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1. The Morlet Wavelets Jo Ann Lee
MAP 4413
March 22, 2006
2. Who was Jean Morlet? French geophysicist
Graduated from the École Polytechnique
Worked at Elf Aquitaine an oil company
3. What does OIL have to do with it? standard way to look for underground oil is to send vibrations into the earth and analyze the echoes that return
PROBLEM: abrupt changes in the wave as it passes from one rock layer to another
limits of Fourier --- Fourier analysis spreads that spatial information out
4. The Morlet Wavelet (1981) Morlet wanted to analyze brief changes in signals
SOLUTION: wavelets of constant shape
his own way of analyzing the seismic signals to create components that were localized in space
Defined by
5. The Morlet Wavelet (1981) Decomposed into real and imaginary parts
Real Imaginary
6. It works but how? Alex Grossman physicist at Centre de Physique Théorique in Marseilles
Grossman and Morlet confirmed that waves could be reconstructed
Joint paper in 1984, brings wavelet into math lexicon
Why wavelets worked better than Fourier: much less sensitive to small errors in the computation