Accurate Structural Dynamic Response Monitoring of Multiple Structures using One CCD Camera and a Novel Targets Configuration

Abstract

Structural impairments can be detected by monitoring and analyzing dynamic structural responses. In this paper, accurate dynamic deformations of multiple vibrating structures are estimated using one off-the-shelf CCD (Charge-coupled Device) camera and a novel target configuration and computation algorithm. In this method, a CCD camera, which can be mounted on either an adjacent vibrating structure or stationary support, is used to track global movements of a vibrating structure. The method utilizes subpixel feature extraction, Zhang’s camera calibration-based method, and a novel approach for target configuration which eliminates the need of having a stationary support for the recording camera. Two scaled models of a traffic signal structure were designed and constructed to implement the proposed method in laboratory conditions. The camera is mounted on one of the structures while facing targets on the other structure. The image data from the camera is processed to extract the structural response of both the structures in the field-of-view (FOV) of the camera as well as the structure on which the camera is mounted. Data from strain gages mounted on these structures provide measurement benchmarks for the dynamic structural responses. Experimental results indicate that one CCD camera and the presented method adequately capture displacements with similar accuracy and precision of strain gages. In practice, a camerabased method may be less expensive and more easily installed