www.pudn.com > multiwavelet.rar > prep2D_appe.m

function fp=prep2D_appe(f,pflt) 
%fp=prep2D_appe(f,pflt) 
% 
%  This function performs critically sampled preprocessing of given  
%  2-dimensional signal. Boundaries are handled by periodic extension. 
%  For description of the algorithm see [SW]. 
% 
%  Input:     
%    pflt       string of characters, name of the prefilter; 
%               for possible names and short descriptions see coef_prep.m 
%    f          n by n real array, input signal;//2-D输入信号 
%    n          n must be of the form r*integer*2^maxlevel, 
% 
%    r          r is the number of scaling functions, //尺度函数的个数 
%    maxlevel   maxlevel is the number of levels of multiwavelet decomposition //多小波分解的层数 
% 
%  Output:  
%    fp         n by n real array, preprocessed data; 
%               for structure of fp see [SW] 
% 
%  Example of Usage: 
%    fp=prep2D_appe(f,'ghmap') 
 
% Author: Vasily Strela 
% COPYRIGHT 1997,98 by Vasily Strela 
 
[PR,PO]=coef_prep(pflt); 
[n1,n2]=size(f); 
fp=zeros(n1,n2); 
[nf,np]=size(PR); 
 
prl=round(n2/nf); 
aa=zeros(nf,prl); 
for i=1:n1 
  aa=prep1D_appe(f(i,:),pflt); 
  for j=1:nf 
    fp(i,(j-1)*prl+1:j*prl)=aa(j,:); 
  end 
end 
 
prl=round(n1/nf); 
aa=zeros(nf,prl); 
for i=1:n2 
  aa=prep1D_appe(fp(:,i)',pflt); 
  for j=1:nf 
    fp((j-1)*prl+1:j*prl,i)=aa(j,:)'; 
  end 
end