title: Three-dimensional measurement: the accuracy and precision of the reflex metrograph.
abstract: The Reflex Metrograph is an optical plotter which is linked directly to a microcomputer and allows direct three-dimensional measurements of irregular shaped objects up to 300 mm maximum dimension without contacting the object. This study shows that it is possible to generate reproducible results with an operator measurement error of less than 0.2 mm for linear distances on objects up to 200 mm maximum dimension. The Reflex Metrograph tends to undermeasure by 0.67% or by up to 2.00 mm per 300 mm and is very slightly less accurate in the vertical plane. The potential use of this measuring instrument is discussed.
authors.affiliation: Department of Oral Surgery and Orthodontics, Dudley Road Hospital, Birmingham, UK.
authors.forename: B
authors.initials: B
authors.lastname: Speculand
authors.forename: G W
authors.initials: GW
authors.lastname: Butcher
authors.forename: C D
authors.initials: CD
authors.lastname: Stephens
mesh_terms: D002508:Cephalometry / Q000295:instrumentation / Q000379:methods; D003199:Computer Systems; D004867:Equipment Design; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation* / Q000379:methods; D008838:Microcomputers; D055095:Optics and Photonics; D012984:Software