Deep anomaly detection for medical images

Deep learning methods have been demonstrated to be effective in many medical tasks. However, these methods normally require a large number of labeled data, which is costly especially for disease screening, where the abnormal/diseased data are more difficult to obtain. The main purpose of this Fi...

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Bibliographic Details
Main Author: Li, Xintong
Other Authors: Lin Zhiping
Format: Final Year Project (FYP)
Language:English
Published: Nanyang Technological University 2020
Subjects:
Online Access:https://hdl.handle.net/10356/140534
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author Li, Xintong
author2 Lin Zhiping
author_facet Lin Zhiping
Li, Xintong
author_sort Li, Xintong
collection NTU
description Deep learning methods have been demonstrated to be effective in many medical tasks. However, these methods normally require a large number of labeled data, which is costly especially for disease screening, where the abnormal/diseased data are more difficult to obtain. The main purpose of this Final Year Project is to investigate transfer learning-based anomaly detection methods that do not require or only require a small number of labeled data instances. In this work, two anomaly detection methods are proposed. A semi-supervised joint learning method (SmSupJL) is proposed to train a feature extractor with two losses, namely, ’cross-entropy loss’ and ’intra-class variance loss’ on a small labeled train set. By applying these two losses, the feature extractor is able to learn discriminative features of normal and abnormal samples and keep the compactness of normal samples. To further reduce the number of labeled data instances needed, we propose an unsupervised domain adaptation method (UnSupDA) which does not require any labeled instances from target domain but a small number of labeled data instances from source domain to detect anomalies. Self-supervised tasks are used to align source domain and target domain and thus transfer the knowledge learned from the source domain to target domain. Experimental results evaluated on Kaggle Diabetic Retinopathy (DR) dataset demonstrated that the performance of these methods is either surpass or comparable to the current state-of-the-art.
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spelling ntu-10356/1405342023-07-07T18:46:47Z Deep anomaly detection for medical images Li, Xintong Lin Zhiping School of Electrical and Electronic Engineering I2R ezplin@ntu.edu.sg Engineering::Electrical and electronic engineering Deep learning methods have been demonstrated to be effective in many medical tasks. However, these methods normally require a large number of labeled data, which is costly especially for disease screening, where the abnormal/diseased data are more difficult to obtain. The main purpose of this Final Year Project is to investigate transfer learning-based anomaly detection methods that do not require or only require a small number of labeled data instances. In this work, two anomaly detection methods are proposed. A semi-supervised joint learning method (SmSupJL) is proposed to train a feature extractor with two losses, namely, ’cross-entropy loss’ and ’intra-class variance loss’ on a small labeled train set. By applying these two losses, the feature extractor is able to learn discriminative features of normal and abnormal samples and keep the compactness of normal samples. To further reduce the number of labeled data instances needed, we propose an unsupervised domain adaptation method (UnSupDA) which does not require any labeled instances from target domain but a small number of labeled data instances from source domain to detect anomalies. Self-supervised tasks are used to align source domain and target domain and thus transfer the knowledge learned from the source domain to target domain. Experimental results evaluated on Kaggle Diabetic Retinopathy (DR) dataset demonstrated that the performance of these methods is either surpass or comparable to the current state-of-the-art. Bachelor of Engineering (Information Engineering and Media) 2020-05-30T09:05:33Z 2020-05-30T09:05:33Z 2020 Final Year Project (FYP) https://hdl.handle.net/10356/140534 en B3139-191 application/pdf Nanyang Technological University
spellingShingle Engineering::Electrical and electronic engineering
Li, Xintong
Deep anomaly detection for medical images
title Deep anomaly detection for medical images
title_full Deep anomaly detection for medical images
title_fullStr Deep anomaly detection for medical images
title_full_unstemmed Deep anomaly detection for medical images
title_short Deep anomaly detection for medical images
title_sort deep anomaly detection for medical images
topic Engineering::Electrical and electronic engineering
url https://hdl.handle.net/10356/140534
work_keys_str_mv AT lixintong deepanomalydetectionformedicalimages