Orientation tracking system and method

• US 8,953,154 B2
• Filed: 07/26/2012
• Issued: 02/10/2015
• Est. Priority Date: 07/26/2012
• Status: Active Grant

• Current Assignee: Vivonics Inc.
• Original Assignee: Vivonics Inc.
• Inventors: Galea, Anna M, LeRoy, Kristen J., Hirschman, Gordon
• Primary Examiner(s): Punnoose, Roy M
• Application Number:
  US13/558,736
• Publication Number:
  US 20140031723A1
• Time in Patent Office: 929 Days
• Field of Search: 356/138, 333/67
• US Class Current: 356/138
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/1113 Local tracking of patients, e.g. in a hospital or private home
• CPC Class Codes: A61B 5/1121 Determining geometric values, e.g. centre of rotation or angular range of movement
• CPC Class Codes: A61B 5/1128 using image analysis A61B5/1127 takes precedence
• CPC Class Codes: G01B 21/04 by measuring coordinates of points

Abstract

An orientation tracking system including a first tracking system subject to drift. A second tracking system is configured to provide an output for calibrating the first tracking system to reduce the drift of the first tracking system. The second tracking system includes at least one inclinometer, each inclinometer including a light source adjacent one side of the inclinometer, a light sensor adjacent an opposing side of the inclinometer, and a light obscuring material within the inclinometer for obscuring the light between the light source and light sensor to indicate an orientation of the inclinometer.

Claims

1. An orientation tracking system comprising:

a first tracking system subject to drift;

a second tracking system configured to provide an output for calibrating the first tracking system to reduce the drift of the first tracking system, the second tracking system including at least one inclinometer, each inclinometer including;

a light source adjacent one side of the inclinometer;

a light sensor adjacent an opposing side of the inclinometer; and

a light obscuring material within the inclinometer for obscuring the light between the light source and light sensor to indicate an orientation of the inclinometer.

2. The system of claim 1 in which each inclinometer includes a hollow toroid having the light obscuring material therein.

3. The system of claim 1 in which the second tracking system includes three inclinometers oriented orthogonally to with respect to each other.

4. The system of claim 1 in which the light obscuring material is a solid ball.

5. The system of claim 4 in which each inclinometer also includes a fluid therein for stabilizing the ball.

6. The system of claim 1 in which the light obscuring material includes an opaque fluid.

7. The system of claim 6 in which the fluid includes a light absorbing fluid.

8. The system of claim 6 in which each inclinometer also includes a second fluid having a lower viscosity than the opaque fluid.

9. The system of claim 6 in which each inclinometer further includes a gas.

10. The system of claim 1 in which the light source includes a light emitting diode (LED).

11. The system of claim 1 in which the light sensor includes a photodiode.

12. The system of claim 1 in which the light sensor includes a phototransistor.

13. An orientation tracking system comprising:

a first tracking system subject to drift;

a second tracking system configured to provide an output for calibrating the first tracking system to reduce the drift of the first tracking system, the second tracking system including at least three inclinometers, each inclinometer including;

a hollow circular tube;

a light source adjacent the tube on one of the inside or the outside of the circular tube;

a light sensor adjacent the tube on the other of the inside or the outside of the circular tube; and

a light obscuring material within the tube for obscuring the light between the light and light sensor to indicate an orientation of each tube.

14. The system of claim 13 in which the three inclinometers are oriented orthogonally to each other.

15. A head orientation tracking system comprising:

a head mountable apparatus;

a first tracking system within the apparatus and subject to drift;

a second tracking system within the apparatus, the second tracking system configured to provide an output for calibrating the first tracking system to reduce the drift of the first tracking system, the second tracking system including at least three inclinometers, each inclinometer including;

a hollow circular tube;

a light source adjacent the tube on one of the inside or the outside of the circular tube;

a light sensor adjacent the tube on the other of the inside or the outside of the circular tube; and

a light obscuring material within the tube for obscuring the light between the light source and light sensor to indicate an orientation of each tube, the output of the second tracking system used to calibrate the first tracking system and reduce drift thereof.

16. The system of claim 15 in which there are three inclinometers oriented orthogonally with respect to each other.

17. The system of claim 15 in which the circular tube includes a hollow toroid which includes the light obscuring material within the toroid.

18. An inclinometer system comprising:

at least one inclinometer, each including;

a hollow circular tube including a hollow toroid which includes a light obscuring material within the toroid;

a light source adjacent the tube on one of the inside or the outside of the circular tube;

a light sensor adjacent the tube on the other of the inside or the outside of the circular tube; and

a light obscuring material within the tube for obscuring the light between the light source and light sensor to indicate an orientation of each tube.

19. The system of claim 18 in which the system includes three inclinometers oriented orthogonally to each other.

20. A method for orientation tracking, the method comprising the steps of:

providing a first tracking system subject to drift; and

providing a second tracking system including a hollow circular tube including a hollow toroid which includes a light obscuring material within the toroid, a light source adjacent the tube on one of the inside or the outside of the circular tube, a light sensor adjacent the tube on the other of the inside or the outside of the circular tube, the light obscuring material within the tube for obscuring the light between the light source and light sensor to indicate an orientation of each tube, the second tracking system in communication with the first tracking system which calibrates the first tracking system to reduce the drift of the first tracking system.

21. The method of claim 20 in which the first tracking system is configured to calculate roll, pitch, and yaw of a person or object.

22. The method of claim 20 in which the second tracking system is configured to calculate a calibration factor.

23. The method of claim 20 further including the step of adding the roll, pitch, and yaw with the calibration factor to determine if the second tracking system is positioned more accurate than the first tracking system.