Jiayang Shi

I am currently a PostDoc researcher at Research Institute for Mathematics and Computer Science (CWI), Amsterdam, the Netherlands, supervised by Tristan van Leeuwen and Joost Batenburg.

My research focuses on solving inverse problems in imaging using learned algorithms, with applications in Computed Tomography (CT) and beyond.

Prior to this, I worked as a PhD student at Leiden University from 2021 to 2025, supervised by Daan Pelt and Joost Batenburg. I earned my bachelor's degree in 2013 from Hangzhou, China, and completed my master's in 2021 in Karlsruhe, Germany.

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Research

Grouped by topic — click a category to expand.

Generative Models for CT Reconstruction2 papers
Efficient Flow Matching for Sparse-View CT Reconstruction
Jiayang Shi, Lincen Yang, Zhong Li, Tristan van Leeuwen, Daan Pelt, Joost Batenburg
International Conference on Medical Image Computing and Computer Assisted Interventions (MICCAI) , 2026  
website / code / arXiv

We propose the first flow-matching-based framework for sparse-view CT reconstruction. Motivated by the strong temporal correlation of velocity fields across time steps, we introduce an efficient variant that reuses previously predicted velocities to significantly reduce computational cost.

DM4CT: Benchmarking Diffusion Models for Computed Tomography Reconstruction
Jiayang Shi, Daan Pelt, Joost Batenburg
International Conference on Learning Representations (ICLR) , 2026  
website / code / dataset / openreview

DM4CT is a comprehensive benchmark for diffusion-based methods in CT reconstruction. It systematically compares ten state-of-the-art diffusion models alongside modern learning-based approaches (e.g., Gaussian Splatting and INRs) and classical reconstruction algorithms across diverse CT datasets. The benchmark provides detailed insights into reconstruction quality, efficiency, and practical trade-offs. In addition, we introduce a new real-world high-resolution synchrotron CT dataset to facilitate realistic evaluation of CT reconstruction methods.

CT Image Quality Enhancement3 papers
Self-supervised Resolution Enhancement for Anisotropic Volumes in Edge Illumination X-ray Phase Contrast Micro-Computed Tomography
Jiayang Shi, Louisa Brown, Amir Zekavat, Daan Pelt*, Charlotte Hagen*
Tomography of Materials and Structures , 2025  
code / paper
* = Equal contribution

A self-supervised approach designed for edge illumination X-ray phase contrast micro-CT to enhance the resolution of anisotropic volumes.

Multi-stage Deep Learning Artifact Reduction for Parallel-beam Computed Tomography
Jiayang Shi, Daan Pelt, Joost Batenburg
Journal of Synchrotron Radiation, 2025  
code / arXiv / paper

A artifact reduction method for CT images based on deep learning. Three CNNs reduce artifacts in a subsequent manner, targeting different types of artifacts. This method is seamlessly integrated into existing CT pipelines.

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SR4ZCT: Self-supervised Through-plane Resolution Enhancement for CT Images with Arbitrary Resolution and Overlap
Jiayang Shi, Daan Pelt, Joost Batenburg
Machine Learning in Medical Imaging (MLMI) in conjunction with MICCAI , 2023  
code / proceeding / paper

A self-supervised approach utilizing off-axis training to improve the resolution of through-plane CT scans. This method is trained using in-plane images and applied to through-plane images, offering flexibility with any resolution and overlap.

Neural Rendering (NeRF-style) CT Reconstruction1 paper
Implicit Neural Representations for Robust Joint Sparse-View CT Reconstruction
Jiayang Shi*, Junyi Zhu*, Daan Pelt, Joost Batenburg, Matthew Blaschko
Transactions on Machine Learning Research (TMLR) , 2024  
code / openreview / paper
* = Equal contribution

A novel Bayesian framework for joint reconstruction of multiple objects from sparse-view CT scans using Implicit Neural Representations (INRs) to improve reconstruction quality. By capturing shared patterns across multiple objects with latent variables, our method enhances the reconstruction of each object, increases robustness to noise, and accelerates the learning process.

Industrial CT Applications2 papers
A Comparative Study of Supervised and Self-Supervised Denoising Techniques for Defect Segmentation in Industrial CT Imaging
Virginia Florian, Jiayang Shi, Willem Jan Palenstijn, Daniël M. Pelt, Joost Batenburg, Thomas Lang, Christoph Heinzl, Christian Kretzer, Stefan Kasperl, Dominik Wolfschläger, Robert H. Schmitt
International Conference on Industrial Computed Tomography (iCT) , 2025  
proceeding / doi

A study of how the choice of denoising method affects downstream defect detection in fast-scan industrial CT. BM3D, a supervised UNet, the self-supervised Noise2Inverse and a multi-stage CNN are compared on two real aluminium samples, scored both on image quality (PSNR/SSIM) and on the Dice score of the defects segmented from their outputs. Denoisers that look good by image-quality metrics can erase the small, low-contrast pores that matter, showing that the denoiser must be selected for the analysis task and not for the metric alone.

LoDoInd: Introducing A Benchmark Low-dose Industrial CT Dataset and Enhancing Denoising with 2.5D Deep Learning Techniques
Jiayang Shi, Omar Elkilany, Andreas Fischer, Alexander Suppes, Daan Pelt, Joost Batenburg
International Conference on Industrial Computed Tomography (iCT) , 2024  
code / dataset / proceeding / paper

A Benchmark Low-dose Industrial CT Dataset Tailored for Deep Learning: This work introduces a dataset specifically designed for industrial CT applications, emphasizing deep learning approaches. It features a comprehensive analysis comparing the effectiveness and efficiency of 2D, 2.5D, and 3D training methodologies in the context of denoising and image enhancement.

Graph Neural Networks and Anomaly Detection2 papers
Graph Neural Network based Log Anomaly Detection and Explanation
Zhong Li, Jiayang Shi, Matthijs van Leeuwen
Full paper on Data Mining and Knowledge Discovery (DMKD), 2026 / short paper on International Conference on Software Engineering (ICSE), 2024  
code / arXiv / short paper

Graph neural network for log anomaly detection.

Cross-Domain Graph Level Anomaly Detection
Zhong Li, Sheng Liang, Jiayang Shi, Matthijs van Leeuwen
IEEE Transactions on Knowledge and Data Engineering (TKDE), 2024  
code / paper

Unsupervised cross-domain graph level anomaly detection.

Surveys: Diffusion for Tabular Data & RL on LLMs2 papers
Diffusion Models for Tabular Data: Challenges, Current Progress, and Future Directions
Zhong Li, Qi Huang, Lincen Yang, Jiayang Shi, Zhao Yang, Niki Van Stein, Thomas Bäck, Matthijs van Leeuwen
Under review, 2026  
code / paper

Survey paper on diffusion models for tabular data.

Modularized Reinforcement Learning on LLMs: From MDP Creation to Exploration and Learning
Zhao Yang, Yuxuan Jiang, Ting-Chih Chen, Lincen Yang, Annie Wong, Chao Gao, Jacob E. Kooi, Zhong Li, Jiayang Shi, Kevin Qiu, Qi Huang, Xinrui Zu, Shiping Yang, Hengyuan Zhang, Ngai Wong, Filip Ilievski, Shujian Yu, Aske Plaat, Zhaochun Ren, Mark Hoogendoorn, Vincent François-Lavet
Under review, 2026  
arXiv / paper

Survey paper on reinforcement learning for LLM post-training.

Other Research1 paper
Spectral reconstruction and disparity from spatio-spectrally coded light fields via multi-task deep learning
Maximilian Schambach, Jiayang Shi, Michael Heizmann
International Conference on 3D Vision (3DV) , 2021  
code / proceeding / arXiv

A novel method to reconstruct a spectral central view and its aligned disparity map from spatio-spectrally coded light fields using multi-task deep learning.

Grants and Awards

Young Researcher and Innovator Conference Grant, EU COST Action CA24131 (ENRICH), 2026

Teaching Assistant

Computational Imaging and Tomography 2022 spring & 2024 spring & 2025 spring
Statistics for Computer Scientists, 2023 fall
Computer Vision, 2024 fall

Supervised Thesis

Donghang Lyu (master student): Res-Swin: Effective Combination of ResNet and Swin Transformer for LDCT Denoising
Omar Elkilany (master student@TUM & WayGate): Beam Hardening Correction using Implicit Neural Representations
Jan Zuromski (master student): Classifier Guided Inversion for Image Reconstruction