Figure 6From: Automated measurement of heterogeneity in CT images of healthy and diseased rat lungs using variogram analysis of an octree decomposition Variograms averaged for each dose group. The dashed line shows the extent of d max , the characteristic lung distance to which variograms were analyzed for heterogeneous variations. The lines get “noisier” at higher distances, indicative of increased spatial variation even within the each group.Back to article page