University of Oulu

Riccardo Barbano et al 2022 Inverse Problems 38 104004

Unsupervised knowledge-transfer for learned image reconstruction

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Author: Barbano, Riccardo1; Kereta, Zeljko1; Hauptmann, Andreas1,2;
Organizations: 1Department of Computer Science, University College London, Gower Street, London WC1E 6BT, United Kingdom
2Research Unit of Mathematical Sciences; University of Oulu, Oulu, Finland
3Department of Mathematics, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, People’s Republic of China
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 4.7 MB)
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Language: English
Published: IOP Publishing, 2022
Publish Date: 2022-08-31


Deep learning-based image reconstruction approaches have demonstrated impressive empirical performance in many imaging modalities. These approaches usually require a large amount of high-quality paired training data, which is often not available in medical imaging. To circumvent this issue we develop a novel unsupervised knowledge-transfer paradigm for learned reconstruction within a Bayesian framework. The proposed approach learns a reconstruction network in two phases. The first phase trains a reconstruction network with a set of ordered pairs comprising of ground truth images of ellipses and the corresponding simulated measurement data. The second phase fine-tunes the pretrained network to more realistic measurement data without supervision. By construction, the framework is capable of delivering predictive uncertainty information over the reconstructed image. We present extensive experimental results on low-dose and sparse-view computed tomography showing that the approach is competitive with several state-of-the-art supervised and unsupervised reconstruction techniques. Moreover, for test data distributed differently from the training data, the proposed framework can significantly improve reconstruction quality not only visually, but also quantitatively in terms of PSNR and SSIM, when compared with learned methods trained on the synthetic dataset only.

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Series: Inverse problems
ISSN: 0266-5611
ISSN-E: 1361-6420
ISSN-L: 0266-5611
Volume: 38
Issue: 10
Article number: 104004
DOI: 10.1088/1361-6420/ac8a91
Type of Publication: A1 Journal article – refereed
Field of Science: 111 Mathematics
112 Statistics and probability
113 Computer and information sciences
217 Medical engineering
Funding: The work of RB is substantially supported by the i4health PhD studentship (UK EPSRC EP/S021930/1) and from The Alan Turing Institute (UK EPSRC EP/N510129/1), and that of ZK, SA and BJ by UK EPSRC EP/T000864/1, and that of SA and BJ also by UK EPSRC EP/V026259/1. AH acknowledges funding by Academy of Finland Projects 336796, 334817, 338408.
Academy of Finland Grant Number: 336796
Detailed Information: 336796 (Academy of Finland Funding decision)
334817 (Academy of Finland Funding decision)
338408 (Academy of Finland Funding decision)
Copyright information: © 2022 The Author(s). Published by IOP Publishing Ltd. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.