Disclosed herein are methods, computer systems and computer program products for labeling components. One method includes the step of labeling (130) with a current label all voxels that are internal to a predetermined sub-volume oriented with respect to an unlabeled voxel, and directly connected to the unmarked voxel. The labeling step is repeated for all voxels that are not internal to the predetermined sub-volume, but which are labeled with a current label. The method includes the step of incrementing the current label and may include the step of increasing a window size to a predetermined maximum. The preceding steps are repeated for remaining unlabeled object voxels.
