www.pudn.com > multiwavelet.rar > thresh_vec1D.m

function transfth=thresh_vec1D(transf,maxlevel,thresh,covname,threshtype) 
%transfth=thresh_vec1D(transf,maxlevel,thresh,covname,threshtype) 
% 
%  This function performs vector thresholding with decorrelation of  
%  1-dimensional multiwavelet transform. Scaling coefficients stay untouched. 
%  For description of the algorithm see  [DS], [SW] 
% 
%  Input:    
%    threshtype  string of characters, either 'hard' or 'soft'; 
%                  threshtype='hard' invokes hard thresholding, 
%                  threshtype='soft' invokes soft thresholding; 
%                for details see [DS] 
%    covname     string of characters, name of covariance matrix used for  
%                decorrelation; for possible names and short descriptions  
%                see coef_dcov1D.m 
%    thresh      real, value of the threshold  
%    maxlevel    integer, number of levels of wavelet decomposition in transf; 
%                maxlevel < 7  
%    transf      r by n real array, wavelet transform of a signal; 
%                r is the number of scaling functions,    
%                n must be of the form integer*2^maxlevel; 
%                for structure of transf see [SW] 
% 
%  Output:   
%    transfth    r by n real array, thresholded multiwavelet coefficients 
% 
%  Example of Usage: 
%    transfth=thresh_vec1D(transf,5,0.75,'clap','hard') 
 
% Author: Vasily Strela 
% COPYRIGHT 1997,98 by Vasily Strela 
 
n0=length(transf(1,:)); 
D=coef_dcov1D(covname); 
r=length(D(:,1)); 
transfth=transf; 
 
for i=1:maxlevel, 
  d=D(:,(i-1)*r+1:i*r); 
  dd=inv(d); 
  for j=n0-(2^i-1)*n0/2^i+1:n0-(2^(i-1)-1)*n0/2^(i-1), 
    tj=sqrt(transfth(:,j)'*dd*transfth(:,j)); 
    if tj