Vibration monitoring of an open-type one-way tensioned membrane structure based on stereovision

Membrane structures are lightweight and flexible, and the responses of them are of great importance to evaluate the dynamic characteristics. However, when observing the dynamic responses by using conventional measurements (e.g., laser displacement meter), there are several disadvantages, such as high-cost, low sampling efficiency, and only one-dimensional data being obtained, especially for the membrane structures in the field of civil engineering. Therefore, a stereovision measurement is organized by proposing a series of algorithms which are based on a newly built mathematical model. The calibration toolbox based on OpenCV is adopted for the camera calibration. After that, edge detection, determination of central pixel coordinates, continuous tracking, and matching of circular feature points between different images are solved in the process of image processing. Finally, the new-formed stereovision measurement system is adopted to observe the responses of an open-type one-way tensioned membrane structure in free-vibration and aeroelastic wind tunnel test. After the feasibility and validity of this measurement system are verified, the full field displacement distributions of this tensioned structure under different wind speeds are presented. This successful application implies that such stereovision measurement can make up the disadvantages of the conventional measurements. Such stereovision measurement can be used to measure the responses of the structures in the field of civil engineering.