Photographic mapping of structural surfaces is accomplished by a projection Moire method. Deformations of the structure surface being investigated are zeroed out when under no load. This is accomplished by projecting a master grille pattern onto a test surface. The reflection then exposes a photographic...http://www.google.com/patents/US4981360?utm_source=gb-gplus-sharePatent US4981360 - Apparatus and method for projection moire mapping
