In case study 1, the general image processing workflow follows that shown schematically in figure . Projections were reconstructed into image volumes using the filtered back projection algorithm and the data was cropped to the ROI. The CT volume Fig. The general workflow for processing image data from both case studies. For both case studies it is critical to have a good particles labels segmentation where each particle is accurately separated and assigned a unique 16-bit label. This segmentation and a correlated 8-bit or 16-bit (unsigned integer) unsmoothed grey-level image are used as inputs into the later GRAPES analysis.