The width of a piece of timber, such as a board is measured with a device including a laser tube emitting laser beam to be reflected by a rotatable mirror polyhedron and a parabolic reflector into a direction along the board, mirror rasters being provided at intervals along the board so as to reflect...http://www.google.com/patents/US4123169?utm_source=gb-gplus-sharePatent US4123169 - Device for measuring the width of timber
