Multi-point displacement probe by combining a micro-lens array with an acousto-optic deflector scanner

A multi-point dynamic displacement probe was developed for measuring dynamic displacement and deformation. This method uses an acousto-optic deflector (AOD) as a diffractive scanner to allow the laser beam to scan a self-focusing microlens array (SMLA), and then uses the resulting focused spot to scan the diffuse surface. The focus information contained In the laser beam reflected from the diffuse surface is then transformed into the variations in shape of spot for detection. Due to the very high scanning speed of the AOD, the relative position of many points, and thus the dynamic deformation, can be measured in near real-time. This paper describes the method's principles, accuracy, and error sources.