• From June 2022 on I am Visiting Researcher at the Department of Electrical and Electronic Engineering at Imperial College London.
• Since September 2021 I am a research associate in Prof. Dr. Dr. h.c. Peter Maaß's working group at University of Bremen.
• During Summer Semester 2021 (01.04.2021 - 30.09.2021) I was interim professor at the Center for Industrial Mathematics at University of Bremen.
• From March 2020 to December 2020 I was Visiting Researcher in Dr. Ayush Bhandari's working group at Imperial College London.
• From October 2014 to September 2021 I was a research assistant/associate in Prof. Dr. Armin Iske's working group at University of Hamburg.

• Approximation theory
• Inverse problems (esp. computerized tomography)
• Machine learning (esp. for inverse problems)
• Signal processing and image analyse

Dissertation

• Matthias Beckmann
  Error Estimates and Convergence Rates for Filtered Back Projection Reconstructions.
  Universität Hamburg, 2018.

Preprints

• Matthias Beckmann and Judith Nickel
  Optimized Filter Functions for Filtered Back Projection Reconstructions.
  arXiv: 2408.06471.

Peer-reviewed Journal Articles

• Matthias Beckmann and Nick Heilenkötter
  Equivariant Neural Networks for Indirect Measurements.
  SIAM Journal on Mathematics of Data Science 6(3), 2024, 579-601.
  DOI: 10.1137/23M1582862.
  
• Matthias Beckmann, Ayush Bhandari and Meira Iske
  Fourier-Domain Inversion for the Modulo Radon Transform.
  IEEE Transactions on Computational Imaging 10, 2024, 653-665.
  DOI: 10.1109/TCI.2024.3388871.
• Matthias Beckmann, Ayush Bhandari and Felix Krahmer
  The Modulo Radon Transform: Theory, Algorithms and Applications.
  SIAM Journal on Imaging Sciences 15(2), 2022, 455-490.
  DOI: 10.1137/21M1424615.
• Matthias Beckmann, Peter Maass and Judith Nickel
  Error Analysis for Filtered Back Projection Reconstructions in Besov Spaces.
  Inverse Problems 37(1), 2021, 014002.
  DOI: 10.1088/1361-6420/aba5ee.
• Matthias Beckmann and Armin Iske
  Saturation Rates of Filtered Back Projection Approximations.
  Calcolo 57(1), 2020, 12.
  DOI: 10.1007/s10092-020-00360-y.
• Matthias Beckmann and Armin Iske
  Error Estimates and Convergence Rates for Filtered Back Projection.
  Mathematics of Computation 88(316), 2019, 801-835.
  DOI: 10.1090/mcom/3343.

Peer-reviewed Proceedings

• Dominik Hauser, Matthias Beckmann, Günther Koliander and H. Siegfried Stiehl
  On Image Processing and Pattern Recognition for Thermograms of Watermarks in Manuscripts - A First Proof-of-Concept.
  International Conference on Document Analysis and Recognition (ICDAR), 2024, 91-107.
  DOI: 10.1007/978-3-031-70543-4_6.
• Matthias Beckmann and Ayush Bhandari
  MR. TOMP: Inversion of the Modulo Radon Transform (MRT) via Orthogonal Matching Pursuit (OMP).
  IEEE International Conference on Image Processing (ICIP), 2022, 3748-3752.
  DOI: 10.1109/ICIP46576.2022.9897428.
• Matthias Beckmann, Felix Krahmer and Ayush Bhandari
  HDR Tomography via Modulo Radon Transform.
  IEEE International Conference on Image Processing (ICIP), 2020, 3025-3029.
  DOI: 10.1109/ICIP40778.2020.9190878.
• Ayush Bhandari, Matthias Beckmann and Felix Krahmer
  The Modulo Radon Transform and its Inversion.
  European Signal Processing Conference (EUSIPCO), 2020, 770-774.
  DOI: 10.23919/Eusipco47968.2020.9287586.
• Matthias Beckmann and Armin Iske
  Convergence Rates for Hölder-Windows in Filtered Back Projection.
  IEEE International Conference on Sampling Theory and Applications (SampTA), 2019.
  DOI: 10.1109/SampTA45681.2019.9030855.
• Matthias Beckmann and Armin Iske
  Sobolev Error Estimates for Filtered Back Projection Reconstructions.
  IEEE International Conference on Sampling Theory and Applications (SampTA), 2017, 251-255.
  DOI: 10.1109/SAMPTA.2017.8024439.
• Matthias Beckmann and Armin Iske
  Error Estimates for Filtered Back Projection.
  IEEE International Conference on Sampling Theory and Applications (SampTA), 2015, 553-557.
  DOI: 10.1109/SAMPTA.2015.7148952.

Other Proceedings

• Matthias Beckmann and Armin Iske
  On the Error Behaviour of the Filtered Back Projection.
  Proc. Appl. Math. Mech. (PAMM) 16(1), 2016, 833-834.
  DOI: 10.1002/pamm.201610405.

Technical Reports

• Matthias Beckmann and Armin Iske
  Approximation of Bivariate Functions from Fractional Sobolev Spaces by Filtered Back Projection.
  Hamburger Beiträge zur Angewandten Mathematik (HBAM) 2017-05, 2017.
• Matthias Beckmann and Armin Iske
  Analysis of the Inherent Reconstruction Error in Filtered Back Projection.
  Hamburger Beiträge zur Angewandten Mathematik (HBAM) 2016-01, 2016.

Lecture Notes

• Matthias Beckmann
  Lecture Notes on Computerized Tomography.
  arXiv: 2312.02393.
  

Invited Talks

• IEEE International Workshop on Machine Learning for Signal Processing (MLSP2024)
  22. - 25. September 2024, London, GB.
  Talk: Equivariant Neural Networks for Indirect Measurements.
  Invited to Special Session on Learning-Based Solutions to Inverse Problems.
• 16th International Workshop on Document Analysis Systems (DAS2024)
  30. - 31. August 2024, Athens, Greece.
  Demo: On Image Processing and Pattern Recognition for Thermograms of Watermarks in Manuscripts - A First Proof-of-Concept.
  
• SIAM Conference on Imaging Science (IS2024)
  28. - 31. May 2024, Atlanta, US.
  Talk: Optimal Transport in Imaging and its Application to Thermography-Based Watermark Recognition.
  Invited to Minisymposium MS68: Computational Optimal Transport meets Imaging.
• 11th Applied Inverse Problems Conference (AIP2023)
  04. - 08. September 2023, Göttingen, Germany.
  Talk: Inversion of the Modulo Radon Transform via Orthogonal Matching Pursuit.
  Invited to Minisymposium MS22: Imaging with Non-Linear Measurements: Tomography and Reconstruction from Phaseless or Folded Data.
• 10th International Congress on Industrial and Applied Mathematics (ICIAM2023)
  21. - 25. August 2023, Tokyo, Japan.
  Talk: High Dynamic Range Tomography via Modulo Radon Transform.
  Invited to Minisymposium MS622: Inverse Problems and Imaging.
• SIAM Conference on Computational Sciences and Engineering (CSE2023)
  26. February - 3. March 2023, Amsterdam, Netherlands.
  Talk: High Dynamic Range Tomography via Modulo Radon Transform.
  Invited to Minisymposium MS61: Problems and Solutions in 3-D Reconstruction.
• Inverse Problems: Modelling and Simulation (IPMS2022)
  22. May - 28. May 2022, Mellieha, Malta.
  Talk: The Modulo Radon Transform and Its Inversion.
  Invited to Minisymposium M6: Generalized Radon Transforms and Applications.
• SIAM Conference on Imaging Science (IS2022)
  21. March - 25. March 2022, Berlin, Germany.
  Talk: The Modulo Radon Transform and Its Inversion.
  Invited to Minisymposium MS8: Tomographic Image Reconstruction with Radon-Type Transforms.
• Oberseminar: Mathematics of Data Analysis (TUM2017)
  18. May 2017, Technische Universität München, München, Germany.
  Talk: Sobolev Error Estimates for Filtered Back Projection Reconstructions.

Contributed Talks

• 18th International Conference on Document Analysis and Recognition (ICDAR2024)
  30. August - 04. September 2024, Athens, Greece.
  Poster: On Image Processing and Pattern Recognition for Thermograms of Watermarks in Manuscripts - A First Proof-of-Concept.
  
• Conference on Harmonic Analysis and Applications (Strobl2024)
  09. - 15. June 2024, Strobl, Austria.
  Poster: Fourier-Domain Inversion for the Modulo Radon Transform.
  
• SIAM Conference on Imaging Science (IS2024)
  28. - 31. May 2024, Atlanta, US.
  Poster: Inversion of the Modulo Radon Transform via Orthogonal Matching Pursuit.
  
• 94. Annual Meeting of GAMM (GAMM2024)
  18. - 22. March 2024, Magdeburg, Germany.
  Talk: Fourier-Domain Inversion for the Modulo Radon Transform.
  
• 93. Annual Meeting of GAMM (GAMM2023)
  30. May - 02. June 2023, Dresden, Germany.
  Talk: Inversion of the Modulo Radon Transform via Orthogonal Matching Pursuit.
  
• 92. Annual Meeting of GAMM (GAMM2022)
  15. - 19. August 2022, Aachen, Germany.
  Talk: High Dynamic Range Tomography via Modulo Radon Transform.
  
• Joint Annual Meeting of DMV and ÖMG (DMV2021)
  27. September - 01. October 2021, Passau, Germany.
  Talk: Error Analysis for Filtered Back Projection Reconstructions.
  
• SIAM Conference on Imaging Science (IS2020)
  06. - 17. July 2020, Toronto, Canada.
  Talk: High Dynamic Range Tomography via Modulo Radon Transform.
• 13th International Conference on Sampling Theory and Applications (SampTA2019)
  08. - 12. July 2019, Université de Bordeaux, Bordeaux, France.
  Talk: Convergence Rates for Hölder-Windows in Filtered Back Projection.
• 16th International Conference on Approximation Theory (AT2019)
  19. - 22. May 2019, Vanderbilt University, Nashville, TN, USA.
  Talk: Approximation of Bivariate Functions by Filtered Back Projection.
• Mecklenburg Workshop "Approximation Methods and Fast Algorithms" (MW2018)
  10. - 14. September 2018, University of Lübeck, Hasenwinkel, Germany.
  Talk: Saturation Rates for Filtered Back Projection.
• SIAM Conference on Imaging Science (IS2018)
  05. - 08. June 2018, Bologna, Italy.
  Talk: Error Analysis for Filtered Back Projection Reconstructions in Fractional Sobolev Spaces.
• YR Meeting & CSE Workshop "Recent Trends and Future Developments in Computational Science & Engineering" (CSE2018)
  26. - 29. March 2018, Technical University Hamburg, Plön, Germany.
  Talk: Saturation Rates for Filtered Back Projection Reconstructions.
• 89. Annual Meeting of GAMM (GAMM2018)
  19. - 23. March 2018, München, Germany.
  Talk: Saturation Rates for Filtered Back Projection Reconstructions.
• GAMM-MSIP Workshop on Mathematical Signal Processing and Data Analysis (GAMM-MSIP2017)
  18. - 20. September 2017, University of Bremen, Bremen, Germany.
  Talk: Error Analysis for Filtered Back Projection Reconstructions in Fractional Sobolev Spaces.
• 12th International Conference on Sampling Theory and Applications (SampTA2017)
  03. - 07. July 2017, Tallinn University, Tallinn, Estland.
  Talk: Sobolev Error Estimates for Filtered Back Projection Reconstructions.
• 88. Annual Meeting of GAMM (GAMM2017)
  06. - 10. March 2017, Weimar, Germany.
  Talk: Error Analysis for Filtered Back Projection Reconstructions in Fractional Sobolev Spaces.
• IM-Workshop on Signals, Images, and Approximation (IM2017)
  27. February - 03. March 2017, Bernried, Germany.
  Talk: Error Analysis for Filtered Back Projection Reconstructions in Fractional Sobolev Spaces.
• 27. Rhein-Ruhr-Workshop on Applied Analysis (RRW2017)
  27. - 28. January 2017, Bestwig, Germany.
  Poster: Analysis of the Inherent Reconstruction Error in Filtered Back Projection.
• International Workshop on Mathematical Imaging and Emerging Modalities (MIEM2016)
  27. - 30. June 2016, University of Osnabrück, Osnabrück, Germany.
  Talk: Analysis of the Inherent Reconstrution Error in Filtered Back Projection.
• SIAM Conference on Imaging Science (IS2016)
  23. - 26. May 2016, Albuquerque, NM, USA.
  Talk: Error Estimates and Convergence Rates for Filtered Back Projection.
• YR Meeting & CSE Workshop "Recent Trends and Future Developments in Computational Science & Engineering" (CSE2016)
  21. - 24. March 2016, University of Hamburg, Plön, Germany.
  Talk: On the Error Behaviour of the Filtered Back Projection.
• Annual Meeting of DMV and GAMM (GAMM2016)
  07. - 11. March 2016, Braunschweig, Germany.
  Talk: On the Error Behaviour of the Filtered Back Projection.
• IM-Workshop on Signals, Images, and Approximation (IM2016)
  29. February - 04. March 2016, Bernried, Germany.
  Talk: Error Estimates and Convergence Rates for Filtered Back Projection.
• 26. Rhein-Ruhr-Workshop on Applied Analysis (RRW2016)
  29. - 30. January 2016, Bestwig, Germany.
  Talk: Fehlerabschätzungen und Konvergenzraten für die gefilterte Rückwärtsprojektion.
• ICERM Workshop "Computational and Analytical Aspects of Image Reconstruction" (CAAIR2015)
  13. - 17. July 2015, Brown University, Providence, RI, USA.
  Poster: Error Estimates for Filtered Back Projection.
• 11th International Conference on Sampling Theory and Applications (SampTA2015)
  25. - 29. May 2015, American University, Washington, DC, USA.
  Talk: Error Estimates for Filtered Back Projection.
• YR Meeting & CSE Workshop "Recent Trends and Future Developments in Computational Science & Engineering" (CSE2015)
  09. - 13. March 2015, Christian-Albrechts-Universität zu Kiel, Plön, Germany.
  Talk: L² - Error Estimates for Filtered Back Projection.
• 25. Rhein-Ruhr-Workshop on Applied Analysis (RRW2015)
  30. - 31. January 2015, Bestwig, Germany.
  Talk: Fehlerabschätzungen für die gefilterte Rückwärtsprojektion.

Supervision of Student Theses

• Current: Tom Bustert, M.Sc. Industrial Mathematics and Data Analysis, University of Bremen
  
• Current: Carla Dittert, M.Sc. Mathematics, University of Bremen
  
• 08/2024: Jürgen Jeschke, M.Sc. Mathematics, University of Bremen
  Generalized Modulo Operators and Recovery Approaches for the Induced Modulo Radon Transform
• 09/2023: Lia Pribnow, M.Sc. Industrial Mathematics, University of Bremen
  The Radon Cumulative Distribution Transform in Image Classification
• 12/2022: Meira Iske, M.Sc. Mathematics, University of Bremen
  Inversion of the Modulo Radon Transform via Direct Fourier Reconstruction
• 11/2022: Nick Heilenkötter, M.Sc. Industrial Mathematics, University of Bremen
  Equivariant Neural Networks for Indirect Measurements
• 03/2021: Max Lewerenz, B.Sc. Mathematics, University of Hamburg
  Support vector machines from statistical learning theoretic point of view (in German)
• 06/2020: Tigran Andrikyan, B.Sc. Mathematics, University of Hamburg
  The short time Fourier transform and Gabor frames in time-frequency analysis (in German)

Courses at University of Bremen

• WiSe 2024/2025: Advanced Topics in Image Processing - The Beauty of Variational Calculus
  Lecture (with Prof. Dr. Dr. h.c. Peter Maaß)
• SoSe 2024: Mathematical Foundations of Machine Learning
  Lecture
• WiSe 2023/2024: Inverse Problems in Imaging
  Lecture (with Prof. Dr. Dr. h.c. Peter Maaß)
• SoSe 2023: Mathematical Foundations of Machine Learning
  Lecture
• WiSe 2022/2023: Inverse Problems
  Lecture
• SoSe 2022: Mathematical Foundations of Machine Learning
  Lecture
• WiSe 2021/2022: Mathematical Methods for Signal and Image Processing
  Lecture
• SoSe 2021: Mathematical Foundations of Machine Learning
  Lecture and Exercise Class
• SoSe 2021: Mathematics 2b for Production Engineers
  Lecture

Courses at University of Hamburg

• WiSe 2020/2021: Computer Tomography
  Lecture
• WiSe 2020/2021: Approximation
  Lecture
• SoSe 2020: Project: Machine Learning
  Project
• WiSe 2019/2020: Computer Tomography
  Lecture and Exercise Class
• SoSe 2019: Functional Analysis
  Exercise Class
• WiSe 2018/2019: (Pro)Seminar über Approximation
  Seminar (with Prof. Dr. Armin Iske)
• WiSe 2017/2018: Approximation
  Exercise Class
• WiSe 2016/2017: Approximation
  Exercise Class
• WiSe 2015/2016: Approximation
  Exercise Class
• WiSe 2014/2015: Approximation
  Exercise Class

Courses at Technical University Hamburg

• SoSe 2020: Complex Functions
  Exercise Classes
• SoSe 2019: Complex Functions
  Exercise Classes
• WiSe 2018/2019: Differential Equations I
  Exercise Classes
• WiSe 2018/2019: Analysis III
  Exercise Classes
• SoSe 2018: Analysis II
  Exercise Classes
• WiSe 2017/2018: Analysis I
  Exercise Classes
• SoSe 2017: Complex Functions
  Exercise Classes
• WiSe 2016/2017: Analysis I
  Exercise Classes
• SoSe 2016: Complex Functions
  Exercise Classes
• WiSe 2015/2016: Differential Equations I
  Exercise Classes
• SoSe 2015: Analysis II
  Exercise Classes

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Photo: Matthias Beckmann