A new method for deducing whether falling point located in secure areas

In light of that the secure areas are general polygons such as convex or concave polygons, a new discrimination method is proposed for deducing whether falling point located in the secure areas, that expands the borders of secure areas firstly, cuts the too acute corners arisen possibly, and discriminates that if the vertexes of the polygons have convex or concave characteristic, then performs combining transaction, so as to deduce whether falling point located in the secure areas. This method solves the problem about accurately eluding the secure areas theoretically.