function [out,wcoef,wcoefrest] = HT(Noisy,L,qmf,sigma)
%  HT -- Hard Threshold Applied to Wavelet Coefficients.
%  Usage 
%    [out,wcoef,wcoefrest] = HT(Noisy,L,qmf,sigma,coef)
%  Inputs
%    Noisy      1-d signal. length(y)= 2^J
%    L      Low-Frequency cutoff for shrinkage (e.g. L=4)
%               Should have L << J!
%    qmf    Quadrature Mirror Filter for Wavelet Transform
%               Optional, Default = Symmlet 8.
%    sigma  Standard deviation of additive Gaussian White Noise.
%  Outputs 
%    out     	estimate, obtained by applying hard thresholding on
%          	wavelet coefficients
%    wcoef	Wavelet Transform of input signal	
%    wcoefrest  Wavelet Transform of estimate
%

  n=length(Noisy) ;
  wcoef = FWT_PO(Noisy,L,qmf) ;
  thresh= sqrt(2*log(n))*sigma;
  wcoefrest = HardThresh(wcoef,thresh);
  out    = IWT_PO(wcoefrest,L,qmf);
  
% Written by Maureen Clerc and Jerome Kalifa, 1997
% clerc@cmapx.polytechnique.fr, kalifa@cmapx.polytechnique.fr
    
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