Bathymetric Inversion from Shore-Based Video Imagery
Models that predict nearshore behavior require as input boundary conditions the bottom profile. Traditionally, beach profiles are measured with differential GPS receivers mounted on amphibious vehicles or small boats. Logistical difficulties in obtaining frequent beach profiles over large nearshore...
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ftohiostateu:oai:kb.osu.edu:1811/32086 2023-05-15T15:47:39+02:00 Bathymetric Inversion from Shore-Based Video Imagery Harris, Erica Lippmann, Thomas 2008-06 application/pdf http://hdl.handle.net/1811/32086 en_US eng The Ohio State University The Ohio State University. Department of Geography Sciences Honors Theses; 2008 http://hdl.handle.net/1811/32086 Attribution 3.0 Unported http://creativecommons.org/licenses/by/3.0/ CC-BY oceanography bathymetry remote sensing ocean waves field methods Thesis 2008 ftohiostateu 2020-08-22T19:35:34Z Models that predict nearshore behavior require as input boundary conditions the bottom profile. Traditionally, beach profiles are measured with differential GPS receivers mounted on amphibious vehicles or small boats. Logistical difficulties in obtaining frequent beach profiles over large nearshore areas have limited their acquisition to a few sites or intensive study periods. In this work, the ability of remote imaging techniques to measure the beach profile using land-based video cameras is evaluated. Such techniques have been developed for video systems on airplanes (Dugan et al., 2001 a, 2001 b), from which the methodology used in this project is based. The airborne techniques will be adapted for use with a fixed, highly oblique video camera mounted on a 20 m high tower erected on the dune at the USACE Field Research Facility (FRF) in the Outer Banks, North Carolina. Water depths are determined by estimating linear wave theory dispersion curves from image intensity energy surfaces in wavenumber-frequency space. Approximately 12 minute video time series over successive, overlapping square sections of the nearshore (100 m on a side) are interrogated from 6 m depths to near the shoreline. Results spanning November 2006 to October 2007 (12 individual surveys) are compared with in situ survey measurements obtained with traditional methods on the same day. Water depths estimated from the video inversion methods were generally within 0.75 m of the in situ surveys all the way to 6 m water depths about 500 m from shore. Larger discrepancies occurred in regions influenced by a large pier in the center of the domain. RMS errors as a function of cross-shore and alongshore position were also computed. RMS errors were typically 0.5-0.75 m within 250 m of the shoreline, and often extending offshore to 500 m. Errors as a function of alongshore position were also less than 0.75 m except in the region blocked by the pier. OSU Arts and Sciences Undergraduate Research Award OSU Social and Behavioral Sciences Research Grant Eleanor McMahon-Ruffing Travel Grant for Women Byrd Polar Research Center's Garry McKenzie Undergraduate Research Grant ONR USACE No embargo Thesis Byrd Polar Research Ohio State University (OSU): Knowledge Bank Byrd Garry ENVELOPE(-62.233,-62.233,-63.350,-63.350) McMahon ENVELOPE(65.148,65.148,-70.835,-70.835) |
institution |
Open Polar |
collection |
Ohio State University (OSU): Knowledge Bank |
op_collection_id |
ftohiostateu |
language |
English |
topic |
oceanography bathymetry remote sensing ocean waves field methods |
spellingShingle |
oceanography bathymetry remote sensing ocean waves field methods Harris, Erica Bathymetric Inversion from Shore-Based Video Imagery |
topic_facet |
oceanography bathymetry remote sensing ocean waves field methods |
description |
Models that predict nearshore behavior require as input boundary conditions the bottom profile. Traditionally, beach profiles are measured with differential GPS receivers mounted on amphibious vehicles or small boats. Logistical difficulties in obtaining frequent beach profiles over large nearshore areas have limited their acquisition to a few sites or intensive study periods. In this work, the ability of remote imaging techniques to measure the beach profile using land-based video cameras is evaluated. Such techniques have been developed for video systems on airplanes (Dugan et al., 2001 a, 2001 b), from which the methodology used in this project is based. The airborne techniques will be adapted for use with a fixed, highly oblique video camera mounted on a 20 m high tower erected on the dune at the USACE Field Research Facility (FRF) in the Outer Banks, North Carolina. Water depths are determined by estimating linear wave theory dispersion curves from image intensity energy surfaces in wavenumber-frequency space. Approximately 12 minute video time series over successive, overlapping square sections of the nearshore (100 m on a side) are interrogated from 6 m depths to near the shoreline. Results spanning November 2006 to October 2007 (12 individual surveys) are compared with in situ survey measurements obtained with traditional methods on the same day. Water depths estimated from the video inversion methods were generally within 0.75 m of the in situ surveys all the way to 6 m water depths about 500 m from shore. Larger discrepancies occurred in regions influenced by a large pier in the center of the domain. RMS errors as a function of cross-shore and alongshore position were also computed. RMS errors were typically 0.5-0.75 m within 250 m of the shoreline, and often extending offshore to 500 m. Errors as a function of alongshore position were also less than 0.75 m except in the region blocked by the pier. OSU Arts and Sciences Undergraduate Research Award OSU Social and Behavioral Sciences Research Grant Eleanor McMahon-Ruffing Travel Grant for Women Byrd Polar Research Center's Garry McKenzie Undergraduate Research Grant ONR USACE No embargo |
author2 |
Lippmann, Thomas |
format |
Thesis |
author |
Harris, Erica |
author_facet |
Harris, Erica |
author_sort |
Harris, Erica |
title |
Bathymetric Inversion from Shore-Based Video Imagery |
title_short |
Bathymetric Inversion from Shore-Based Video Imagery |
title_full |
Bathymetric Inversion from Shore-Based Video Imagery |
title_fullStr |
Bathymetric Inversion from Shore-Based Video Imagery |
title_full_unstemmed |
Bathymetric Inversion from Shore-Based Video Imagery |
title_sort |
bathymetric inversion from shore-based video imagery |
publisher |
The Ohio State University |
publishDate |
2008 |
url |
http://hdl.handle.net/1811/32086 |
long_lat |
ENVELOPE(-62.233,-62.233,-63.350,-63.350) ENVELOPE(65.148,65.148,-70.835,-70.835) |
geographic |
Byrd Garry McMahon |
geographic_facet |
Byrd Garry McMahon |
genre |
Byrd Polar Research |
genre_facet |
Byrd Polar Research |
op_relation |
The Ohio State University. Department of Geography Sciences Honors Theses; 2008 http://hdl.handle.net/1811/32086 |
op_rights |
Attribution 3.0 Unported http://creativecommons.org/licenses/by/3.0/ |
op_rightsnorm |
CC-BY |
_version_ |
1766382563702603776 |