Dynamic magnetometer calibration

• US 8,851,996 B2
• Filed: 08/17/2012
• Issued: 10/07/2014
• Est. Priority Date: 08/17/2012
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Russo, David
• Primary Examiner(s): Suhol, Dmitry
• Assistant Examiner(s): YEN, JASON TAHAI
• Application Number:
  US13/588,954
• Publication Number:
  US 20140051518A1
• Time in Patent Office: 781 Days
• Field of Search: 324/202, 324/207.11, 324/207.25, 345/157, 345/419, 455/556.1, 463 32- 33, 463 37- 38, 702/93
• US Class Current: 463/38
• CPC Class Codes: A63F 13/211 using inertial sensors, e.g. accelerometers or gyroscopes
• CPC Class Codes: A63F 13/22 Setup operations, e.g. calibration, key configuration or button assignment
• CPC Class Codes: A63F 13/235 using a wireless connection, e.g. infrared or piconet
• CPC Class Codes: A63F 13/245 specially adapted to a particular type of game, e.g. steering wheels
• CPC Class Codes: A63F 2300/1018 Calibration; Key and button assignment
• CPC Class Codes: A63F 2300/1031 using a wireless connection, e.g. Bluetooth, infrared connections
• CPC Class Codes: A63F 2300/105 using inertial sensors, e.g. accelerometers, gyroscopes
• CPC Class Codes: A63F 2300/1062 being specially adapted to a type of game, e.g. steering wheel
• CPC Class Codes: G01C 17/30 Earth-inductor compasses
• CPC Class Codes: G01R 33/0035 Calibration of single magnetic sensors, e.g. integrated calibration

Abstract

Embodiments related to calibrating a game controller including a magnetometer during game play are disclosed. One embodiment provides a method comprising sampling magnetic information received from the magnetometer, and outputting, to a computing device, an initial game controller orientation signal derived from a first sample of a plurality of samples of the magnetic information and from directional offset data. The method further comprises calculating updated directional offset data based on the plurality of samples of the magnetic information and on the directional offset data, and outputting to the computing device a calibrated game controller orientation signal derived from a second sample of the plurality of samples of the magnetic information and the updated directional offset data.

Claims

1. A method of calibrating a game controller including a magnetometer during game play, comprising:

sampling magnetic information received from the magnetometer, each sample of the magnetic information including a vector component of an ambient magnetic field along each of a first axis, a second axis, and a third axis, the first axis, the second axis, and the third axis being orthogonal to each other;

outputting, to a computing device, an initial game controller orientation signal derived from a first sample of a plurality of samples of the magnetic information and from directional offset data including a first directional offset along the first axis, a second directional offset along the second axis, and a third directional offset along the third axis;

calculating updated directional offset data by filtering unfiltered directional offset data with the directional offset data; and

outputting to the computing device a calibrated game controller orientation signal derived from a second sample of the plurality of samples of the magnetic information and the updated directional offset data.

2. The method of claim 1, wherein calculating the updated directional offset data further comprises:

identifying a first set of samples of the plurality of samples of the magnetic information;

identifying a second set of samples of the plurality of samples of the magnetic information; and

determining the unfiltered directional offset data based on the first set of samples and the second set of samples.

3. The method of claim 2, wherein identifying the first set of samples and the second set of samples includes:

identifying a first valid sample;

identifying a first candidate sample;

determining an angle between the vector components of the first valid sample and the vector components of the first candidate sample;

if the angle is greater than a threshold angle, acknowledging the first candidate sample as a second valid sample.

4. The method of claim 3, wherein the threshold angle is 75 degrees.

5. The method of claim 2, wherein filtering the unfiltered directional offset data with the directional offset data includes using an increment/decrement filter.

6. The method of claim 2, wherein the first set of samples and the second set of samples each include three samples of the magnetic information.

7. The method of claim 1, wherein the initial game controller orientation signal and the calibrated game controller orientation signal are usable by the computing device to effect control over a virtual object presented by the computing device.

8. The method of claim 1, further comprising storing the updated directional offset data.

9. A game controller comprising:

a magnetometer configured to output magnetic information representing an ambient magnetic field;

a communication subsystem configured to provide communication with a computing device;

a logic subsystem; and

a storage subsystem storing instructions that are executable by the logic subsystem to;

sample the magnetic information received from the magnetometer, each sample of the magnetic information including a vector component of the ambient magnetic field along each of a first axis, a second axis, and a third axis, the first axis, the second axis, and the third axis being orthogonal to each other;

output, to a computing device, an initial game controller orientation signal derived from a first sample of a plurality of samples of the magnetic information and from directional offset data including a first directional offset along the first axis, a second directional offset along the second axis, and a third directional offset along the third axis;

calculate updated directional offset data by filtering unfiltered directional offset data with the directional offset data; and

output to the computing device a calibrated game controller orientation signal derived from a second sample of the plurality of samples of the magnetic information and the updated directional offset data.

10. The game controller of claim 9, further comprising a handle portion coupled to the magnetometer and configured to be held in one or both hands, the handle portion comprising one or more of a U-shaped wheel and an O-shaped wheel.

11. The game controller of claim 9, wherein the communication subsystem is configured to communicate with the computing device via a wireless connection.

12. The game controller of claim 9, wherein the initial game controller orientation signal and the calibrated game controller orientation signal are usable by the computing device to effect control over a virtual object presented by the computing device.

13. The game controller of claim 9, wherein calculating the updated directional offset data further comprises:

identifying a first set of samples of the plurality of samples of the magnetic information;

identifying a second set of samples of the plurality of samples of the magnetic information; and

determining the unfiltered directional offset data based on the first set of samples and the second set of samples.

14. The game controller of claim 13, wherein filtering the unfiltered offset data with the directional offset data comprises using an increment/decrement filter.

15. A method of calibrating a game controller including a magnetometer during game play, comprising:

obtaining a first plurality of samples of magnetic information received from a magnetometer, each sample of the first set of samples including a vector component of an ambient magnetic field along each of a first axis, a second axis, and a third axis;

obtaining directional offset data previously calculated during game play, the directional offset data including a first directional offset along the first axis, a second directional offset along the second axis, and a third directional offset along the third axis;

outputting to a computing device a first game controller orientation signal derived from the directional offset data and a first sample of the first plurality of samples of the magnetic information;

updating the directional offset data by filtering unfiltered directional offset data with the directional offset data;

obtaining a second plurality of samples of the magnetic information received from the magnetometer;

outputting to the computing device a second game controller orientation signal derived from updated directional offset data and a first sample of the second plurality of samples of the magnetic information.

16. The method of claim 15, wherein updating the directional offset data further comprises:

identifying a first set of samples of the first plurality of samples of the magnetic information;

updating the second directional offset data and third directional offset data based on the first set of samples;

identifying a second set of samples of the plurality of samples of the magnetic information; and

updating the first directional offset data and the third directional offset data based on the second set of samples.

17. The method of claim 16, wherein identifying the first set of samples and the second set of samples comprises determining if an angle between each of the samples is greater than a threshold angle.

18. The method of claim 17, wherein the threshold angle is 75 degrees.

19. The method of claim 15, wherein the first game controller orientation signal and the second game controller orientation signal are usable by the computing device to effect control over a virtual object presented by the computing device.

20. The method of claim 15, further comprising storing the updated directional offset data.