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Lake Maggiore - Italy, 3-6 April 2000

VEGETATION image processing methods in the CTIV

Xavier Passot
VEGETATION System Engineer
CNES (Centre National d'Etudes Spatiales)
18 avenue Edouard Belin

Paper (pdf file, 40 k)

This paper describes the main image processing steps performed in the Image Processing Center , in VITO (Mol, Belgium), to elaborate deliverable products, from the raw telemetry received from the Receiving Station in Esrange (Kiruna, Sweden).

A geometrical modelling computes some location grids, which are archived with the raw image data. An operated Ground Control Point workshop is used to improve the location accuracy, thanks to a large control points dat base.

The synthesis elaboration process starts by the computation of top of atmosphere reflectances, then by a map projection in Plate -Carrée using a bicubical interpolation; atmospherical corrections rely on the SMAC method and Meteo France water vapor data. The synthesis algorithm is based on the NDVI Maximum Value Composite, not taking into account the bad quality data, or cloudy masked data. This method implies well known artefcats mainly coming from the directional effects.

The deliverable VGT-P products are map projected, top of atmosphere reflectances. They are cut to the user's region of interest, and delivered on CD-R or by ftp.

The VGT-S products are some extracts from the daily or decadly synthesis. They can be reprojected on demand. A reminder of the VEGETATION product format is appended.