Search Results for author: Martin Welk

Found 10 papers, 1 papers with code

An Approach to Colour Morphological Supremum Formation using the LogSumExp Approximation

no code implementations21 Dec 2023 Marvin Kahra, Michael Breuß, Andreas Kleefeld, Martin Welk

These are based on the construction of a supremum or infimum with respect to an order over the tonal range in a certain section of the image.

Tackling the Class Imbalance Problem of Deep Learning Based Head and Neck Organ Segmentation

1 code implementation5 Jan 2022 Elias Tappeiner, Martin Welk, Rainer Schubert

Both the patch-size and the loss function are parameters with direct influence on the class imbalance and their optimization leads to a 3\% increase of the Dice score and 22% reduction of the 95% Hausdorff distance compared to the baseline, finally reaching $0. 8\pm0. 15$ and $3. 17\pm1. 7$ mm for the segmentation of seven HAN organs using a single and simple neural network.

Image Segmentation Medical Image Segmentation +3

Multivariate Medians for Image and Shape Analysis

no code implementations31 Oct 2019 Martin Welk

Having been studied since long by statisticians, multivariate median concepts found their way into the image processing literature in the course of the last decades, being used to construct robust and efficient denoising filters for multivariate images such as colour images but also matrix-valued images.

Denoising

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

Graph entropies in texture segmentation of images

no code implementations28 Dec 2015 Martin Welk

In the present paper we focus on texture descriptors in which the graph indices are entropy-based, and use them in a geodesic active contour framework for image segmentation.

Image Segmentation Segmentation +2

Multivariate Median Filters and Partial Differential Equations

no code implementations27 Sep 2015 Martin Welk

Multivariate median filters have been proposed as generalisations of the well-established median filter for grey-value images to multi-channel images.

Amoeba Techniques for Shape and Texture Analysis

no code implementations12 Nov 2014 Martin Welk

Morphological amoebas are image-adaptive structuring elements for morphological and other local image filters introduced by Lerallut et al. Their construction is based on combining spatial distance with contrast information into an image-dependent metric.

Texture Classification

A Robust Variational Model for Positive Image Deconvolution

no code implementations8 Oct 2013 Martin Welk

In this paper, an iterative method for robust deconvolution with positivity constraints is discussed.

Computational Efficiency Image Deconvolution +1

Analysis of Amoeba Active Contours

no code implementations30 Sep 2013 Martin Welk

They achieve similar results as the well-known geodesic active contour and self-snakes PDEs.

Algorithmic Optimisations for Iterative Deconvolution Methods

no code implementations26 Apr 2013 Martin Welk, Martin Erler

Both approaches are demonstrated in the context of Richardson-Lucy deconvolution but are not restricted to this method.

Image Deconvolution

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