Automated DEM Extraction and Orthoimage Generation from EROS-A1 satellite images of Mt. Etna. Italy

We present a tri-dimensional reconstruction of the summit area of Mount Etna volcano using remote sensed images. The recent eruptions at Mt. Etna have drastically changed the morphology of the summit area. Thanks to Eros A1 satellite stereo images availability, we performed a DGPS survey for the collection of GPC (ground control point) useful to detect new topographic features necessary for the 3D model generation. Two types of GCP were collected: the first type were marked on new topographic features using reflectors visible from high resolution satellite camera (2 m x 2 m), the second type were collected using existing visible objects. The placement and marking of new reflectors have been necessary because the upper part of the volcano lacks of enough referenced features. We have therefore devised and placed a grid of new reflectors taking into account the slope characteristics of the volcano, in terms of elevation and visibility. The aim of the project is to validate and improve the techniques for the extraction of Digital Elevation Models (DEM) in areas charaterised by high morphologic complexity and to produce a DEM of Mt Etna for studying, monitoring and quantifying the volcanic changes. The extracted DEM has been quantitatively analysed in a GIS environment to obtain the up-to-date morphometry of the volcano.