Operational modal analysis of a cantilever beam by phase-based sub-pixel motion estimated from experimental videos

Vibration study, also called modal analysis, plays an important role in the structural health monitoring of mechanical structures. During the last decade, video-based modal analysis methods have emerged to provide dense vibration estimation using each pixel as a contactless sensor. Dense subpixel motion is estimated and is then processed by a modal analysis algorithm to extract the modal basis composed of natural frequencies, damping ratios, and mode shapes. This paper introduces a new single-subband phase-based method for subpixel motion estimation. It is compared with state-of-the-art motion estimation method on synthetic and experimental videos of a cantilever beam.