MaRegularizationStrategiesAxdt

Chair for Computer Aided Medical Procedures & Augmented Reality
Lehrstuhl für Informatikanwendungen in der Medizin & Augmented Reality

Master's thesis: Manifold-based regularization of spherical functions in anisotropic X-ray dark-field tomography

Thesis by:
Advisor: Tobias Lasser
Supervision by: Matthias Wieczorek

Abstract

X-ray grating interferometry enables the simultaneous acquisition of absorption contrast, phase contrast and dark-field contrast. The directionally dependent dark-field data allows the tomographic reconstruction of anisotropic scattering coefficients inside the sample. This allows the recovery of structural orientations without the need to explicitly resolve them in the X-ray detector. The anisotropic scattering coefficients can be represented as spherical functions, such as spherical harmonics. Based on a closed-form spherical harmonics based forward model, the anisotropic dark-field data can be reconstructed in three dimensions. We refer to this technique as "Anisotropic X-ray Dark-field Tomography", or in short AXDT.

Tasks

Subject of this Master's thesis is the regularization of the spherical functions in Anisotropic X-ray Dark-field Tomography (AXDT). The aim is to investigate manifold-based regularization approaches to AXDT, to implement them in our existing C++ reconstruction framework and to evaluate them against existing non-regularized methods. The focus of the work may shift attention from the regularization term to the application of it, for example as denoising after reconstruction or alternating optimization during reconstruction or similar.

Requirements

Scientific programming, strong mathematic background, C++

Contact


ProjectForm
Title: Manifold-based regularization of spherical functions in anisotropic X-ray dark-field tomography
Abstract: X-ray grating interferometry enables the simultaneous acquisition of absorption contrast, phase contrast and dark-field contrast. The directionally dependent dark-field data allows the tomographic reconstruction of anisotropic scattering coefficients inside the sample. This allows the recovery of structural orientations without the need to explicitly resolve them in the X-ray detector. The anisotropic scattering coefficients can be represented as spherical functions, such as spherical harmonics. Based on a closed-form spherical harmonics based forward model, the anisotropic dark-field data can be reconstructed in three dimensions. We refer to this technique as "Anisotropic X-ray Dark-field Tomography", or in short AXDT.
Student:  
Director: Tobias Lasser
Supervisor: Matthias Wieczorek
Type: Master Thesis
Area: Medical Imaging
Status: open
Start: 2017/11/15
Finish:  
Thesis (optional):  
Picture:  


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