CoastalWQL: an open-source tool for drone-based mapping of coastal turbidity using push broom hyperspectral imagery
Uncrewed-Aerial Vehicles (UAVs) and hyperspectral sensors are emerging as effective alternatives for monitoring water quality on-demand. However, image mosaicking for largely featureless coastal water surfaces or open seas has shown to be challenging. Another pertinent issue observed is the systemat...
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sg-ntu-dr.10356-1748652024-04-19T15:35:36Z CoastalWQL: an open-source tool for drone-based mapping of coastal turbidity using push broom hyperspectral imagery Pak, Hui Ying Kieu, Hieu Trung Lin, Weisi Khoo, Eugene Law, Adrian Wing-Keung School of Civil and Environmental Engineering Interdisciplinary Graduate School (IGS) School of Computer Science and Engineering Nanyang Environment and Water Research Institute Environmental Process Modelling Centre Earth and Environmental Sciences Remote sensing Water quality monitoring; software Uncrewed-Aerial Vehicles (UAVs) and hyperspectral sensors are emerging as effective alternatives for monitoring water quality on-demand. However, image mosaicking for largely featureless coastal water surfaces or open seas has shown to be challenging. Another pertinent issue observed is the systematic image misalignment between adjacent flight lines due to the time delay between the UAV-borne sensor and the GNSS system. To overcome these challenges, this study introduces a workflow that entails a GPS-based image mosaicking method for push-broom hyperspectral images, together with a correction method to address the aforementioned systematic image misalignment. An open-source toolkit, CoastalWQL, was developed to facilitate the workflow, which includes essential pre-processing procedures for improving the image mosaic’s quality, such as radiometric correction, de-striping, sun glint correction, and object masking classification. For validation, UAV-based push-broom hyperspectral imaging surveys were conducted to monitor coastal turbidity in Singapore, and the implementation of CoastalWQL’s pre-processing workflow was evaluated at each step via turbidity retrieval. Overall, the results confirm that the image mosaicking of the push-broom hyperspectral imagery over featureless water surface using CoastalWQL with time delay correction enabled better localisation of the turbidity plume. Radiometric correction and de-striping were also found to be the most important pre-processing procedures, which improved turbidity prediction by 46.5%. National Research Foundation (NRF) Public Utilities Board (PUB) Singapore Maritime Institute (SMI) Published version This research was funded by the Singapore Maritime Institute (SMI) under the research project “UAV-based Remote Sensing of Turbidity in Coastal Waters”, grant number SMI-2020-MA-02. The first author would also like to thank Public Utilities of Singapore (PUB)—Singapore’s National Water Agency, for granting the scholarship for the PhD study. This research is supported by the National Research Foundation, Singapore, and PUB, Singapore’s National Water Agency under its RIE2025 Urban Solutions and Sustainability (USS) (Water) Centre of Excellence (CoE) Programme, awarded to Nanyang Environment & Water Research Institute (NEWRI), Nanyang Technological University, Singapore (NTU). 2024-04-15T01:34:39Z 2024-04-15T01:34:39Z 2024 Journal Article Pak, H. Y., Kieu, H. T., Lin, W., Khoo, E. & Law, A. W. (2024). CoastalWQL: an open-source tool for drone-based mapping of coastal turbidity using push broom hyperspectral imagery. Remote Sensing, 16(4), 16040708-. https://dx.doi.org/10.3390/rs16040708 2072-4292 https://hdl.handle.net/10356/174865 10.3390/rs16040708 2-s2.0-85185710596 4 16 16040708 en SMI-2020-MA-02 Remote Sensing © 2024 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). application/pdf |
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Earth and Environmental Sciences Remote sensing Water quality monitoring; software Pak, Hui Ying Kieu, Hieu Trung Lin, Weisi Khoo, Eugene Law, Adrian Wing-Keung CoastalWQL: an open-source tool for drone-based mapping of coastal turbidity using push broom hyperspectral imagery |
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Uncrewed-Aerial Vehicles (UAVs) and hyperspectral sensors are emerging as effective alternatives for monitoring water quality on-demand. However, image mosaicking for largely featureless coastal water surfaces or open seas has shown to be challenging. Another pertinent issue observed is the systematic image misalignment between adjacent flight lines due to the time delay between the UAV-borne sensor and the GNSS system. To overcome these challenges, this study introduces a workflow that entails a GPS-based image mosaicking method for push-broom hyperspectral images, together with a correction method to address the aforementioned systematic image misalignment. An open-source toolkit, CoastalWQL, was developed to facilitate the workflow, which includes essential pre-processing procedures for improving the image mosaic’s quality, such as radiometric correction, de-striping, sun glint correction, and object masking classification. For validation, UAV-based push-broom hyperspectral imaging surveys were conducted to monitor coastal turbidity in Singapore, and the implementation of CoastalWQL’s pre-processing workflow was evaluated at each step via turbidity retrieval. Overall, the results confirm that the image mosaicking of the push-broom hyperspectral imagery over featureless water surface using CoastalWQL with time delay correction enabled better localisation of the turbidity plume. Radiometric correction and de-striping were also found to be the most important pre-processing procedures, which improved turbidity prediction by 46.5%. |
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School of Civil and Environmental Engineering |
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School of Civil and Environmental Engineering Pak, Hui Ying Kieu, Hieu Trung Lin, Weisi Khoo, Eugene Law, Adrian Wing-Keung |
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Pak, Hui Ying Kieu, Hieu Trung Lin, Weisi Khoo, Eugene Law, Adrian Wing-Keung |
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Pak, Hui Ying |
title |
CoastalWQL: an open-source tool for drone-based mapping of coastal turbidity using push broom hyperspectral imagery |
title_short |
CoastalWQL: an open-source tool for drone-based mapping of coastal turbidity using push broom hyperspectral imagery |
title_full |
CoastalWQL: an open-source tool for drone-based mapping of coastal turbidity using push broom hyperspectral imagery |
title_fullStr |
CoastalWQL: an open-source tool for drone-based mapping of coastal turbidity using push broom hyperspectral imagery |
title_full_unstemmed |
CoastalWQL: an open-source tool for drone-based mapping of coastal turbidity using push broom hyperspectral imagery |
title_sort |
coastalwql: an open-source tool for drone-based mapping of coastal turbidity using push broom hyperspectral imagery |
publishDate |
2024 |
url |
https://hdl.handle.net/10356/174865 |
_version_ |
1800916178436096000 |