| Mean Hausdorff Distance (nasal cavity) (mm) | Mean Hausdorff Distance (pharyngeal region) (mm) | Dice Similarity Coefficient | Void Fraction (%) | Volume Ratio | Volumetric Similarity |
Global Thresholding | 0.28 | 0.2 | 0.85 | 20 | 0.93 | 1.04 |
Multi-step level-set | 0.40 | 0.16 | 0.89 | 13 | 0.93 | 1.04 |
Thresholding | 0.38 | 0.2 | 0.90 | 14 | 0.98 | 0.98 |
Clustering | 0.59 | 0.4 | 0.96 | 6 | 1.53 | 0.79 |
Classification | 0.36 | 0.16 | 0.92 | 12 | 1.03 | 1.01 |
Ideal value | 0 | 0 | 1 | 0 | 1 | 0 |