The coefficient of restitution (COR) is one of the fundamental particle properties needed in the setup of discrete element modelling (DEM) simulations. The more accurate the input parameters for DEM are, the more accurate the resulting simulation outputs will be. The determination of the COR for spherical particles is a relatively straightforward process, however, when considering irregular shaped particles, the unpredictable behaviour of particles after impact makes the analysis of the COR more involved. This paper presents an experimental method to determine the COR using high-speed video in a three-dimensional environment to capture the random behaviour of irregular shaped polyethylene pellets. The angular displacement and angular velocity of particles are experimentally determined and the process used to determine the coefficient of restitution using various equations is presented.