Particle Image Velocimetry (PIV) is increasingly used to investigate unsteady velocity fields instantaneously. At DLR an experimental set-up for PIV has been developed which can be operated under the rough environmental conditions (noise, vibrations) of a large wind tunnel. This system has successfully been applied as well to low speed as to high speed flows (U = 10. 500 m/s). The evaluation and post processing of the PIV recordings runs filly automatical on a work station