PIVMat Getting Started |
The PIVMat Toolbox for Matlab contains a set of command-line functions to import, post-process and analyse 2D vector fields from PIV (particle image velocimetry), DIC (digital image correlation) SS (synthetic schlieren) or BOS (background-oriented schlieren) applications.
It is compatible with several data formats, including DaVis (LaVision) (FlowMaster/StrainMaster packages) and VidPIV (Oxford Laser).
The PIVMat Toolbox enables to handle and perform complex operations over large amount of velocity fields, and to produce high-quality vector/scalar outputs. This toolbox in itself does not perform any PIV computations.
DaVis is a commercial software for imaging applications developed by LaVision.
For PIV or Synthetic Schlieren applications, DaVis computes vector fields (velocity or displacement fields) from image correlations. These fields can be saved in a specific DaVis file format (VEC or VC7 files), which can be imported in Matlab using the ReadIMX Loader package provided by LaVision. Based on this package, the PIVMat Toolbox offers a number of command-line functions to further post-process and analyze those vector fields.
The first step is to import some vector fields into a MATLAB structure array. The simplest way to import data is to double-click on a file on the Current Directory Browser. You can also import data using the function loadvec. Each element of this structure array contains the two matrices of the velocity components, the coordinate system, and some additional informations (units, axe names, PIV parameters...)
Once imported, the velocity fields can be displayed using showf, or converted into scalar fields using vec2scal.
A sample directory, named sample, with 3 experimental series of PIV fields, is provided with the toolbox to test the following examples (note that these examples work with any file format supported by PIVMat).
Example 1
v = loadvec('B00001.VC7'); % loads the file B00001.VC7
showf(v); % displays it
curl = vec2scal(filterf(v,2),'rot'); % computes the filtered vorticity
figure, showf(curl); % displays it
Example 2
Various statistics may be computed from vector and scalar fields:
v = loadvec('*.vc7'); % loads all the VC7 files
curl = vec2scal(filterf(v,2),'rot'); % computes the filtered vorticity
showf(curl); % displays it as a movie
showf(averf(curl)); % displays its ensemble-average
histscal_disp(curl); % displays its histogram
statf(v) % computes some statistics
Go to the Frequently Asked Questions section or to the Function by category section to learn more about this toolbox.
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