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Analysing retinal fundus images with deep learning models

Thesis (PhD)--Stellenbosch University, 2023.

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Bibliographic Details
Main Author: Ofosu Mensah, Samuel
Other Authors: Bah, Bubacarr
Format: Thesis
Language:en_ZA
en_ZA
Published: Stellenbosch : Stellenbosch University 2023
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access_status_str Open Access
author Ofosu Mensah, Samuel
author2 Bah, Bubacarr
author_browse Bah, Bubacarr
Ofosu Mensah, Samuel
author_facet Bah, Bubacarr
Ofosu Mensah, Samuel
author_sort Ofosu Mensah, Samuel
collection Thesis
dc_rights_str_mv Stellenbosch University
description Thesis (PhD)--Stellenbosch University, 2023.
format Thesis
id oai:scholar.sun.ac.za:10019.1/128788
institution Stellenbosch University (South Africa)
language en_ZA
en_ZA
last_indexed 2026-06-10T12:43:10.408Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository
publishDate 2023
publishDateRange 2023
publishDateSort 2023
publisher Stellenbosch : Stellenbosch University
publisherStr Stellenbosch : Stellenbosch University
record_format dspace
source_str SUNScholar — Stellenbosch University Repository
spelling oai:scholar.sun.ac.za:10019.1/128788 Analysing retinal fundus images with deep learning models Ofosu Mensah, Samuel Bah, Bubacarr Brink, Willie Stellenbosch University. Faculty of Science. Dept. of Mathematical Sciences. Applied Mathematics Division. Deep learning (Machine learning) Computer vision Convolutional neural networks Convolutions (Mathematics) Neural networks (Computer science) Diabetic retinopathy Thesis (PhD)--Stellenbosch University, 2023. ENGLISH ABSTRACT: Convolutional neural networks (CNNs) have successfully been used to classify diabetic retinopathy but they do not provide immediate explanations for their decisions. Explainability is relevant, especially for clinicians. To make results explainable, we use a post-attention technique called gradient-weighted class activation mapping (Grad- CAM) on the penultimate layer of deep learning models to produce localisation maps on retinal fundus images after using them to classify diabetic retinopathy. Moreover, the models were initialised using pre-trained weights obtained from training models on the ImageNet dataset. The results of this are fewer training epochs and improved performance. Next, we predict cardiovascular risk factors (CVFs) using retinal fundus images. In detail, we use a multi-task learning (MTL) model since there are several CVFs. The impact of using an MTL model is the advantage of simultaneously training for and predicting several CVFs rather than doing so individually. Also, we investigate the performance of the fundus cameras used to capture the retinal fundus images. We notice a superior performance of the desktop fundus cameras to the handheld fundus camera. Finally, we propose a hybrid model that fuses convolutions and Transformer encoders. This is done to harness the benefits of convolutions and Transformer encoders. We compare the performance of the proposed model with other attention-based models and observe on-par performance. AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar. Doctorate 2023-11-27T05:31:13Z 2024-01-08T11:11:35Z 2023-11-27T05:31:13Z 2024-01-08T11:11:35Z 2023-12 Thesis https://scholar.sun.ac.za/handle/10019.1/128788 en_ZA en_ZA Stellenbosch University xvii, 117 pages : illustrations application/pdf Stellenbosch : Stellenbosch University
spellingShingle Deep learning (Machine learning)
Computer vision
Convolutional neural networks
Convolutions (Mathematics)
Neural networks (Computer science)
Diabetic retinopathy
Ofosu Mensah, Samuel
Analysing retinal fundus images with deep learning models
title Analysing retinal fundus images with deep learning models
title_full Analysing retinal fundus images with deep learning models
title_fullStr Analysing retinal fundus images with deep learning models
title_full_unstemmed Analysing retinal fundus images with deep learning models
title_short Analysing retinal fundus images with deep learning models
title_sort analysing retinal fundus images with deep learning models
topic Deep learning (Machine learning)
Computer vision
Convolutional neural networks
Convolutions (Mathematics)
Neural networks (Computer science)
Diabetic retinopathy
url https://scholar.sun.ac.za/handle/10019.1/128788
work_keys_str_mv AT ofosumensahsamuel analysingretinalfundusimageswithdeeplearningmodels