Using a smartphone device to quantify particle size and shape descriptors

Abstract

This paper describes a procedure to obtain particle size and shape descriptors through a 2D image processing algorithm using a smartphone device. This open-source tool is automatic and only requires a simple initial calibration of the camera lens, which is described herein. The output of the tool consists of a spreadsheet with particle size and shape descriptors for each grain, as well as their average values for the entire sample. Optical ready-to-use tools such as this one would benefit the geotechnical community due to the strong link between particle morphology and its mechanical properties. As an application, the script was used to obtain particle shape descriptors of a sand with known critical state parameters in order to evaluate them through particle shape predictive models. The results indicate that a minimum of 30 particles per image is enough to obtain a good match with the experimental data. These results highlight the advantages of the tool as a first estimate and as a complement to a full experimental program.