On Improving the Training of Models for the Semantic Segmentation of Benthic Communities from Orthographic Imagery

The semantic segmentation of underwater imagery is an important step in the ecological analysis of coral habitats. To date, scientists produce fine-scale area annotations <i>manually</i>, an exceptionally time-consuming task that could be efficiently automatized by modern CNNs. This pape...

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Main Authors: Gaia Pavoni, Massimiliano Corsini, Marco Callieri, Giuseppe Fiameni, Clinton Edwards, Paolo Cignoni
Format: Article
Language:English
Published: MDPI AG 2020-09-01
Series:Remote Sensing
Subjects:
Online Access:https://www.mdpi.com/2072-4292/12/18/3106
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author Gaia Pavoni
Massimiliano Corsini
Marco Callieri
Giuseppe Fiameni
Clinton Edwards
Paolo Cignoni
author_facet Gaia Pavoni
Massimiliano Corsini
Marco Callieri
Giuseppe Fiameni
Clinton Edwards
Paolo Cignoni
author_sort Gaia Pavoni
collection DOAJ
description The semantic segmentation of underwater imagery is an important step in the ecological analysis of coral habitats. To date, scientists produce fine-scale area annotations <i>manually</i>, an exceptionally time-consuming task that could be efficiently automatized by modern CNNs. This paper extends our previous work presented at the 3DUW’19 conference, outlining the workflow for the automated annotation of imagery from the first step of dataset preparation, to the last step of prediction reassembly. In particular, we propose an ecologically inspired strategy for an efficient dataset partition, an over-sampling methodology targeted on ortho-imagery, and a score fusion strategy. We also investigate the use of different loss functions in the optimization of a Deeplab V3+ model, to mitigate the class-imbalance problem and improve prediction accuracy on coral instance boundaries. The experimental results demonstrate the effectiveness of the ecologically inspired split in improving model performance, and quantify the advantages and limitations of the proposed over-sampling strategy. The extensive comparison of the loss functions gives numerous insights on the segmentation task; the Focal Tversky, typically used in the context of medical imaging (but not in remote sensing), results in the most convenient choice. By improving the accuracy of automated ortho image processing, the results presented here promise to meet the fundamental challenge of increasing the spatial and temporal scale of coral reef research, allowing researchers greater predictive ability to better manage coral reef resilience in the context of a changing environment.
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spelling doaj.art-2dba6afc7c284064a6b6f64283dedba22023-11-20T14:43:26ZengMDPI AGRemote Sensing2072-42922020-09-011218310610.3390/rs12183106On Improving the Training of Models for the Semantic Segmentation of Benthic Communities from Orthographic ImageryGaia Pavoni0Massimiliano Corsini1Marco Callieri2Giuseppe Fiameni3Clinton Edwards4Paolo Cignoni5Visual Computing Lab (ISTI-CNR), 56124 Pisa, ItalyVisual Computing Lab (ISTI-CNR), 56124 Pisa, ItalyVisual Computing Lab (ISTI-CNR), 56124 Pisa, ItalyNVIDIA AI Technology Centre (NVAITC), 40134 Bologna, ItalyScripps Institution of Oceanography, UC San Diego, La Jolla, CA 92037, USAVisual Computing Lab (ISTI-CNR), 56124 Pisa, ItalyThe semantic segmentation of underwater imagery is an important step in the ecological analysis of coral habitats. To date, scientists produce fine-scale area annotations <i>manually</i>, an exceptionally time-consuming task that could be efficiently automatized by modern CNNs. This paper extends our previous work presented at the 3DUW’19 conference, outlining the workflow for the automated annotation of imagery from the first step of dataset preparation, to the last step of prediction reassembly. In particular, we propose an ecologically inspired strategy for an efficient dataset partition, an over-sampling methodology targeted on ortho-imagery, and a score fusion strategy. We also investigate the use of different loss functions in the optimization of a Deeplab V3+ model, to mitigate the class-imbalance problem and improve prediction accuracy on coral instance boundaries. The experimental results demonstrate the effectiveness of the ecologically inspired split in improving model performance, and quantify the advantages and limitations of the proposed over-sampling strategy. The extensive comparison of the loss functions gives numerous insights on the segmentation task; the Focal Tversky, typically used in the context of medical imaging (but not in remote sensing), results in the most convenient choice. By improving the accuracy of automated ortho image processing, the results presented here promise to meet the fundamental challenge of increasing the spatial and temporal scale of coral reef research, allowing researchers greater predictive ability to better manage coral reef resilience in the context of a changing environment.https://www.mdpi.com/2072-4292/12/18/3106coral reef monitoringorthomosaicsorthoprojectionssemantic segmentationdeep learning
spellingShingle Gaia Pavoni
Massimiliano Corsini
Marco Callieri
Giuseppe Fiameni
Clinton Edwards
Paolo Cignoni
On Improving the Training of Models for the Semantic Segmentation of Benthic Communities from Orthographic Imagery
Remote Sensing
coral reef monitoring
orthomosaics
orthoprojections
semantic segmentation
deep learning
title On Improving the Training of Models for the Semantic Segmentation of Benthic Communities from Orthographic Imagery
title_full On Improving the Training of Models for the Semantic Segmentation of Benthic Communities from Orthographic Imagery
title_fullStr On Improving the Training of Models for the Semantic Segmentation of Benthic Communities from Orthographic Imagery
title_full_unstemmed On Improving the Training of Models for the Semantic Segmentation of Benthic Communities from Orthographic Imagery
title_short On Improving the Training of Models for the Semantic Segmentation of Benthic Communities from Orthographic Imagery
title_sort on improving the training of models for the semantic segmentation of benthic communities from orthographic imagery
topic coral reef monitoring
orthomosaics
orthoprojections
semantic segmentation
deep learning
url https://www.mdpi.com/2072-4292/12/18/3106
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