Algorithm 1 Multi-organ segmentation based on OCG
Input: Target image I(x), OCG =< V, E >, number of stages jmax
Output: Label images of each organ {Lv(x) | v ∈ V}
1:	Vsegmented ← ∅
2:	$V_{\text{target}}^0\leftarrow V_1$
3:	for j = 0 to jmax do
4:	for all $v\in V_{\text{target}}^j$ do
5:	$S^{\ast }\leftarrow \{{\mathbf{s}}_k^{\ast }|k\in V_{\text{in}}(v)\cap V_{\text{segmented}}\}$
6:	Lv(x) = S eg(I(x); A(S*))
7:	${\mathbf{s}}_v^{\ast }$ ← shape vector calculated by fitting SSM to Lv(x)
8:	end for
9:	$V_{\text{target}}^{j+1}\leftarrow {\cup }_{v\in V_{\text{target}}^j}{V}_{\text{out}}(v)$
10:	$V_{\text{segmented}}\leftarrow V_{\text{segmented}}\cup V_{\text{target}}^j$
11:	end for