Development and implementation of image-based algorithms for measurement of deformations in material testing

This paper presents the development and implementation of three image-based methods used to detect and measure the displacements of a vast number of points in the case of laboratory testing on construction materials. Starting from the needs of structural engineers, three ad hoc tools for crack measurement in fibre-reinforced specimens and 2D or 3D deformation analysis through digital images were implemented and tested. These tools make use of advanced image processing algorithms and can integrate or even substitute some traditional sensors employed today in most laboratories. In addition, the automation provided by the implemented software, the limited cost of the instruments and the possibility to operate with an indefinite number of points offer new and more extensive analysis in the field of material testing. Several comparisons with other traditional sensors widely adopted inside most laboratories were carried out in order to demonstrate the accuracy of the implemented software. Implementation details, simulations and real applications are reported and discussed in this paper.