PY2DIC: a new image correlation software for displacement field measurements

Abstract

Recently, there has been a growing interest in studying non-contact techniques for strain and displacement measurement. Within
photogrammetry, Digital Image Correlation (DIC) has received particular attention thanks to the recent advances in the field of
lowcost, high resolution digital cameras and computer power. DIC is indeed a non-contact technique able to measure full-field
displacements and strains by comparing digital images of the surface of a material sample at different stages of deformation and it
plays a major role in structural monitoring applications.
For all these reasons, a new free and open source two-dimensional (2D) DIC software, named py2DIC, was developed at the
Geodesy and Geomatics Division of DICEA, University of Rome ”La Sapienza”. The software is completely implemented in Python
and it is based on the template matching method to compute the displacement and strain fields. The potentialities of py2DIC were
evaluated by processing the images acquired during tensile test performed in the Laboratory of Structural Engineering. Specifically,
three different Glass Fiber Reinforced Polymer samples were subjected to tensile tests by means of a universal testing machine.
The results were compared with those independently measured by several strain gauges fixed on the sample surfaces. They
demonstrate the possibility to successfully characterize the deformation mechanism of the investigated material. py2DIC is indeed
able to highlight displacements at few microns level, in reasonable agreement with the reference, both in terms of displacements and
Poisson’s module.