Table 1: Features calculation of every potential nodule object.

FeaturesDefinition

Intensity Mean value , in 2D space
Standard deviation , in 2D space
Mean of intensityIn 3D space
Standard deviation of intensityIn 3D space

PositionCentroid ( , ) ,

Shape Area , in 2D space
Perimeter , in 2D space
Diameter Long axis in 2D space,
Ellipticity , are the long axis and short axis, respectively, in 2D space
Circularity , in 2D space
Slenderness , in 2D space
Rectangle degree , in 2D space
Compactness , is the perimeter of region contour. is the area in 2D space
Compactness ratio reflects degree closing to circle and smoothness of region. And can be used to detect the rough feature of edge
Concavity ratio , is area of concave region, is difference of convex hull and original region, and reflects cupped degree of boundary
Volume In 3D space
Volumetric quotientIn 3D space
The long axis of the circumsphereIn 3D space

Texture Energy, contrast, entropy, and adverse momentIn 2D space