Elaboration d'un Code de Filtrage des Données Géophysiques par la Méthode des Ondelettes

Abstract

The fundamental starting point for the realization of this work is the acquisition of discrete geophysical data (Bouguer anomalies), whose treatment will give birth to regional anomalies on one hand and on the other hand residual anomalies. Thus, this work will consist mainly on elaborating a MATLAB code which will help us in the separation of data based on: - Decomposition in wavelets by discrete wavelet transforms (i.e. the representation of the initial geophysical data in the form of independent wavelets coefficients) by using the order 5 Daubechies and Meyer wavelets. - filtering by Thresholding method, which will consist firstly in determining the threshold of the data grouped in profile: (Stein Unbaised Risk Estimator); secondly, to evaluate the share of wavelets coefficients by soft Thresholding whose inverse wavelets transform will give birth to regionals anomalies; the residuals anomalies ones is deduced by differences between Bouguer and regionals anomalies . These data obtained will give birth to anomalies charts whose analysis and interpretations will lead to the detection and the localization.