 Usage:  datt = sure2d (dat,l,pro)  
 
 Input:

  dat                    n x n array, wavelet coefficients 
                         
  l                      integer, l^2 is the number of the father wavelet coefficients 
                         
  pro                    string, "stein","soft" or "hard" indicating the chosen 
                         wished method 
                         
 Output:

  datt                   n x n array, thresholded wavelet coefficients 
                         
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(C) MD*TECH Method and Data Technologies, 17.8.2000
