This function implements the spatial-temporal speckle correlation [1] 
  technique. The correlation is applied between K0 image and
  all other images. 
  Use as input data a 3D matrix created grouping NTIMES intensity matrices I(k)
  1<=k<=NTIMES

  L    = [1:NTIMES]-K0
  LTau = L * Tau

  $corr(A,B)= \frac{E[(A-\mu_A)(B-\mu_B)]}{\sqrt{E[(A-\mu_A)^2]E[(B-\mu_B)^2]}}$

  $C(k)= corr(I(K0),I(k))$,  $\forall~1 \leq k \leq NTIMES$

  [1] ZDUNEK, A. et al. New nondestructive method based on spatial-temporal
      speckle correlation technique for evaluation of apples quality during
      shelf-life. International Agrophysics, v. 21, n. 3, p. 305-310, 2007. 

  After starting the main routine just type the following command at the
  prompt:
  C          = stscorr(DATA,Tau,K0)
  [C LTau]   = stscorr(DATA,Tau,K0)
  [C LTau L] = stscorr(DATA,Tau,K0)
  
  Input:
  DATA is the speckle data pack. Where DATA is a 3D matrix created grouping NTIMES 
       intensity matrices with NLIN lines and NCOL columns. When N=size(DATA), then
       N(1,1) represents NLIN and
       N(1,2) represents NCOL and
       N(1,3) represents NTIMES.
  Tau  is the sampling rate in seconds.
  K0   is the number of the reference frame used in correlation analysis.

  Output: 
  C    is the correlation vector. This corresponds with the C(l*tau) values used 
       in [1] at equation (7), with the difference that negative values of 
       l*tau also are calculated.
  LTau [Optional] is the vector with the values of time l*tau in the vector C. This
       can have negative values.
  L    [Optional] is the vector with the values of index l in the vector C. This
       can have negative values.


  For help, bug reports and feature suggestions, please visit:
  http://nongnu.org/bsltl/

Package: bsltl