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Semi-supervised learning in computer vision

Thesis (MSc) -- Stellenbosch University, 2022.

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Main Author: Louw, Christiaan
Other Authors: Brink, Willie
Format: Thesis
Language:en_ZA
Published: Stellenbosch : Stellenbosch University 2022
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access_status_str Open Access
author Louw, Christiaan
author2 Brink, Willie
author_browse Brink, Willie
Louw, Christiaan
author_facet Brink, Willie
Louw, Christiaan
author_sort Louw, Christiaan
collection Thesis
dc_rights_str_mv Stellenbosch University
description Thesis (MSc) -- Stellenbosch University, 2022.
format Thesis
id oai:scholar.sun.ac.za:10019.1/126121
institution Stellenbosch University (South Africa)
language en_ZA
last_indexed 2026-06-10T12:46:53.692Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository
publishDate 2022
publishDateRange 2022
publishDateSort 2022
publisher Stellenbosch : Stellenbosch University
publisherStr Stellenbosch : Stellenbosch University
record_format dspace
source_str SUNScholar — Stellenbosch University Repository
spelling oai:scholar.sun.ac.za:10019.1/126121 Semi-supervised learning in computer vision Louw, Christiaan Brink, Willie Stellenbosch University. Faculty of Science. Dept. of Applied Mathematics. Supervised learning (Machine learning) Computer vision Deep learning Image classification UCTD Thesis (MSc) -- Stellenbosch University, 2022. ENGLISH ABSTRACT: Deep learning models have proven to be successful at tasks such as image classification. A major drawback of supervised learning is the need for large labelled datasets to obtain good classification accuracy. This can be a bar rier to those in resource-constrained environments wanting to implement a classification model in a previously unexplored field. Recent advancements in unsupervised learning methods, such as contrastive learning, have made it viable to perform representation learning without labels, which when com bined with supervised learning on relatively small labelled datasets can lead to state-of-the-art performance on image classification tasks. We study this technique, called semi-supervised learning, and provide an in vestigation into three semi-supervised learning frameworks. Our work starts by discussing the implementations of the SimCLR, SimSiam and FixMatch frameworks. We compare the results of each framework on the CIFAR-10 and STL-10 datasets in label-scarce scenarios and show that: (1) all frameworks outperform a purely supervised learning baseline when the number of labels is reduced, (2) the improvement in performance of the frameworks over the su pervised baseline increases as the number of available labels is decreased and (3) in most cases, the semi-supervised learning frameworks are able to match or outperform the supervised baseline with 10% as many labels. We also investigate the performance of the SimCLR and SimSiam framework on class-imbalanced versions of the CIFAR-10 and STL-10 datasets, and find that: (1) the improvements over the supervised learning baseline is less sub stantial than in the results with fewer overall, but balanced, class labels, and (2) with basic oversampling implemented the results are significantly improved, with the semi-supervised learning frameworks benefiting the most. The results in this thesis indicate that unsupervised representation learning can indeed lower the number of labelled images required for successful image classification by a significant degree. We also show that each of the frameworks considered in this work serves this function well. "Geen opsomming beskikbaar" Masters 2022-11-22T09:04:01Z 2023-01-16T12:51:09Z 2022-11-22T09:04:01Z 2023-01-16T12:51:09Z 2022-12 Thesis http://hdl.handle.net/10019.1/126121 en_ZA Stellenbosch University iv, 61 pages : illustrations application/pdf Stellenbosch : Stellenbosch University
spellingShingle Supervised learning (Machine learning)
Computer vision
Deep learning
Image classification
UCTD
Louw, Christiaan
Semi-supervised learning in computer vision
title Semi-supervised learning in computer vision
title_full Semi-supervised learning in computer vision
title_fullStr Semi-supervised learning in computer vision
title_full_unstemmed Semi-supervised learning in computer vision
title_short Semi-supervised learning in computer vision
title_sort semi supervised learning in computer vision
topic Supervised learning (Machine learning)
Computer vision
Deep learning
Image classification
UCTD
url http://hdl.handle.net/10019.1/126121
work_keys_str_mv AT louwchristiaan semisupervisedlearningincomputervision