Absolute Value of the Differences (AVD) method. This function implements
  the modification proposed by BRAGA, R.A. et al. [1] that is a modification
  of the Inertia Moment (IM) index.
  The AVD index can be implemented using:

  $Y\approx E[|i-j|]$
  $Y2\approx E[|i-j|^2]$
  $Y3\approx E[|i-j|^2] - E[|i-j|]^2$

  TYPE 1: The normalized co-occurrence matrix (COM) proposed by 
          CARDOSO, R.R. et al. [2]. The AVD first moment: $Y$.
  TYPE 2: The CARDOSO, R.R. et al. [2] COM normalization with quadratic AVD  
          The AVD second moment: $Y2$.
  TYPE 3: The AVD center second moment: $Y3$.
  TYPE 4: The normalized co-occurrence matrix (COM) proposed by 
          ARIZAGA, R. et al. [3] (Other pseudo first moment): $Y4$.

  References:
  [1]  BRAGA, R.A. et al. Evaluation of activity through dynamic laser speckle 
       using the absolute value of the differences, Optics Communications, v. 284, 
       n. 2, p. 646-650, 2011.
  [2]  BRAGA R.A. CARDOSO, R.R. Enhancement of the robustness on dynamic speckle 
       laser numerical analysis. Optics and Lasers in Engineering, 
       63(Complete):19-24, 2014.
  [3]  ARIZAGA, R. et al. Speckle time evolution characterization by the 
       co-occurrence matrix analysis. Optics and Laser Technology, Amsterdam, 
       v. 31, n. 2, p. 163-169, 1999.

  After starting the main routine just type the following command at the
  prompt:
           [Y] = avd(COM);
        [Y Y2] = avd(COM,2);
  [Y Y2 Y3 Y4] = avd(COM,2,3,4);
  [Y Y4 Y3 Y2] = avd(COM,4,3,2);

  Input:
  COM  is a 2D matrix, with 256 lines and 256 columns, that represents the 
       Co-Occurrence Matrix of a THSP matrix. The element COM(a,b) in the 
       co-occurrence matrix represents the quantity of times that in two 
       successive columns, of THSP matrix, the intensity values jump from 
       a-1 to b-1.
  TYPE [Optional] can be used many options. When it is used
       the function returns an additional result in the same position.
       If TYPE is equal to 2, the function also returns the AVD second moment, using 
       CARDOSO[2] COM normalization with ARIZAGA[3] value difference.
       If TYPE is equal to 3, the function also returns the AVD center second moment. 
       If TYPE is equal to 4, the function also returns the AVD with ARIZAGA[3] 
       COM normalization.

  Output:
  Y     is the value of AVD first moment [1].

  Ytype If TYPE is equal to 2, the function also returns the AVD second moment, using 
        CARDOSO[2] COM normalization with ARIZAGA[3] value difference.
        If TYPE is equal to 3, the function also returns the AVD center second moment. 
        If TYPE is equal to 4, the function also returns the AVD with ARIZAGA[3] COM normalization.


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

Package: bsltl