“…In particular, finite difference methods such as the Osher-Sethian schemes [22,23,32] and the Rouy-Tourin method [25,38] are widely-used in this context. PDE-based algorithms for dilation/erosion offer two advantages over classical set-theoretic schemes [2,8,26]: first of all, they give excellent results for nondigitally scalable structuring elements whose shapes cannot be represented correctly on a discrete grid, for instance discs or ellipses. Secondly, the time t plays the role of a continuous scale parameter.…”