Dynamic Characterization of Flexible Structures Through Vision-Based Vibration Measurements

Vibration Monitoring of Multiple Bridge Points by Means of a Unique Vision-Based Measuring System

“…In some applications active targets are used; for example in [5] LEDs are used for suspension bridge vibration monitoring. Markerless solutions are proposed in literature, to monitor cable vibrations in cablestayed bridges [17], power head transmission lines [18] and bridges structures. In [19] vibration measurements obtained through image acquisition and processing are used to develop a modal analysis of a simple structure.…”

“…The choice of the pattern type is related to the algorithm used to analyse the acquired images in order to estimate the motion. It is possible to use state-of-the art algorithms, such as pattern matching [11], edge detection [18], digital image correlation [20,21] or optical flow [22]. Nevertheless some authors developed and proposed software tools specifically optimised to recover the structure motion relying on image sequences; for example in [23] and [24] the point reconstruction rules are used, while a robust object search algorithm is proposed in [25].…”

Indexes for performance evaluation of cameras applied to dynamic measurements

“…Currently, a basic imaging device can easily acquires 1 Megapixel images with a 25 fps grabbing frequency, which means that it is possible to perform a dynamic analysis up to 12.5 Hz at full resolution, but there are also top level cameras able to acquire 2-3 Megapixel images with more than 2 kHz grabbing frequency. One of the most common application of vision-based techniques to dynamic analysis is the structural health monitoring (SHM), where visionbased measurements are used to identify displacements and vibrations of whole civil structures and their components [8][9][10][11][12].…”