Apparatus for determining the location of a physical feature, such as a hole in a panel, relative to two coordinate axes by optically scanning across the panel and hole from a reference while measuring the distance of the hole from the reference and the length of the hole chord for each of a plurality...http://www.google.ca/patents/US4596037?utm_source=gb-gplus-sharePatent US4596037 - Video measuring system for defining location orthogonally
