Table 1 Overview of the 29 shape features in three categories

Geometric

Net area, thickness, elongation, filled area, perimeter, circularity, fibre length, fibre width, convex area, convex perimeter, roundness, convexity, solidity, major axis length, major axis angle, minor axis length, bounding box area, eccentricity, and curl

Boundary

Bending energy, total absolute curvature, radial mean, radial standard deviation, entropy, area ratio, zero crossing count, and normalized moment classifier

Topological

Number of holes and number of protrusions