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| Le Bivic, Rejanne; Allemand, Pascal; Quiquerez, Amelie; Delacourt, Christophe. |
| Over the last 10 years, the accessibility of high spatial resolution remote sensing images has strongly increased. These images are available in ortho-rectified format which do not necessitate any further geometrical processing to be analyzed. In parallel, image correlation software has become more efficient and friendly. In this paper, image correlation methods are tested to evaluate their potential and limitations to measure the surface displacements in a complex case of a landslide located in a tropical environment. This studied landslide, called "Mare a Poule d'Eau", is located in the Salazie erosion watershed in Reunion Island (France). This landslide is monitored daily by a DGPS station which registers the south-north displacements. Two pairs of... |
| Tipo: Text |
Palavras-chave: SPOT-5; Image correlation; Landslide; Reunion Island. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00638/75042/75670.pdf |
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| Jaud, Marion; Passot, Sophie; Le Bivic, Rejanne; Delacourt, Christophe; Grandjean, Philippe; Le Dantec, Nicolas. |
| For monitoring purposes and in the context of geomorphological research, Unmanned Aerial Vehicles (UAV) appear to be a promising solution to provide multi-temporal Digital Surface Models (DSMs) and orthophotographs. There are a variety of photogrammetric software tools available for UAV-based data. The objective of this study is to investigate the level of accuracy that can be achieved using two of these software tools: Agisoft PhotoScan((R)) Pro and an open-source alternative, IGN((c)) MicMac((R)), in sub-optimal survey conditions (rugged terrain, with a large variety of morphological features covering a range of roughness sizes, poor GPS reception). A set of UAV images has been taken by a hexacopter drone above the Riviere des Remparts, a river on... |
| Tipo: Text |
Palavras-chave: Image processing; SfM photogrammetry software; Digital Surface Model; UAV; Orthophoto; Accuracy assessment. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00639/75081/75581.pdf |
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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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