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  • Gruppenfoto vom Team der Professur Inverse Probleme am Lehrstuhl für Mathematik IX der Universität Würzburg
Inverse Problems

Holder of the Professorship

Prof. Dr. Frank Werner

Holder of the Professorship
Professorship for Mathematics at the Chair of Mathematics IX
Emil-Fischer-Straße 30
97074 Würzburg
Building: 30 (Mathematik West)
Room: 00.008

Memberships

Research Interests

My research is located at the interface between statistics and inverse problems, and I am particularly interested in the following topics:

  • (Nonlinear) statistical inverse problems and regularization theory,
  • uncertainty quantification by simultaneous (minimax) tests for inverse problems and
  • applications in biophysics (e.g. fluorescence microscopy), especially with non-Gaussian noise.

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Publications

  • (with K. Bätz ): L^1 data fitting for Inverse Problems yields optimal rates of convergence in case of discretized white Gaussian noise: arXiv: 2511.11321
  • (with E. Pfarr, R. Timofte ): Analyzing the Error of Generative Diffusion Models: From Euler-Maruyama to Higher-Order Schemes: arXiv: 2601.18425

  • (with J. Dornbusch, E. Pfarr, F. Vasluianu, R. Timofte ): A Simple Combination of Diffusion Models for Better Quality Trade-Offs in Image Denoising, Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR) Workshops, 2025, pp. 895-904. CVPR 2025 open access repository:
    Older version: available on arXiv: 2503.14654
  • (with M. Warmuth, N. Lämmermann, C. Uhl): A Continuous and Robust Version of Dynamcial Component Analysis, Eur. Phys. J. Spec. Top. (2025). DOI: 10.1140/epjs/s11734-025-01911-6
  • (with R. Kretschmann): Maximum a posteriori testing in statistical inverse problems: Inverse Problems and Imaging, Volume 19, Issue 6, 2025. DOI: 10.3934/ipi.2025015
    Older version:  available on arXiv: 2402.00686
  • (with B. Hofmann):A Unified Concept of the Degree of Ill-posedness for Compact and Non-Compact Linear Operator Equations in Hilbert Spaces Under the Auspices of the Spectral Theorem: Numerical Functional Analysis and Optimization, Volume 46, Issue 4-5, pp. 322-347, 2025. DOI: 10.1080/01630563.2025.2451922 
    Older version: available on arXiv: 2408.01148
  • (with C. Kanzow, F. Krämer, P. Mehlitz, G. Wachsmuth): Variational Poisson denoising via augmented Lagrangian methods: ETNA Electronic Transactions on Numerical Analysis, Volume 63, pp. 33–62, 2025. DOI: 10.1553/etna_vol63s33
    Older version: available on arXiv: 2304.06434
  • (with C. König, A. Munk): Multiscale scanning with nuisance parameters: Journal of the Royal Statistical Society: Series B, qkae100, 2024. DOI: 10.1093/jrsssb/qkae100 
    Older version: available on arXiv.
  • (with H. Li): Adaptive minimax optimality in statistical inverse problems via SOLIT -- Sharp Optimal Lepskii-Inspired Tuning: Inverse Problems, Volume 40, Number 2, 025005, 2024. DOI 10.1088/1361-6420/ad12e0
    Older version: available on arXiv: 2304.10356
  • (with R. Kretschmann, D. Wachsmuth): Optimal regularized hypothesis testing in statistical inverse problems: Inverse Problems, Volume 40, Number 1, Dez. 2023, DOI 10.1088/1361-6420/ad1132
    Older version: available on arXiv.
  • (with K. Proksch, J. Keller-Findeisen, H. Ta, A. Munk): Towards quantitative super-resolution microscopy: Molecular maps with statistical guarantees. Editor's choice: Microscopy. dfad053, DOI: 10.1093/jmicro/dfad053
    Older version: available on arXiv, DOI: 10.1093
  • (with M. Pohlmann, A. Munk): Minimax detection of localized signals in statistical inverse problems: Information and Inference: A Journal of the IMA, Volume 12, Issue 3, September 2023, iaad026, DOI:  10.1093/imaiai/iaad026
  • (with N. K. Chada, M. A. Iglesias, S. Lu): On a Dynamic Variant of the Iteratively Regularized Gauss-Newton Method with Sequential Data:  SIAM Journal on Scientific Computing Vol. 45, Issue 6, 2023. DOI: 2207.13499
    Older version: available on arXiv 
  • (with B. Hofmann, Y. Deng): On uniqueness and ill-posedness for the deautoconvolution problem in the multi-dimensional case: Inverse Problems, Volume 39, Number 6, DOI 10.1088/1361-6420/acd07b
    Older version: available on arXiv 
  • (with Y. Deng, B. Hofmann): Deautoconvolution in the two-dimensional case: ETNA. Volume 59, pp. 24-42, 2023, DOI:  10.1553/etna_vol59s24
    Older version: available on arXiv 
  • (with T. Hohage): Error estimates for variational regularization of Inverse Problems with general noise models for data and operator: ETNA. Volume 57, pp. 127-152, 2022, DOI: 10.1553/etna_vol57s127
  • (with R. Siegmund, S. Jakobs, C. Geisler, A. Egner: isoSTED microscopy with water-immersion lenses and background reduction: Biophysical Journal. vol 120, Issue 14, 2021, DOI: 10.1016/j.bpj.2021.05.031
  • (with M. Alamo, H. Li und Axel Munk): Variational multiscale nonparametric regression: Algorithms 2020, 13(11), 296. DOI:  10.3390/a13110296 
    Older version: available on arXiv 
  • (with G. Kulaitis, A. Munk ): What is resolution? A statistical minimax testing perspective on super-resolution microscopy.
    Annals of Statistics. 49(4): 2292-2312 (August 2021). DOI: 10.1214/20-AOS2037
    Older version: available on arXiv: 2005.07450
  • (mit S. Lu and P. Niu ): On the asymptotical regularization for linear inverse problems in presence of white noise.
    In: SIAM/ASA Journal on Uncertainty Quantification. 1-28, vol 9, Issue 1, 2020. DOI:  10.1137/20M1330841
  • (with F. Enikeeva, A. Munk and M. Pohlmann): Bump detection in the presence of dependency: Does it ease or does it load?. Bernoulli, 26 (2020), no. 4, 3280--3310. DOI: 10.3150/20-BEJ1226
    Older version: available on arXiv.
  • (with A. Munk and T. Staudt): Statistical Foundations of Nanoscale Photonic Imaging. In: Nanoscale Photonic Imaging125-143, vol 134, Springer, 2020. DOI: 10.1007/978-3-030-34413-9_4
  • (with A. Munk, H. Li and K. Proksch): Photonic imaging with statistical guarantees. From Multiscale Testing to Multiscale Estimation. In: Nanoscale Photonic Imaging283-312 , vol 134, Springer, 2020. DOI: 10.1007/978-3-030-34413-9_11
  • (with H. Li): Empirical Risk Minimization as Parameter Choice Rule for General Linear Regularization Methods. Annales de l’Institut Henri Poincaré, 56 (2020), no. 1, 405-427, 2020. DOI: 10.1214/19-AIHP966
    Older version: available on arXiv.
  • (with C. König and A. Munk): Multidimensional multiscale scanning in Exponential Families: Limit theory and statistical consequences. The Annals of Statistics, 2020, Vol. 48, No. 2, 655-678. DOI: 10.1214/18-AOS1806
    Older version: available on arXiv.
  • (with B. Hofmann): Convergence Analysis of (Statistical) Inverse Problems under Conditional Stability Estimates. Inverse Problems 36 015004, 2020. DOI: 10.1088/1361-6420/ab4cd7
    Older version: available on arXiv.
  • (with K. Proksch and A. Munk): Multiscale Scanning in Inverse Problems. The Annals of Statistics, 46(6B), 3569-3602, 2018. DOI: 10.1214/17-AOS1669
    Older version: available on arXiv.
  • Adaptivity and Oracle Inequalities in Linear Statistical Inverse Problems: a (numerical) survey. In: New Trends in Parameter Identification for Mathematical Models, 291-316, Birkhäuser, 2018. DOI: 10.1007/978-3-319-70824-9_15
  • (with F. Enikeeva and A. Munk): Bump detection in heterogeneous Gaussian regression. Bernoulli 24(2): 1266-1306, 2018. DOI: 10.3150/16-BEJ899
    Older version: available on arXiv.
  • (with T. Hohage): Inverse Problems with Poisson Data: statistical regularization theory, applications and algorithms. Topical Review for Inverse Problems 32 093001, 2016. DOI: 10.1088/0266-5611/32/9/093001
  • (with C. König and T. Hohage): Convergence Rates for Exponentially Ill-Posed Inverse Problems with Impulsive Noise. SIAM Journal on Numerical Analysis 54(1), 341-360, 2016. DOI: 10.1137/15M1022252
    Older version: available on arXiv.
  • (with A. Munk): Discussion of "Hypothesis testing by convex optimization" by A. Goldenshluger, A. Juditsky and A. Nemirovski. Electronic Journal of Statistics 9(2): 1720-1722, 2015. DOI: 10.1214/14-EJS980
  • On convergence rates for iteratively regularized Newton-type methods under a Lipschitz-type nonlinearity condition. Journal of Inverse and Ill-posed problems 23(1): 75-84, 2015. DOI: 10.1515/jiip-2013-0074
  • (with T. Hohage): Convergence rates for Inverse Problems with Impulsive Noise. SIAM Journal on Numerical Analysis 52(3), 1203-1221, 2014. DOI: 10.1137/130932661
    Older Version: available on arXiv.
  • (with T. Hohage): Iteratively regularized Newton-type methods with general data misfit functionals and applications to Poisson data. Numerische Mathematik 123(4), 745-779, 2013. DOI: 10.1007/s00211-012-0499-z
    Older Version: available on arXiv.
  • (with T. Hohage): Convergence rates in expectation for Tikhonov-type regularization of Inverse Problems with Poisson data. Inverse Problems 28 104004, 2012. DOI: 10.1088/0266-5611/28/10/104004
    Older Version: (Preprint), also available on arXiv.

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  • Inverse problems with Poisson data: Tikhonov-type regularization and iteratively regularized Newton methods, 2012 (PhD thesis)

  • Ein neuer numerischer Ansatz zur L^p-Regularisierung, 2008 (Diploma thesis - in German)

(link to my articles on arXiv)
(link to my MathSciNet author page)

 

Further Information

Education 

2004 - 2009 Studies of mathematics at the Georg-August-Universität Göttingen
23.01.2009: Examination (Diplom) in mathematics (passed with distinction) Thesis: "Ein neuer numerischer Ansatz zur Lp-Regularisierung" (in German)
2009 - 2012 PhD studies in mathematics at the Georg-August-Universität Göttingen Thesis: "Inverse Problems with Poisson data: Tikhonov-type regularization and iteratively regularized Newton methods"
2012 - 2014 Postdoctoral research fellow at the institute for numerical and applied mathematics
2014 - 2020 Group leader 'Statistical Inverse Problems in Biophysics' at the MPIBPC
2020 - Holder of the professorship "Inverse Problems" at the Chair of Scientific Computing in Würzburg

I am married and father of two sons (*2012 and *2015)

Upcoming Events

  • Organisation of "Sektion S28: Inverse Probleme" within the 96th Annual Meetings of the GAMM from March 16th to 20th, 2026 in Stuttgart
  • Visiting Prof. Thorsten Hohage at Uni Göttingen, March 30-31, 2026
  • Round Table Exchange on "Applied Mathematics" at KIT Karlsruhe, May 4-5, 2026
  • Visiting Prof. Shuai Lu at the School of Mathematical Sciences, Fudan University, China, Oct 30 to Nov 7, 2026

Academic Travels and Talks

2026

  • Vortrag am Gymnasium in Marktbreit am 13.02.2026 im Rahmen von "Mathematiker besuchen Ihre Schule" des Instituts für Mathematik
  • Visiting Prof. Thorsten Hohage at Uni Göttingen, Jan. 4-6, 2026

2025

2024

2023

2022

2021

2020

  • Chemnitz Symposium on Inverse Problems, integrated into the DMV-Jahrestagung, September 14-17, Chemnitz.

2019

2018

2017

2016

2015

2014

2013

2012

  • November 16-25, 2012: Research stay at the Australian National University, Canberra, also joining the Canberra Symposium On Regularisation: "Convergence rates in expectation for Tikhonov-type regularization of inverse problems with Poisson data" (slides).
  • Oberwolfach workshop Computational Inverse Problems, Oberwolfach, Germany: "Inverse Problems with Poisson data"
  • DMV Annual Meeting, Saarland University, Saarbrücken, Germany: "Convergence rates in expectation for Tikhonov-type regularization of inverse problems with Poisson data" (slides).
  • PhD defense January 23rd: "Inverse Probleme mit Poisson Daten: Verallgemeinerte Tikhonov-Regularisierung und iterativ regularisierte Newton Methoden" (slides, german)

2011

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