| Wavelet Toolbox | |
Single-level reconstruction of 2-D wavelet decomposition
Syntax
Description
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.
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 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
See Also
idwt2, upcoef2, wavedec2
| | upwlev | wavedec | |