Mesure de l' Evolution des Glaciers Alpins par Télédétection Optique et Radar
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Photogrammétrie    Mesures GPS    Mesures GPR    Synthése temporelle    Interférométrie différentielle    Filtrage adaptatif    Champ de vitesse    Analyse PolInSAR

## Le traitement des photographies aériennes numérisées et l'indentification d'amers mesurées par GPS différentiel, nous ont permis d'élaborer un MNT de résolution métrique sur les glaciers de la Mer de glace et d'Argentière.

 Mer de Glace : photographies aériennes numérisées MNT haute résolution (Mer de glace) Identification d'amers mesurés par GPS différentiel
(2007) Landes T., Grussenmeyer P., Koehl M.,, Physics in Signal and Image Processing, Mulouse France

## Petite explication sur les méthodes d'interpolation testées...

Triangulation  This method generates the gridded image in two steps. The first step constructs a TIN (Triangulated Irregular Network) from the set of input points, with the vertices of each triangle corresponding to and having the same height value as each input point. This produces an irregular ungridded DEM. The second step "regularizes" the grid by using a linear approximation for each triangle to calculate values at grid points. Triangulation works best when the input points are evenly distributed over the grid area. If the data sets contain areas with widely distributed points, then a surface plot or contour map will have distinct triangular facets.

Minimum Curvature

The minimum Curvature interpolation method generates a surface similar to a thin linearly elastic plate passing through each of the input points. It generates the smooth surface by repeatedly applying an equation over the grid. This continues until either the user specified maximum number of iterations is reached or the successive changes in the values are less than a pre-set convergence limit. A common drawback of this method is that it may have large oscillations and extraneous inflection points particularly in sparse data areas.

The diagram below illustrates the differences between the Triangulation and Minimum Curvature methods.

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