Non-phase unwrapping interferometric approach for a real-time in-plane rotation measurement.

This Letter proposes a novel interferometric approach for the in-plane rotation measurement. With a simple and compact measurement system, the rotation angle and its direction can be determined simultaneously in real time by applying the spatial carrier frequency. Besides, the phase unwrapping process is not required for the angular evaluation, which simplifies the data processing procedure. Theoretically, the relationship between the in-plane rotation and the phase change distribution has been deduced to demonstrate the possibility of this interferometric method. Practically, the preliminary experiments have been carried out to verify the feasibility of this approach and quantify the measurement accuracy.