Figure 3.

Fibula segmentation with different SPs (case 1). Segmentation of the fibula with one background SP outside of the fibula (red point), and three/two/one foreground SPs (green points in (a)$-1$, (b)$-1$, and (c)$-1$, respectively) inside the fibula. The red curves in (a)$-2$, (b)$-2$, and (c)$-2$, in (a)$-3$, (b)$-3$, and (c)$-3$, and in (a)$-4$, (b)$-4$, and (c)$-4$ represent the segmentation results using RW, GC, and SPARSE, respectively. The green curves are the ground truth segmentation.