Author/Editor		Cecchi, Emmanuelle; Lavest, Jean-Marc; van Wyk de Vries, Benjamin
Title		Videogrammetric reconstruction applied to volcanology: perspectives for a new measurement technique in volcano monitoring
Type		članek
Source		Image Anal Stereol
Vol. and No.		Letnik 20, št. Suppl 1
Publication year		2001
Volume		str. 313-8
Language		eng
Abstract		This article deals with videogrammetric reconstruction of volcanic structures. As a first step, the method is tested in laboratory. The objective is to reconstruct small sand and plaster cones, analogous to volcanoes, that deform with time. The initial stage consists of modelling the sensor and positioning extrinsic geometry, using a multi-view calibration method. In practice two sets of views are taken: a first one around the calibration target and a second one around the studied object. Both sets are combined in the calibration software to simultaneously compute the internal parameters modelling the sensor, and the external parameters giving the spatial location of each view around the cone. Following this first stage, a reconstruction process is carried out. The principle is as follows: an initial generic model of the cone is iteratively deformed so that the projected texture of each facet of the meshed model is coherent in all views (by estimation of a correlation criterion). At present, this reconstruction method and its precision are being validated at laboratory scale. The objective will be then to follow analogue model deformation with time for accurate quantitative analysis. In the future, the method will be applied to real volcanic structures. Modifications of the iiutial code will certainly be required, however excellent reconstruction accuracy, valuable simplicity and flexibility of the technique are expected, compared to classic stereophotogrammetric techniques used in volcanology.
Descriptors		VOLCANIC ERUPTION VIDEO RECORDING CALIBRATION PHOTOGRAMMETRY IMAGE PROCESSING, COMPUTER-ASSISTED