Calibration of magnetic and optical sensors in a virtual reality or augmented reality display system

Patent metadata

Field	Value
Publication number	US-11150310-B2
Application number	US-201916692969-A
Country	US
Kind code	B2
Filing date	Nov 22, 2019
Priority date	Sep 26, 2016
Publication date	Oct 19, 2021
Grant date	Oct 19, 2021

Abstract

A system for calibrating alignment of two or more sensors in a virtual reality (VR) or augmented reality (AR) display device, the two or more sensors in the display device including at least one magnetic sensor. The system can include a first pair of conductive loops oriented in parallel planes and spaced apart along a first axis. The system can also include a mount configured to attach to the display device and to support the display device in a first predetermined spatial relationship with respect to the first pair of conductive loops.

First claim

What is claimed is:

1. A system for calibrating alignment of two or more sensors in a virtual reality (VR) or augmented reality (AR) display device, the two or more sensors in the display device including at least one magnetic sensor, wherein the system comprises:
one or more pairs of conductive loops comprising a first pair of conductive loops oriented in parallel planes and spaced apart along a first axis; and
a mount configured to attach to the display device and to support the display device in a first predetermined spatial relationship with respect to the one or more pairs of conductive loops.

2. The system of claim 1 , further comprising an actuator connected to the mount and configured to move the display device to a second predetermined spatial relationship with respect to the one or more pairs of conductive loops.

3. The system of claim 1 , wherein the two or more sensors in the display device further comprise at least one optical sensor.

4. The system of claim 3 , further comprising one or more optical fiducial markers supported in a predetermined spatial relationship with respect to the one or more pairs of conductive loops.

5. The system of claim 1 , further comprising:
a controller;
a waveform generator configured to generate calibration waveforms under control of the controller; and
an electrical driver configured to receive calibration waveforms generated by the waveform generator, and to energize the one or more pairs of conductive loops with electrical output currents corresponding to the received calibration waveforms.

6. The system of claim 5 , wherein the controller is configured to communicate with the display device to identify the at least one magnetic sensor, and to cause the waveform generator to generate one or more calibration waveforms based on the identification of the at least one magnetic sensor.

7. The system of claim 5 , wherein the first pair of conductive loops is configured to produce a magnetic field in a direction along the first axis when energized.

8. The system of claim 5 , wherein each of the one or more pairs of conductive loops is configured to produce a magnetic field within a volume of space when energized.

9. The system of claim 8 , wherein to support the display device in the first predetermined spatial relationship with respect to the one or more pairs of conductive loops, the mount is configured to position the display device within the volume of space.

10. The system of claim 1 , wherein the at least one magnetic sensor comprises an inertial measurement unit (IMU).

11. The system of claim 1 , wherein the one or more pairs of conductive loops further comprise:
a second pair of conductive loops oriented in parallel planes and spaced apart along a second axis, the second axis being orthogonal to the first axis.

12. The system of claim 11 , wherein the one or more pairs of conductive loops further comprise:
a third pair of conductive loops oriented in parallel planes and spaced apart along a third axis, the third axis being orthogonal to the first and second axes.

13. The system of claim 1 , further comprising a frame configured to support the one or more pairs of conductive loops.

14. The system of claim 13 , further comprising an actuator connected to the frame and configured to move the one or more pairs of conductive loops to a second predetermined spatial relationship with respect to the display device.

15. The system of claim 1 , wherein each of the one or more pairs of conductive loops is arranged in a Helmholtz coil configuration.

16. The system of claim 1 , wherein to support the display device in the first predetermined spatial relationship with respect to the one or more pairs of conductive loops, the mount is configured to position the display device within a volume of space between the one or more pairs of conductive loops.

Assignees

• Magic Leap Inc

Inventors

• Woods Michael
• Nortman Scott David

Classifications

• G06F3/011 Primary

  Arrangements for interaction with the human body, e.g. for user immersion in virtual reality (blind teaching G09B21/00) · CPC title

• G01R23/16

  Spectrum analysis; Fourier analysis · CPC title

• G01R33/0029 Primary

  Treating the measured signals, e.g. removing offset or noise · CPC title

• G01R33/0005

  Geometrical arrangement of magnetic sensor elements; Apparatus combining different magnetic sensor types (G01R33/0206 takes precedence) · CPC title

• G06F1/163

  Wearable computers, e.g. on a belt · CPC title