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waverec2

Multilevel 2-D wavelet reconstruction

Syntax

X = waverec2(C,S,'wname')
X = waverec2(C,S,Lo_R,Hi_R)
waverec2(wavedec2(X,N,'wname'),'wname')
X = waverec2(C,S,'wname')
X = appcoef2(C,S,'wname',0)

Description

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 character vector 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).

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

More About

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Tips

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.

See Also

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Introduced before R2006a

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