Northern Digital Inc.

Christian J Schilling

Stefan R Kirsch

Hans R Schild

Mark R Schneider

Georg Brunner

Vladimir F Kogan

Stephen Eldon Leis

Nikolai Mikuszeit

Donald Dieter Frantz

Westley D Ashe

Olaf Zerres

Stefan Kirsch

A system comprising: a sensor configured to be introduced into a clearance hole of a surgical implant, wherein the sensor is configured to be introduced in proximity to a generated magnetic field and cause distortion of the magnetic field; and one or more field measuring coils configured to: measure a characteristic of the magnetic field when the sensor is in proximity to the magnetic field; and provide, to a computing device, a signal representative of the measured characteristic of the magnetic field, wherein the computing device is configured to determine one or both of a position and an orientation of the sensor and the clearance hole based on the measured characteristic of the magnetic field.

Tracking a cylindrical opening

A system for determining the position, orientation and system gain factor of a probe includes a plurality of magnetic field sources and at least one magnetic field sensor, such that a combination of a magnetic field sensor and a magnetic field source generates a unique measured magnetic field value. The system includes a probe whose gain, position, and orientation affect these unique measured magnetic field values. A processor is configured to receive and iteratively process these unique measured magnetic field values to determine a system gain factor indicative of the gain of the probe and a plurality of location factors indicative of the position and orientation of the probe. The number of unique measured magnetic field values generated must be at least equal to the sum of the number of gain and location factors calculated.

Gain factor and position determination system

A system for determining the position, orientation and system gain factor of a probe includes a plurality of magnetic field sources and at least one magnetic field sensor, such that a combination of a magnetic field sensor and a magnetic field source generates a unique measured magnetic field value. The system includes a probe whose gain, position, and orientation affect these unique measured magnetic field values. A processor is configured to receive and iteratively process these unique measured magnetic field values to determine a system gain factor and a plurality of location factors. The system gain factor is indicative of the gain of the probe, and the plurality of location factors are indicative of the position and orientation of the probe. The number of unique measured magnetic field values generated must be at least equal to the sum of the number of gain and location factors calculated.

A process detects distortions to magnetic location or orientation determinations. The process includes measuring a plurality of magnetic field values, determining one of a probe's location and a probe's orientation from an extremum of an optimization function. The measured values depend on the probe's location and orientation. The optimization function depends on the measured field values and field values calculated from a model. The process also includes indicating that a distortion to the determining exists in response to the extremum belonging to a preselected range.

Errors in systems using magnetic fields to locate objects

A system for determining spatial position and/or orientation of one or more objects. The system includes an optical subsystem and a non-optical subsystem. The optical subsystem includes optical subsystem light sources mounted to one or more of the objects and an optical subsystem sensor adapted to detect energy from the optical subsystem light sources. The optical subsystem has an optical subsystem coordinate system in a fixed relationship with the optical subsystem sensor. The optical subsystem sensor produces position and/or orientation signals relative to the optical subsystem coordinate system in response to optical subsystem light source detected energy. The non-optical subsystem has a non-optical coordinate system and is adapted to produce position and/or orientation signals of one or more of the objects relative to the non-optical subsystem coordinate system. A coupling arrangement is provided for producing position and/or orientation signals indicative of the position and/or orientation of the selected one of the optical or non-optical subsystems relative to the coordinate system of the other one of the optical or non-optical subsystems. A processor is responsive to signals produced by the coupling arrangement and the individual subsystem sensors for determining the position and/or orientation of one or more of the objects relative to some conveniently defined coordinate system.

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Wuerenlingen, Switzerland

Christian J Schilling