Abstract

There are many possible laser velocimetry designs for rotation measurement which can be modified in fiber format to be used for remote sensing in unaccessible environments. However, to our knowledge, there is no remote optical system to monitor and test the off-axis movement of a rotating body. Such a system is of particular importance for uses such as the governor shaft of engines (aerospace industries), monitoring of the movement of the rotating axis of a helicopter, etc. In this paper we describe an optical system that is capable of measuring the off-axis movement of a uniformly rotating body. Two fibers are located at opposite sides of a rotating body which has a mark at the imaging position. The images are transferred to a remote location and are then fed into a CCD camera. The camera subsequently displays these two images onto an electrically addressed spatial light modulator leading to a real-time optical correlation system. The cross-correlation between these two images can be computed at high speed, and the normalized peak intensity provides a precise measure of the off-axis movement of the rotating body.

© 1991 Optical Society of America