| 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.   |