An Optical Approach to Structural Displacement Measurement and Its Application

Abstract

A number of optical devices are commercially available now for measurement. Some of them, such as laser devices and still and video cameras with high resolution, may be used effectively and efficiently for measuring structural displacement. This paper presents an approach to this type of application using a charge-coupled-device camera. It can acquire digitized images for low cost, to be used to identify structural displacement via digital signal processing. It is shown that this approach’s resolution for point measurement is comparable with traditional sensors such as dial gages. Furthermore, it offers a new capability of displacement measurement for a large number of points on a structure, and it can provide spatially intensive displacement data. This kind of data may be used for structural damage detection and health monitoring, as suggested and demonstrated herein.