Particle Image Velocimetry tool Enrico Segre (Aug 2003).					

PIV stands Particle Image Velocimetry, a method of reconstructing
velocity fields in fluid flows seeded with tracer particles, by 
comparing successive snapshots of the flow. 

Here is an implementation in Scilab of the classical digital particle 
image velocimetry method, based on correlation of interrogation windows 
of couple of images. Subpixel interpolation by gaussian fit to
a 3x3 neigborhood of the correlation peak is now implemented.
This is part of a project I had to deal with some time ago; I thought 
it may be of interest to submit it even in this unfinished form. As a
part of it I also developed multiplane scanning, reconstruction of
the third component of the velocity and generation of 3d flowlines, all
within scilab. That part of the coding, however, is more dependent
on the particularities of my scanner and of the data format I choose. I 
think that that would be of lower general interest and I do not include
it here, but who is interested can email me about.

References: random refs of the bunch Willert, Gharib, Adrian.
            The method of multipass refining should be ascribed to
            Hart or Westerweels. Boh.

Author: Enrico Segre, enrico.segre@weizmann.ac.il
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12/8/2003 revision:
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Contents of the directory:

README   -  this file

macros:
  dpiv.sci -  main function to compute piv
  refpiv.sci - evolved function which performs multipass refining PIV
  medianvalid.sci - ancillary function for validating a piv vectorfield
                  (replaces bad vectors with the average of their
                    neighbours)
  subpixel.sci  - ancillary, subpixel interpolation of the correlation
                  peak
                    
man
  documentation in .cat (text) form

scripts: useless snippets that I wanted to keep together
  piv.sce - an example of use, implementing the method of active 
            refinement of the interrogation window. This script employs
            several functions of the ENRICO toolbox
  testsubpix.sce - a quick test of the subpixel interpolation

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INSTALLING:

building: exec PIVtool/builder.sce;
Loading: exec PIVtool/loader.sce;