www.pudn.com > ex5-5.rar > func_Mywavedec2.m

function [c,s] = func_Mywavedec2(x,n,varargin) 
%WAVEDEC2 Multilevel 2-D wavelet decomposition. 
%   [C,S] = WAVEDEC2(X,N,'wname') returns the wavelet 
%   decomposition of the matrix X at level N, using the 
%   wavelet named in string 'wname' (see WFILTERS). 
%   Outputs are the decomposition vector C and the 
%   corresponding bookkeeping matrix S. 
%   N must be a strictly positive integer (see WMAXLEV). 
% 
%   Instead of giving the wavelet name, you can give the 
%   filters. 
%   For [C,S] = WAVEDEC2(X,N,Lo_D,Hi_D), 
%   Lo_D is the decomposition low-pass filter and 
%   Hi_D is the decomposition high-pass filter. 
% 
%   The output wavelet 2-D decomposition structure [C,S] 
%   contains the wavelet decomposition vector C and the  
%   corresponding bookeeping matrix S.  
%   Vector C is organized as: 
%     C = [ A(N)   | H(N)   | V(N)   | D(N) | ...  
%   H(N-1) | V(N-1) | D(N-1) | ...  | H(1) | V(1) | D(1) ]. 
%     where A, H, V, D, are row vectors such that:  
%   A = approximation coefficients,  
%   H = hori. detail coefficients, 
%   V = vert. detail coefficients, 
%   D = diag. detail coefficients, 
%   each vector is the vector column-wise storage of a matrix.  
%   Matrix S is such that: 
%     S(1,:) = size of app. coef.(N) 
%     S(i,:) = size of det. coef.(N-i+2) for i = 2,...,N+1 
%     and S(N+2,:) = size(X). 
% 
%   See also DWT2, WAVEINFO, WAVEREC2, WFILTERS, WMAXLEV. 
 
%   M. Misiti, Y. Misiti, G. Oppenheim, J.M. Poggi 12-Mar-96. 
%   Last Revision: 04-Dec-2001. 
%   Copyright 1995-2002 The MathWorks, Inc. 
% $Revision: 1.14 $ 
 
% Check arguments. 
if errargn(mfilename,nargin,[3:4],nargout,[0:2]), error('*'), end 
if errargt(mfilename,n,'int'), error('*'), end 
if nargin==3 
    [Lo_D,Hi_D] = wfilters(varargin{1},'d'); 
else 
    Lo_D = varargin{1};   Hi_D = varargin{2}; 
end 
 
% Initialization. 
s = [size(x)]; 
c = []; 
 
for i=1:n 
    [x,h,v,d] = dwt2(x,Lo_D,Hi_D,'mode','per'); % decomposition 
    c = [h(:)' v(:)' d(:)' c];     % store details 
    s = [size(x);s];               % store size 
 
end 
 
% Last approximation. 
c = [x(:)' c]; 
s = [size(x);s];