Wavelet Toolbox |

Single-level reconstruction of 1-D wavelet decomposition

**Syntax **

**Description **

`upwlev`

is a one-dimensional wavelet analysis function.

`[NC,NL,cA] = upwlev(C,L,`

'

'*wname*`)`

performs the single-level reconstruction of the wavelet decomposition structure `[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`

.

'

' is a string containing the wavelet name, *wname*`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.

**See Also**

```
idwt, upcoef, wavedec
```

upcoef2 | upwlev2 |