Tooth measurement without calbration bodies

US5604817A · kind A · utility

Assignee

• KALTENBACH & VOIGT GMBH · DE

Inventors

• Robert Massen · Schallstadt, DE
• Christian Konz · Radolfzell, DE
• Joachim Gassler · Geisingen, DE
• Harald Richter · Neuenbürg, DE

Key dates

• Filing date: Aug 18, 1993
• Grant date: Feb 18, 1997
• Expiry date: Aug 18, 2013

Classification

• Technology area (CPC A): Human Necessities
• CPC primary: A61C9/004
• WIPO field: Medical technology
• WIPO sector: Instruments

Abstract

A method for the optical three dimensional measurement of a tooth without calibration bodies. An optical projection system projects a pattern onto a tooth, and an optical imaging system images the pattern projected thereon, from a first position in space and subsequently from a second position in space, with the images from the two positions in space having a common imaged area of the tooth. The image patterns are evaluated to calculate three dimensional coordinate data of the tooth surface relative to the respective imaging position for each image and also for the two images combined, to produce a single three dimensional tooth surface data record. In this method, points and/or surfaces are selected from the common imaged area with the aid of properties of the tooth surface contour which are invariant under displacement and rotation, so that they can be clearly correlated with each other. The change in position between the first and second positions in space is determined with the aid of the selected points and/or surfaces and their relative coordinate data.