Digital speckle-pattern interferometry as a full-field fluid-velocimetry technique.

We present a novel fluid-velocimetry technique based on speckle interferometry. The light scattered from an illuminated plane is recorded with a CCD camera at the same time as a speckled reference beam. Substraction of two nonsimultaneous frames provides information about the velocity field for an out-of-plane component. An application to a Rayleigh-Bénard convective flow is given.