Wavelet Toolbox™

Energy for 1-D wavelet or wavelet packet decomposition

Syntax

• [Ea,Ed] = wenergy(C,L)
  E = wenergy(T)
  

Description

For a one-dimensional wavelet decomposition [C,L] (see wavedec for details), [Ea,Ed] = wenergy(C,L) returns Ea, which is the percentage of energy corresponding to the approximation and Ed, which is the vector containing the percentages of energy corresponding to the details.

For a wavelet packet tree T (see wptree, wpdec, wpdec2), E = wenergy(T) returns a vector E, which contains the percentages of energy corresponding to the terminal nodes of the tree T. In this case, wenergy is a method of the wptree object T, which overloads the previous wenergy function.

Examples

• % Example 1: 1-D wavelet decomposition
  %-------------------------------------
  load noisbump
  [C,L] = wavedec(noisbump,4,'sym4');
  [Ea,Ed] = wenergy(C,L)
  
  Ea =
  
     88.2860
  
  Ed =
  
      2.1560    1.2286    1.4664    6.8630
  
  % Example 2: 1-D wavelet packet decomposition
  %--------------------------------------------
  load noisbump
  T = wpdec(noisbump,3,'sym4');
  E = wenergy(T)
  
  E =
  
  95.0329    1.4664    0.6100    0.6408    0.5935    0.5445    0.5154    
  0.5965
  

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