Table 1.

Parameters and empirically determined shape descriptor thresholds

	Thoracic Segmentation	Core Segmentation	Complete Segmentation
Minimum Area (pixels)	(Field of View)/(2*Pixel Dimension)2	350/(Pixel Dimension)2	550/(Pixel Dimension)2
Maximum Area (pixels)	-	(Thoracic Size)/2	(Thoracic Size)/2
Minimum Contour Length	-	45/(Pixel Dimension)	60/(Pixel Dimension)
Minimum Compactness*	15	2	5
Center of Mass Thresholds	-	-	x ∈ [50,215] y ∈ [50,200]
Maximum number of pixels crossing rolling ball surface (Contortion)	-	-	85% of filter boundary arc
Minimum number of pixels for contour segment to be identified as a possible protrusion by the rolling ball filter	-	-	8 pixels
Minimum Circularity	-	-	0.4

^*Compactness²⁰ (C) is defined as: $C=\frac{100\ast 4\pi \ast \left(region\_area\right)}{{\left(region\_perimeter\right)}^2}$