Automated Extraction of Mode Shapes Using Motion Magnified Video and Blind Source Separation

Abstract

Traditionally, experimental and operational modal analysis requires wired sensors that are physically attached to the structure of interest for vibration measurements. The instrumentation of these sensors on structures for long-term applications (e.g., structural health monitoring) is costly, time-consuming, and requires significant maintenance. Even if a wireless sensor network is used, there still exist substantial challenges associated with security, available bandwidth, and providing energy to the network. As a non-contact method, optics measurements from digital cameras combined with vision based algorithms have been successfully used for experimental vibration measurement and analysis. This opens the door to replacing physical sensors with remote sensing techniques, which could eliminate many of the problems associated with conventional distributed sensor networks. However, research to date has focused on simple structures that can be represented using a single edge. In this work, we propose a novel phase-based video motion magnification and Blind Source Separation (BSS) based method to perform operational modal analysis in a relatively efficient and automated manner.