Dynamic transmitter power control for magnetic tracker

Patent metadata

Field	Value
Publication number	US-10900808-B2
Application number	US-201916572196-A
Country	US
Kind code	B2
Filing date	Sep 16, 2019
Priority date	Dec 22, 2016
Publication date	Jan 26, 2021
Grant date	Jan 26, 2021

Abstract

A system determines the transmission strength of the magnetic field signal. The magnetic field signal is transmitted from a first magnetic-sensor device to a second magnetic-sensor device. The system then determines a first projected distance between the first magnetic-sensor device and the second magnetic-sensor device. Based at least in part on the first projected distance, the system calculates an adjusted transmission strength for the magnetic field signal. The system then causes the first magnetic-sensor device to transmit an adjusted magnetic field signal. The adjusted magnetic field signal comprises the adjusted transmission strength. The system receives, from the second magnetic-field device, the adjusted magnetic field signal. Based at least in part upon the received adjusted magnetic field signal, the system, computes a first pose of the first magnetic-sensor device in relation to the second magnetic-sensor device.

First claim

What is claimed is:

1. A head-mounted device (HMD) comprising:
a wearable display;
a magnetic field transceiver;
a processor; and
a computer-readable hardware storage device having stored thereon computer-executable instructions that are executable by the processor to cause the HMD to perform at least the following:
cause the magnetic field transceiver to transmit a magnetic field signal to a remote magnetic field transceiver;
receive, from the remote magnetic field transceiver, a response to the magnetic field signal; and
based on the received response, compute a pose of the remote magnetic field transceiver with respect to the HMD.

2. The HMD of claim 1 , wherein execution of the computer-executable instructions further causes the HMD to:
identify magnetic noise associated with the transmitted magnetic field signal; and
based at least in part on the magnetic noise, calculate a transmission strength for the magnetic field signal.

3. The HMD of claim 1 , wherein execution of the computer-executable instructions further causes the HMD to:
based on the pose, calculate a predicted second pose of the remote magnetic field transceiver; and
based on the predicted second pose, calculate an adjusted transmission strength for the magnetic field signal.

4. The HMD of claim 1 , wherein execution of the computer-executable instructions further causes the HMD to:
identify a movement of the HMD;
based on the movement of the HMD, calculate a projected distance between the HMD and the remote magnetic field transceiver; and
based on the projected distance, calculate a transmission strength for the magnetic field signal.

5. The HMD of claim 4 , wherein execution of the computer-executable instructions further causes the HMD to:
based on continued movement of the HMD, calculate an adjustment rate at which the transmission strength of the magnetic field is adjusted in response to the continued movement of the HMD.

6. The HMD of claim 4 , wherein the HMD includes an inertial measurement unit (IMU), and wherein the HMD identifies the movement using data generated by the IMU.

7. The HMD of claim 1 , wherein the pose of the remote magnetic field transceiver is determined based on a near field fall off relationship of the magnetic field signal.

8. The HMD of claim 1 , wherein the remote magnetic field transceiver is disposed in a handheld controller.

9. The HMD of claim 1 , wherein the pose of the remote magnetic field transceiver is determined based on a measured characteristic of the magnetic field signal.

10. The HMD of claim 1 , wherein execution of the computer-executable instructions further causes the HMD to:
during a transition phase from a first transmission strength to a second transmission strength, receive, from the remote magnetic field transceiver, a set of transmission strengths being emitted by the magnetic field transceiver of the HMD; and
based on the set of transmission strengths, compute the pose.

11. A method for enabling a head-mounted device to determine a pose of a remote magnetic field transceiver via use of one or more determined characteristic(s) of a magnetic field signal that is transmitted between the HMD and the remote magnetic field transceiver, said method comprising:
causing a magnetic field transceiver of a head-mounted device (HMD) to transmit a magnetic field signal to a remote magnetic field transceiver;
receiving, from the remote magnetic field transceiver, a response to the magnetic field signal; and
based on the received response, computing a pose of the remote magnetic field transceiver with respect to the HMD.

12. The method of claim 11 , further comprising:
identifying magnetic noise associated with the transmitted magnetic field signal; and
based on the magnetic noise, calculating a transmission strength for the magnetic field signal.

13. The method of claim 11 , further comprising:
based on the pose, calculating a predicted second pose of the remote magnetic field transceiver; and
based on the predicted second pose, calculating an adjusted transmission strength for the magnetic field signal.

14. The method of claim 11 , further comprising:
identifying a movement of the HMD;
based on the identified movement, calculating a projected distance between the HMD and the remote magnetic field transceiver.

15. The method of claim 14 , further comprising:
calculating a transmission strength of the magnetic field.

16. The method of claim 14 , wherein the HMD comprises a first inertial measurement unit (IMU) and the remote magnetic field transceiver comprises a second IMU.

17. The method of claim 11 , wherein the pose of the remote magnetic field transceiver is determined based on a combination of camera image data and the received response.

18. The method of claim 11 , wherein the remote magnetic field transceiver is disposed within a handheld controller.

19. The method of claim 11 , wherein the pose of the remote magnetic field transceiver is determined based on (i) camera image data, (ii) a measured characteristic of the magnetic field signal, and (iii) a near field fall off relationship of the magnetic field signal.

20. A computer system comprising:
a magnetic field transceiver;
a processor; and
a computer-readable hardware storage device having stored thereon computer-executable instructions that are executable by the processor to cause the computer system to:
cause the magnetic field transceiver to transmit a magnetic field signal to a remote magnetic field transceiver;
receive, from the remote magnetic field transceiver, a response to the magnetic field signal; and
based on the received response, compute a pose of the remote magnetic field transceiver with respect to the computer system.

Assignees

• Microsoft Technology Licensing Llc

Inventors

• Miller Quentin Simon Charles
• Fullam Scott Francis
• Cherkashin Lev
• Velat Steven James

Classifications

• G01R33/02 Primary

  Measuring direction or magnitude of magnetic fields or magnetic flux (G01R33/20 takes precedence) · CPC title

• G01D5/12 Primary

  using electric or magnetic means (G01D5/06 takes precedence) · CPC title

• G01B7/14

  for measuring distance or clearance between spaced objects or spaced apertures (G01B7/30 takes precedence) · CPC title