PARTICLE IMAGE VELOCIMETRY WITH OPTICAL-FLOW

An optical Flow technique based on the use of Dynamic Programming has been applied to Particle Image Velocimetry thus yielding a significant increase in the accuracy and spatial resolution of the velocity field . Results are presented for calibrated synthetic sequences of images a nd for sequences of real images taken for a thermally driven flow of w ater with a freezing front. The accuracy remains better than 0.5 pixel /frame for tested two-image sequences and 0.2 pixel/frame for four-ima ge sequences, even with a 10% added noise level and allowing 10% of pa rticles of appear or disappear. A velocity vector is obtained for ever y pixel of the image.