Signal Processing for geologists and geophysicists

ABOUT THIS COURSE This course introduces signal processing tools currently used in geophysics. It has been elaborated both from the book "Signal processing for geologists and geophysicists" (J.L. Mari, F. Glangeaud, F. Coppens, 1999) and from the CD "Signal processing in geosciences" (F. Glangeaud ,J.L. Mari, 2000). For signal processing specialists, it will be a source of how classical or new theories can be applied to field data.Teaching staff should find it provides a means of tackling the teaching signal processing techniques. - - - FOREWORD This on line course presents a succession of lessons classed by theme. The different themes that are tackled are: • The Fourier Transformation • Common functions in spectral analysis • Sampling • Correlation • Wave separation • Seismic applications • The Hilbert transformation • Filtering • Near Surface Geophysics • Stochastic Signal Processing • Attributes Each theme has an introduction and a series of lessons which are associated with it. A lesson comprises of text, a video, a formulary, if judged necessary, and in some cases an applet to practice. • The text present has been voluntarily reduced; its objective is put across by the animation. This objective may be the presentation of a specific transform used in signal processing and applied in seismic processing. The term "transform" is used here in a very general sense. It covers at times the notion of transformation, such as the Fourier transformation or filters such as the Wiener filter. The objective perhaps being to show the application of a "transform" on simulated synthetic data or on real acquired geophysical data. • The video is an illustration of the text. It permits a visualization of the data, to study the influence of processing parameters on the data. The images were conceived in a manner which permits an immediate visual comparison and that enables an evaluation of the influence of a parameter change on the data processing. If an applet is associated with the video, some parameters can be modified by moving the cursors, the calculations taking place in real time. • The formulary gives the mathematical formula used in the animation. The reader is invited to use the book cited above as a reference for the notations used and the demonstrations. The formulary should be considered as a simple memory aid. The videos and the applets have been created thanks to the MUSTIG software ( mustig.free.fr, Gérard Lejeune). In this on line course, 20 lessons can be selected. For the animations based on field data measurement, the authors or organisms that provide with them are mentioned. This on line course does not constitute a complete course in itself ; referral to the basic signal processing texts remains essential. - - - THE AUTHOR Jean-Luc Mari is at present a geophysics professor at IFP School and an IFPEN expert. He supervises the MSc research program in "Lithosphere, Basins, Petroleum" part of the Master's program in Science and Technology (Paris VI). Jean-Luc Mari is a member of the European Association of Geoscientists and Engineers. Jean-Luc Mari is author and co-author of patents (in the field of acoustic well logging), numerous scientific articles and books on geophysical methods and signal processing. He has been involved in the design and development of specific teaching aids (on-line (http://www-ig.unil.ch/cours/) and CD-ROMs). His main fields of expertise are seismic acquisition and processing, geophysics of reservoirs and civil engineering.