Although 3D X-ray tomographic analysis of mineral particles in packed particle beds has been developed in past years and applied successfully for irregularly shaped particles, it has been a challenge to accurately analyze multisize particles due to segmentation limitations. An improved image segmentation technique for multisize particlet has been developed for accurate analysis with reduced scanning and image processing time. In this paper, tomographic images of coarse particles (762 x 635 mm) produced with a high speed milliscanner and fine particles (5 x 035 mm) produced with a highTesolution microscanner are segmented by means of a 3D morphological algorithm, based on a multiscale extraction of markers for watershed segmentation. In this way, multisize particles in a packed particle bed which range in size by an order of magnitude can be imaged with good accuracy. (C) 2016 Elsevier B.V. All rights reserved.