TY - JOUR
T1 - Zero-shot super-resolution with a physically-motivated downsampling kernel for endomicroscopy.
AU - Szczotka, Agnieszka Barbara
AU - Shakir, Dzhoshkun Ismail
AU - Clarkson, Matthew J.
AU - Pereira, Stephen P.
AU - Vercauteren, Tom
N1 - Funding Information:
Manuscript received February 1, 2021; revised March 12, 2021; accepted March 14, 2021. Date of publication March 19, 2021; date of current version June 30, 2021. This work was supported in part by the Wellcome Trust under Grant 203145Z/16/Z and Grant 203148/Z/16/Z; in part by the Engineering and Physical Sciences Research Council (EPSRC) under Grant NS/A000050/1, Grant NS/A000049/1, and Grant NS/A000027/1; and in part by the Department of Health (DoH) National Institute for Health Research (NIHR) University College London Hospitals (UCLH) Biomedical Research Centre (BRC) Funding Scheme through University College London (UCL) and UCLH. The work of Agnieszka Barbara Szczotka was supported by Mauna Kea Technologies, Paris, France. The work of Tom Vercauteren was supported by the Medtronic/Royal Academy of Engineering Research Chair under Grant RCSRF1819/7/34. (Corresponding author: Agnieszka Barbara Szczotka.) Agnieszka Barbara Szczotka and Matthew J. Clarkson are with the Wellcome/EPSRC Centre for Interventional and Surgical Sciences, University College London, WC1E 6BT London, U.K. (e-mail: [email protected]; [email protected]).
Publisher Copyright:
© 1982-2012 IEEE.
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2021/7
Y1 - 2021/7
N2 - Super-resolution (SR) methods have seen significant advances thanks to the development of convolutional neural networks (CNNs). CNNs have been successfully employed to improve the quality of endomicroscopy imaging. Yet, the inherent limitation of research on SR in endomicroscopy remains the lack of ground truth high-resolution (HR) images, commonly used for both supervised training and reference-based image quality assessment (IQA). Therefore, alternative methods, such as unsupervised SR are being explored. To address the need for non-reference image quality improvement, we designed a novel zero-shot super-resolution (ZSSR) approach that relies only on the endomicroscopy data to be processed in a self-supervised manner without the need for ground-truth HR images. We tailored the proposed pipeline to the idiosyncrasies of endomicroscopy by introducing both: a physically-motivated Voronoi downscaling kernel accounting for the endomicroscope's irregular fibre-based sampling pattern, and realistic noise patterns. We also took advantage of video sequences to exploit a sequence of images for self-supervised zero-shot image quality improvement. We run ablation studies to assess our contribution in regards to the downscaling kernel and noise simulation. We validate our methodology on both synthetic and original data. Synthetic experiments were assessed with reference-based IQA, while our results for original images were evaluated in a user study conducted with both expert and non-expert observers. The results demonstrated superior performance in image quality of ZSSR reconstructions in comparison to the baseline method. The ZSSR is also competitive when compared to supervised single-image SR, especially being the preferred reconstruction technique by experts.
AB - Super-resolution (SR) methods have seen significant advances thanks to the development of convolutional neural networks (CNNs). CNNs have been successfully employed to improve the quality of endomicroscopy imaging. Yet, the inherent limitation of research on SR in endomicroscopy remains the lack of ground truth high-resolution (HR) images, commonly used for both supervised training and reference-based image quality assessment (IQA). Therefore, alternative methods, such as unsupervised SR are being explored. To address the need for non-reference image quality improvement, we designed a novel zero-shot super-resolution (ZSSR) approach that relies only on the endomicroscopy data to be processed in a self-supervised manner without the need for ground-truth HR images. We tailored the proposed pipeline to the idiosyncrasies of endomicroscopy by introducing both: a physically-motivated Voronoi downscaling kernel accounting for the endomicroscope's irregular fibre-based sampling pattern, and realistic noise patterns. We also took advantage of video sequences to exploit a sequence of images for self-supervised zero-shot image quality improvement. We run ablation studies to assess our contribution in regards to the downscaling kernel and noise simulation. We validate our methodology on both synthetic and original data. Synthetic experiments were assessed with reference-based IQA, while our results for original images were evaluated in a user study conducted with both expert and non-expert observers. The results demonstrated superior performance in image quality of ZSSR reconstructions in comparison to the baseline method. The ZSSR is also competitive when compared to supervised single-image SR, especially being the preferred reconstruction technique by experts.
UR - http://www.scopus.com/inward/record.url?scp=85103303786&partnerID=8YFLogxK
U2 - 10.1109/TMI.2021.3067512
DO - 10.1109/TMI.2021.3067512
M3 - Article
SN - 0278-0062
VL - 40
SP - 1863
EP - 1874
JO - IEEE Transactions on Medical Imaging
JF - IEEE Transactions on Medical Imaging
IS - 7
M1 - 9381880
ER -