Three-dimensional (3-D) topographic data defining a remote surface in terms of the 3-D positions of M.times.N sample points on that surface may be obtained by (1) illuminating the scene with an array of M.times.N (simultaneous) laser beams, (2) sequencing the array of laser beams through a series of...http://www.google.co.uk/patents/US4294544?utm_source=gb-gplus-sharePatent US4294544 - Topographic comparator
