A voxel is the region surrounding a sample. In the first step we construct classification probabilities, which estimate the probabilities of different combinations of materials within a voxel. The second step, classification, iterates over each voxel applying the classifier to determine the most likely materials. Benefits of histograms of vector-valued data. We show histograms of an object with three materials.
Brighter points represent larger values of the histogram.
The histogram shows that mean values often move away from collinearity in higher dimensions. The grid lines show how the material regions may span voxels. The result is a sampled dataset of volume ratio densities. These values correspond to the Gaussian-shaped peaks centered around vA and vB in the histograms, which are shown on their sides to emphasize the axis that they share. Feature space lies along this axis.