A novel particle representation is presented that allows the description of particle roundness as an additional measure, aiming at the characterization of entire particle ensembles during an attrition process. The particle representation is based on a combination of a convex polyhedron and a solid sphere which is known as Minkowski addition in the field of convex geometry. An image analysis procedure and a subsequent roundness estimation procedure are presented, utilizing a Hough transformation and a local optimal fit of the proposed shape model. The technique has been verified based on simulated particles and tested in a proof of concept experiment featuring potassium alum which was exposed to high stirring rates resulting in considerable attrition and abrasion. The results demonstrate that the proposed model and image analysis procedure are valuable tools to monitor and study attrition behavior. (C) 2014 Elsevier B.V. All rights reserved.