PIVlab - Time-Resolved Digital Particle Image Velocimetry Tool for MATLAB

PIVlab 1.3

2012-01-27T14:00:00.002+01:00

PIVlab version 1.3 is out!

New features:

Modify vector color
Apply to all frames in area / line extractions
Post-processing from commandline
Load user-generated masks
Plot only every nth vector
Line Integral Convolution (LIC) feature from the Matlab Vector Field Visualization toolkit (http://sccn.ucsd.edu/~nima/)
Add display update between individual passes
Image preview during image selection
Modified interrogation area preview
Several small improvements

Screenshots of some of the changes:

Modify plot appearance

Area extractions (do extractions for all frames)

Image preview

Preview of the interrogation area

Line Integral Convolution

Poly line extractions (do extractions for all frames)

A quick note on processing speed

2011-11-24T13:29:00.001+01:00

Soon, I will need to analyze a large dataset (441.000 image pairs), so I did some tests to speed up the data processing. When using a QuadCore computer (actually 8 virtual cores in this case), up to eight Matlab instances can run in parallel to increase speed. Running more instances will result in a decrease in speed.
A similar effect is also possible with a DualCore computer. Running two Matlab instances in parallel increases the speed by almost 100%.
If you also need to save time, you might try to split your data and run as many Matlab instances as there are (virtual) CPU cores on your computer. Starting the PIV analysis from the commandline (see example in PIVlab_commandline.m), and starting Matlab with the "-nodesktop" command will additionally increase speed.

Processing time for the analysis of one large image pair with multiple passes on different systems

PIVlab 1.2 vortex ring analysis

2011-07-14T12:44:00.000+02:00

Watch it in HD on Vimeo:
http://vimeo.com/26375991

PIV vortex ring from B. Thielicke on Vimeo.

PIVlab 1.2: Window deformation & streamlines

2011-07-07T13:30:00.002+02:00

The new PIVlab release supports an advanced correlation technique (I want to thank Kyle Lynch for the discussion about this). Using a multipass window deformation technique, significantly reduces noise in the data. The maximal vector resolution can also be increased and peak-locking is reduced a lot. PIV images that have a low quality can now be processed with higher precision (see the video at the bottom).
Additionally, it is possible to draw some streamlines and streamline rakes, this is useful for adding some qualitative information to the analyses.
The image export procedure has also been improved, it is possible to export the displayed result at any desired resolution (only limited by the RAM on your computer).

Standard direct cross-correlation (DCC) analysis using a 14*14px interrogation area with 50% overlap:

Multipass, window-deformation using a 6*6px interrogation area with 50% overlap in the final pass:

Streamlines:

Processing low quality images:

The new code will be uploaded to MATLAB Central soon, I just have to do some final tests.

PIVlab 1.13 released

2011-04-11T10:57:00.000+02:00

Changed figure and all UI element units from pixels to points. This hopefully solves some problems with displaying the GUI.
Statistics toolbox no longer required to run PIVlab (implemented NaN Suite by J. Gläscher into PIVlab)

Download PIVlab 1.13 @ Matlab Central

PIVlab 1.1 released

2010-11-18T19:40:00.000+01:00

PIVlab v 1.1, added features / improvements:

better smoothing algorithm (smoothn.m) if supported (otherwise gaussian kernel is used)
removed several known bugs/ pitfalls
added a feature to extract tangential velocity along a series of circles with increasing radius (useful to calculate vortex circulation)
added a feature to extract circulation via integrating the vorticity over area for a series of an increasing area
added a feature to calculate the weighted centroid of derived parameters
improvements in the particle image generation algorithm
added several flow simulations (including Hamel-Oseen vortices and vortex pairs)
vector width is user selectable

Download PIVlab @ Matlab Central

PIVlab analysis

2010-11-18T13:20:00.000+01:00

Synthetic PIV images were created using PIVlab's built-in image generator:

PIVlab 1.0 released

2010-05-20T16:01:00.002+02:00

PIVlab is now available for download (see right hand side of this blog for the link).
Here is a recent video showing a standard PIV analysis:

Time-resolved Kármán vortex street behind a cylinder, PIV in Matlab

2010-04-15T18:54:00.001+02:00

Some PIV images analyzed in MATLAB with PIVlab

2010-03-31T13:32:00.000+02:00

Here are some images that were analyzed with PIVlab. Click for higher resolution.

Intro

2010-03-12T09:04:00.000+01:00

Particle Image Velocimetry (PIV) is a method to measure space- and time-resolved flow velocities in fluids. I will work a lot with this method during my PhD. In the past, I got to know some commercial PIV software systems (e.g. "Flowmanager" and "VidPIV"), but I was never totally happy with these. I also had a look at several free PIV systems (mostly based on MATLAB), but these were not suitable for my demands. Since I am going to spend a lot of time with PIV calculations, E.J. Stamhuis and me recently developed a PIV software (called PIVlab) that takes advantage of numerous MATLAB features. I also created an extensive GUI for the software which makes it easy to get results with ease.