释义 |
Haar FunctionDefine
| (1) |
and
| (2) |
where the Functions plotted above are
Then a Function can be written as a series expansion by
| (3) |
The Functions and are all Orthogonal in , with
| (4) |
| (5) |
These functions can be used to define Wavelets. Let a Function be defined on intervals,with a Power of 2. Then an arbitrary function can be considered as an -Vector , and theCoefficients in the expansion can be determined by solving the Matrix equation
| (6) |
for , where is the Matrix of basis functions. For example,
| (7) |
The Wavelet Matrix can be computed in steps, compared to for theFourier Matrix.See also Wavelet, Wavelet Transform References
Haar, A. ``Zur Theorie der orthogonalen Funktionensysteme.'' Math. Ann. 69, 331-371, 1910.Strang, G. ``Wavelet Transforms Versus Fourier Transforms.'' Bull. Amer. Math. Soc. 28, 288-305, 1993. |