Wavelet Toolbox  upwlev2

Single-level reconstruction of 2-D wavelet decomposition

Syntax

• ```[NC,NS,cA] = upwlev2(C,S,'`wname`')
[NC,NS,cA] = upwlev2(C,S,Lo_R,Hi_R)
```

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`).

% 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
```

```idwt2, upcoef2, wavedec2 ``` upwlev wavedec 