Level-set method

Summary

The level-set method tracks a moving curve or surface as the zero level set of a function $\phi(x, t)$ defined on a fixed grid. The motion of the interface becomes a Hamilton–Jacobi equation for $\phi$, which is solved with finite difference schemes. It was introduced by Stanley Osher and James Sethian. Its main strength is that merging and splitting of interfaces need no special treatment, and normals and curvature are computed from derivatives of $\phi$. See the definition.