FIG. 2.

Graph construction for OSS. (a) Centerpoint ce_k and utilized node structure; the spherical mesh is symbolized by a circle. For each node, a cost is assigned. (b) Intracolumn edge structure (red) with infinite capacity, pointing toward the center. [(c) and (d)] Intercolumn edge structure. (c) The hard smoothness constraint is implemented by introducing edges with infinite capacity shown in green. (d) The soft smoothness constraint is implemented by introducing bidirectional edges with low finite capacity shown in cyan. (See color online version.)