Computer Vision Technique for Blind Identification of Modal Frequency of Structures from Video Measurements †

Abstract

Operational modal analysis (OMA) is required for the maintenance of large-scale civil structures. This paper developed a novel methodology of non-contact-based blind identification of the modal frequency of a vibrating structure from its video measurement. There are two stages in the proposed methodology. The first stage is extracting the motion data of the vibrating structure from its video using a complex steerable pyramid. In the second stage, the principal component analysis combined with analytical mode decomposition is used for modal frequency separation from the motion data. Numerical validation of the methodology on a 10 DOF model is presented. The application of the proposed methodology on the London Millennium Bridge is also presented.