Siemens Aktiengesellschaft

Wolfgang Schorr

Bernd Nickel

A method for measuring the position, attitude and/or positional or attitudinal change of a fixed body in space, such as the lower jaw of a patient in a dental examination, utilizes signals obtained from a number of magnetic flux pickup blocks arranged at a distance from a magnetic field generator, the magnetic field generator being disposed on or a short distance from the fixed body and generating a defined irregular field. The pickup blocks detect the field flux, or the field flux alteration, during a measurement. In order to eliminate interference signals occurring in the region of the measuring system the signals from all of the pickup blocks are first added and the aggregate interference signals formed therefrom are respectively subtracted from the individual pickup block signals.

Method for eliminating spurious signals in a measuring installation for

In an exemplary embodiment, one or more flux pickups with ferromagnetic properties, preferably Hall generators provided with antennas, are provided for the detection of a field flux or of a change of field flux proceeding from a field generator. Magnetization pulses (I.sub.2) are provided in periodic sequence to the flux pickups (I through VIII), the pulse height and width (t.sub.im) being selected in such manner that the saturation field strength (M.sub.s) of the flux pickups is therewith achieved, so as to produce a maximum residual magnetization (M.sub.R). The flux pickups (I through VIII) are preferably driven by means of pulse-shaped signals (I.sub.1), with the magnetization pulses being supplied in the pulse interval (i.sub.s) of these signals synchronous to the pulse repetition rate. The method is particularly employed in gnathography for recording the lower jaw movement of a human being.

Method for preventing remanence phenomena from interfering with magnetic

In an exemplary embodiment, a field generator preferably a magnetic field generator which generates a defined irregular field is arranged directly on the body or at an interval thereto, pickups independent of the body are arranged at an interval from the field generator, said pickups having field-flux-dependent sensor elements for sensing a field flux or, respectively, a change of field flux during a measurement, and an electronic circuit obtains and evaluates electric signals arising in a field flux or, respectively, a field flux change. The sensor elements of the pickups or, respectively, the reference points of the pickups decisive for sensing the field flux or the change of field flux are arranged in such manner that they form the corner points of a cuboid. Thereby, the field generator is arranged within a space determined by the cuboid. The device is particularly provided for use in dental medicine, namely for sensing the lower jaw movement of a patient.

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Heppenheim, Germany

Wolfgang Schorr