US 2025/0165062 A1 · A HEAD TRACKING SYSTEM

Abstract

A head tracking system HTS (100, 200) and associated method and head worn assembly, configured to determine a head position and/or a head orientation of a user, the HTS comprising: one or more optical sensors (112) producing optical measurements; and one or more inertial sensors (104) producing inertial measurements; a processor configured, when the optical sensors fail to provide optical measurements to determine the head location and the head orientation of a user, to operate in a coasting mode using the inertial measurements from the one or more inertial sensors to determine the head location and the head orientation of a user, the processor configured to further: determine a figure of merit FOM (346) for coasting errors based on a combination of one or more of errors in an estimated inertial sensor bias, a random drift and noise of the inertial sensor and the inertial sensor gain and alignment errors; compare (348) the FOM with a threshold to determine whether the inertial measurements provide a valid or invalid head location and/or head orientation; and determine a subsequent operation from a plurality of possible subsequent operations of the HTS based on whether the head location and/or head orientation is valid or invalid.

Claims21

Dependent claims

A head tracking system (HTS), configured to determine a head position and/or a head orientation of a user, the HTS comprising:

an optical sensor configured to produce an optical measurement;
an inertial sensor configured to produce an inertial measurement;
and
a processor configured to operate in a coasting mode, when the optical sensor fails to provide the optical measurement to determine the head location and the head orientation of a user, the coasting mode using the inertial measurement from the inertial sensor to determine the head location and the head orientation of a user, the processor configured to:
determine a figure of merit (FOM) for a coasting error based on a combination of an error in an estimated bias of the inertial sensor, an error due to random drift and noise of the inertial sensor, and an error due to gain and alignment errors of the inertial sensor,
compare the FOM with a threshold to determine whether the inertial measurement provides a valid or invalid head location and/or head orientation;
and
determine a subsequent operation from a plurality of possible subsequent operations of the HTS based on whether the head location and/or head orientation is valid or invalid.

5 more elements

A method to determine a head location and a head orientation of a user to which real and virtual images are to be presented using a head tracking system (HTS) configured to produce optical measurements and to produce inertial measurements, the method comprising:

using, when optical measurements are unavailable, the inertial measurements to determine the head location and position;
determining a figure of merit FOM (FOM) for coasting errors based on a combination of an error in an estimated bias of an inertial sensor that produces one or more of the inertial measurements, an error due to random drift and noise of the inertial sensor, and an error due to gain and alignment errors of the inertial sensor;
comparing the FOM with a threshold to determine whether the one or more inertial measurements provide a valid or invalid head location and/or head orientation;
and
determining a subsequent operation from a plurality of possible subsequent operations of the HTS based on whether the head location and/or head orientation is valid or invalid.

2 more elements

Dependencies are inferred from the claim text.

A head tracking system

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A head tracking system

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Abstract

Claims21