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| Jaud, Marion; Letortu, Pauline; Augereau, Emmanuel; Le Dantec, Nicolas; Beauverger, Mickael; Cuq, Veronique; Prunier, Christophe; Le Bivic, Rejanne; Delacourt, Christophe. |
| The georeferencing process is crucial to the accuracy of terrestrial laser scanner (TLS) data, in particular in the context of diachronic studies relying on multi-temporal surveys. The use of Ground Control Points in the georeferencing process can however be complex when confronted with the practical constraints of coastal surveying. A simple and quick alternative method called "pseudo-direct georeferencing" is proposed in the present paper. This method involves internal inclinometers to measure roll and pitch angles and a centimetric GPS to measure the position of the TLS center and the position of one backsight target. When assessing the transformational uncertainty by using a set of independent ground validation points for both classical indirect and... |
| Tipo: Text |
Palavras-chave: Terrestrial laser scanning; Coastal monitoring; Direct georeferencing; Indirect georeferencing; Multi-temporal surveys; Geomorphological evolution. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00638/75050/75683.pdf |
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| Jaud, Marion; Delacourt, Christophe; Le Dantec, Nicolas; Allemand, Pascal; Ammann, Jerome; Grandjean, Philippe; Nouaille, Henri; Prunier, Christophe; Cuq, Veronique; Augereau, Emmanuel; Cocquempot, Lucie; Floc'H, France. |
| In the dual context of coastal hazard intensification and the growing number of stakes exposed to these hazards, coastal observatories are in demand to provide a structured framework dedicated to long-term monitoring. This article describes the drone-based photogrammetry monitoring performed since 2006 on Porsmilin Beach (Brittany, France) in the framework of the DYNALIT (Littoral and Coastline Dynamics) observatory, focusing on data quality and the consistency of long-term time series under the influence of multiple technological evolutions: Unmanned Aerial Vehicles (UAV) platforms with the arrival of electric multirotor drones, processing tools with the development of structure-from-motion (SfM) photogrammetry, and operational modes of survey. A study... |
| Tipo: Text |
Palavras-chave: UAV; SfM photogrammetry; Coastal observatory; Beach monitoring. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00637/74927/76116.pdf |
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| Didier, David; Bernatchez, Pascal; Augereau, Emmanuel; Caulet, Charles; Dumont, Dany; Bismuth, Eliott; Cormier, Louis; Floc'H, France; Delacourt, Christophe. |
| Increasingly used shore-based video stations enable a high spatiotemporal frequency analysis of shoreline migration. Shoreline detection techniques combined with hydrodynamic conditions enable the creation of digital elevation models (DEMs). However, shoreline elevations are often estimated based on nearshore process empirical equations leading to uncertainties in video-based topography. To achieve high DEM correspondence between both techniques, we assessed video-derived DEMs against LiDAR surveys during low energy conditions. A newly installed video system on a tidal flat in the St. Lawrence Estuary, Atlantic Canada, served as a test case. Shorelines were automatically detected from time-averaged (TIMEX) images using color ratios in low energy conditions... |
| Tipo: Text |
Palavras-chave: Video monitoring; Shoreline detection; Beach morphology; Mobile terrestrial LiDAR; Erosion; Atlantic Canada. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00638/75022/75656.pdf |
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