Single-level reconstruction of 2-D wavelet decomposition
[NC,NS,cA] = upwlev2(C,S,'wname')
[NC,NS,cA] = upwlev2(C,S,Lo_R,Hi_R)
upwlev2 is a two-dimensional wavelet analysis function.
[NC,NS,cA] = upwlev2(C,S,'wname') performs the single-level reconstruction of wavelet decomposition structure [C,S] giving the new one [NC,NS], and extracts the last approximation coefficients matrix cA.
[C,S] is a decomposition at level n = size(S,1)-2, so [NC,NS] is the same decomposition at level n-1 and cA is the approximation matrix at level n.
'wname' is a string containing the wavelet name, C is the original wavelet decomposition vector, and S the corresponding bookkeeping matrix (for detailed storage information, see wavedec2).
Instead of giving the wavelet name, you can give the filters.
For [NC,NS,cA] = upwlev2(C,S,Lo_R,Hi_R), Lo_R is the reconstruction low-pass filter and Hi_R is the reconstruction high-pass filter.
% 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 db1. [c,s] = wavedec2(X,2,'db1'); sc = size(c) sc = 1 65536 val_s = s val_s = 64 64 64 64 128 128 256 256 % One step reconstruction of wavelet % decomposition structure [c,s]. [nc,ns] = upwlev2(c,s,'db1'); snc = size(nc) snc = 1 65536 val_ns = ns val_ns = 128 128 128 128 256 256