RapidPIV: Full Flow-Field kHz PIV for Real-Time Display and Control

We present a novel architecture for accelerating particle image velocimetry (PIV) calculations. An optical flow hardware accelerator calculates initial flow estimates, with cross-correlation providing corrections in post-processing. The result is RapidPIV: a software program for real-time PIV on Nvidia Turing-gen (or newer) GPUs. Dense vector fields and vorticity are displayed in real time when connected to a compatible camera. We achieve 1,150 frames-per-second on 1 megapixel images, with latency of 1ms. Accuracy, repeatability, and robustness are tested with physical experiments involving an accelerated flat plate and a cylinder wake. RapidPIV's accuracy, precision and ability to handle high displacement, velocity gradients, out-of-plane motion, and low seeding density compare favorably with the trusted multi-grid correlation software, while performing thousands of times faster than CPU-based software.