System and a method for mapping a magnetic field

• US 10,488,471 B2
• Filed: 01/04/2017
• Issued: 11/26/2019
• Est. Priority Date: 10/11/2007
• Status: Active Grant

• Current Assignee: Elbit Systems Limited
• Original Assignee: Elbit Systems Limited
• Inventors: Efrat, Ilan, Gurovich, Evgeni, Mencel, Guy, Ophir, Yoav, Gandelsman, Mark
• Primary Examiner(s): Kim, Eunhee
• Application Number:
  US15/398,316
• Publication Number:
  US 20170115364A1
• Time in Patent Office: 1,056 Days
• Field of Search: 703 10, 703 13
• CPC Class Codes: G01R 33/072 Constructional adaptation of the sensor to specific applications
• CPC Class Codes: G01R 33/10 Plotting field distribution ; Measuring field distribution

Abstract

System for mapping a magnetic-field including a magnetic-field-transmitter, a freestanding magnetic-field-detector operative to freely move within a volume of interest and acquire measurements of the flux of the magnetic-field at a plurality of poses, a pose-information-acquisition-module for measuring information related to the pose of the magnetic-field-detector and a processor, coupled with the magnetic-field-detector and with said pose-information-acquisition-module and determines pose-related-information respective of each of at least a portion of the magnetic-flux-measurements, according to said information related to the pose of said magnetic-field-detector, the processor further estimating the entire set of parameters of a magnetic-field-model-template according to the magnetic-flux-measurements and the respective pose-related-information the magnetic flux measurements, the processor incorporates the entire set of parameters into said magnetic field model template, thereby determining said magnetic field model, the entire set of parameters includes the coefficients, the order, the number and location of the centers of expansion of the model.

Claims

1. A system for mapping a magnetic field in a volume of interest, the system comprising:

a magnetic field transmitter, generating a magnetic field in said volume of interest;

at least one freestanding magnetic field detector, operative to freely move within said volume of interest, said at least one freestanding magnetic field detector acquiring measurements of a flux of said magnetic field at a plurality of poses;

at least one pose information acquisition module for measuring information related to the pose of said freestanding magnetic field detector for at least a portion of said plurality poses; and

a processor, coupled with said magnetic field detector and with said at least one pose information acquisition module, said processor determining pose related information respective of each of at least a portion of said measurements of the flux of said magnetic field, according to said information related to the pose of said freestanding magnetic field detector at said at least a portion of said plurality of poses, said processor further estimating an entire set of parameters of a magnetic field model template according to said magnetic field flux measurements and the respective pose related information of said magnetic field flux measurements, said processor incorporating said entire set of parameters into said magnetic field model template, thereby determining said magnetic field model,

wherein, said entire set of parameters includes the coefficients of said magnetic field model, the order of said magnetic field model, the number of the centers of expansion and the locations of the centers of expansion of said magnetic field model.

2. The system according to claim 1, wherein each of said at least one pose information acquisition module includes being one of:

at least one imager and at least one light emitter;

inertial tracking sensors;

at least one ultrasound sensor and at least one ultrasound transmitters;

a mechanical tracking module;

a Light Detection And Ranging module; and

a motion capture module.

3. The system according to claim 2, wherein each one of said at least one imager and each one of said at least one light emitter is adapted to be fixedly coupled with said freestanding magnetic field detector and with a reference location in said system.

4. The system according to claim 3, including at least two imagers and at least two light emitters, each of said at least two imagers is adapted to be fixedly coupled with a respective different one of said magnetic field detector and said reference location.

5. The system according to claim 2, including two different pose information acquisition modules, each for measuring information related to the pose of said freestanding magnetic field detector, each of said at least two pose information acquisition modules being coupled with said processor,

said processor determining pose related information respective of at least a first portion of said measurements according to said information related to the pose of said freestanding magnetic field detector measured by one of said at least two pose information acquisition modules,

said processor determining pose related information respective of at least a second portion of said measurements according to said information related to the pose of said freestanding magnetic field detector measured by the other one of said at least two pose information acquisition modules.

6. The system according to claim 5, wherein said one of said at least two pose information acquisition modules is said at least one imager and at least one light emitter, and

wherein the other one of said at least two pose information acquisition modules is said inertial tracking sensors.

7. The system according to claim 5, wherein said first portion of measurements and said second portion measurements are one of:

mutually exclusive;

partially overlap; and

completely overlap.

8. The system according to claim 6, wherein said processor fuses said pose related information respective of a measurement acquired from one of said at least two pose information acquisition modules with the pose related information respective of said measurement acquired by the other one of said at least two pose information acquisition modules.

9. The system according to claim 1, wherein said pose related information respective of at least a portion of said measurements includes information relating to only selected pose parameters.

10. The system according to claim 9, wherein said pose related information of each of the portion of magnetic field flux measurement may comprises different pose parameters.

11. The system according to claim 1, wherein said pose related information respective of at least a portion of said measurements includes information relating to one of a set of locations, a set of orientations and a set of combinations of location and orientation.

12. The system according to claim 1, wherein said processor employs said pose related information respective of at least a portion of said measurements as constraints when estimating the parameters characterizing said magnetic field model.

13. The system according to claim 1, further including a freestanding mapping handle operative to freely move within said volume of interest, said at least one freestanding magnetic field detector being fixedly coupled with said freestanding mapping handle.

14. The system according to claim 1, wherein said at least one freestanding magnetic field detector is moved within said volume of interest at a random trajectory.

15. The system according to claim 1, wherein said at least one freestanding magnetic field detector is moved within said volume of interest through a plurality of mapping regions.

16. The system according to claim 1, wherein said processor is further coupled with said magnetic field transmitter.

17. The system according to claim 1, wherein said system further comprises at least two magnetic field detectors.

18. The system according to claim 17, wherein each of said magnetic field detectors includes three magnetic field sensors.

19. The system according to claim 17, wherein the spatial relationship between said two magnetic field detectors is known.

20. The system according to claim 1, wherein said magnetic field transmitters includes three magnetic field generators.

21. A method for mapping a magnetic field in a volume of interest, the method comprising the procedures of:

freely moving a magnetic field detector within said volume of interest;

acquiring measurements of a magnetic field flux at a plurality of poses of said freestanding magnetic field detector within said volume of interest;

determining pose related information respective of each of at least a portion of said measurement of magnetic field flux, according to information related to the pose of said freestanding magnetic field detector at least a portion of said plurality of poses; and

estimating an entire set of parameters characterizing a magnetic field model according to said magnetic field flux measurements and said respective pose related information of said measurement of magnetic field flux,

wherein, said entire set of parameters includes the coefficients of said magnetic field model, the order of said magnetic field model, the number of the centers of expansion and the locations of the centers of expansion of said magnetic field model.

22. The method according to claim 21, further including the preliminary procedure of determining a magnetic field model template.

23. The method according to claim 21, further including the preliminary procedure of determining a volume of interest.

24. The method according to claim 21, wherein said pose related information respective of at least a portion of said measurements includes information relating to only selected pose parameters.

25. The method according to claim 24, wherein said pose related information of each of the portion of magnetic field flux measurement comprises different pose parameters.

26. The method according to claim 21, wherein said pose related information respective of at least a portion of said measurements includes information relating to one of a set of locations, a set of orientations and a set of combinations of location and orientation.

27. The method according to claim 21, wherein said pose related information respective of at least a portion of said measurements is employed as constraints when estimating the parameters characterizing said magnetic field model.