| Wavelet Toolbox™ | |
| Provide feedback about this page |
Reconstruct single branch from 2-D wavelet coefficients
Syntax
X = wrcoef2('type',C,S,'wname',N) X = wrcoef2('type',C,S,Lo_R,Hi_R,N) X = wrcoef2('type',C,S,'wname') X = wrcoef2('type',C,S,Lo_R,Hi_R)
Description
wrcoef2 is a two-dimensional wavelet analysis function. wrcoef2 reconstructs the coefficients of an image.
X = wrcoef2('type',C,S,'wname',N) computes the matrix of reconstructed coefficients of level N, based on the wavelet decomposition structure [C,S] (see wavedec2 for more information).
'wname' is a string containing the name of the wavelet (see wfilters for more information). If 'type' = 'a', approximation coefficients are reconstructed; otherwise if 'type' = 'h' ('v' or 'd', respectively), horizontal (vertical or diagonal, respectively) detail coefficients are reconstructed.
Level N must be an integer such that 0 
N size(S,1)-2 if 'type' = 'a' and such that 1 N size(S,1)-2 if 'type' = 'h', 'v', or 'd'.
Instead of giving the wavelet name, you can give the filters.
For X = wrcoef2('type',C,S,Lo_R,Hi_R,N), Lo_R is the reconstruction low-pass filter and Hi_R is the reconstruction high-pass filter.
X = wrcoef2('type',C,S,'wname') or X = wrcoef2('type',C,S,Lo_R,Hi_R) reconstruct coefficients of maximum level N = size(S,1)-2.
Remarks
If C and S are obtained from an indexed image analysis (respectively a truecolor image analysis) then X is an m-by-n matrix (respectively an m-by-n-by-3 array).
For more information on image formats, see the reference pages of image and imfinfo functions.
Examples
% The current extension mode is zero-padding (see dwtmode).
% Load an image.
load woman;
% X contains the loaded image.
% Perform decomposition at level 2
% of X using sym5.
[c,s] = wavedec2(X,2,'sym5');
% Reconstruct approximations at
% levels 1 and 2, from the wavelet
% decomposition structure [c,s].
a1 = wrcoef2('a',c,s,'sym5',1);
a2 = wrcoef2('a',c,s,'sym5',2);
% Reconstruct details at level 2,
% from the wavelet decomposition
% structure [c,s].
% 'h' is for horizontal,
% 'v' is for vertical,
% 'd' is for diagonal.
hd2 = wrcoef2('h',c,s,'sym5',2);
vd2 = wrcoef2('v',c,s,'sym5',2);
dd2 = wrcoef2('d',c,s,'sym5',2);
% All these images are of same size sX.
sX = size(X)
sX =
256 256
sa1 = size(a1)
sa1 =
256 256
shd2 = size(hd2)
shd2 =
256 256
See Also
appcoef2, detcoef2, wavedec2
| Provide feedback about this page |
| wrcoef | wrev | |
| © 1984-2008- The MathWorks, Inc. - Site Help - Patents - Trademarks - Privacy Policy - Preventing Piracy - RSS |