Computing a shortest weakly externally visible line segment for a simple polygon
A simple polygon P is said to be weakly externally visible from a line segment L if it lies outside P and for every point p on the boundary of P there is a point q on L such that no point in the interior of   lies inside P. In this paper, a linear time algorithm is proposed for computing a shortest line segment from which P is weakly externally visible. This is done by a suitable generalization of a linear time algorithm which solves the same problem for a convex polygon.
external visibility polygon weak visibility shortest visible line segment