from Generic Video Cues

no code implementations5 Oct 2019 Amirhossein Kardoost, Sabine Müller, Joachim Weickert, Margret Keuper

Our simple method can provide competitive results compared to the costly CNN-based methods with parameter tuning.

Object Optical Flow Estimation +4

Stable Backward Diffusion Models that Minimise Convex Energies

no code implementations8 Mar 2019 Leif Bergerhoff, Marcelo Cárdenas, Joachim Weickert, Martin Welk

Furthermore, we establish a comprehensive theory for the time-continuous evolution and we show that stability carries over to a simple explicit time discretisation of our model.

Deblurring Image Enhancement

Anisotropic osmosis filtering for shadow removal in images

1 code implementation17 Sep 2018 Simone Parisotto, Luca Calatroni, Marco Caliari, Carola-Bibiane Schönlieb, Joachim Weickert

We present an anisotropic extension of the isotropic osmosis model that has been introduced by Weickert et al.~(Weickert, 2013) for visual computing applications, and we adapt it specifically to shadow removal applications.

Analysis of PDEs 68U10, 94A08, 49K20, 65M06,

Space-Filling Curve Indices as Acceleration Structure for Exemplar-Based Inpainting

no code implementations18 Dec 2017 Tim Dahmen, Patrick Trampert, Pascal Peter, Pinak Bheed, Joachim Weickert, Philipp Slusallek

The approach has the advantage of being agnostic to most modelbased parts of exemplar-based inpainting such as the order in which patches are processed and the cost function used to determine patch similarity.

Dimensionality Reduction

Optimising Spatial and Tonal Data for PDE-based Inpainting

no code implementations15 Jun 2015 Laurent Hoeltgen, Markus Mainberger, Sebastian Hoffmann, Joachim Weickert, Ching Hoo Tang, Simon Setzer, Daniel Johannsen, Frank Neumann, Benjamin Doerr

Moreover, is more generic than other data optimisation approaches for the sparse inpainting problem, since it can also be extended to nonlinear inpainting operators such as EED.

Image Compression

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