Fig. 2.

(Top) For the histogram-based segmentation method, the “bone” and “non-bone” histogram peaks were identified, and the midpoint between these peaks was selected as the global segmentation threshold (histogram from a 6 μm voxel size scan). (Bottom) For smaller voxel sizes (6–10 μm), the two segmentation methods selected similar thresholds (1–8% difference), while for larger voxel sizes (15–30 μm) the two methods selected considerably different thresholds (21–25% difference).