Single-level reconstruction of 1-D wavelet decomposition
[NC,NL,cA] = upwlev(C,L,wname)
[NC,NL,cA] = upwlev(C,L,Lo_R,Hi_R)
upwlev is a one-dimensional
wavelet analysis function.
[NC,NL,cA] = upwlev(C,L, performs the
single-level reconstruction of the wavelet decomposition structure
[C,L] giving the new one
[NC,NL], and extracts the last approximation
[C,L] is a decomposition at level
= length(L)-2, so
[NC,NL] is the same
decomposition at level
the approximation coefficients vector at level
wname is a character vector or string scalar specifying the wavelet,
C is the original wavelet decomposition vector,
L the corresponding bookkeeping vector (for detailed
storage information, see
Instead of giving the wavelet name, you can give the filters.
[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.
% 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.