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Capabilities of BIOMASS tomography for investigating tropical forests / Ho Tong Minh Dinh in IEEE Transactions on geoscience and remote sensing, vol 53 n° 2 (February 2015)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 53 n° 2 (February 2015) . - pp 965 - 975 Titre : Capabilities of BIOMASS tomography for investigating tropical forests Type de document : Article/Communication Auteurs : Ho Tong Minh Dinh, Auteur ; Stefano Tebaldini, Auteur ; Fabio Rocca, Auteur ; et al., Auteur Année de publication : 2015 Article en page(s) : pp 965 - 975 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] bande P [Termes IGN] Biomass [Termes IGN] biomasse (combustible) [Termes IGN] dégradation d'image [Termes IGN] forêt équatoriale [Termes IGN] Guyane française [Termes IGN] hauteur des arbres [Termes IGN] image aérienne [Termes IGN] image radar moirée [Termes IGN] tomographie radar Résumé : (Auteur) The objective of this paper is to provide a better understanding of the capabilities of the BIOMASS tomography concerning the retrieval of forest biomass and height in tropical areas. The analysis presented in this paper is carried out on airborne data acquired by Office National d'Etudes et de Recherches Aérospatiales (ONERA) over the site of Paracou, French Guiana, during the European Space Agency campaign TropiSAR. This high-resolution data set (125-MHz bandwidth) was reprocessed in order to generate a new data stack consistent with BIOMASS as for the bandwidth (6 MHz) and the azimuth resolution (about 12 m). To do this, two different processing approaches have been considered. One approach consisted of degrading the resolution of the airborne data through the linear filtering of raw data, followed by standard SAR processing. The other approach consisted of recovering the 3-D distribution of the scatterers at a high resolution, which was then reprojected onto the BIOMASS geometry. The latter procedure allows us to obtain a data stack that is the most realistic emulation of BIOMASS imaging capabilities. In both approaches, neither ionospheric disturbances nor temporal decorrelation has been considered. The connection to the forest biomass has been examined in both cases by investigating the correlation between the backscatter at different forest heights and the above-ground biomass (AGB) values from in situ data. As expected, the reduction of the system bandwidth to 6 MHz resulted in significant vertical resolution losses compared with the original airborne data. Nevertheless, it was possible to retrieve the forest height to within an accuracy of better than 4 m, whereas the backscattered power at the volume height (30 m above the ground) exhibited a correlation higher than 0.8 with the in situ data and no bias phenomena over the AGB values ranging from 250 to 450 t/ha. Numéro de notice : A2015-108 Affiliation des auteurs : non IGN Thématique : FORET/GEOMATIQUE/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2014.2331142 En ligne : https://doi.org/10.1109/TGRS.2014.2331142 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=75626 [article]

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Ground-based array for tomographic imaging of the tropical forest in P-band / Ho Tong Minh Dinh in IEEE Transactions on geoscience and remote sensing, vol 51 n° 8 (August 2013)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 51 n° 8 (August 2013) . - pp 4460 - 4472 Titre : Ground-based array for tomographic imaging of the tropical forest in P-band Type de document : Article/Communication Auteurs : Ho Tong Minh Dinh, Auteur ; Stefano Tebaldini, Auteur ; Fabio Rocca, Auteur ; et al., Auteur Année de publication : 2013 Article en page(s) : pp 4460 - 4472 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications [Termes IGN] bande P [Termes IGN] flore locale [Termes IGN] forêt tropicale [Termes IGN] Guyane (département français) [Termes IGN] polarisation [Termes IGN] tomographie Résumé : (Auteur) In this paper, we discuss the design concepts and preliminary results relating to the European Space Agency's ground-based campaign TropiScat, whose main goal is to evaluate temporal coherence at P-band in a tropical forest in quad-polarization, considering temporal lags ranging from hours to months and at different heights within the vegetation layer. The experiment has been successfully set up and operated since October 2011 at the Paracou field station, French Guiana, where the equipment was installed on top of the 55-m high Guyaflux Tower to illuminate the forest below. The system consists of a vector network analyzer connected to 20 antennas through a switchbox, which allows the use of any of them either as a transmitter or as a receiver. Vertical imaging and fully polarimetric capabilities are achieved by operating the 20 antennas in a multistatic fashion, resulting in an equivalent monostatic array consisting of 15 phase centers displaced along the vertical direction in each polarization. Such a design allows unambiguous imaging of the vegetation while yielding a minimum distance between nearby antennas on the order of 0.8 m, so as to minimize coupling effects. The equipment allows the gathering of signals with the tomographic array within a few minutes, resulting in the possibility to produce a tomographic image of the forest with a temporal sampling of 15 min. System calibration and validation was performed by employing a 2-m trihedral reflector and a rotating dihedral reflector. This allowed the evaluation of the system pulse response in all polarizations and also assessment of the extent of tower motions. As a result, tomographic images have been generated from 500 (P-band) to 900 MHz in all polarizations. Results from real data acquired in Fall 2011 confirm the feasibility of carrying out reliable coherence measurements for the whole duration of the campaign. Numéro de notice : A2013-418 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2013.2246795 En ligne : https://doi.org/10.1109/TGRS.2013.2246795 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32556 [article]

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Phenomenology of ground scattering in a tropical forest through polarimetric synthetic aperture radar tomography / Mauro Mariotti d'Alessandro in IEEE Transactions on geoscience and remote sensing, vol 51 n° 8 (August 2013)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 51 n° 8 (August 2013) . - pp 4430 - 4437 Titre : Phenomenology of ground scattering in a tropical forest through polarimetric synthetic aperture radar tomography Type de document : Article/Communication Auteurs : Mauro Mariotti d'Alessandro, Auteur ; Stefano Tebaldini, Auteur ; Fabio Rocca, Auteur Année de publication : 2013 Article en page(s) : pp 4430 - 4437 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications [Termes IGN] bande P [Termes IGN] forêt tropicale [Termes IGN] Guyane (département français) [Termes IGN] image radar moirée [Termes IGN] niveau du sol [Termes IGN] polarimétrie radar [Termes IGN] tomographie Résumé : (Auteur) This paper aims at characterizing the scattering mechanisms occurring at the ground level in a tropical forest illuminated by a P-band synthetic aperture radar (SAR). The analysis is carried out based on the multibaseline, fully polarimetric, data set collected by ONERA over Paracou, French Guyana, in the frame of the European space agency campaign TropiSAR. The favorable baseline distribution of this data set results in the possibility of removing most contributions from the vegetation layer by tomographic techniques, thus allowing the generation of a new fully polarimetric single look complex SAR image relative to scattering contributions from the ground level only. Such a ground layer image is then analyzed by considering the variation of its polarimetric signature with respect to terrain local slope and Radar look angle. Two major conclusions are drawn: 1) double bounce scattering from trunk-ground interactions is observed to be the dominant scattering mechanism at the ground level on flat terrains, whereas it rapidly tends to vanish as the topographic slope increases, and 2) the characteristic parameter that rules trunk-ground scattering is not the tree height, but rather the available free path facing the tree, as a result of the presence of nearby trees, undulating topography, or understory preventing double bounce scattering from taking place whenever the ground bounce occurs too far away from the considered tree. The mean free path length resulting from the analysis of this data-set is found to be L ? 7 m. Finally, we discuss how the concept of free path length can be accounted for in simple terms by assuming an equivalent extinction model characterized by a variation along the horizontal dimension. Numéro de notice : A2013-415 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2013.2246573 En ligne : https://doi.org/10.1109/TGRS.2013.2246573 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32553 [article]

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065-2013081	RAB	Revue	Centre de documentation	En réserve L003	Disponible