Gpiv features

General

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.

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.