Wavelet Toolbox™

1-D detail coefficients

Syntax

• D = detcoef(C,L,N)
  D = detcoef(C,L)
  

Description

detcoef is a one-dimensional wavelet analysis function.

D = detcoef(C,L,N) extracts the detail coefficients at level N from the wavelet decomposition structure [C,L]. See wavedec for more information on C and L.

Level N must be an integer such that 1 N NMAX
where NMAX = length(L)-2.

D = detcoef(C,L) extracts the detail coefficients at last level NMAX.

If N is a vector of integers such that 1 N(j) NMAX:

• DCELL = detcoef(C,L,N,'cells') returns a cell array where DCELL{j} contains the coefficients of detail N(j).
• If length(N) > 1, DCELL = detcoef(C,L,N) is equivalent to DCELL = detcoef(C,L,N,'cells').
• DCELL = detcoef(C,L,'cells') is equivalent to DCELL = detcoef(C,L,[1:NMAX]).
• [D1, ... ,Dp] = detcoef(C,L,[N(1), ... ,N(p)]) extracts the details coefficients at levels [N(1), ... ,N(p)].

Examples

• % The current extension mode is zero-padding (see dwtmode).
  
  % Load original one-dimensional signal. 
  load leleccum; 
  s = leleccum(1:3920); 
  
  % Perform decomposition at level 3 of s using db1. 
  [c,l] = wavedec(s,3,'db1');
  
  % Extract detail coefficients at levels 
  % 1, 2 and 3, from wavelet decomposition 
  % structure [c,l]. 
  [cd1,cd2,cd3] = detcoef(c,l,[1 2 3]);
  
  % Using some plotting commands,
  % the following figure is generated.
  
  
  

See Also
appcoef, wavedec

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