waverec2

Purpose

Multilevel 2-D wavelet reconstruction

Syntax

• X = waverec2(C,S,'wname')
  X = waverec2(C,S,Lo_R,Hi_R)
  

Description

waverec2 is a two-dimensional wavelet analysis function.

X = waverec2(C,S,'wname') performs a multilevel wavelet reconstruction of the matrix X based on the wavelet decomposition structure [C,S]. For detailed storage information, see wavedec2. 'wname' is a string containing the name of the wavelet. See wfilters for more information.

Instead of specifying the wavelet name, you can specify the filters.

• X = waverec2(C,S,Lo_R,Hi_R), Lo_R is the reconstruction low-pass filter
• Hi_R is the reconstruction high-pass filter.

waverec2 is the inverse function of wavedec2 in the sense that the abstract statement waverec2(wavedec2(X,N,'wname'),'wname') returns X.

X = waverec2(C,S,'wname') is equivalent to X = appcoef2(C,S,'wname',0).

Remarks

If C and S are obtained from an indexed image analysis or a truecolor image analysis, X is an m-by-n matrix or an m-by-n-by-3 array, respectively.

For more information on image formats, see the image and imfinfo reference pages.

Examples

• % The current extension mode is zero-padding (see dwtmode).
  % Load original image. 
  load woman; 
  % X contains the loaded image.
  % Perform decomposition at level 2 
  % of X using sym4. 
  [c,s] = wavedec2(X,2,'sym4');
  % Reconstruct X from the wavelet 
  % decomposition structure [c,s]. 
  a0 = waverec2(c,s,'sym4');
  % Check for perfect reconstruction. 
  max(max(abs(X-a0)))
  ans =
      2.5565e-10
  

See Also

appcoef2, idwt2, wavedec2

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