pr_seat_thresh

 Thresholding by Signal Estimation Algorithm
 FORMAT w = pr_seat_thresh(X)

 Inputs
 X        - vector of wavelet coefficients (variance is supposed 1);
 
 Outputs
 w        - threshold
             
  Reference
    Polchlopek HM, Noonan JP (1997) "Wavelets, Detection, Estimation
    and Sparsity", Digital Signal Processing, 7:28-36

    Federico E. Turkheimer
    August 13th, 1998

 $Id: pr_seat_thresh.m,v 1.1 2005/06/05 04:17:42 matthewbrett Exp $

0001 function w = pr_seat_thresh(X)
0002 % Thresholding by Signal Estimation Algorithm
0003 % FORMAT w = pr_seat_thresh(X)
0004 %
0005 % Inputs
0006 % X        - vector of wavelet coefficients (variance is supposed 1);
0007 %
0008 % Outputs
0009 % w        - threshold
0010 %
0011 %  Reference
0012 %    Polchlopek HM, Noonan JP (1997) "Wavelets, Detection, Estimation
0013 %    and Sparsity", Digital Signal Processing, 7:28-36
0014 %
0015 %    Federico E. Turkheimer
0016 %    August 13th, 1998
0017 %
0018 % $Id: pr_seat_thresh.m,v 1.1 2005/06/05 04:17:42 matthewbrett Exp $
0019         
0020   X    = abs(X);
0021   n    = length(X);
0022   chi  = sum(X.^2);
0023   sig  = chi-n;
0024   
0025   if(sig < 0),
0026     w=inf;
0027   else
0028     for k=n:-1:1,
0029       s = sum(X(k:n).^2);
0030       if (s>sig),
0031     w=X(k);
0032     break
0033       end
0034     end
0035   end
0036   
0037