Fiber optic tracking system and method for tracking a substantially rigid object

• US 9,050,131 B2
• Filed: 06/17/2009
• Issued: 06/09/2015
• Est. Priority Date: 06/18/2008
• Status: Active Grant

• Current Assignee: MAKO Surgical Corporation (Stryker Corporation)
• Original Assignee: MAKO Surgical Corporation (Stryker Corporation)
• Inventors: Van Vorhis, Robert, Hagag, Benny, Kang, Hyosig, Lightcap, Chris, Abovitz, Rony
• Primary Examiner(s): BUI PHO, PASCAL M
• Application Number:
  US12/486,382
• Publication Number:
  US 20090314925A1
• Time in Patent Office: 2,183 Days
• Field of Search: 250/216, 250/227.28, 250/227.27, 250/227.11, 250/227.14, 25022715-22721, 318/560, 318/568.11, 318/568.16, 901/1, 901/2, 901 14- 18, 901 27- 29, 901/46, 901/47, 348/94, 348/95, 385/12, 385/13, 385/4, 385/5, 385/10, 600/101, 600/424, 600/407, 600/109, 606/15, 606/16, 606/1, 606/10, 359/34
• US Class Current: 1/1
• CPC Class Codes: A61B 2034/2055 Optical tracking systems
• CPC Class Codes: A61B 2034/2059 Mechanical position encoders
• CPC Class Codes: A61B 2034/2061 using shape-sensors, e.g. fiber shape sensors with Bragg gratings
• CPC Class Codes: A61B 2090/067 for measuring angles
• CPC Class Codes: A61B 2090/3983 Reference marker arrangements for use with image guided surgery
• CPC Class Codes: A61B 34/20 Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
• CPC Class Codes: A61B 34/30 Surgical robots
• CPC Class Codes: G02B 6/02042 Multicore optical fibres
• CPC Class Codes: G02B 6/02057 comprising gratings

Abstract

A fiber optic tracking system for tracking substantially rigid object(s) is described. The fiber optic tracking system includes a light source, an optical fiber having a sensing component configured to modify optical signals from the light source, the optical fiber being configured to attach to the substantially rigid object, a detection unit arranged to receive the modified optical signals from the sensing component, and a calculation unit configured to determine a pose of the substantially rigid object in six degrees of freedom based on the modified optical signals.

Claims

1. A fiber optic tracking system for tracking a substantially rigid object, comprising:

a light source that provides optical signals;

an optical fiber having a sensing component configured to modify optical signals from the light source, the optical fiber being configured to attach to the substantially rigid object;

a detection unit arranged to receive the modified optical signals from the sensing component; and

a calculation unit configured to determine a pose of the substantially rigid object in six degrees of freedom based on the modified optical signals,

wherein the sensing component includes at least a first set of optical elements comprising a first sensing point and a second set of optical elements comprising a second sensing point, wherein the first and second sensing points are separated at a distance along the optical fiber, and

wherein a position and orientation of the first set of optical elements is fixed relative to a position and orientation of the second set of optical elements and the positions and orientations of the first and second sets of optical elements are fixed with non-collinear fiber orientations relative to the same substantially rigid object.

2. The fiber optic tracking system of claim 1, wherein the substantially rigid object includes at least one of a portion of a body and an instrument.

3. The fiber optic tracking system of claim 1, wherein the optical fiber includes at least one of a multi-core fiber and a plurality of single core fibers.

4. The fiber optic tracking system of claim 1, wherein the optical fiber is configured to at least one of attach directly to the substantially rigid object and attach to an element that is attached directly to the substantially rigid object.

5. The fiber optic tracking system of claim 1, wherein at least one of the detection unit and the calculation unit is configured to detect a difference between the optical signals from the light source and the modified optical signals.

6. The fiber optic tracking system of claim 1, wherein one of the first and second sets of optical elements include at least one of a fiber Bragg grating, microbend sensor, and an interferometric sensor.

7. The fiber optic tracking system of claim 1,

wherein a portion of the optical fiber that includes the first and second set of optical elements is constrained to have a fixed geometry.

8. The fiber optic tracking system of claim 7, wherein the pose of the substantially rigid object in six degrees of freedom is determined based at least in part on a location of the first set of optical elements, a first vector along a direction of the optical fiber at the location of the first set of optical elements, and a second vector along a direction of the optical fiber at a location of the second set of optical elements.

9. The fiber optic tracking system of claim 7, wherein the portion of the optical fiber that includes the first and second set of optical elements is constrained to have a predetermined geometry.

10. The fiber optic tracking system of claim 9, wherein the predetermined geometry includes at least one of a planar arc and a planar loop.

11. The fiber optic tracking system of claim 10, wherein the planar loop has a constant radius.

12. The fiber optic tracking system of claim 10, wherein the planar loop includes a fixed crossing point where a first point on the optical fiber overlaps a second point on the optical fiber.

13. The fiber optic tracking system of claim 7, wherein the first and second set of optical elements are disposed on a plane perpendicular to an axis of revolution of a joint of the substantially rigid object.

14. The fiber optic tracking system of claim 1, wherein the sensing component includes at least three sets of optical elements, and wherein the optical fiber is constrained such that positions of the three sets of optical elements are non-collinear.

15. The fiber optic tracking system of claim 14, wherein the calculation unit is configured to calculate the pose based on basis vectors determined from positions of the at least three sets of optical elements.

16. The fiber optic tracking system of claim 14, wherein the calculation unit is configured to calculate the pose based on a least squares fit method using the positions of the at least three sets of optical elements.

17. The fiber optic tracking system of claim 14, wherein the calculation unit is configured to calculate the pose based on a point cloud registration method using the positions of the at least three sets of optical elements.

18. The fiber optic tracking system of claim 1, wherein the optical fiber has a second sensing component configured to modify optical signals from the light source to provide second modified optical signals, the optical fiber being configured to attach to a second substantially rigid object;

the detection unit is arranged to receive the second modified optical signals from the second sensing component; and

the calculation unit is configured to determine a pose of the second substantially rigid object in six degrees of freedom based on the second modified optical signals.

19. A method for tracking a substantially rigid object using a fiber optic tracking system, comprising:

providing a light source;

attaching an optical fiber, having a sensing component configured to modify the optical signals from the light source, to the substantially rigid object, wherein the sensing component includes at least a first set of optical elements comprising a first sensing point and a second set of optical elements comprising a second sensing point, wherein the first and second sensing points are separated at a distance along the optical fiber;

constraining the optical fiber such that a position and orientation of the first set of optical elements is fixed relative to a position and orientation of the second set of optical elements and the positions and orientations of the first and second sets of optical elements are fixed with non-collinear fiber orientations relative to the same substantially rigid object; and

determining a pose of the substantially rigid object in six degrees of freedom based on the modified optical signals.

20. The method of claim 19, further comprising:

at least one of attaching the optical fiber directly to the substantially rigid object and attaching the optical fiber directly to an element that is attached directly to the substantially rigid object.

21. The method of claim 19, further comprising:

determining the pose of the substantially rigid object in six degrees of freedom based at least in part on a location of the first set of optical elements, a first vector along a direction of the optical fiber at the location of the first set of optical elements, and a second vector along a direction of the optical fiber at the location of the second set of optical elements.

22. The method of claim 19, further comprising:

constraining a portion of the optical fiber that includes the first set of optical elements and the second set of optical elements to have a fixed geometry.

23. A computer program product embedded on a non transitory computer readable medium storing a program for tracking a substantially rigid object using a fiber optic tracking system, which when executed by a computer performs a method comprising:

determining a pose of the substantially rigid object in six degrees of freedom based on modified optical signals received from a sensing component of an optical fiber attached to the substantially rigid object,

wherein the sensing component includes at least a first set of optical elements comprising a first sensing point and a second set of optical elements comprising a second sensing point, wherein the first and second sensing points are separated at a distance along the optical fiber, and

wherein a position and orientation of the first set of optical elements is fixed relative to a position and orientation of the second set of optical elements and the positions and orientations of the first and second sets of optical elements are fixed with non-collinear fiber orientations relative to the same substantially rigid object.

24. The computer program product of claim 23, further comprising:

determining the pose of the substantially rigid object in six degrees of freedom based at least in part on a location of the first set of optical elements in the optical fiber, a first vector along a direction of the optical fiber at the location of the first set of optical elements, and a second vector along a direction of the optical fiber at a location of the second set of optical elements in the optical fiber.

25. The computer program product of claim 23,

wherein a portion of the optical fiber that includes the first and second sets of optical elements is constrained to have a fixed geometry.