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Channel: PIVlab - Digital Particle Image Velocimetry Tool for MATLAB
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Donation complete!

January 21, 2015, 11:11 am
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Hey, we just reached the goal of 134 Euros! Thanks! I just downloaded MATLAB and will soon start working on PIVlab v1.4 ! I already noticed that R2014b is quite fast in comparison to previous releases.
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Working on r2014b release...

March 16, 2015, 12:40 pm
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I am making progress with the r2014 update of PIVlab, several incompatibilities are fixed already. This requires some extra attention, because PIVlab must stay compatible with earlier Matlab releases. I think that I will be ready to post a beta release of PIVlab 1.4 at the end of this week.
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PIVlab 1.4

March 18, 2015, 10:42 am
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I just uploaded the 1.4 release (compatible with R2014b and earlier). Download it here:
PIVlab1.4

PIVlab is now also available as 'App'. You can install it in Matlab by double-clicking on 'PIVlab.mlappinstall'.

Features:
  • MATLAB R2014b compatibility (yaay!)
  • Backwards compatible (the oldest version I could test is R2011a, but it should also work with much older releases)
  • Improved speed of FFT and the spline window deformation (due to some changes in R2014b)
  • Speed testing tool (run Testspeed.m to benchmark your hardware)
  • New default colormap Parula
  • Packaged app makes installation and execution simpler
  • Several minor fixes / improvements
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PIVlab 1.41 - now 10x faster processing!

February 12, 2016, 3:17 pm
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Recently, Sergey, a Junior Researcher at the ISSP RAS contacted me and told me that he found a way to make PIVlab (specifically the DFT window deformation part) much faster. He rewrote PIV_FFTmulti.m in a way that doesn't use 'for loops' anymore. The result is a heavily improved processing speed of PIVlab. I tested MATLAB versions 2011a, 2014b and 2015a. The speed was improved by a factor between 7.9 and 10.6 for a 'standard analysis' with three passes. Improvements up to a factor of 30 seem possible.

Thanks a lot Sergey, this will save a lot of people a lot of time!!

Download: http://www.mathworks.com/matlabcentral/fileexchange/27659-pivlab-time-resolved-particle-image-velocimetry--piv--tool
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PIVlab direct download

July 1, 2017, 3:44 am
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Hi everybody! For those who do not want to register on the Matlab website in order to download PIVlab, I added a direct link to the zip archive (see the column on the right side). You can also click here to get the zipped PIVlab toolbox:

http://william.thielicke.org/PIVlab/PIVlab.zip

There were no updates of PIVlab since quite a while. The reason is that I am currently not working with particle image velocimetry after I finished my PhD. That is a pity. But the good thing is that I converted one of my other hobbies into a profession: Since 2014, I am working as a mechanical design engineer at TobyRich GmbH. Over there, I am responsible for the design of fixed-wing drones, which is - similar to doing PIV - a lot of fun.
I am sorry that (in most cases) I can not react to your emails or forum entries. My life is currently filled up with too many other things that require my attention.
Success with your analyses!!
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PIVlab on the playground...

November 7, 2017, 12:37 pm
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This is a quick and dirty analysis of my daughters on the playground. Solid body rotation X-D.

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PIVlab 1.42 update

January 10, 2018, 5:57 am
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  • Fixed a graphics issue in the user interface 
As my latest Matlab is version R2015b, I cannot check how well PIVlab runs with more recent Matlab releases. Any issues...? I might consider to start a new "crowd funding" for PIVlab if there are issues. This would help me to collect the necessary 70 USD for an update of Matlab (which would enable me to update PIVlab). 
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What is YOUR machines processing speed?

January 10, 2018, 7:32 am
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Hi!
How fast is your computer running PIVlab? There is a script included with PIVlab, that allows to test your computers processing speed. Just run Testspeed.m from the command window to see your results. You can post them as a comment.  Here are my results:

Surface Pro 3

Intel Core i5-4300U @ 1.9GHz 2.5GHz
8 GB RAM
64 bit Win 8.1 Pro
MATLAB R2014b 64 bit

DCC calculation speed: 13.8081 ms
DFT calculation speed: 0.30431 ms
Linear interpolation speed: 0.56215 ms
Spline interpolation speed: 1.9602 ms

PC

Intel Core i7-2600K @ 3.4GHz
16 GB RAM
64 bit Win 7 Pro
MATLAB R2014b 64 bit

DCC calculation speed: 6.0144 ms
DFT calculation speed: 0.28481 ms
Linear interpolation speed: 0.53755 ms
Spline interpolation speed: 1.1093 ms

Acer Switch5

Intel Core i5-7200U CPU @ 2.50GHz
8 GB RAM
64 bit Win 10 Home
MATLAB 8.6.0.267246 (R2015b)

DCC calculation speed: 4.1283 ms
DFT calculation speed: 0.18304 ms
Linear interpolation speed: 0.25262 ms
Spline interpolation speed: 0.8413 ms
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PIVlab screen capture

January 20, 2018, 10:55 am
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Here is a quick screen capture, showing how easy PIVlab can be used. Only 9 clicks for a PIV analysis. But PIVlab is packed with pre- and post-processing tools that you can also use - if you want.


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Video interview: PIVlab - Background and quick start guide

February 7, 2018, 1:47 pm
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I am talking about why I developed PIVlab and how you can use it for your flow study:


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Please support PIVlab!

February 17, 2018, 11:40 am
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Please support PIVlab here:

PIVlab needs to be updated from time to time, in order to keep track with new and modified Matlab features. Otherwise it might happen that PIVlab doesn't work anymore. My last and current Matlab license is for R2015b. This is more than two years old.

I am trying to collect money to buy a recent Matlab Home license and keep on updating PIVlab.
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PIVlab Update 1.43

March 6, 2018, 12:59 am
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Slow motion of clothes in a drying machine...

May 11, 2018, 12:15 pm
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One PIVlab user wanted to analyse the motion of clothes in a drying machine. He had some problems with his setup, so I decided to check on my own if an analysis would actually work. Surprisingly, it works pretty well!

The original slow motion footage was taken from Youtube:


And this is the analysis:



Keep in mind that this is a very quick and dirty analysis, made with footage that was not meant to be analysed by PIV at all...
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600 citations on Google Scholar!

July 17, 2018, 1:15 am
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Thank you dear users of PIVlab for making this software pretty popular!
I will keep on improving the features whenever possible.

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PIVlab Update v1.50

October 27, 2018, 10:36 am
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This update brings some new features and performance enhancements:

'Repeated correlation'

I added the option 'repeated correlation'. I got the idea while I was working with another software (PIVview). 'Repeated correlation' can enhance your data yield when you are working with very noise or gernerally bad PIV images. It does the cross-correlation not only once per vector, but 5 times in total. Each time, it slightly shifts the interrogation windows (the distance depends on the size of your interrogation area, but it's about 5-10 pixels). This happens during each pass in a multipass analysis. In the end, it multiplies the 5 resulting matrices, which results in less noise an a very clear peak. But it also takes about 3 times longer to calculate...
You'll find this option in the PIV settings.

Problematic PIV data without 'Repeated correlation'
Problematic PIV data without 'Repeated correlation'. The data yield increases.

Background elimination

The next big addition is the background elimination GUI. If you have recorded a longer time series of image data, it makes sometimes sense to calculate the average of all images, and subtract it from each image before analysis. I added an extra GUI for this task. You can run it by launching 'Background_GUI.m', or clicking the button in the image pre-processing tab. You can have the same background for all images, or generate a seperate background for image_A and image_B.
The 'Background GUI' can be accessed from the image pre-processing tab

This is how the background GUI looks like

Disable auto-correlation

Again, I got the idea for this option when I was working with PIVview: Sometimes, background subtraction is not enough. It might still be the case, that your signal is so weak, that the background signal dominates. Usually, the analysis will then lock on the background, reporting zero displacement. When you choose the option 'disable auto-correlation', then each correlation matrix will be masked in the center, disallowing near-zero displacement. The algorithm will then look for the second highest peak which is (hopefully) the desired signal. 

This option can be found in the PIV settings
There are two signals overlaying in this PIV image: Some particles are moving in a circle, and some are not moving at all. The analysis looks bad, because the algorithm doesn't know which signal to take....
... until you tell PIVlab to disable auto-correlation, which will ignore particle shifts close to zero.

Better 16-bit handling

PIVlab had some problems working with 16-bit image data, this should be fixed now. Additionally, you can now adjust the histogram of your 16-bit image prior to analysis (note that the analysis still uses 8-bit data, your 16-bit images will be converted):
The histogram of some images isn't optimal for display or analysis. This image is too dark with not enough contrast.
With the new 'Auto contrast stretch' feature, the contrast is enhanced for the analysis. This is very important for working with 16-bit images. It is therefore turned on by default.


All derivatives available in exported files

When you export an ASCII or Matlab file from PIVlab, you will finally have all the derivatives available in the exported files:



That's it, I hope that you like it.
As usual, the update is available here: https://de.mathworks.com/matlabcentral/fileexchange/27659-pivlab-particle-image-velocimetry-piv-tool
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The beauty of PIV cross-correlation!

October 29, 2018, 2:13 am
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Do you like cross-correlation? You should when you visited this website...


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Order a book about PIVlab!

November 5, 2018, 7:12 am
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I still have a number of my dissertation books, it contains an extensive chapter on PIVlab. You can order a copy for 3 Euros + shipping (the money will be used to add to my Paypal money pool which will one day be used to renew my Matlab license).



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Major update: PIVlab 2.0

November 13, 2018, 11:37 am
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In the past, it happened quite often that the user interface of PIVlab was not displayed correctly on Mac computers. So I decided to completely reprogram the user interface "by hand" (that means without using Matlabs built-in GUI IDE called "GUIDE"). It was quite some work, but I believe PIVlab is now future-proof and easier to maintain. GUIDE was crashing pretty often in the last months, making enhancements very difficult.

I needed to print the whole interface on paper to correctly recreate it from scratch


So these are the changes:

  • GUI rewritten from scratch, should now be displayed correctly on all operating systems
  • Added prefernces in the menu: You can change the panel width of the UI if the UI elements are not scaled correctly.
  • Changed "Load external mask": You can now make masks outside of PIVlab and save them as black-and-white TIFs. When you import these masks, then white will become a masked area and black is non-masked area.
  • Added TECPLOT file format for export.
  • Background subtraction GUI only worked with grayscale images --> fixed.   
  • "Save as Matlab file" improved: Will now save in a slightly different format. If you click "Save all frames", then only one mat-file will be generated that contains the data of all frames.
  • Improved "Save session": Now uses compression and a more recent file format.
  • Fixed bug when exporting as image files
  • Enhanced the "Disable autocorrelation" method
  • Fixed bug when zooming
  • Fixed minor UI bugs
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Update PIVlab 2.01

January 21, 2019, 2:38 pm
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New features:
  • The user can now load time-resolved masks instead of single masks
  • The user can now select the color of the color legend label
  • The PIV settings are now checked automatically, and a warning is given if unusual parameters were selected 

Bug fixes:
  • Loading session files from older PIVlab versions is now possible (forum post)
  • Fixed bug where the tools panel showed slightly incorrect data sometimes (forum post)
  • Fixed bug where a warning message was displayed too often (forum post)





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Donations complete - thank you!

February 13, 2019, 1:48 pm
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As my personal Matlab license was pretty old, I was asking for donations for renewing my license during the last 365 days. It is important that I have a recent Matlab version to keep PIVlab alive.

And today, the donations reached 99.37 EUR, and I just renewed my Matlab license :-D Thank you! The new Matlab release even makes PIVlab 10.24 % faster!

Paypal Moneypool - Success!

Matlab R2018b - Installed!

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