QUANTIFICATION OF POROUS MEDIA USING COMPUTERIZED TOMOGRAPHY AND A STATISTICAL SEGREGATION THRESHOLD
Ho-Nien Hsieh, G. O. Brown, M. L. Stone · Transactions of the ASAE · 1998
A statistical segregation threshold (SST) that determines the spatial distribution of solids and pores incomputerized tomography (CT) images of porous media is presented. The proposed algorithm combines basic imageprocessing techniques with consideration of measurement errors and CT scanning resolution. While traditional thresholdmethods use only one or two parameters to identify pore features in CT images, the SST characterizes the spatialdistribution of features by segregating image voxels into groups and treating each group differently according to its knownstatistical properties. This provides a major improvement when pores are smaller than the image resolution. By classifyingthe CT image into mixed-component, peak and tail-voxel fractions, the proposed algorithm provides a semi-automatic andtheoretically sound technique for component segregation. The SST algorithm results are insensitive to the local thresholdvalue and sample heterogeneity. Three acrylic test objects with various void sizes and water content are used to test anddemonstrate the SST.