Non classé Remote sensing

Remote sensing

  • Radar interferometry

    Contact : Jean-Luc Froger

    Activities

    The computing and image processing platform is specialised in the processing of SAR and ASAR radar images from the European Space Agency’s ERS and ENVISAT satellites, allowing the calculation of interferograms. The latter provide a high-density monitoring of the ground displacements linked to volcanic activity, both in time and space.

    Post-processing of the data allows us to establish precise maps of displacements in radar geometry and in 3D on the ground, lava flow maps, digital terrain models, and thus to estimate the characteristics of the underlying sources of deformation.

    Most of the image processing can be done with more advanced skills in aerial and satellite stereophotogrammetry (IMAGINE and ENVI/DEM extract software).

    This work is strongly linked to the National observation service OI2 at OPGC.

    Monitoring the progress of lava flows at Piton de la Fournaise during the May 2004 eruption

    Map of the average coherence on Piton de la Fournaise between July 2003 and April 2005.

    Interferogram on Piton de la Fournaise covering the September 2003 eruption.

  • Infrared remote sensing

    Contact : Mathieu Gouhier

    The LMV volcanology team is expert in remote sensing, whether by ground or UAV measurements (Doppler radar, FLIR and SO2 cameras, DOAS, MultiGas, etc.) or by satellite (radar interferometry, IR imaging, etc.). Satellite image analysis is supported by the National accredited observation services OI2 and Hotvolc (Observatoire de Physique du Globe de Clermont-Ferrand).

    Equipment list :

    •  FLIR A655sc and SC655 cameras.
    • Dual-band SO2 camera (QSI 620s) with UV spectrometer (Ocean OPtics USB2000+).
    • DOAS (UV spectrometer USB4000 280-422 nm).
    • MultiGas.
    • Parsivel-2 OTT Hydromet disdrometer.
    • Transportable Doppler radar VOLDORAD-1 1238 MHz.
    • Transportable Doppler Radar VOLDORAD-2.
    • Transportable Doppler Radar VOLDORAD-2B 1274 MHz.
    • Transportable Doppler Radar VOLDORAD-3 95GHz.
    • Raven Escadrone octocopter drone.
    • DJI Phantom quadricopter drone.
  • Photogrametry

    Contact : Thierry Souriot

    We have over 25 years of expertise in photogrammetry. We process satellite, aerial (digital or print), ground and more recently UAV images. Our objectives are mainly the generation of DTMs for various analyses (interferometry, volume calculation, morphological evolution). The installation of high-resolution cameras on the side of a volcano also allows us to follow the evolution of the edifice (e.g. Merapi volcano in Java).

    Examples of achievements:


    DEM of the Dolomieu crater (Reunion Island) produced by multi-image ground photogrammetry (Structure-from-Motion technique).
    Fly-over the Nyiragongo volcano crater. 3d model made by multi-image photogrammetry (Raphaël Paris).
  • Processing

    Contact : Thierry Souriot

    Laboratoire de traitement numérique

    Data processing may take place in a  dedicated room, equipped with 8 to 10 workstations, as well as specialised software and scanners (A3, slide, 3D, …). This room also houses part of the computing resources of the numerical volcanology  and geophysics facilities.

    See the description and access details.

    Numerous image and geophysical data processing software are available (WinGLink Geosystem, Oasis montaj Geosoft, ENVI, DIAPASON, ESA-SNAP, AGISOFT Photoscan Pro, Leica Photogrammetry Suite, Surfer-Grapher-Didger, Matlab, etc)

    Internal developments are the following: Interferomatic (automated interferogram calculation chain), Manip-Raster (satellite image processing), and CASOAR (satellite database with web interface).

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