In computational geometry, an alpha shape, or α-shape, is a family of piecewise linear simple curves in the Euclidean plane associated with the shape of a finite set of points. (wiki)

From the above figure, we can see that by increasing the alpha parameter, the hull envelopes more points. By assuming unknown alpha parameter and allowing data to decide it, we can represent a more objective, data-driven solution.

Note that alpha shape uses the subcomplexes of the Delaunay triangulation of the point set.

My research paper is currently under review and it will be posted here soon!