3-D MEASUREMENT OF MOVING PARTICLES BY CIRCULAR IMAGE SHIFTING

A new approach to the three-dimensional (3-D) measurement of position and velocity of moving particles is introduced, A single TV camera wit h an apparatus to add circular shift to the image enables us to record the 3-D movement of particles as spiral streaks on a single image, Ev ery shape of the spiral streak on the image plane is related to the po sition and the velocity of the individual particle, The information ab out 3-D movement of particles is extracted from the image using an ima ge processing technique, We applied the technique to the measurement o f the 3-D water-flow field seeded with tracer particles in a test tank and obtained satisfactory results.