An image visibility based pre-processing method for fast ray tracing in urban environments

This paper presents an efficient pre-processing technique for fast ray-object intersection test. The visibility region of the images are described by lit polygons. The visible buildings within the lit polygons, that form the shadow regions, are represented by the dark polygons. This representation ensures that only a few validation checks are required for the ray-object intersection test. Validation results show a significant acceleration in the ray calculation times in urban areas.