Posts

Podcast by Inspiring Computing about PIVlab

Image
Gareth Thomas from  Inspiring Computing did an interview about PIVlab with me. Listen to the podcast here: https://www.buzzsprout.com/2107763/15106425 Join the conversation with  William Thielicke , the developer of  PIVlab , as he shares insights into the world of particle image velocimetery (PIV) and its applications. Discover how PIV accurately measures fluid velocities, non invasively revolutionising research across the industries. Delve into the development journey of PI lab, including collaborations, key features and future advancements for aerodynamic studies, explore the advanced hardware setups camera technologies, and educational prospects offered by PIVlab, for enhanced fluid velocity measurements. If you are interested in the hardware he speaks of check out the company:   Optolution .  

PIVlab 3.00 released

Image
  I have just released PIVlab 3.00. There are several changes in the way the graphics are drawn, the way the data is exported and the way it interacts with masks / calibration and region of interest: New graphics: Transparency, masks are transparent, only ROI is opaque Colorbar is now outside the plot for much improved readability Export image data as .mp4 and as .png image Completely new mask handling, allowing much easier mask creation / modification. Mask stay editable all the time. Much easier to create holes in masks Mask operations like shrink/grow/simplify/subdivide/optimize Automatic mask generator, capable of automatic masking of bright areas / dark aread / low-contrast areas. Possibility to add more automatic mask generators in the future Mask import (of user generated masks) heavily improved Matlab Online fully supported New line extraction and area extraction interface: More straightforward and faster. Better interaction Natural file name sorting when importing image files

The new eduPIV system

Image
Hey, I just finished making a complete educational PIV (eduPIV) system! This is a small water tunnel equipped with a pulsed laser, synchronizer and camera. Everything can be controlled from my software "PIVlab". It comes with two types of wings and a cylinder that generate nice wakes and that can be manipulated from outside the tank. It may sound funny, but I think this _really_ is an awesome system to get PIV in your lab (or home...?). Maybe this is even better than watching vortex rings illuminated by a LED ;) Watch the video here:  

A video on laser diodes, cameras etc. in PIVlab!

Image
 

Significant speed and memory improvements in PIVlab!

Image
Mehdi (Manager Mechanical & Aerospace Engineering) from MATHWORKS (the company behind Matlab) approached me a while ago and we discussed how they can support the development of PIVlab. PIVlab seems to be have some importance a relevance to MATHWORKS as it is a pretty popular 3rd party toolbox for Matlab. Together, we identified potential areas in PIVlab that could be improved and MATHWORKS then initiated an internal proposal for programming support. They selected the dutch company Vortech.nl for this project, and Maarten then started to optimize the most important part of PIVlab "PIV_fftmulti.m". He significantly improved the speed of calculations (factor 3), and lowered the memory consumption enormously. This especially helps when processing large images with fine grids, and also makes it possible to benefit from parallel processing of large images. This hasn't been possible before, because at some point RAM was full and the hard disk was used to store temporary dat

New in v2.57: PIVlab Batch Sessions

Image
 PIVlab can now run in batch mode with the GUI: To prepare a batch session, perform your setup as before (including image loading, calibration, pre- and post processing, but WITHOUT hitting the "Analyze all frames" button ). Then save your session. To perform a batch analysis, you can now enter the following: PIVlab_GUI(1,'c:\folder\my_first_PIVlab_session.mat'); PIVlab_GUI(1,'c:\folder\my_second_PIVlab_session.mat'); PIVlab_GUI(1,'c:\folder\my_third_PIVlab_session.mat'); Where the first number is the number of CPU cores to use (when you have the parallel computing toolbox), and the second argument is the path to your session file. PIVlab will then start, load the session file, perform the analysis, and save the session file in the same folder and with the string '_BATCH' attached to the filename. This allows you to prepare large amounts of image data for analysis, and process them all at once e.g. during the night.

PIVlab is becoming super popular!

Image
(updated 2024) PIVlab seems to become the most cited PIV software of all available PIV softwares (commercial [co] and open source [os]). I performed a search on Google scholar using all PIV software names that I could think of. The per-year-keyword-occurance might be a good indicator for the popularity of a software in academic research. Steep increase in Keyword occurance for PIVlab (magenta)... These are the search terms I used for Google scholar. I wrote a Matlab script that queries Google scholar for these search terms for each year between 2005 and 2023. Google limits the amount of requests per IP, so I had to use a VPN and change the IP frequently: "lavision" AND "davis" AND ("piv" | "particle image velocimetry") ("pivlab" | "piv lab") AND ("piv" | "particle image velocimetry") -"@pivlab.net" "dantec" AND ("dynamic studio" | "dynamicstudio") AND ("piv"

Very high power pulsed laser diode array prototype :)

Image
Last week, I have assembled a 20 W pulsed laser diode array for PIV with PIVlab. I just finished the first test and successfully measured velocities in air of up to 20 m/s with a small field of view (47x47 mm) and with the pco.panda 26 DS. The interframe time was 10 microseconds with a pulse length of 10 microseconds. Images with 25 megapixels (= no pixel binning) were captured. As the light intensity is pretty low at these short pulses, pixel binning is recommended however. In water, this will give really awesome results, I will test it the coming week. I was using a third-party laser driver for this test which isn't very good for such short pulses (laser light takes 2 microseconds to ramp up with this driver). So some light will be lost with this third-party driver. With my own circuit, which uses the iC-HGP laser driver chip, this will become much better (only 150 nanoseconds ramp up time). But I'll need to use several of these chips to drive groups of laser diodes because t

High-speed low-cost PIV with the pulsed laserdiode: Examples

Image
Recently, I asked Prof. de Payrebrune from the University Kaiserslautern / Computational Physics in Engineering if they could lend me their Chronos 1.4 low-cost high-speed camera for some tests. She agreed to support the development of PIVlab which is very cool and kind of her!! Now I did some tests with the camera (captures data at 1.3 megapixels at 1000 Hz) and my new LD-PS pulsed laser diode. The LD-PS has a built-in synchronizer, so it triggers the Chronos and can also do frame-straddling. The Chronos has absolutely brilliant trigger characteristics, as you have complete control over the exposure timing. Now I am not limited to an interframe-time of 1/1000s anymore, but can go down to 10 µs.  When capturing data at 1000 fps, the duty cycle of the illumination becomes quite high. So I added two little fans to the LD-PS housing. Now a duty cycle of up to 50% can be reached without the laser or the driver becoming too hot. The awesome Chronos high-speed camera from krontech.ca Latest

Low-cost PIV, pulsed laser illumination update

Image
An updated version of my 5W pulsed diode laser module is finished... I changed the PCB and I am now using a dedicated pulsed laser driver chip. There was not really an urgent need to do this, but this chip seemed very sexy. Unfortunately, this is only available as QFN package, but soldering still worked like a charm. Typical PIV application (5 W version): Water: velocities up to 2.5 m/s and illuminated area up to 300 x 200 mm Air: velocities up to 1.5 m/s and illuminated area up to 200 x 150 mm There is raw PIV image data available for you to download here: 1000 µs pulse length, Δ t = 1000 µs, 16 megapixels 50 µs pulse length , Δ t = 200 µs , 16 megapixels 20 µs pulse length , Δ t = 100 µs, 1 megapixel The datasheet is available here .  

Low-cost particle image velocimetry setup: Pulsed laser diode for PIV illumination

Image
I just finished designing a PIV illumination system that uses one or more laser diodes to generate a thin & bright light sheet. Naturally, this illumination can not compete with e.g. our 200 mJ double-pulsed PIV laser (which costs something between 30 and 40k Euros). But it is very good for illuminating smaller areas (e.g. 300 x 200 mm) and low flow velocities (up to 2.5 m/s). It has a built-in synchronizer for pco cameras, and can be controlled wirelessly from PIVlab. Power consumption is very low, so it can be powered by any standard USB-C phone charger or power bank. PIV products for PIVlab Data sheet

PIV uncertainty: Help and Feedback wanted

Image
Pretty often, you are asking for a method to quantify the PIV uncertainty. I implemented a method from 2013, and I need your help and feedback to finalize this. It is actually pretty simple, and my code is very straightforward I think. So anyone that had some math in school will be able to help. If you want PIVlab to be improved, then just invest some of your time please. Here is all the information with many images: https://github.com/Shrediquette/PIVlab/issues/58#issuecomment-966591348

Working on sub 5k Euros PIV system NOW!

Image
OPTOLUTION aims high and I am trying to make a complete PIV System (with laser, camera, synchronizer and software) in the range of 3k Euros. That is the price that you usually don't even get the PIV software for. We will see if it works out, but initial tests were already pretty promising. These are the specs I want to achieve: Illumination of a 200x300 mm area Max. velocity of 2 m/s 2 MP camera resolution 500 µs or 1 ms minimum interframe time 5 fps double-image framerate Fully integrated in PIVlabs image acquisition module Compatible with Matlab R2019b and later (Image Processing Toolbox required) Designed for Windows, but should also work with Apple and Linux If you are interested in this system, then let me know!

PIV like a PRO with PIVlab hardware!

Image
 This video shows a demo of several PIVlab hardware features and image acquisition features. I developed all of this at Optolution.com , an it is available for sale there too.

Aerodynamics of a hot coffee cup

Image
 Just for fun:

Free jet with 4 mm diameter: PIV test

Image
PIVlab's acquisition module can now also control our wireless custom mini seeding generator (all hardware available through OPTOLUTION.com ). That means that a single button click in PIVlab starts the whole measurement. I could add more remote controlled devices to control other hardware via PIVlab too (e.g. start a motor, open a valve, or whatever). Here, I wanted to measure the flow velocity at the exit of the wireless mini seeding generator. Example images can be found below. The field of view in this experiment was about 11 * 9 mm, and the pipe is D6, d4 mm.

PIVlab Paper is out

Image
 Finally, the new paper that is describing and validating some of PIVlabs new features is out: https://openresearchsoftware.metajnl.com/articles/10.5334/jors.334/

Real-time PIV in PIVlab!

Image
Today, I quickly tested if I can do real-time particle image velocimetry in PIVlab, and it works :D. Data rate is about 3 Hz, but the code is not optimized yet and running on a core i5 laptop:

PIVlab v2.50 with parallel processing and camera / laser control released! And: New tutorial videos.

Image
At least for me, this is a great update as processing speed is improved quite a bit, and I can now capture image data and control our laser directly in PIVlab. Sooooo much easier to do experiments for our customers...! With some additional hardware, PIVlab can control a laser and a camera directly. Hardware is available at OPTOLUTION The new PIV acquisition panel - very comfortable and simple. PIVlab-SimpleSync with wireless USB dongle. I also recorded three new tutorial videos for PIVlab: PIVlab tutorial, part 1/3: Quickstart PIVlab tutorial, part 2/3: Pre-processing, analysis and data validation PIVlab tutorial, part 3/3: Data exploration and data export

PIVlab will soon capture images!

Image
Soon, PIVlab will be more than just a PIV post-processing tool! I am currently implementing some additional features, so that PIVlab can control our laser and the camera directly. I am doing this, because we are using PIVlab for commercial services, and I want to have a PIV setup that is really handy in practice. I also developed a small synchronizer (see picture) that controls our Quantel Evergreen 200 PIV laser and synchronizes it with the ILA5150 PIV.Nano double-image camera. And this synchronizer (which is wireless by the way) is also controlled directly from PIVlab. Everything is as simple as it can get: Press a single button to start camera and laser, images will be saved to your hard disk and directly loaded into PIVlab. Awesome! If you want to have this too for your research, you'll need the PIVlab-SimpleSync ( Optolution.com ), the ILA5150 PIV.Nano camera, and a double-puls laser (e.g. Quantel EVG00070). The PIVlab-SimpleSync wireless synchronizer controls Lamp 1&2, Q