Oberseminar Analysis


Dienstag, 03.11.2015, 14:15 Uhr

Variational approaches for image segmentation and registration

Benjamin Berkels, RWTH Aachen

Abstract: Image segmentation and registration are two of the fundamental image processing problems.
Segmentation is to decompose an image into disjoint regions that are roughly homogeneous in a suitable
sense. If three or more regions are sought, one speaks of multi-phase segmentation. We first review
how to find global minimizers of the non-convex binary Mumford-Shah model to solve the classical twophase
segmentation problem. Then, we propose a novel method for multi-phase segmentation of images
based on the Mumford-Shah model and high-dimensional local feature vectors. While the method was developed
for the segmentation of extremely noisy crystal images based on localized Fourier transforms, the
resulting framework is not tied to specific feature descriptors. For instance, using local spectral histograms
as features, it allows for robust texture segmentation.
Image registration is the task of transforming two or more images into a common coordinate system. After
a short introduction to variational image registration, we discuss how a series of hundreds of noisy scanning
transmission electron microscopy (STEM) images can be registered to obtain an improved image that
enables sub-picometer precision measurements of atom positions surpassing the quality attainable by single
shot STEM images. Particular challenges here are input data with a low signal-to-noise ratio and periodic
structures. Finally, non-rigid approaches in the context of medical imaging are discussed.

Interessierte sind herzlich eingeladen.

Zeit: 14:15 Uhr

Ort: Seminarraum 001, Erdgeschoss,  Pontdriesch 14-16 , 52062 Aachen