• Data storage in ASCII or HDF format.
  • Integration within the Gnome desktop:
    Loading of images with "drag and drop" from the gnome file-manager Nautilus into the buffer list.
    Inclusion of Gpiv launcher into menu and taskbar (pre-compiled package).
  • Pipeline execution of enabled processes.
  • Batch processing on selected buffers.
  • Minimizing the console interface when desired by undisplaying the parameter settings tabulator and detaching the buffer list.
  • Quick execution by means of toolbar buttons.
  • On-line help from info line, tooltips and manual.


  • Visualization of the image(pair).
  • Shows interrogation area contours that will be highlighted when pointing to them.
  • Displaying of pointer position and belonging estimated values.
  • In and out zooming of displayed features.
  • Defining vector length.
  • Showing of vector colors related to specified criterium (validation threshold, correlation peak number, enabled/disabled)
  • Displaying of derived scalar quantities (vorticity and strain) as background.


  • Triggering of lasers and camera by means of RTAI over the parallel port of the Computer.
  • Recording images from a IIDC-compliant (CCD) camera that is connected to the Computer by the IEEE1394 (Firewire, I-Link) protocol. A list of such cameras can be found here.


  • Displaying image name, dimensions and type of correlation (cross or auto).
  • Defining of spatial and time scales, position of image within the experiment.
  • Adding and updating header information (date of creation, project, comment etc).


  • Interrogation by means of image-deformation techniques, using 5th order B-spline interpolation.
  • Adaptive interrogation area sizes.
  • Grid refinement by using bi-linear interpolation with shifted knots.
  • Validation after each iterative interrogation step.
  • Global pre-shifting.
  • Local pre-shifting or zero offsetting of the interrogation areas with forward or central difference scheme at integer number of pixels.
  • Three interpolation schemes for sub-pixel estimation.
  • Cross and auto correlation.
  • Choice of correlation peak for estimating particle displacements.
  • Arbitrary interrogation area dimensions.
  • Interrogation at the entire image or at an Area Of Interest, resulting into a displacement field on a rectangular grid.
  • Interrogation at a single arbitrary point, along a vertical or horizontal line by pointing in the image frame.
  • Re-interrogation of a single area with different parameters.
  • Dragging a single interrogation area from the rectangular grid.
  • Visualization of interrogation area's and correlation function.

Data validation

  • Enabling and disabling of PIV estimators manually.
  • Graphical representation of histogram containing displacements at sub-pixel level to check on peak-locking effects.
  • Graphical representation of histogram of residuals, calculation of threshold for acceptance of PIV estimators.
  • Validation on outliers by SNR value or median test from normalized residus.


  • Time and spatial scaling.
  • Calculation of statistics and subtraction of the mean value from the estimators.
  • Calculation of vorticity and strain.

Gerbervan der Graaf
email: gerber_graaf AT users DOT sourceforge DOT net

Last modified: Mon Nov 17 09:31:44 CET 2008