Three-dimensional digital image correlation method based on a light field camera

With the recent development of computer vision and photographic technology, many three-dimensional (3D) modelling methods have emerged. This paper introduces a new method that combines digital image correlation (DIC) with a light field camera to reconstruct the surface of an object. Before experimentation, the surface of the object was sprayed with a speckle pattern. The parameters of the light field camera, such as the micro-lens, focus, and lens distortion, were pre-calibrated. During the experiments, raw images of the samples were recorded by a light field camera, then each was extracted to two sub-aperture images. Using the digital image correlation method, feature point matching of the corresponding sub-images was executed and the 3D space coordinates of all of the matching points were calculated using the binocular vision principle with surface topography information. The experimental results demonstrate that the method can realise 3D reshape and 3D deformation measurements using a single camera. The system has the advantage of a simple structure, large depth of field, and wide measurement range for out-of-plane deformation. The light field camera is also applied to 3D-DIC.