Three-Dimensional Particle Tracking Velocimetry

We develop 3D-PTV for many years. Standing on the shoulders of giants, we extended the original design from ETH Zurich into a real-time image-processing pipeline running at 6.25 Gb/sec. This lets us recover turbulent Lagrangian trajectories of fluid tracers, inertial particles, droplets, bubbles, and bio-organisms in real time.

Our system tracks thousands of particles simultaneously across the full measurement volume, resolving individual Lagrangian trajectories, velocities, and accelerations rather than the time-averaged, Eulerian picture given by PIV. The same real-time tracking pipeline underlies much of the lab's other work, from inertial particles and stratified turbulence to canopy flows and biomedical flows.

We develop and share our methods as open, reproducible software through OpenPTV (openptv.net), so that 3D-PTV is accessible to the wider fluid mechanics community, and we continue to push resolution, particle concentration, and processing speed in new hardware and algorithm designs.

Our real-time pipeline runs on custom FPGA hardware, performing particle detection and tracking directly in the imaging chain at line rate rather than in later post-processing.

Related video: 3D-PTV with FPGA for Lagrangian measurements in a wind tunnel — slideshow from ISPIV2023 — https://www.youtube.com/watch?v=9e7hqfd4B7c