IDENTIFICATION OF A ROBUST LICHEN INDEX FOR THE DECONVOLUTION OF LICHEN AND ROCK MIXTURES USING PATTERN SEARCH ALGORITHM (CASE STUDY: GREENLAND)
Lichens are the dominant autotrophs of polar and subpolar ecosystems commonly encrust the rock outcrops. Spectral mixing of lichens and bare rock can shift diagnostic spectral features of materials of interest thus leading to misinterpretation and false positives if mapping is done based on perfect...
Published in: | The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences |
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2016
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Online Access: | https://doi.org/10.5194/isprs-archives-XLI-B7-973-2016 https://doaj.org/article/2439c24092864d93b1506ca68c59b55e |
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ftdoajarticles:oai:doaj.org/article:2439c24092864d93b1506ca68c59b55e 2023-05-15T16:28:28+02:00 IDENTIFICATION OF A ROBUST LICHEN INDEX FOR THE DECONVOLUTION OF LICHEN AND ROCK MIXTURES USING PATTERN SEARCH ALGORITHM (CASE STUDY: GREENLAND) S. Salehi M. Karami R. Fensholt 2016-06-01T00:00:00Z https://doi.org/10.5194/isprs-archives-XLI-B7-973-2016 https://doaj.org/article/2439c24092864d93b1506ca68c59b55e EN eng Copernicus Publications https://www.int-arch-photogramm-remote-sens-spatial-inf-sci.net/XLI-B7/973/2016/isprs-archives-XLI-B7-973-2016.pdf https://doaj.org/toc/1682-1750 https://doaj.org/toc/2194-9034 doi:10.5194/isprs-archives-XLI-B7-973-2016 1682-1750 2194-9034 https://doaj.org/article/2439c24092864d93b1506ca68c59b55e The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XLI-B7, Pp 973-979 (2016) Technology T Engineering (General). Civil engineering (General) TA1-2040 Applied optics. Photonics TA1501-1820 article 2016 ftdoajarticles https://doi.org/10.5194/isprs-archives-XLI-B7-973-2016 2022-12-31T14:12:21Z Lichens are the dominant autotrophs of polar and subpolar ecosystems commonly encrust the rock outcrops. Spectral mixing of lichens and bare rock can shift diagnostic spectral features of materials of interest thus leading to misinterpretation and false positives if mapping is done based on perfect spectral matching methodologies. Therefore, the ability to distinguish the lichen coverage from rock and decomposing a mixed pixel into a collection of pure reflectance spectra, can improve the applicability of hyperspectral methods for mineral exploration. The objective of this study is to propose a robust lichen index that can be used to estimate lichen coverage, regardless of the mineral composition of the underlying rocks. The performance of three index structures of ratio, normalized ratio and subtraction have been investigated using synthetic linear mixtures of pure rock and lichen spectra with prescribed mixing ratios. Laboratory spectroscopic data are obtained from lichen covered samples collected from Karrat, Liverpool Land, and Sisimiut regions in Greenland. The spectra are then resampled to Hyperspectral Mapper (HyMAP) resolution, in order to further investigate the functionality of the indices for the airborne platform. In both resolutions, a Pattern Search (PS) algorithm is used to identify the optimal band wavelengths and bandwidths for the lichen index. The results of our band optimization procedure revealed that the ratio between R 894-1246 and R 1110 explains most of the variability in the hyperspectral data at the original laboratory resolution (R 2 =0.769). However, the normalized index incorporating R 1106-1121 and R 904-1251 yields the best results for the HyMAP resolution (R 2 =0.765). Article in Journal/Newspaper Greenland Sisimiut Directory of Open Access Journals: DOAJ Articles Greenland Sisimiut ENVELOPE(-53.674,-53.674,66.939,66.939) Bare Rock ENVELOPE(-45.589,-45.589,-60.704,-60.704) Liverpool Land ENVELOPE(-22.200,-22.200,70.917,70.917) The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B7 973 979 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Technology T Engineering (General). Civil engineering (General) TA1-2040 Applied optics. Photonics TA1501-1820 |
spellingShingle |
Technology T Engineering (General). Civil engineering (General) TA1-2040 Applied optics. Photonics TA1501-1820 S. Salehi M. Karami R. Fensholt IDENTIFICATION OF A ROBUST LICHEN INDEX FOR THE DECONVOLUTION OF LICHEN AND ROCK MIXTURES USING PATTERN SEARCH ALGORITHM (CASE STUDY: GREENLAND) |
topic_facet |
Technology T Engineering (General). Civil engineering (General) TA1-2040 Applied optics. Photonics TA1501-1820 |
description |
Lichens are the dominant autotrophs of polar and subpolar ecosystems commonly encrust the rock outcrops. Spectral mixing of lichens and bare rock can shift diagnostic spectral features of materials of interest thus leading to misinterpretation and false positives if mapping is done based on perfect spectral matching methodologies. Therefore, the ability to distinguish the lichen coverage from rock and decomposing a mixed pixel into a collection of pure reflectance spectra, can improve the applicability of hyperspectral methods for mineral exploration. The objective of this study is to propose a robust lichen index that can be used to estimate lichen coverage, regardless of the mineral composition of the underlying rocks. The performance of three index structures of ratio, normalized ratio and subtraction have been investigated using synthetic linear mixtures of pure rock and lichen spectra with prescribed mixing ratios. Laboratory spectroscopic data are obtained from lichen covered samples collected from Karrat, Liverpool Land, and Sisimiut regions in Greenland. The spectra are then resampled to Hyperspectral Mapper (HyMAP) resolution, in order to further investigate the functionality of the indices for the airborne platform. In both resolutions, a Pattern Search (PS) algorithm is used to identify the optimal band wavelengths and bandwidths for the lichen index. The results of our band optimization procedure revealed that the ratio between R 894-1246 and R 1110 explains most of the variability in the hyperspectral data at the original laboratory resolution (R 2 =0.769). However, the normalized index incorporating R 1106-1121 and R 904-1251 yields the best results for the HyMAP resolution (R 2 =0.765). |
format |
Article in Journal/Newspaper |
author |
S. Salehi M. Karami R. Fensholt |
author_facet |
S. Salehi M. Karami R. Fensholt |
author_sort |
S. Salehi |
title |
IDENTIFICATION OF A ROBUST LICHEN INDEX FOR THE DECONVOLUTION OF LICHEN AND ROCK MIXTURES USING PATTERN SEARCH ALGORITHM (CASE STUDY: GREENLAND) |
title_short |
IDENTIFICATION OF A ROBUST LICHEN INDEX FOR THE DECONVOLUTION OF LICHEN AND ROCK MIXTURES USING PATTERN SEARCH ALGORITHM (CASE STUDY: GREENLAND) |
title_full |
IDENTIFICATION OF A ROBUST LICHEN INDEX FOR THE DECONVOLUTION OF LICHEN AND ROCK MIXTURES USING PATTERN SEARCH ALGORITHM (CASE STUDY: GREENLAND) |
title_fullStr |
IDENTIFICATION OF A ROBUST LICHEN INDEX FOR THE DECONVOLUTION OF LICHEN AND ROCK MIXTURES USING PATTERN SEARCH ALGORITHM (CASE STUDY: GREENLAND) |
title_full_unstemmed |
IDENTIFICATION OF A ROBUST LICHEN INDEX FOR THE DECONVOLUTION OF LICHEN AND ROCK MIXTURES USING PATTERN SEARCH ALGORITHM (CASE STUDY: GREENLAND) |
title_sort |
identification of a robust lichen index for the deconvolution of lichen and rock mixtures using pattern search algorithm (case study: greenland) |
publisher |
Copernicus Publications |
publishDate |
2016 |
url |
https://doi.org/10.5194/isprs-archives-XLI-B7-973-2016 https://doaj.org/article/2439c24092864d93b1506ca68c59b55e |
long_lat |
ENVELOPE(-53.674,-53.674,66.939,66.939) ENVELOPE(-45.589,-45.589,-60.704,-60.704) ENVELOPE(-22.200,-22.200,70.917,70.917) |
geographic |
Greenland Sisimiut Bare Rock Liverpool Land |
geographic_facet |
Greenland Sisimiut Bare Rock Liverpool Land |
genre |
Greenland Sisimiut |
genre_facet |
Greenland Sisimiut |
op_source |
The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XLI-B7, Pp 973-979 (2016) |
op_relation |
https://www.int-arch-photogramm-remote-sens-spatial-inf-sci.net/XLI-B7/973/2016/isprs-archives-XLI-B7-973-2016.pdf https://doaj.org/toc/1682-1750 https://doaj.org/toc/2194-9034 doi:10.5194/isprs-archives-XLI-B7-973-2016 1682-1750 2194-9034 https://doaj.org/article/2439c24092864d93b1506ca68c59b55e |
op_doi |
https://doi.org/10.5194/isprs-archives-XLI-B7-973-2016 |
container_title |
The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences |
container_volume |
XLI-B7 |
container_start_page |
973 |
op_container_end_page |
979 |
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1766018114515894272 |