Stereo-Digital Image Correlation (DIC) measurements with one single camera using a biprism

In this paper we present and test a Digital Image Correlation (DIC)-based single camera pseudo-stereo system that uses a biprism in front of the camera objective to split the scene into two equivalent lateral stereo views in the two halves of the sensor. Such optical arrangement simplifies image pairs matching and, more importantly, makes possible a compact set-up suitable for miniaturization. To correct the image distortion caused by the refraction through the biprism, a proper optimization-based procedure is used to map the 3D reconstruction error function over the entire measurement volume. The inverse of the volumetric distortion function is then applied to the double-image of a spherical sample placed in an arbitrary position to evaluate the shape reconstruction accuracy. Finally, the capability of the proposed system to accurately track deformation in real-time is tested via an inflation test on a circular latex membrane.