waverec2

2-D wavelet reconstruction

Syntax

X = waverec2(C,S,wname)
X = waverec2(C,S,Lo_R,Hi_R)
X = waverec2(C,S,wname)
X = appcoef2(C,S,wname,0)


Description

X = waverec2(C,S,wname) performs a multilevel wavelet reconstruction of the matrix X based on the wavelet decomposition structure [C,S]. For detailed storage information, see wavedec2. wname is a character vector or string scalar specifying the wavelet. See wfilters for more information.

Instead of specifying the wavelet name, you can specify the filters.

• X = waverec2(C,S,Lo_R,Hi_R), Lo_R is the reconstruction low-pass filter

• Hi_R is the reconstruction high-pass filter.

waverec2 is the inverse function of wavedec2 in the sense that the abstract statement waverec2(wavedec2(X,N,wname),wname) returns X.

X = waverec2(C,S,wname) is equivalent to X = appcoef2(C,S,wname,0).

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 sym4. 
[c,s] = wavedec2(X,2,'sym4');
% Reconstruct X from the wavelet 
% decomposition structure [c,s]. 
a0 = waverec2(c,s,'sym4');
% Check for perfect reconstruction. 
max(max(abs(X-a0)))
ans =
    2.5565e-10

Tips

If C and S are obtained from an indexed image analysis or a truecolor image analysis, X is an m-by-n matrix or an m-by-n-by-3 array, respectively.

For more information on image formats, see the image and imfinfo reference pages.

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

• Variable-size data support must be enabled.

• The input wname must be constant.