upwlev
Single-level reconstruction of 1-D wavelet decomposition
Syntax
[NC,NL,cA] = upwlev(C,L,wname)
[NC,NL,cA] = upwlev(C,L,Lo_R,Hi_R)
Description
upwlev is a one-dimensional
wavelet analysis function.
[NC,NL,cA] = upwlev(C,L, performs the
single-level reconstruction of the wavelet decomposition structure
wname)[C,L] giving the new one
[NC,NL], and extracts the last approximation
coefficients vector cA.
[C,L] is a decomposition at level n
= length(L)-2, so [NC,NL] is the same
decomposition at level n-1 and cA is
the approximation coefficients vector at level n.
wname is a character vector or string scalar specifying the wavelet,
C is the original wavelet decomposition vector,
and L the corresponding bookkeeping vector (for detailed
storage information, see wavedec ).
Instead of giving the wavelet name, you can give the filters.
For [NC,NL,cA] = upwlev(C,L,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 one-dimensional signal.
load sumsin; s = sumsin;
% Perform decomposition at level 3 of s using db1.
[c,l] = wavedec(s,3,'db1');
subplot(311); plot(s);
title('Original signal s.');
subplot(312); plot(c);
title('Wavelet decomposition structure, level 3')
xlabel(['Coefs for approx. at level 3 ' ...
'and for det. at levels 3, 2 and 1'])
% One step reconstruction of the wavelet decomposition
% structure at level 3 [c,l], so the new structure [nc,nl]
% is the wavelet decomposition structure at level 2.
[nc,nl] = upwlev(c,l,'db1');
subplot(313); plot(nc);
title('Wavelet decomposition structure, level 2')
xlabel(['Coefs for approx. at level 2 ' ...
'and for det. at levels 2 and 1'])
% Editing some graphical properties,
% the following figure is generated.
