Matthijs Mars
I am Matthijs, a postdoctoral researcher at Leiden University working on the application of machine learning techniques to high contrast imaging for direct imaging of exoplanets. Prior to this, I completed my PhD through the College for Doctoral Training in Data Intensive Science at UCL’s Mullard Space Science Lab, where I worked with Jason McEwen and Marta Betcke on developing innovative machine learning approaches for astronomical imaging.
My doctoral research focused on advancing image reconstruction methods for radio interferometry, a crucial tool in astronomy used to study phenomena from the epoch of reionisation to cosmic magnetism and distant galaxies. With next-generation telescopes like the Square Kilometre Array (SKA) set to generate unprecedented volumes of data, my work addressed the pressing need for efficient and scalable reconstruction techniques. I developed two novel approaches: a fully data-driven method and a hybrid approach combining data-driven learning with model-based optimization. These methods were initially developed for SPIDER, an optical interferometer concept, before being extended to radio interferometry.
A key challenge I tackled was adapting these learned reconstruction methods to handle the varying visibility coverages inherent in radio interferometry, developing robust training strategies that made the models coverage-agnostic. I also integrated these approaches into a generative framework capable of quantifying uncertainties in the reconstructions – a crucial feature for scientific interpretation. The resulting methods demonstrated significant improvements in both computational efficiency and reconstruction quality compared to traditional approaches, enabling real-time imaging for SPIDER and offering efficient, high-quality reconstructions with uncertainty quantification for radio interferometric telescopes.
During my PhD, I also collaborated on several other projects. I worked with Spotify to enhance their podcast dataset by precomputing audio features for the TREC Podcast track, a data challenge focused on information retrieval from podcasts. Additionally, I spent 6 months at the STFC Hartree Centre developing deep reinforcement learning methods for controlling plasma shape in nuclear fusion reactors, under the supervision of Adriano Agnello, George Holt, and Nicola Amorisco.
Publications
Using conditional GANs for convergence map reconstruction with uncertainties
Jessica Whitney, Tobías Liaudat, Matt Price, Matthijs Mars, Jason D. McEwen "Learned radio interferometric imaging for varying visibility coverage." ArXiv e-print, 2024.
Learned radio interferometric imaging for varying visibility coverage
Matthijs Mars, Marta Betcke, Jason McEwen, "Learned radio interferometric imaging for varying visibility coverage." ArXiv e-print, 2024.
FreeGSNKE: A Python-based dynamic free-boundary toroidal plasma equilibrium solver
Nicola C. Amorisco, Adriano Agnello, George Holt, Matthijs Mars, James Buchanan, Stanislas Pamela. "FreeGSNKE: A Python-based dynamic free-boundary toroidal plasma equilibrium solver." PoP, 2024.
Learned interferometric imaging for the SPIDER instrument
Matthijs Mars, Marta Betcke, Jason McEwen, "Learned Interferometric Imaging for the SPIDER Instrument." RASTI 2023.
Fast emulation of anisotropies induced in the cosmic microwave background by cosmic strings
Matthew A. Price, Matthijs Mars, Matthew M. Docherty, Alessio Spurio Mancini, Augustin Marignier, Jason. D. McEwen, "Fast emulation of anisotropies induced in the cosmic microwave background by cosmic strings." ArXiv e-print, 2023.
Audio Features, Precomputed for Podcast Retrieval and Information Access Experiments
Abigail Alexander, Matthijs Mars, Josh Tingey, Haoyue Yu, Chris Backhouse, Sravana Reddy, Jussi Karlgren, "Audio Features, Precomputed for Podcast Retrieval and Information Access Experiments." In the proceedings of Experimental IR Meets Multilinguality, Multimodality, and Interaction, 2021.
Talks and Posters
Generative imaging for fast image reconstruction and uncertainty quantification in radio interferometry
4th IMA Conference on Inverse Problems from Theory to Application
Bath, United Kingdom
Generative imaging for fast image reconstruction and uncertainty quantification in radio interferometry
EAS Annual meeting 2024
Padova, Italy
Learned Image Reconstruction for Interferometric Imaging
ESO AI Forum
Garching, Germany (Virtual)
Learned Image Reconstruction for Interferometric Imaging Permalink
Space Science interest group at the Alan Turing Institute
London, United Kingdom
Learned radio interferometric imaging for varying visibility coverage. Permalink
European Astronomical Society (EAS) Annual Meeting
Kraków, Poland
Learned Interferometric Imaging for the SPIDER Instrument Permalink
Biomedical and Astronomical Signal Processing (BASP) Frontiers
Villars-sur-Ollon, Switzerland
Learned Interferometric Imaging for the SPIDER Instrument Permalink
Interfacing Bayesian Statistics, Machine Learning, Applied Analysis, and Blind and Semi-Blind Imaging Inverse Problems
Edinburgh, UK
Learned methods for image reconstruction in interferometric imaging with the SPIDER instrument
3rd IMA Conference on Inverse Problems from Theory to Application
Edinburgh, UK