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US 6,052,610 AGranted
Magnetic catheter tracker and method therefor
AssigneeInternational Business Machines Corporation
InventorRoger Hilsen Koch
Life of this patent
Estimating the term…
Abstract
A method, apparatus, and system for tracking an object within a volume, includes coupling a rotating magnetic dipole to the object, measuring the magnetic fields either remotely, on the surface of, or exterior to the volume, to produce measurements; and based on the measurements, determining the position and the orientation of the magnetic dipole, thereby to determine a position and orientation of the object.
Claims10
A method of tracking an object within a volume, the method comprising steps of:
- coupling a rotating permanent magnet to said object;
- measuring magnetic fields produced by the rotating permanent magnet remotely or on the surface of or exterior to the volume, to produce measurements;
- and
- based on said measurements, determining a position and an orientation of the rotating permanent magnet and a position and orientation of said object to which said permanent magnet is coupled comprising:
- inputting said measurements to a processor, said measurements comprising signals representing values of the magnetic fields;
- filtering said signals to produce filtered signals;
- digitizing said filtered signals;
- recording a reference signal from the rotating permanent magnet synchronously with the rotating magnetic dipole;
- performing a direct current (DC) level shift of said digitized signals and the reference signal to reduce an offset from zero of an average magnetic field and produced a level-shifted value;
- and
- performing a digital lock-in operation based on said level-shifted value.
8 more elements
A system for tracking an object in a volume, comprising:
- a rotating permanent magnet coupled to said object;
- at least two detectors for measuring magnetic fields exterior to the volume produced by said rotating permanent magnet, to produce measurements;
- a determining unit for determining, based on said measurements, a position of the permanent magnet and a position of said object to which said permanent magnet is coupled;
- a bandpass filter for filtering outputs from said at least two detectors, thereby providing a band pass around a rotational frequency of the permanent magnet, a filter being provided corresponding to each said at least two detectors;
- and
- an analog-to-digital (A/D) converter for converting filtered outputs from said filter to digital values representing the magnetic fields, said digital values being inputted into said determining unit, said determining unit comprising a computer.
3 more elements
A system for tracking an object in a volume, comprising:
- a rotating permanent magnet coupled to said object;
- a detector for measuring magnetic fields exterior to the volume produced by said rotating permanent magnet, to produce measurements;
- and
- a determining unit for determining, based on said measurements, a position of the permanent magnet and a position of said object to which said permanent magnet is coupled comprising:
- means for recording a reference signal from the rotating permanent magnet synchronously with the rotating permanent magnet;
- a direct current (DC) level shifter for shifting a level of said digitized signals and the reference signal, to reduce an offset from zero of an average magnetic field and produced a level-shifted value;
- and
- a digital lock-in unit for performing a digital lock-in operation based on said level-shifted value.
5 more elements
Dependencies are inferred from the claim text.