Abstract

A three dimensional digitizer is provided for determining and digitizing the coordinates of a three dimensional object. A hand-held stylus is used for tracing and determining points of interest on the surface of the object. A plurality of antennas for radiating electromagnetic energy are provided, the antennas being embedded in a table having a work surface upon which the object is placed. The radiating antennas have independent components which define a reference coordinate frame. A transmitter applies electrical signals to the radiating antennas which generate a plurality of distinguishable radio frequency electromagnetic fields. The stylus is provided with a projection for defining a point of contact between the stylus and the surface of the object of interest. A plurality of receiving antennas are disposed in the stylus. The receiving antennas have a known relationship with the projection and the point of contact on the object. The receiving antennas are provided with a plurality of independent components for detecting each of the transmitted electromagnetic fields. The output of the receiving antennas is supplied to an analyzer which converts the components of the electromagnetic fields received by the receiving antennas into the remote position and orientation of the receiving antennas relative to the reference coordinate frame. Since the point of contact of the stylus and the receiving antennas are provided with a known relationship, the coordinates of the surface of the three dimensional object touched by the stylus are also determined in the analyzer.

Other References

• SAC Technical Bulletin GP-6-CRT 3.81