The wavelet packet method is a generalization of wavelet
decomposition that offers a richer range of possibilities for signal
processing. In wavelet analysis, a signal is split into an approximation
and detail. The approximation is then itself split into a second
level approximation and detail. So for n-level decomposition there
are n + 1 possible ways to decompose the signal. In the wavelet
packet analysis the details can also be split as well as the approximations.
This yields 2n different ways to encode the signal. Continuous
wavelet transform (WT) of function f(t) is represented as: