Automatic detection of small icebergs in fast ice using satellite wide-swath SAR images
Automatic detection of icebergs in satellite images is regarded a useful tool to provide information necessary for safety in Arctic shipping or operations over large ocean areas in near-real time. In this work, we investigated the feasibility of automatic iceberg detection in Sentinel-1 Extra Wide S...
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Online Access: | https://epic.awi.de/id/eprint/49655/ https://hdl.handle.net/10013/epic.fa66cb28-960e-4e4b-a790-8f05e7545113 |
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ftawi:oai:epic.awi.de:49655 2023-05-15T15:17:38+02:00 Automatic detection of small icebergs in fast ice using satellite wide-swath SAR images Halland-Soldal, Ingri Dierking, Wolfgang Korosov, Anton Marino, Armando 2019-04-03 https://epic.awi.de/id/eprint/49655/ https://hdl.handle.net/10013/epic.fa66cb28-960e-4e4b-a790-8f05e7545113 unknown MDPI Halland-Soldal, I. , Dierking, W. orcid:0000-0002-5031-648X , Korosov, A. and Marino, A. (2019) Automatic detection of small icebergs in fast ice using satellite wide-swath SAR images , Remote Sensing, 11 (7) . doi:10.3390/rs11070806 <https://doi.org/10.3390/rs11070806> , hdl:10013/epic.fa66cb28-960e-4e4b-a790-8f05e7545113 EPIC3Remote Sensing, MDPI, 11(7) Article isiRev 2019 ftawi https://doi.org/10.3390/rs11070806 2021-12-24T15:44:42Z Automatic detection of icebergs in satellite images is regarded a useful tool to provide information necessary for safety in Arctic shipping or operations over large ocean areas in near-real time. In this work, we investigated the feasibility of automatic iceberg detection in Sentinel-1 Extra Wide Swath (EWS) SAR images which follow the preferred image mode in operational ice charting. As test region, we selected the Barents Sea where the size of many icebergs is on the order of the spatial resolution of the EWS-mode. We tested a new approach for a detection scheme. It is based on a combination of a filter for enhancing the contrast between icebergs and background, subsequent blob detection, and final application of a Constant False Alarm Rate (CFAR) algorithm. The filter relies mainly on the HV-polarized intensity which often reveals a larger difference between icebergs and sea ice or open water. The blob detector identifies locations of potential icebergs and thus shortens computation time. The final detection is performed on the identified blobs using the CFAR algorithm. About 2000 icebergs captured in fast ice were visually identified in Sentinel-2 Multi Spectral Imager (MSI) data and exploited for an assessment of the detection scheme performance using confusion matrices. For our performance tests, we used four Sentinel-1 EWS images. For judging the effect of spatial resolution, we carried out an additional test with one Sentinel-1 Interferometric Wide Swath (IWS) mode image. Our results show that only 8–22 percent of the icebergs could be detected in the EWS images, and over 90 percent of all detections were false alarms. In IWS mode, the number of correctly identified icebergs increased to 38 percent. However, we obtained a larger number of false alarms in the IWS image than in the corresponding EWS image. We identified two problems for iceberg detection: 1) with the given frequency–polarization combination, not all icebergs are strong scatterers at HV-polarization, and (2) icebergs and deformation structures present on fast ice can often not be distinguished since both may reveal equally strong responses at HV-polarization. Article in Journal/Newspaper Arctic Barents Sea Iceberg* Sea ice Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) Arctic Barents Sea The Blob ENVELOPE(-124.933,-124.933,-73.400,-73.400) Remote Sensing 11 7 806 |
institution |
Open Polar |
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Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
op_collection_id |
ftawi |
language |
unknown |
description |
Automatic detection of icebergs in satellite images is regarded a useful tool to provide information necessary for safety in Arctic shipping or operations over large ocean areas in near-real time. In this work, we investigated the feasibility of automatic iceberg detection in Sentinel-1 Extra Wide Swath (EWS) SAR images which follow the preferred image mode in operational ice charting. As test region, we selected the Barents Sea where the size of many icebergs is on the order of the spatial resolution of the EWS-mode. We tested a new approach for a detection scheme. It is based on a combination of a filter for enhancing the contrast between icebergs and background, subsequent blob detection, and final application of a Constant False Alarm Rate (CFAR) algorithm. The filter relies mainly on the HV-polarized intensity which often reveals a larger difference between icebergs and sea ice or open water. The blob detector identifies locations of potential icebergs and thus shortens computation time. The final detection is performed on the identified blobs using the CFAR algorithm. About 2000 icebergs captured in fast ice were visually identified in Sentinel-2 Multi Spectral Imager (MSI) data and exploited for an assessment of the detection scheme performance using confusion matrices. For our performance tests, we used four Sentinel-1 EWS images. For judging the effect of spatial resolution, we carried out an additional test with one Sentinel-1 Interferometric Wide Swath (IWS) mode image. Our results show that only 8–22 percent of the icebergs could be detected in the EWS images, and over 90 percent of all detections were false alarms. In IWS mode, the number of correctly identified icebergs increased to 38 percent. However, we obtained a larger number of false alarms in the IWS image than in the corresponding EWS image. We identified two problems for iceberg detection: 1) with the given frequency–polarization combination, not all icebergs are strong scatterers at HV-polarization, and (2) icebergs and deformation structures present on fast ice can often not be distinguished since both may reveal equally strong responses at HV-polarization. |
format |
Article in Journal/Newspaper |
author |
Halland-Soldal, Ingri Dierking, Wolfgang Korosov, Anton Marino, Armando |
spellingShingle |
Halland-Soldal, Ingri Dierking, Wolfgang Korosov, Anton Marino, Armando Automatic detection of small icebergs in fast ice using satellite wide-swath SAR images |
author_facet |
Halland-Soldal, Ingri Dierking, Wolfgang Korosov, Anton Marino, Armando |
author_sort |
Halland-Soldal, Ingri |
title |
Automatic detection of small icebergs in fast ice using satellite wide-swath SAR images |
title_short |
Automatic detection of small icebergs in fast ice using satellite wide-swath SAR images |
title_full |
Automatic detection of small icebergs in fast ice using satellite wide-swath SAR images |
title_fullStr |
Automatic detection of small icebergs in fast ice using satellite wide-swath SAR images |
title_full_unstemmed |
Automatic detection of small icebergs in fast ice using satellite wide-swath SAR images |
title_sort |
automatic detection of small icebergs in fast ice using satellite wide-swath sar images |
publisher |
MDPI |
publishDate |
2019 |
url |
https://epic.awi.de/id/eprint/49655/ https://hdl.handle.net/10013/epic.fa66cb28-960e-4e4b-a790-8f05e7545113 |
long_lat |
ENVELOPE(-124.933,-124.933,-73.400,-73.400) |
geographic |
Arctic Barents Sea The Blob |
geographic_facet |
Arctic Barents Sea The Blob |
genre |
Arctic Barents Sea Iceberg* Sea ice |
genre_facet |
Arctic Barents Sea Iceberg* Sea ice |
op_source |
EPIC3Remote Sensing, MDPI, 11(7) |
op_relation |
Halland-Soldal, I. , Dierking, W. orcid:0000-0002-5031-648X , Korosov, A. and Marino, A. (2019) Automatic detection of small icebergs in fast ice using satellite wide-swath SAR images , Remote Sensing, 11 (7) . doi:10.3390/rs11070806 <https://doi.org/10.3390/rs11070806> , hdl:10013/epic.fa66cb28-960e-4e4b-a790-8f05e7545113 |
op_doi |
https://doi.org/10.3390/rs11070806 |
container_title |
Remote Sensing |
container_volume |
11 |
container_issue |
7 |
container_start_page |
806 |
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1766347886392508416 |