Ensemble Deep Learning for the Detection of COVID-19 in Unbalanced Chest X-ray Dataset

The ongoing COVID-19 pandemic has caused devastating effects on humanity worldwide. With practical advantages and wide accessibility, chest X-rays (CXRs) play vital roles in the diagnosis of COVID-19 and the evaluation of the extent of lung damages incurred by the virus. This study aimed to leverage...

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Autores principales: Khin Yadanar Win, Noppadol Maneerat, Syna Sreng, Kazuhiko Hamamoto
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Publicado: MDPI AG 2021
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spelling oai:doaj.org-article:4cb34389d3d5420d848a1865b585639c2021-11-25T16:30:51ZEnsemble Deep Learning for the Detection of COVID-19 in Unbalanced Chest X-ray Dataset10.3390/app1122105282076-3417https://doaj.org/article/4cb34389d3d5420d848a1865b585639c2021-11-01T00:00:00Zhttps://www.mdpi.com/2076-3417/11/22/10528https://doaj.org/toc/2076-3417The ongoing COVID-19 pandemic has caused devastating effects on humanity worldwide. With practical advantages and wide accessibility, chest X-rays (CXRs) play vital roles in the diagnosis of COVID-19 and the evaluation of the extent of lung damages incurred by the virus. This study aimed to leverage deep-learning-based methods toward the automated classification of COVID-19 from normal and viral pneumonia on CXRs, and the identification of indicative regions of COVID-19 biomarkers. Initially, we preprocessed and segmented the lung regions usingDeepLabV3+ method, and subsequently cropped the lung regions. The cropped lung regions were used as inputs to several deep convolutional neural networks (CNNs) for the prediction of COVID-19. The dataset was highly unbalanced; the vast majority were normal images, with a small number of COVID-19 and pneumonia images. To remedy the unbalanced distribution and to avoid biased classification results, we applied five different approaches: (i) balancing the class using weighted loss; (ii) image augmentation to add more images to minority cases; (iii) the undersampling of majority classes; (iv) the oversampling of minority classes; and (v) a hybrid resampling approach of oversampling and undersampling. The best-performing methods from each approach were combined as the ensemble classifier using two voting strategies. Finally, we used the saliency map of CNNs to identify the indicative regions of COVID-19 biomarkers which are deemed useful for interpretability. The algorithms were evaluated using the largest publicly available COVID-19 dataset. An ensemble of the top five CNNs with image augmentation achieved the highest accuracy of 99.23% and area under curve (AUC) of 99.97%, surpassing the results of previous studies.Khin Yadanar WinNoppadol ManeeratSyna SrengKazuhiko HamamotoMDPI AGarticleCOVID-19chest X-raysdeep learningensemble learningimage augmentationoversamplingTechnologyTEngineering (General). Civil engineering (General)TA1-2040Biology (General)QH301-705.5PhysicsQC1-999ChemistryQD1-999ENApplied Sciences, Vol 11, Iss 10528, p 10528 (2021)
institution DOAJ
collection DOAJ
language EN
topic COVID-19
chest X-rays
deep learning
ensemble learning
image augmentation
oversampling
Technology
T
Engineering (General). Civil engineering (General)
TA1-2040
Biology (General)
QH301-705.5
Physics
QC1-999
Chemistry
QD1-999
spellingShingle COVID-19
chest X-rays
deep learning
ensemble learning
image augmentation
oversampling
Technology
T
Engineering (General). Civil engineering (General)
TA1-2040
Biology (General)
QH301-705.5
Physics
QC1-999
Chemistry
QD1-999
Khin Yadanar Win
Noppadol Maneerat
Syna Sreng
Kazuhiko Hamamoto
Ensemble Deep Learning for the Detection of COVID-19 in Unbalanced Chest X-ray Dataset
description The ongoing COVID-19 pandemic has caused devastating effects on humanity worldwide. With practical advantages and wide accessibility, chest X-rays (CXRs) play vital roles in the diagnosis of COVID-19 and the evaluation of the extent of lung damages incurred by the virus. This study aimed to leverage deep-learning-based methods toward the automated classification of COVID-19 from normal and viral pneumonia on CXRs, and the identification of indicative regions of COVID-19 biomarkers. Initially, we preprocessed and segmented the lung regions usingDeepLabV3+ method, and subsequently cropped the lung regions. The cropped lung regions were used as inputs to several deep convolutional neural networks (CNNs) for the prediction of COVID-19. The dataset was highly unbalanced; the vast majority were normal images, with a small number of COVID-19 and pneumonia images. To remedy the unbalanced distribution and to avoid biased classification results, we applied five different approaches: (i) balancing the class using weighted loss; (ii) image augmentation to add more images to minority cases; (iii) the undersampling of majority classes; (iv) the oversampling of minority classes; and (v) a hybrid resampling approach of oversampling and undersampling. The best-performing methods from each approach were combined as the ensemble classifier using two voting strategies. Finally, we used the saliency map of CNNs to identify the indicative regions of COVID-19 biomarkers which are deemed useful for interpretability. The algorithms were evaluated using the largest publicly available COVID-19 dataset. An ensemble of the top five CNNs with image augmentation achieved the highest accuracy of 99.23% and area under curve (AUC) of 99.97%, surpassing the results of previous studies.
format article
author Khin Yadanar Win
Noppadol Maneerat
Syna Sreng
Kazuhiko Hamamoto
author_facet Khin Yadanar Win
Noppadol Maneerat
Syna Sreng
Kazuhiko Hamamoto
author_sort Khin Yadanar Win
title Ensemble Deep Learning for the Detection of COVID-19 in Unbalanced Chest X-ray Dataset
title_short Ensemble Deep Learning for the Detection of COVID-19 in Unbalanced Chest X-ray Dataset
title_full Ensemble Deep Learning for the Detection of COVID-19 in Unbalanced Chest X-ray Dataset
title_fullStr Ensemble Deep Learning for the Detection of COVID-19 in Unbalanced Chest X-ray Dataset
title_full_unstemmed Ensemble Deep Learning for the Detection of COVID-19 in Unbalanced Chest X-ray Dataset
title_sort ensemble deep learning for the detection of covid-19 in unbalanced chest x-ray dataset
publisher MDPI AG
publishDate 2021
url https://doaj.org/article/4cb34389d3d5420d848a1865b585639c
work_keys_str_mv AT khinyadanarwin ensembledeeplearningforthedetectionofcovid19inunbalancedchestxraydataset
AT noppadolmaneerat ensembledeeplearningforthedetectionofcovid19inunbalancedchestxraydataset
AT synasreng ensembledeeplearningforthedetectionofcovid19inunbalancedchestxraydataset
AT kazuhikohamamoto ensembledeeplearningforthedetectionofcovid19inunbalancedchestxraydataset
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