An intra-visibility matrix based environment pre-processing for efficient Ray tracing

An Efficient Ray-Tracing Based Model Dedicated to Wireless Sensor Network Simulators for Smart Cities Environments

“…In [64], the solution was optimized for the treatment of several receivers, by mapping in pre-process the lit polygons to a coarse grid to limit the number of intersection tests needed in RT. In [65], the use of the polar sweep algorithm [62] is added to compute an intra visibility matrix in pre-process. It stores the visibility relationship between each pair of geometrical elements (faces or edges), as the extreme angles for which some parts of the two elements are visible.…”

“…In [66], the intra visibility matrix is reused jointly with a visibility table containing the list of faces/edges visible from an emitter moving along a linear route. This allows significant acceleration of the preprocessing time compared to [65] in the case of a mobile emitter, but it still takes a lot of time. In [67], a new algorithm is proposed to provide a dynamic visibility table taking into account the modifications of the visibility relations between a mobile emitter and mobile obstacles.…”

“…Hence, it remains too large for WSN simulators. In the rest of this article, the efficiency of the proposed solution will be compared to those of [65] and [66].…”