Digital image correlation with a moving camera using structure from motion calibration

摘要

The application of digital image correlation (DIC) in structural monitoring can benefit from the use of remote controlled image acquisition systems such as unmanned aerial vehicles (UAVs) in cases where the structure to be assessed is of difficult accessibility. However, this configuration does not always allow normal camera calibration procedures to be followed. In this work, a camera is manually moved around an object prepared with a speckle pattern, in a reference state and later in a loaded state, in an attempt to emulate the behaviour of a UAV. A structure from motion (SfM) algorithm is applied to the captured images in order to obtain camera calibration parameters for each image, using the features found in the object's surroundings. An image pair from each state is chosen and 3D DIC is performed on the object using the previously obtained calibration.