TABLE IV.

Ablation study on the both data set for the non-local module (Non-local) and the geometric features (Geometric) into the two-stage cascading framework. Boldface denotes that a result is significantly better than others in the same column (p < 0.01 with Bonferroni correction).

(a) COPD results
Method	Two-stage	Non local	Geometric	ASSD	IOU
only two-stage	✓			1.122±1.315	0.940±0.031
w/o geometric	✓	✓		0.956±1.395	0.942±0.031
RTSU-Net	✓	✓	✓	0.607±0.537	0.949±0.026
(b) COVID-19 results
Method	Two-stage	Non local	Geometric	ASSD	IOU
only two-stage	✓			1.025±0.893	0.916±0.045
w/o geometric	✓	✓		1.370±1.582	0.918±0.037
RTSU-Net	✓	✓	✓	0.866±0.729	0.922±0.04