Method for tracking objects using optical and non-optical sensors

• US 9,271,804 B2
• Filed: 03/02/2015
• Issued: 03/01/2016
• Est. Priority Date: 09/26/2012
• Status: Active Grant

• Current Assignee: Stryker Corporation
• Original Assignee: Stryker Corporation
• Inventors: Wu, Chunwu
• Primary Examiner(s): Lamprecht, Joel
• Application Number:
  US14/635,402
• Publication Number:
  US 20150164609A1
• Time in Patent Office: 365 Days
• US Class Current: 1/1
• CPC Class Codes: A61B 2034/2048 using an accelerometer or inertia sensor
• CPC Class Codes: A61B 2034/2053 Tracking an applied voltage gradient
• CPC Class Codes: A61B 2034/2055 Optical tracking systems
• CPC Class Codes: A61B 2090/0818 Redundant systems, e.g. using two independent measuring systems and comparing the signals
• CPC Class Codes: A61B 2090/3945 Active visible markers, e.g. light emitting diodes
• 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: A61B 5/064 using markers A61B5/062 takes precedence
• CPC Class Codes: A61B 90/39 Markers, e.g. radio-opaque or breast lesions markers
• CPC Class Codes: Y10S 901/47 Optical

Abstract

Systems and methods that utilize optical sensors and non-optical sensors to determine the position and/or orientation of objects. A navigation system includes an optical sensor for receiving optical signals from markers and a non-optical sensor, such as a gyroscope, for generating non-optical data. A navigation computer determines positions and/or orientations of objects based on optical and non-optical data.

Claims

1. A method for tracking an object during a surgical procedure using a plurality of optical sensors, a tracker including three markers and a non-optical sensor, and a computing system including at least one processor, said method comprising the steps of:

receiving optical signals sequentially from the markers with the plurality of optical sensors;

generating non-optical signals with the non-optical sensor;

determining, with the at least one processor, a position of a first of the markers at a first time based on a first optical signal from the first marker;

determining, with the at least one processor, positions of a second and third of the markers at the first time based on the first optical signal and a non-optical signal from the non-optical sensor; and

correlating, with the at least one processor, the determined positions of the first, second, and third markers to the object to track a position of the object during the surgical procedure.

2. A method as set forth in claim 1 including placing the non-optical sensor in a known position relative to each of the markers.

3. A method as set forth in claim 1 including sequentially emitting optical signals from the markers such that the first marker emits the first optical signal at the first time and prior to the second and third markers emitting optical signals.

4. A method as set forth in claim 1 including calculating the positions of the second and third markers by calculating a first velocity of the first marker based on the first optical signal and by calculating velocities of the second and third markers based on the first velocity and the non-optical signal in the first time.

5. A method as set forth in claim 1 including correlating the determined positions of the first, second, and third markers to the object to track a position and orientation of the object.

6. A method as set forth in claim 1 including measuring initial positions of the first, second, and third markers at an initial time to establish initial position data.

7. A method as set forth in claim 6 including measuring the initial positions of the first, second, and third markers to establish the initial position data by sequentially firing the first, second, and third markers to transmit light signals to the plurality of optical sensors.

8. A method as set forth in claim 6 including calculating velocities of the first, second, and third markers while establishing the initial position data and comparing the calculated velocities to a predetermined threshold.

9. A method as set forth in claim 6 including comparing the measured initial positions of the first, second, and third markers at the initial time to a model of the first, second, and third markers stored in the computing system.

10. A method as set forth in claim 9 including matching the first, second, and third markers to the model and provide a best-fit to the model.

11. A method as set forth in claim 10 including matching one or more virtual markers to the model to provide the best-fit to the model.

12. A method as set forth in claim 1 including calculating a linear velocity vector of the first marker.

13. A method as set forth in claim 12 including measuring an angular velocity of the tracker at the first time.

14. A method as set forth in claim 13 including calculating a relative velocity vector of an origin of a tracker coordinate system based on the measured angular velocity.

15. A method as set forth in claim 14 including calculating relative velocity vectors for the second and third markers based on the measured angular velocity.

16. A method as set forth in claim 15 including calculating a velocity vector of the origin of the tracker coordinate system based on the calculated linear velocity vector of the first marker and the calculated relative velocity vector of the origin.

17. A method as set forth in claim 16 including calculating velocity vectors of the second and third markers at the first time based on the calculated velocity vector of the origin and the calculated relative velocity vectors of the second and third markers.

18. A method as set forth in claim 17 including calculating the positions of the second and third markers at the first time based on the calculated velocity vectors of the second and third markers at the first time.

19. A method as set forth in claim 18 including calculating relative velocity vectors for one or more virtual markers.

20. A method as set forth in claim 19 including calculating velocity vectors of the one or more virtual markers at the first time based on the calculated velocity vector of the origin and the calculated relative velocity vectors of the one or more virtual markers.

21. A method as set forth in claim 20 including calculating the position of the one or more virtual markers at the first time based on the calculated velocity vectors of the one or more virtual markers at the first time.