level set的用法和樣例：
例句
- The model based on the implicit variational level set methods can handle topological changes automatically.
它基於隱式水平集變分方法，能夠自動處理曲面拓撲結構的變化。 - A new level set way based on GVF was proposed, in order to solve the problem that the level set evolving curve will often stop on the local maximum or isolated edge.
摘要針對傳統水平集分割圖像會出現演化曲線停止於梯度的局部極大值或孤立的邊緣處的缺點，對速度停止項進行了改進。
