About me

This is me

I am an applied mathematician and assistant professor for computational and mathematical methods for imaging at the University of Hamburg. Therefore, I am member of Center of Optimization and Approximation.

My actual research covers large-scale inverse problems in biological and medical applications such as for example fluorescence microscopy, photo acoustic tomography and magnetic particle imaging. More precisely, I am working on variational regularization methods, dynamic inverse problems, Bayesian inversion, and approximation error modelling.

Members of the research group

PhD students
  • Christiane Schmidt
Master students
  • Lina Nawwas
  • Ikram Jumakulyyev
  • Ivan Pabon
  • Aoxiang Geng
  • Julian Muldoon
  • Inga Glöckner
  • Christopfer Fichtlscherer
Bachelor students
  • Dennis Hamann

Former members of the research group

  • Thomas Yu, Msc
  • Frederico Lucchesi, Msc

News

Our project "Multi-messenger x-ray science - Solving inverse problems of x-ray crystallography with constraints by x-ray emission spectra" has been accepted for funding from the DESY Strategy Fond


Upcoming conferences

I will give a talk at the EUCO in Trier in September 2018.


Research group

Welcome to Christiane Schmidt in our research group. She starts on 1st December her PhD project.


SIAM Imaging 2018

Our mini-symposium "Mathematical and Computational Aspects in Magnetic Particle Imaging" is accepted for the SIAM Imaging.


Old news

My research

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Published publications

Article

    Bathke, C.; Kluth, T.; Brandt, C. & Maaß, P.: Improved image reconstruction in magnetic particle imaging using structural a priori information. International Journal On Magnetic Particle Imaging, 3(1):2017.
online availble here

    Storath, M.; Brandt, C.; Hofmann, M.; Knopp, T.; Salamon, J.; Weber, A. & Weinmann, A.: Edge preserving and noise reducing reconstruction for magnetic particle imaging. IEEE Transactions on Medical Imaging, 36(1):74-85, 2017.
doi:10.1109/TMI.2016.2593954

    Brandt, C., Maass, P., Piotrowska-Kurczewski, I., Schiffler, S., Riemer,O., and Brinksmeier, E.: Mathematical methods for optimizing high precision cutting operations. International Journal of Nanomanufacturing, 8(4):306–325, 2012.
doi:10.1504/IJNM.2012.048580.

    Brandt, C., Niebsch, J., Ramlau, R., and Maass, P.: Modeling the influence of unbalances for ultra-precision cutting processes. ZAMM - Journal of Applied Mathematics and Mechanics / Zeitschrift für Angewandte Mathematik und Mechanik, 91(10):795–808, 2011.
doi:10.1002/zamm.201000155.

    Piotrowska, I., Brandt, C., Karimi, H. R., and Maass, P.: Mathematical model of micro turning process The International Journal of Advanced Manufacturing Technology, Volume 45(1):33–40, 2009.
doi:10.1007/s00170-009-1932-z.

    Brandt,C., Niebsch, J., and Vehmeyer, J.: Modelling of ultra-precision turning process in consideration of unbalances. Advanced Materials Research, 223:839–848, 2011.
doi:10.4028/www.scientific.net/AMR.223.839

    Gossiaux, P.B., Aichelin, J., Brandt, C., Gousset, T., and Peigné, S.: Energy loss of a heavy quark produced in a finite-size quark-gluon plasma. Journal of Physics G: Nuclear and Particle Physics, 34(8):S817, 2007.
doi:10.1088/0954-3899/34/8/S103.

    Gossiaux, P.B., Peigné, S., Brandt, C., and Aichelin, J.: Energy loss of a heavy quark produced in a finite size medium. Journal of High Energy Physics, 4(04):012, 2007.
doi:10.1088/1126-6708/2007/04/012.

Thesis

    Brandt, C.: Regularization of Inverse Problems for Turning Processes. Ph.D. thesis, University of Bremen, Logos, 2012
available by Logos

Book chapter

    Andres, M., Blum, H., Brandt, C., Carstensen, C., Maass, P., Niebsch, J., Rademacher, R., Ramlau, R., Schröder, A., Stephan, E.-P., and Wiedemann, S.: Process Machine Interactions, Adaptive finite elements and mathematical optimization methods. Lectures Notes in Production Engineering. Springer, 2013.
doi:DOI:10.1007/978-3-642-32448-2.

    Brandt, C., Krause, A., Niebsch, J., Vehmeyer, J., Brinksmeier, E., Maass, P., and Riemer, O.: Process Machine Interactions, Surface Generation Process with Consideration ot the Balancing State in Diamond Machining. Lectures Notes in Production Engineering. Springer, 2013.
doi:DOI: 10.1007/978-3-642-32448-2.

    Piotrowska-Kurczewski, I., Brandt, C., Maass, P., and Riemer, O.: Micro Metal Forming, chapter Simulation technologies - Inverse Modelling, pages 368–379. Springer, 2013.

    Brandt, C., Piotrowska, I., Karimi, H., Niebsch, J., Ramlau, R., Krause, A., Riemer, O., and Maass, P.: Process machine interaction model for turning processes. International Journal of Control Theory and Applications, 1(2):145–153, 2008.

Conference proceedings (reviewed)

    Storath, M., Brandt, C., Hofmann, M., Knopp, T. , Weber, A., Weinmann, A.: Fused lasso regularization for magnetic particle imaging. Proceedings of the International Workshop on Magnetic Particle Imaging 2016, March 16-18. 2016, Lübeck, Germany, 2016.

    Brandt, C., Niebsch, J., and Vehmeyer, J.: Modelling of ultra-precision turning process in consideration of unbalances. In Outeiro, J.C., editor, Proceedings of the 13th CIRP Conference on Modeling of Machining Operations, May 12-13. 2011, Sintra, Portugal, volume 223, pages 839–848. 2011. www.scientific.net/AMR.223.839>

    Niebsch, J., Ramlau, R., and Brandt, C.: On the interaction of unbalances and surface quality in ultra-precision cutting machinery. In SIRM 2011, Darmstadt, Germany. 2011.

    Brandt, C., Niebsch, J., Maass, P., and Ramlau, R.: Simulation of process machine interaction for ultra precision turning. In Proceedings of the 2nd International Conference on Process Machine Interactions, June 10-11, 2010, Vancouver, Canada. 2010.

    Brandt, C., Krause, A., Brinksmeier, E., and Maass, P.: Force modelling in diamond machining with regard to the surface generation process. In Proceedings of the 9th International Conference and Exhibition on Laser Metrology, machine tool, CMM and robotic performance, LAMDAMAP 2009, London, 30.06.-02.07.2009, pages 377–386. 2009.

    Gossiaux, P.B., Peigné, S., Brandt, C., and Aichelin, J.: Energy loss of a heavy quark produced in a finite-size quark-gluon plasma
doi:10.1088/0954-3899/34/8/S103. QM2006 Proceedings; 19th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions (QM2006), Shanghai, China, November 14-20, 2006.

Find my papers on researchgate

Upcoming talks

The next talks I will give ....

Recovery from model errors in magnetic particle imaging - approximation error modeling approach.
at Siam Imaging 2018
May 2018, Bologna

I am invited to give a plenary talk at the EUCCO 2018 in Trier during September 2018.

Conference talks

List of all talks in the last years

2018

Challenges in image reconstruction for 4D magnetic particle imaging
GAMM, March 2018
München, China
Invited by Felix Krahmer and Benedict Wirth

2017

Approximation error modelling for magnetic particle imaging
Conference on Applied Inverse Problems, May 2017
Hangzhou, China

2016

Edge Preserving Image Reconstruction for 4D Magnetic Particle Imaging
Imaging with modulated/incomplete data, 22.-24.9.2016
Graz, Austria


Image reconstruction for 4D Magnetic Particle Imaging
Inverse problems seminar at Helsinki University, 15.6.2016
Helsinki, Finland
Invited by Samuli Siltanen

Edge Preserving Image Reconstruction for 3D Magnetic Particle Imaging
SIAM Imaging 2016
23.-26.5.2016, Albuquerque, USA
Invited by Cecile Louchet

Fused Lasso Regularization for Magnetic Particle Imaging
International Workshop on Magnetic Particle Imaging IWMPI 2016
16.-18.3.2016, Lübeck, Germany

2015

Fused Lasso based Image Reconstruction for Magnetic Particle Imaging
Inverse Days 2015, 8.-10.12.2015
Lappeenranta, Finland

Sparse Image Reconstruction for Magnetic Particle Imaging
Mini-symposium on "Mathematical Methods for MPI" at the DMV 2015, 21.-25.9.2015,Hamburg
Invited by Wolfgang Erb

Photoacoustic Tomography: Sparse Image Reconstruction Using Shearlets
Applied Inverse Problems 2015
May 2015, Helsinki, Finland


2014

Photoacoustic Tomography: Sparse Image Reconstruction Using Shearlets
Seminar AG Imaging, University Münster,
3.12.2014
Invited by Martin Burger

Solving inverse problems for fluorescence microscopy
DSR seminar at the Helmholtz Institut München
7.7.2014
Invited by Frank Filbir

Sparse Image Reconstruction for Photoacoustic Tomography Using Shearlets
Workshop "Wavelets and Applications"
22.5.2014, Université Libre de Bruxelles, Belgium
Invited by Christine de Mol

Inversion of Photoacoustic Tomography using l1-norm Regularization of Shearlet Coefficients
SIAM Conference on Imaging Science
12-14.5.2014, Hongkong, China


Faltungsprobleme in der Biologie
Workshop Mathematics for Imaging
02.-04.04.2014, Bad Harzburg

Group photo of the participants
Image Reconstruction for Photoacoustic Tomography using Shearlets,
Mecklenburger Workshop "Approximationsmethoden und schnelle Algorithmen, 17-20.03.2014, Hasenwinkel



2013

Inversion of Photoacoustic Tomography using l1-norm Regularization of Shearlet Coefficients
Advances In Mathematical Image Processing, 30.09.-2.10.2013, Annweiler

Effective Discretization for Regularized Algebraic Reconstruction Techniques,
Applied Inverse Problems Conference AIP 2013, 1.-5.07.2013, Daejeon, Korea

2012

Sparsity Optimization in High Precision Cutting: an ODE based inverse problem
Inverse Problems: Modelling and Simulation 2012, 21.-26.05.2012, Antalya, Turkey

Parameter Identification in Ultra Precision Cutting: an ODE based Inverse Problem,
Oberseminar Analysis Universität Osnabrück, 14.05.2013, Osnabrück
(invited talk)

Parameteridentifikation bei gewöhnlichen Differentialgleichungen von hochpräzisen Zerspanprozessen,
Winterseminar der AG Technomathematik der Universität Bremen, 2012, 28.-29.2.2912, Ganderkesee

Magnetic particle imaging

MPI is a novel imaging modality for biomedical diagnostics ...

Magnetic Particle Imaging (MPI) is a novel imaging modality for biomedical diagnostics that determines the spatial distribution of magnetic nanoparticles by measuring the non-linear magnetization response of the particles to an applied magnetic field. The advantages of MPI are the high dynamic spatial and temporal resolution and that it does not employ any ionizing radiation.

Actual research projects on MPI

Bimodal reconstructions for MRI-MPI, joint work with Christine Bathke, Tobias Kluth and Peter Maass

Joint reconstruction in multi-color MPI, joint work with Martin Storath, Martin Hofmann and Tobias Knopp

Approximation error modelling for model-based MPI, joint work with Aku Seppänen

Time based regularization for 4D MPI, joint work Andreas Hauptmann

Mathematical methods for Magnetic Particle Imaging

In this scientific network founded by the German Research Foundation ....

Magnetic Particle Imaging (MPI) is a novel imaging modality for biomedical diagnostics that determines the spatial distribution of magnetic nanoparticles by measuring the non-linear magnetization response of the particles to an applied magnetic field. The advantages of MPI are the high dynamic spatial and temporal resolution and that it does not employ any ionizing radiation.

It is a joint research within of the scientific network "Mathematical methods for Magnetic Particle Imaging (MIEM). The network funded by the DFG consists of 9 researchers and it is lead by Dr. Wolfgang Erb from the University of Lübeck. For more information, see the official MIEM homepage.

Visit Network Webpage

Approximation error modeling in large scale inverse problems in imaging (09/2015-08/2018)



The main objective of this research is the development of mathematical methods for three imaging modalities in biological and medical applications: fluorescence microscopy (FM), photo-acoustic tomography (PAT) and magnetic particle imaging (MPI). All imaging applications have in common that the desired object such as in PAT and MPI the cancer cell in the human body is not directly observable but can be measured only indirectly.

In order to reconstruct the desired object, one has to solve the so-called inverse problem. In this project, mathematical methods for solving inverse problems are developed which consider modelling errors and uncertainties of the underlying models in the inversion. It is expected that the image reconstruction quality will be increased significantly in all three applications. In particular, the improvements are assumed to contribute to the development of PAT and MPI as medical imaging techniques in clinical practice.

This project is founded by the Academy of Finland.

Related Publications:

    Brandt, C.; Seppänen, A. : Recovery from errors due to domain truncation in magnetic particle imaging -- approximation error modeling approach. Journal of Mathematical Imaging and Vision, 2018.
10.1007/s10851-018-0807-z

Preprints

    Erb, W.; Weinmann, A.; Ahlborg, M.; Brandt, C.; Bringout, G.; Buzug, T.M.; Frikel, J.; Kaethner, C.; Knopp, T.; März, T.; Möddel, M.; Storath, M.; Weber, A.: Mathematical Analysis of the 1D Model and Reconstruction Schemes for Magnetic Particle Imaging. Inverse Problems, 2018.

    Brandt, C.; Seppänen, A. : Recovery from errors due to domain truncation in magnetic particle imaging -- approximation error modeling approach. Journal of Mathematical Imaging and Vision, 2018.
10.1007/s10851-018-0807-z

Research interests

I am currently working on inversion methods ...

I am currently working on inversion methods for magnetic particle imaging and as well as for deconvolution problems in fluorescence microscopy. Moreover, I am studying how to use shearlets for sparse reconstruction in photoacoustic tomography.

More generally my research interests are :
  • Medical and biological imaging
  • Modelling and simulation
  • Regularization with sparsity constraints
  • Dynamic inverse problems
  • Bayesian inversion and approximation error modelling

Collaborations

Dr. Martin Storath

Image Analysis and Learning Group
University of Heidelberg

Prof. Tobias Knopp, Dr. Martin Hofmann

Universitätsklinikum Hamburg-Eppendorf
Sektion für Biomedizinische Bildgebung

Institut für Biomedizinische Bildgebung
Technische Universität Hamburg

Dr. Wolfgang Erb

University of Hawaii at Manoa
USA

Prof. Maass, Christine Bathke, Dr. Tobias Kluth

Center for Industrial Mathematics
Universiy of Bremen

Andreas Hauptmann

University College London
Great Britain

Aku Seppänen

University of Eastern Finland
Kuopio, Finland

Teaching

Actual courses

Optimization

I will give the bachelor course on optimization during sommer semester 2018. The course will cover a introduction to optimization techniques in finite dimensions including theory and practical implementations.


Course webpage


Wirkung sucht Ursache - Inverse Probleme in den Naturwissenschaften

I organise together with Stefan Heitmann the Lothar Collatz Seminar

Inverse Probleme nennt man in den Naturwissenschaften solche Fragestellungen, in denen man von beobachtbaren Wirkungen auf deren Ursachen schließen möchte. Bildgebende medizinische Verfahren sind ein inzwischen alltägliches Beispiel, die Wettervorher-sage ein anderes. In dieser Vortragsreihe beleuchten wir nur scheinbar verschiedene Anwendungen und deren gemeinsames mathematisches Rückgrat.

Supervision of theses

I am offering topics for thesis such that inverse problems, image reconstruction, optimization methods and Bayesian inversion related to applications in bio/medical imaging. There is also the possibility to have a joint project with the Medical university center Eppendorf (UKE). Current theses are:
  • Aoxiang Geng, Improving calibration measurements in magnetic particle imaging by compressed sensing, Msc University of Hamburg, superivision together with Dr. Martin Möddel (UKE HH Eppendorf)
  • Ikram Jumakulyyev, Joint motion estimation and image reconstruction by incorporating a priori edge information, Msc University of Hamburg
  • Ivan Pabon, Adaptive spatio-temporal regularization for robust nonlinear registration in artifact-affected 4D medical images, Msc University of Hamburg, supervision together with Dr. Rene Wernder (UKE HH Eppendorf)
  • Lina Nawwas, Bias-reduction for sparsity promoting regularization in magnetic particle imaging, Msc, University of Hamburg
  • Dennis Hamann, Non-convex stochastic optimization, Bsc, University of Hamburg
Examplary open topics can be fined here.

Previous Courses

Computer tomography

Course on computer tomography and short introduction to inverse problems (Winter semester 2017)

Optimization

Course on convex optimization in infinite dimesions (Summer semester 2017)

Inverse Problems

Exercises on inverse problems during winter semester 2016

Inverse Problems

course together with Prof. Kunis (Summer semester 2014)

Mathematics I for production engineering

2 tutorials during winter semester 2012

Analysis II

2 tutorials during summer semester 2012

Supervised theses and projects


  • Thomas Yu, Optimization for HDR brachytherapy, Msc 2017, University of Hamburg, supervision together with Prof. Schlaefer, TUHH
  • Federico Lucchesi, Adversarial domain adaption for semantic segmentation Msc 2017, Unversity of Hamburg, supervision together with Prof. Vazquez, Universitat Autònoma de Barcelona
  • Tuukka Heiskanen, Superresolution in microscopy, Bsc 2017, University of Eastern Finland
  • Arun Pandey and Ikram Jumakulyyev, Optical flow estimation, Summer project 2017, University of Hamburg
  • Tuukka Heiskanen, Deconvolution in fluorescence microscopy, Summer trainee 2016, University of Eastern Finland
  • Phil Gralla, Mathematical methods for controlling ultra precise processes of machining, Bsc 2012, Secondary Supervisor with Dr. I. Piotrowska, University of Bremen.
  • Philipp Welz, Regenerative chattering for micro cutting processes, Bsc 2011, together with Prof. P. Maass, University of Bremen.
  • Florian Dollinger, A continuous model for determination of dwell periods for a form corrective polishing process, Diploma thesis 2010 , Secondary supervision with Dr. I. Piotrowska, University of Bremen.
  • Thi Bach, Mathematical optimization of micro polishing, Student project (12 month) 2010, Main supervision together with Dr. I. Piotrowska, University Bremen.

Short CV

Academic positions

Since 03 2017

Assistant professor at the University of Hamburg.

Research group: Mathematical and computational methods in medical imaging

09/2015 - 02 2017

Academy post-doctoral researcher in the Inverse Problems group at the Eastern University of Finland in Kuopio.

  • Academy of Finland project "Approximation error modelling in large scale inverse problems in imaging" (2015-2018)

Kuopio

04/2013 - 08/2015

Post-doctoral researcher in the research group "Applied and Numerical Analysis" at the University Osnabrück working within the

  • Helmholtz young investigator group "Fast algorithms for biomedical imaging" (Helmholtz Zentrum München)

Osnabrueck

01/2008 - 04/2013

Research assistant in the at the WG Industrial Mathematics at the Center for Industrial Mathematics at the University Bremen, working within the

  • DFG priority program SPP1180, project "Mathematical methods for precision balancing of machine tool" (2008-2011)
  • SFB "Micro cold forming" (2012-2013)

Zetem

11/2007 - 12/2007

Research assistant in the research group "Solid physics" at the University Rostock, working within the SFB 652, project B1 Exciton matter in mesoscopic potentials

  • Tasks: Implementation of a phase retrieval algorithm for ultrashort laser pulses

Rostock

Education

2008 - 2012

Doctoral studies in the research group "Industrial mathematics" at the University Bremen

2012: Doctorate degree in mathematics, University Bremen

  • Thesis: "Regularization of Inverse Problems for Turning Processes"
  • Supervisor: Prof Peter Maass

Bremen

10/2001 - 08/2007

08/2007

Diploma studies in mathematics , University Rostock

Diploma degree in mathematics, University Rostock

  • Thesis: "Numerical phase reconstruction" (Numerical phase retrieval)
  • Supervisor: Prof Manfred Tasche

Rostock

10/2002 - 08/2007

10/2006 - 07/2006

08/2007

Diploma studies in physics, University Rostock

Master studies in physics, Erasmus exchange program, University Nantes

Master degree in physics, University Nantes (France)

  • Master thesis: "Energy loss of a parton in a quark-gluon-plasma"
  • Supervisor: Stéphane Peigné

Nantes

Contact me

Office adress

Universität Hamburg
Department of Mathematics
Bundesstraße 55
20146 Hamburg

Office: Geomatikum 104

Phone: +49 -40 42838 4076
Mail: Christina.Brandt(ad)uni-hamburg.de

Postal address

Universität Hamburg
Fachbereich Mathematik
Bundesstraße 55
20146 Hamburg
Germany