An out-of-plane displacement measurement system based on hardware tracking

Abstract

In this work, we propose an laser-interference based measurement method that employs a hardware device in the reference arm to track the out-of-plane displacement in the objective arm. Then a real-time one-point out-of-plane displacement measurement system is built up using a Michelson interferometer, a PZT device, a CCD camera and a tracking control system. The system works by checking the movement of fringes and then promoting PZT to track the displacement. A tracking algorithm including direction judgment and correlation computation is developed to decide whether PZT is started and the distance that PZT is ordered to move. Experimental results demonstrate the effectiveness of the system and finally the detailed mechanism of the system is discussed.