English

Reconstructing a convex polygon from its $\omega$-cloud

Computational Geometry 2019-03-21 v3

Abstract

An ω\omega-wedge is the closed set of points contained between two rays that are emanating from a single point (the apex), and are separated by an angle ω<π\omega < \pi. Given a convex polygon PP, we place the ω\omega-wedge such that PP is inside the wedge and both rays are tangent to PP. The set of apex positions of all such placements of the ω\omega-wedge is called the ω\omega-cloud of PP. We investigate reconstructing a polygon PP from its ω\omega-cloud. Previous work on reconstructing PP from probes with the ω\omega-wedge required knowledge of the points of tangency between PP and the two rays of the ω\omega-wedge in addition to the location of the apex. Here we consider the setting where the maximal ω\omega-cloud alone is given. We give two conditions under which it uniquely defines PP: (i) when ω<π\omega < \pi is fixed/given, or (ii) when what is known is that ω<π/2\omega < \pi/2. We show that if neither of these two conditions hold, then PP may not be unique. We show that, when the uniqueness conditions hold, the polygon PP can be reconstructed in O(n)O(n) time with O(1)O(1) working space in addition to the input, where nn is the number of arcs in the input ω\omega-cloud.

Keywords

Cite

@article{arxiv.1801.02162,
  title  = {Reconstructing a convex polygon from its $\omega$-cloud},
  author = {Elena Arseneva and Prosenjit Bose and Jean-Lou De Carufel and Sander Verdonschot},
  journal= {arXiv preprint arXiv:1801.02162},
  year   = {2019}
}

Comments

16 pages, 6 figures

R2 v1 2026-06-22T23:38:30.414Z