Northern Digital Inc.

Ascension Technology Corporation

Kenji Fujioka

Mark R Schneider

Westley S Ashe

A system comprising: a magnetic transmitter configured to generate magnetic fields; a magnetic sensor configured to generate signals based on characteristics of the magnetic fields received at the magnetic sensor; and one or more computer systems configured to: receive the signals from the magnetic sensor; determine, based on the signals received from the magnetic sensor, an electromagnetic (EM) pose of the magnetic sensor relative to the magnetic transmitter; determine one or both of: i) an inertial pose of the magnetic sensor relative to the magnetic transmitter based on inertial data associated with the magnetic transmitter and the magnetic sensor, or ii) an optical pose of the magnetic sensor relative to the magnetic transmitter based on optical data associated with the magnetic transmitter and the magnetic sensor; determine an estimated pose of the magnetic sensor relative to the magnetic transmitter based on the EM pose and the one or both of the inertial pose or the optical pose; determine distorted magnetic fields based on the EM pose; determine estimated clean magnetic fields based on the estimated pose; determine estimated distorted magnetic fields based on the distorted magnetic fields and the estimated clean fields; and determine an improved EM pose of the magnetic sensor relative to the magnetic transmitter based on the estimated distorted magnetic fields.

Compensating for distortion in an electromagnetic tracking system

A system comprising: a magnetic transmitter configured to generate magnetic fields; a magnetic sensor configured to generate signals based on characteristics of the magnetic fields; and one or more computer systems configured to: cause the magnetic transmitter to generate a first plurality of magnetic fields at a first frequency; receive a first plurality of signals from the magnetic sensor; determine data indicative of a position and orientation of the magnetic sensor at a first position of the magnetic sensor; determine a distortion term that corresponds to a first position of the magnetic sensor; cause the magnetic transmitter to generate a third plurality of magnetic fields at the first frequency; receive a third plurality of signals from the magnetic sensor; and determine a second position and orientation of the magnetic sensor relative to the magnetic transmitter, wherein the first frequency is greater than the second frequency.

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Burlington, VT, United States of America

Kenji Fujioka