Texture anisotropy in 3-D images

Two approaches to the characterization of three-dimensional (3-D) textures are presented: One based on gradient vectors and one on generalized co-occu rrence matrices. They are investigated with the help of simulated data for their behavior in the presence of noise and for various values of the param eters they depend on. They are also applied to several medical volume image s characterized by the presence of microtextures and their potential as dia gnostic tools and tools for quantifying and monitoring the progress of vari ous pathologies is discussed. No firm medical conclusions can be drawn as n ot enough clinical data are available. The gradient based method appears to be more appropriate for the characterization of microtextures. It also sho ws more consistent behavior as a descriptor of pathologies than the general ized co-occurrence matrix approach.