“…To find the overall performance for a vectorisation method, researchers used the unweighted mean of the VRI scores. To the best of our knowledge, this seems to be the case in all of the research publications (Wang et al, 2010;Bonnici and Camilleri, 2013;Wu et al, 2013;Zhang et al, 2015;Kasimov et al, 2017;Bonnici et al, 2019;Alwan et al, 2019) that use VRI as the preferred performance criterion as well as papers published by the authors of VRI (Liu et al, 2001). However, using the unweighted mean is only accurate if all the images (ground truth images) have the same number of primitives (graphical entities) which is rarely the case.…”