Each voxel comprising any object in the segmented image is tagged with a unique integer describing the number of `layers' that separate this voxel from the closest surface voxel of the object. We refer to this integer as the `burn' number of the voxel, in prosaic reference to the method of its computation. Specifically the burn number is the digitized, max-norm distance between the object voxel and the nearest object surface voxel. The distance data is stored in separate files.
It is possible to perform the following calculations on this data sets.