wrcoef

Purpose

Reconstruct single branch from 1-D wavelet coefficients

Syntax

• X = wrcoef('type',C,L,'wname',N)
  X = wrcoef('type',C,L,Lo_R,Hi_R,N)
  X = wrcoef('type',C,L,'wname')
  X = wrcoef('type',C,L,Lo_R,Hi_R)
  

Description

wrcoef reconstructs the coefficients of a one-dimensional signal, given a wavelet decomposition structure (C and L) and either a specified wavelet ('wname', see wfilters for more information) or specified reconstruction filters (Lo_R and Hi_R).

X = wrcoef('type',C,L,'wname',N) computes the vector of reconstructed coefficients, based on the wavelet decomposition structure [C,L] (see wavedec for more information), at level N. 'wname' is a string containing the wavelet name.

Argument 'type' determines whether approximation ('type' = 'a') or detail ('type' = 'd') coefficients are reconstructed. When 'type' = 'a', N is allowed to be 0; otherwise, a strictly positive number N is required. Level N must be an integer such that N length(L)-2.

X = wrcoef('type',C,L,Lo_R,Hi_R,N) computes coefficients as above, given the reconstruction filters you specify.

X = wrcoef('type',C,L,'wname') and X = wrcoef('type',C,L,Lo_R,Hi_R) reconstruct coefficients of maximum level N = length(L)-2.

Examples

• % The current extension mode is zero-padding (see dwtmode).
  
  % Load a one-dimensional signal. 
  load sumsin; s = sumsin; 
  
  % Perform decomposition at level 5 of s using sym4. 
  [c,l] = wavedec(s,5,'sym4');
  
  % Reconstruct approximation at level 5, 
  % from the wavelet decomposition structure [c,l].
  a5 = wrcoef('a',c,l,'sym4',5);
  
  % Using some plotting commands,
  % the following figure is generated.
  
    
  

See Also

appcoef, detcoef, wavedec

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