Pixelwise immersion factor calibration for underwater hyperspectral imaging instruments
In situ spectral reflectance initially captured at high spatial resolution with underwater hyperspectral imaging (UHI) is effective for classification and quantification in oceanic biogeochemical studies; however, the measured spectral radiance is rarely used as an absolute quantity due to challenge...
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Online Access: | https://hdl.handle.net/11250/3131564 https://doi.org/10.1364/OE.523641 |
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ftntnutrondheimi:oai:ntnuopen.ntnu.no:11250/3131564 2024-06-23T07:50:28+00:00 Pixelwise immersion factor calibration for underwater hyperspectral imaging instruments Liu, Hongbo Summers, Natalie Maria Chen, Yi-Chun Løvås, Håvard Snefjellå Johnsen, Geir Koestner, Daniel Warren Sætre, Camilla Hamre, Børge 2024 application/pdf https://hdl.handle.net/11250/3131564 https://doi.org/10.1364/OE.523641 eng eng Optical Publishing Group urn:issn:1094-4087 https://hdl.handle.net/11250/3131564 https://doi.org/10.1364/OE.523641 cristin:2270905 Navngivelse 4.0 Internasjonal http://creativecommons.org/licenses/by/4.0/deed.no 19854-19880 32 Optics Express 11 Journal article Peer reviewed 2024 ftntnutrondheimi https://doi.org/10.1364/OE.523641 2024-06-03T23:32:50Z In situ spectral reflectance initially captured at high spatial resolution with underwater hyperspectral imaging (UHI) is effective for classification and quantification in oceanic biogeochemical studies; however, the measured spectral radiance is rarely used as an absolute quantity due to challenges in calibration of UHI instruments. In this paper, a commercial UHI instrument was calibrated for radiometric flat field response and pixelwise immersion effect to support in situ measurement of absolute spectral radiance. The radiometric and immersion factor calibrations of the UHI instrument were evaluated quantitatively through comparative experiments with a spectroradiometer and a spectrometer. Results show that the immersion factor of the center pixel of the tested UHI instrument was 1.763 in pure water at 600 nm, and the averaged difference in immersion factor between the center and edge pixel of the UHI instrument in the visible light band was only 1∼3% across its half angle field of view of 35° in air. The new calibration coefficients were further used to calculate the spectral radiance of transmitted sunlight through ice algae clusters in sea ice measured by the UHI instrument during an Arctic under-ice bio-optical survey. publishedVersion Article in Journal/Newspaper Arctic ice algae Sea ice NTNU Open Archive (Norwegian University of Science and Technology) Arctic Optics Express 32 11 19854 |
institution |
Open Polar |
collection |
NTNU Open Archive (Norwegian University of Science and Technology) |
op_collection_id |
ftntnutrondheimi |
language |
English |
description |
In situ spectral reflectance initially captured at high spatial resolution with underwater hyperspectral imaging (UHI) is effective for classification and quantification in oceanic biogeochemical studies; however, the measured spectral radiance is rarely used as an absolute quantity due to challenges in calibration of UHI instruments. In this paper, a commercial UHI instrument was calibrated for radiometric flat field response and pixelwise immersion effect to support in situ measurement of absolute spectral radiance. The radiometric and immersion factor calibrations of the UHI instrument were evaluated quantitatively through comparative experiments with a spectroradiometer and a spectrometer. Results show that the immersion factor of the center pixel of the tested UHI instrument was 1.763 in pure water at 600 nm, and the averaged difference in immersion factor between the center and edge pixel of the UHI instrument in the visible light band was only 1∼3% across its half angle field of view of 35° in air. The new calibration coefficients were further used to calculate the spectral radiance of transmitted sunlight through ice algae clusters in sea ice measured by the UHI instrument during an Arctic under-ice bio-optical survey. publishedVersion |
format |
Article in Journal/Newspaper |
author |
Liu, Hongbo Summers, Natalie Maria Chen, Yi-Chun Løvås, Håvard Snefjellå Johnsen, Geir Koestner, Daniel Warren Sætre, Camilla Hamre, Børge |
spellingShingle |
Liu, Hongbo Summers, Natalie Maria Chen, Yi-Chun Løvås, Håvard Snefjellå Johnsen, Geir Koestner, Daniel Warren Sætre, Camilla Hamre, Børge Pixelwise immersion factor calibration for underwater hyperspectral imaging instruments |
author_facet |
Liu, Hongbo Summers, Natalie Maria Chen, Yi-Chun Løvås, Håvard Snefjellå Johnsen, Geir Koestner, Daniel Warren Sætre, Camilla Hamre, Børge |
author_sort |
Liu, Hongbo |
title |
Pixelwise immersion factor calibration for underwater hyperspectral imaging instruments |
title_short |
Pixelwise immersion factor calibration for underwater hyperspectral imaging instruments |
title_full |
Pixelwise immersion factor calibration for underwater hyperspectral imaging instruments |
title_fullStr |
Pixelwise immersion factor calibration for underwater hyperspectral imaging instruments |
title_full_unstemmed |
Pixelwise immersion factor calibration for underwater hyperspectral imaging instruments |
title_sort |
pixelwise immersion factor calibration for underwater hyperspectral imaging instruments |
publisher |
Optical Publishing Group |
publishDate |
2024 |
url |
https://hdl.handle.net/11250/3131564 https://doi.org/10.1364/OE.523641 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic ice algae Sea ice |
genre_facet |
Arctic ice algae Sea ice |
op_source |
19854-19880 32 Optics Express 11 |
op_relation |
urn:issn:1094-4087 https://hdl.handle.net/11250/3131564 https://doi.org/10.1364/OE.523641 cristin:2270905 |
op_rights |
Navngivelse 4.0 Internasjonal http://creativecommons.org/licenses/by/4.0/deed.no |
op_doi |
https://doi.org/10.1364/OE.523641 |
container_title |
Optics Express |
container_volume |
32 |
container_issue |
11 |
container_start_page |
19854 |
_version_ |
1802641366052765696 |