3D full-field deformation measurement using stereo vision

Abstract

Measuring 3D deformation and strain are crucial parameters in structural engineering applications both at the construction and operational stages. Precise 3D full-field measurements are useful in structural optimization, damage detection and retrofitting. Digital Image Correlation is a non-contact optic-based measurement technique that is proven to be an ideal candidate in this regard. It has the potential to become a cheap, simple, and precise solution for deformation measurement. However, the currently available Digital Image Correlation measuring systems require expensive dedicated software packages and physical resources which are difficult to access. Therefore, there is a need to develop a cost-effective measuring technique to effectively use it in the local context. This research focuses on the development and validation of a precise non-contact-based deformation measurement technique. In the proposed method, 3D full-field deformation of the deforming object is measured by processing stereo photographs taken with commonly available digital cameras using the image processing toolbox available in the MATLAB commercial package. Further, the proposed method is enhanced by developing it as a standalone application, which can be installed and conveniently used by any technician. Capability of using the developed application in common civil engineering laboratory experiments has been demonstrated.