The visibility polygon or visibility region for a point p in the plane among non-transparent obstacles is the possibly unbounded polygonal region of all points of the plane visible from p.
If the visibility polygon is bounded then it is a star-shaped polygon. This is the case, e.g., if the obstacles are the edges of a polygon and p is inside the polygon. In the latter case the visibility polygon may be found in linear time.[1]
Visibility polygons are studied in computational geometry and find their applications in motion planning.