About Me
I am a research associate in Dr CarolaBibiane Schönlieb's group Cambridge Image Analysis at the Department for Applied Mathematics and Theoretical Physics, University of Cambridge.
Previously I have been working as a research associate at the Centre for Inverse Problems and the Centre for Medical Image at the University College London (UCL). In 2015, I completed my PhD in medical imaging under the supervision of Professor Simon Arridge and Dr Kris Thielemans. My research is focussed on inverse problems in medical imaging, from models to algorithms; particularly concentrating on two aspects: i) joint reconstruction and ii) efficient stochastic algorithms. The problem of joint reconstruction naturally arises in modern medical imaging. Stateoftheart PETMRI (positron emission tomography and magnetic resonance imaging) scanners simultaneously acquire functional PET and anatomical MRI data. As function follows structure, both images are likely to show similar structures. A general aim of my research is to develop new methods that can exploit such expected correlation when these inverse problems are solved jointly. When dealing with real world data sets, one often encounters that algorithms to compute stateoftheart solutions (from a mathematical perspective) are not suitable for this large amount of data. The algorithms are often generic and therefore suboptimal for many specific problem classes. One problem class I am looking at are (dual) separable problems which are encountered in many applications, including PET, CT, parallel MRI. It is known that Kaczmarztype algorithms that operate on subsets of the data work very well on those. However, these only apply to the simple problem of solving linear systems and may fail to converge. In my research, I study modern algorithms that can cope with much more difficult problems and extend them to be efficient for these kind of problemswith convergence guarantees and robustness! My general research interests comprise inverse problems, nonsmooth / (non)convex / stochastic optimization, sparsity, and signal and image processing in particular application of these techniques to medical imaging. News

m.j.ehrhardt@damtp.cam.ac.uk Cambridge Image Analysis Department for Applied Mathematics and Theoretical Physics University of Cambridge Pavillion G 2.06, Centre for Mathematical Sciences, Wilberforce Road Cambridge CB3 0WA, United Kingdom 