Accuracy and resolution of a dynamic-speckle profilometer

We propose and demonstrate a new technique for fast noncontact and continuous profile measurement of a rough surface. The technique is based on frequency tracking of the power modulation of spatially filtered scattered light. A dynamic speckle pattern is created when the laser beam scans the surface under study. The main advantage of the proposed technique is high scanning speed, which provides an extremely short response time of the distance sensor (<0.1 (mu)s). Parameters that affect accuracy and resolution of the system are analyzed. Possible ways for further improvement of the measurements accuracy are discussed.