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Wavelets - Caltech Multi-Res Modeling Group

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We can reconstruct the signal as:<br />

Z<br />

da dt<br />

f (t) =c WF ( ;a) ha; (t)<br />

a2 INTRODUCTION 13<br />

where c is a constant depending on h(t). The reconstruction looks like a sum of coefficients of orthogonal<br />

bases, but the ha; (t) are in fact highly redundant, since they are defined for every point in the a; space.<br />

Nevertheless the formula above is correct if R h 2 (t) dt is finite and R h(t) dt = 0 (well, almost).<br />

7 From Continuous to Discrete and Back<br />

Since there is a lot of redundancy in the continuous application of the basic wavelet, a natural question<br />

if whether we can discretize a and in such a way that we obtain a true orthonormal basis. Following<br />

Daubechies [49] one can notice that if we consider two scales a0

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