Fredrik Kahl

I am a professor at Chalmers University of Technology leading the Computer Vision Group. I am an applied mathematician interested in geometry, optimization, computer vision and machine learning, in particular, geometric deep learning.

I was previously a professor at the department of mathematics, Lund University (2006-2018) and before that, a post-doctoral fellow at the department of Computer Science, University of California San Diego (2005-2006) and at the Australian National University (2004-2005). I did my PhD at Lund University under the supervision of Profs. Anders Heyden and Gunnar Sparr (1997-2001).

Email  /  Google Scholar  /  LinkedIn  /  My homepage at Chalmers

• Equivariance and steerability for keypoint matching! Accepted as an oral for CVPR 2024 with top reviews 5,5,5! Available on arXiv.
• Should we give up optimization and learn Structure from Motion? Here's a step in that direction, read our Learning Structure-from-Motion with Graph Attention Networks. Accepted as an oral for CVPR 2024!
• Lucas Brynte defended his PhD Thesis on February 2, 2024 at Chalmers with flying colors! Faculty opponent was Prof. Konrad Schindler, ETH Zurich.
• One paper accepted at WACV 2024 with Erik Wallin, Lennart Svensson and Lars Hammarstrand on semi- and self-supervised learning! Read the paper.
• I will be an area chair for ECCV 2024 in Milano.
• One paper accepted at NeurIPS 2023 with Georg Bökman on equivariance! Read the paper.
• One paper accepted at CVPR 2023 with Kunal Chelani, Torsten Sattler and Zuzana Kukelova on privacy-preserving localization! Read the paper.

• I am the main PI for the WASP-NEST project 3D Scene Perception, Embeddings and Neural Rendering. Collaborative research project with co-PIs Kathlén Kohn and Mårten Björkman at KTH.
• Interested in the visual localization problem? We are running a benchmark site: Visual Localization. Try it out with your algorithm!
• Interested in my mathematical ancestors and descendants? You can find them here at the Mathematics Genealogy Project.
• My Erdös number is 4 via the path: Fredrik Kahl - Gunnar Sparr - Jaak Peetre - Svante Janson - Paul Erdös.
• ERC-project GlobalVision, 2008-2013. Starting Independent Research Grant, funded by the European Research Council.
• Learn more about 3D reconstruction form large-scale image sets and visit Örebro castle at the same time. For more info, read the paper. More reconstructions by Carl Olsson.
• Want to scan yourself? Read our paper CopyMe3D: Scanning and printing persons in 3D.
• Read more about my research here.

• Investigating how ReLU-networks encode symmetries, G Bökman, F Kahl
  Neural Information Processing Systems, 2023.
• Long-Term Visual Localization Revisited
  C Toft, W Maddern, A Torii, L Hammarstrand, E Stenborg, M Okutomi, M Pollefeys, J Sivic, T Pajdla, F Kahl, T Sattler
  IEEE Transactions on Pattern Analysis and Machine Intelligence, 2021
• Rotation Averaging with the Chordal Distance: Global Minimizers and Strong Duality
  A Eriksson, C Olsson, F Kahl, T-J Chin
  IEEE Transactions on Pattern Analysis and Machine Intelligence, 2021
• Tractable algorithms for robust model estimation
  O Enqvist, E Ask, F Kahl, K Åström
  International Journal of Computer Vision (IJCV), 2015
• Real-time camera tracking and 3D reconstruction using signed distance functions
  E Bylow, J Sturm, C Kerl, F Kahl, D Cremers
  Robotics: Science and Systems (RSS), 2013
• Generalized roof duality
  F Kahl, P Strandmark
  Discrete applied mathematics, 2012
• Global optimization through rotation space search
  R Hartley, F Kahl
  International Journal of Computer Vision, 2009
• Multiple-view geometry under the L_∞-norm
  F Kahl, R Hartley
  IEEE Transactions on Pattern Analysis and Machine Intelligence, 2008
• Critical configurations for projective reconstruction from multiple views
  R Hartley, F Kahl
  International Journal of Computer Vision, 2007
• Critical motions for auto-calibration when some intrinsic parameters can vary
  F Kahl, B Triggs, K Åström
  Journal of Mathematical Imaging and Vision, 2000

For an up-to-date list of all my publications, please see my Google Scholar profile.

• Kunal Chelani, Computer Vision Group, Chalmers University of Technology (co-supervised with Torsten Sattler)
• Josef Bengtsson, Computer Vision Group, Chalmers University of Technology
• Roman Naeem, Computer Vision Group, Chalmers University of Technology (co-supervised with Lennart Svensson)
• Georg Bökman, Computer Vision Group, Chalmers University of Technology
• Erik Wallin, Signal Processing Group, Chalmers University of Technology (co-supervised with Lars Hammarstrand, Lennart Svensson)
• David Hagerman Olzon, Signal Processing Group, Chalmers University of Technology (co-supervised with Lennart Svensson)

Former PhD students:

• Lucas Brynte, PhD 2024.
• José Pedro Lopes Iglesias, PhD 2023, Irisity AB.
• Fredrik Hellström, PhD 2023, postdoc at University College London.
• Carl Toft, PhD 2021, Eigenvision AB.
• Måns Larsson, PhD 2020, Eigenvision AB.
• Jennifer Alvén, PhD 2020, postdoc at Gothenburg University.
• Viktor Larsson, PhD 2018, postdoc at ETH Zurich.
• Erik Bylow, PhD 2018, Qualcomm Inc.
• Johan Fredriksson, PhD 2016, Apple Inc.
• Matilda Landgren, PhD 2016, Cross Technology Solutions AB.
• Fangyuan Jiang, PhD 2015, self-driving car company AutoX Inc in San Jose, California.
• Linus Svärm, PhD 2015, Vårdinnovation AB.
• Johannes Ulén, PhD 2014, Eigenvision AB.
• Yubin Kuang, PhD 2014, co-founder of Mapillary, acquired by Facebook/Meta.
• Petter Strandmark, PhD 2013, Apple Inc.
• Olof Enqvist, PhD 2011, CEO and co-founder of Eigenvision AB.
• Martin Byröd, PhD 2010, Apple Inc.
• Klas Josephson, PhD 2010, Spiideo AB in Lund.
• Carl Olsson, PhD 2009, Associate Professor, Lund University and Chalmers University of Technology.
• Jan-Erik Solem, PhD 2006, CEO and co-founder of Mapillary, which was acquired by Facebook/Meta.
• Nicolas Guilbert, CEO and founder of Ange Optimization Aps.

• I am an expert at SVT Nyheter (Swedish television): Hånat filmgrepp får upprättelse med ny teknik.
• Han skapar framtidens artificiella radiologer in Elektroniktidningen.
• Snart kan AI förhindra hjärtinfarkt, Göteborgs-Posten.
• Algoritmen varnar innan hjärtinfarkten är ett faktum in forskning.se with my former PhD student Jennifer Alvén.
• Jan-Erik Solem's and my patent which was acquired by Apple reaches the news tabloids!
• We are featured in Sydsvenskan!
• Read about my ERC-project in Svenska Dagbladet.

• Several of my PhD students have received the bi-annual Best Nordic Thesis Award which I consider to be my top achievement!
  • Jennifer Alvén, Best Swedish Thesis Award 2019-2020: Combining Shape and Learning for Medical Image Analysis. Footnote: Nordic version canceled due to Covid-19 pandemic.
  • Petter Strandmark, Best Nordic Thesis Award 2013-2014: Discrete Optimization in Early Vision.
  • Carl Olsson, Best Nordic Thesis Award 2009-2010: Global Optimization in Computer Vision: Convexity, Cuts and Approximation Algorithms.
  • Jan-Erik Solem, Best Nordic Thesis Award 2005-2006: Variational Problems and Level Set Methods in Computer Vision - Theory and Applications.
  • Fredrik Kahl, Best Nordic Thesis Award 2001-2002: Geometry and Critical Configurations of Multiple Views.
• We won the Best Industry Paper at the Swedish Symposium on Image Analysis, Göteborg, 2019 for our work on 3D Object Detection by Eskil Jörgensen, Christopher Zach and Fredrik Kahl. We get state-of-the-art results on monocular 3D object detection on Kitti! Read the paper. More videos here.
  
• We won the Best Industry Paper at the Swedish Symposium on Image Analysis, Stockholm, 2018 for our work on Visual Localization by Carl Toft et al.
• The Best Student Paper Award is awarded to "Shape-Aware Multi-Atlas Segmentation" at ICPR 2016, Cancun, Mexico! Read the paper.
• I received the Marr Prize in 2005, which is considered to be one of the most prestigious prizes in computer vision.

• I am co-founder and on the board of the computer vision consultancy Eigenvision AB.
• I am co-founder and on the board of the AI start-up Taigatech AB.
• I worked in the Management Group of CHAIR - Chalmers AI Research Centre, CHAIR, 2019-2021.
• I was on Program Management Group of WASP-AI, 2018-2020.
• The Computer Vision Group organized the Swedish Symposium on Image Analysis, March 19-20, 2019 in Göteborg.
• Tutorial in Salt Lake City at CVPR 2018 on Optimisation in Multiple View Geometry: The L-infinity Way. Tutors: Tat-Jun Chin, Anders Eriksson and Fredrik Kahl.
• Organiser of the first Swedish Symposium on Deep Learning (SSDL), June 20-21, 2017. Location: KTH, Stockholm.
• I was the main PI for the SSF project Semantic Mapping and Visual Navigation for Smart Robots a collaboration between computer vision, automatic control, machine learning and mathematics. Budget: 31.1 MSEK during 2016-2022. Funded by Swedish Foundation for Strategic Research.
• Summer School in Convex and Discrete Optimization on the island of Als, Denmark. Tutors: Fredrik Kahl and Richard Hartley, August 2015.
• Tutorial in Zurich at ECCV'14 on Robust Optimization Techniques in Computer Vision successfully completed with more than 150 registered participants. Tutors: Olof Enqvist, Fredrik Kahl and Richard Hartley.
• I was on the Editorial Board of Journal of Mathematical Imaging and Vision, 2014-2018.
• Mathematical Methods in Computer Vision, 2008-2014. A project in the programme Future Research Leaders, funded by the Swedish Foundation for Strategic Research. Read the feature article (Swedish only).
• Discrete Optimization. A PhD course in mathematics, given spring 2011.
• Optimization in Computer Vision. A one week PhD School, 19-23 May 2008 in Copenhagen, Denmark. Co-organized with Henrik Aanaes, DTU. Lectures include Prof. Richard Hartley, Phil Torr and Lieven Vanderberge.
• Want to see research in the making? .

This website is based on the source code of Jon Barron's website.