Method and system for field mapping using integral methodology

1. A method for electromagnetic tracking, said method comprising:

selecting a set of sources on a surface of a volume;

determining mutual inductances from said set of sources on said surface with a distortion measurement module;

calculating distortion from said volume using said mutual inductances from said set of sources on said surface with a calculation module, wherein said distortion is calculated using an integral method and a finite element analysis; and

tracking an object with a tracking module, wherein said tracking comprises accounting for said distortion during measurement of tracking information.

2. The method of claim 1 , further comprising modeling said volume as a simplified construct.

3. The method of claim 2 , wherein said construct comprises at least one of a ring model, a coil array with straight line segments model, a polygon model, and a dipole array model.

4. The method of claim 2 , further comprising adjusting a model of said volume based on said distortion calculated from said volume.

5. A method comprising:

identifying a distorter volume in a tracking coordinate system;

using at least one computing device to select a model to represent said distorter volume in said tracking coordinate system;

using the at least one computing device to measure a subset of a surface of said distorter volume; and

using the at least one computing device to map a magnetic field generated by said distorter volume using said model and measurements of said subset of said surface, wherein said mapping step further comprises using an integral method and a finite element analysis.

6. The method of claim 5 , further comprising adjusting model parameters based on said measurements.

7. The method of claim 5 , wherein said model comprises at least one of a ring model, a coil array with straight line segments model, a polygon model, and a dipole array model.

8. The method of claim 5 , wherein said magnetic field is mapped based on an approximate set of field sources on a surface of said distorter and adjusted using at least one of an integral method and a finite element analysis.

9. The method of claim 5 , further comprising characterizing said tracking coordinate system using a robot.

10. The method of claim 5 , further comprising tracking an object using said mapping of said magnetic field.

11. The method of claim 5 , wherein said measurements are obtained using a plurality of positions on said surface and one orientation.

12. A system comprising:

a distortion measurement module measuring data from a plurality of mutual inductance sources located on a surface of a volume;

a calculation module calculating distortion from said volume using said plurality of mutual inductance sources using at least one of an integral method and a finite element analysis;

a mapping module mapping a magnetic field around an object, said mapping including effects of said distortion; and

a tracking module tracking said object, said tracking module using said magnetic field mapping to track said object.

13. The system of claim 12 , wherein said integral method includes use of a Green's function to calculate distortion.

14. The system of claim 12 , wherein said distortion measurement module approximates said volume using a model.

15. The system of claim 14 , wherein said model includes at least one of a ring model, a coil array with straight line segments model, a polygon model, and a dipole array model.

16. The system of claim 14 , wherein parameters of said model are adjusted based on measurements from said volume.

17. The system of claim 12 , wherein said distortion measurement module obtains measurements using a plurality of positions on said surface and one orientation.

18. The system of claim 12 , wherein said distortion measurement module measures magnetic fields from said plurality of sources located on said surface of said volume.