Research Associate (wissenschaftlicher Mitarbeiter)

We offer a PhD position within the Data Science in Hamburg Helmholtz Graduate School for the Structure of Matter (DASHH).

If you consider applying please send a note with your CV  to timo.gerkmann@uni-hamburg.de

Further information on the school can be found here:

https://www.dashh.org

Our Project is entitled:

11. Phase Retrieval in Imaging and Speech Enhancement

Supervisors: Prof. Henry Chapman (DESY, CFEL, UHH, Fachbereich Physik), Prof. Timo Gerkmann (UHH, Fachbereich Informatik)

Abstract:

Advanced sources such as free-electron lasers produce intense and coherent beams of X-rays that are opening up new possibilities to image biological materials, such as single molecules, at atomic resolution. Since atomic-resolution lenses do not exist such methods usually rely upon retrieving the structural information encoded in the far-field coherent diffraction pattern [Shechtman et al, 2015]. This intensity pattern corresponds to the Fourier magnitude of the object, and is thus an incomplete measurement since the spectral phase cannot be measured. To reconstruct the original structure, the missing phase information needs to be retrieved . A very similar problem of phase retrieval is encountered in speech source separation and enhancement, which has received increasing attention recently [Gerkmann et al, 2015]. Just in the last few years, modern machine learning methods have been successfully applied to the problem aiming to obtain faster and more accurate results.
The goal of this project is to explore common concepts in X-ray imaging and speech enhancement. Recent advances in the application of machine learning in speech analysis will be transferred and tailored to X-ray imaging, obtaining deeper insights into this challenging inverse problem and providing new opportunities for high-resolution structure determination of biological systems.