Presented is a process for use in the area of geophysical data processing, for computing a three dimensional grid of traveltimes from a three dimensional grid of velocities. The process involves a finite-difference solution to the eikonal equation in spherical coordinates, with refinements which increase...http://www.google.de/patents/US5394325?utm_source=gb-gplus-sharePatent US5394325 - Robust, efficient three-dimensional finite-difference traveltime calculations
