Automatic sensor orientation calibration

1 . A wearable audio device, comprising:

a sensor configured to:

capture rotational motion data, wherein at least a portion of the captured rotational motion data corresponds to head motion of a user; and

generate a sensor orientation of the sensor based on the rotational motion data; and

a controller configured to:

receive the rotational motion data and the sensor orientation from the sensor;

generate, based on the rotational motion data, an orientation calibration parameter; and

map the sensor orientation to a head orientation of the user based on the orientation calibration parameter, wherein the controller is further configured to:

calculate, based on the rotational motion data, a series of rotation axes, wherein each of the series of rotation axes corresponds to one of a series of event periods during a movement period;

determine a rotational dispersion of the series of rotation axes; and

determine the orientation calibration parameter based on the rotational motion data if the rotational dispersion is within a dispersion threshold.

2 . The wearable audio device of claim 1 , wherein the sensor is an inertial measurement unit (IMU).

3 . The wearable audio device of claim 1 , wherein the rotational motion data comprises angular velocity.

4 . The wearable audio device of claim 1 , wherein the head motion comprises a yaw motion.

5 . The wearable audio device of claim 1 , wherein the head motion comprises a pitch rotation.

6 . The wearable audio device of claim 1 , wherein the dispersion threshold is less than or equal to 10 degrees.

7 . The wearable audio device of claim 1 , wherein the dispersion threshold is determined by a neural network model trained by historic rotation data.

8 . The wearable audio device of claim 1 , wherein the movement period is less than one minute.

9 . The wearable audio device of claim 1 , wherein the sensor orientation is defined by a sensor x-axis, a sensor y-axis, and a sensor z-axis.

10 . The wearable audio device of claim 1 , wherein the wearable audio device is an earbud.

11 . A method for automatically calibrating a sensor orientation of a sensor of a wearable audio device, comprising:

capturing, via the sensor, rotational motion data, wherein at least a portion of the captured rotational motion data corresponds to head motion of a user;

generating, via the sensor, the sensor orientation of the sensor based on the rotational motion data;

generating, based on the rotational motion data, an orientation calibration parameter; and mapping the sensor orientation to a head orientation of the user based on the orientation calibration parameter, wherein calibrating the sensor orientation of the sensor further comprises:

calculating, based on the rotational motion data, a series of rotation axes, wherein each of the series of rotation axes corresponds to one of a series of event periods during a movement period;

determining a rotational dispersion of the series of rotation axes; and

determining the orientation calibration parameter based on the rotational motion data if the rotational dispersion is within a dispersion threshold.

12 . The method of claim 11 , wherein the sensor is an inertial measurement unit (IMU).

13 . The method of claim 11 , wherein the rotational motion data comprises angular velocity.

14 . The method of claim 11 , wherein the head motion comprises a yaw motion.

15 . The method of claim 11 , wherein the head motion comprises a pitch motion.

16 . The method of claim 12 , wherein the dispersion threshold is less than or equal to 10 degrees.

17 . The method of claim 12 , wherein the dispersion threshold is determined by a neural network model trained by historic rotation data.

18 . The method of claim 11 , wherein the sensor orientation is defined by a sensor x-axis, a sensor y-axis, and a sensor z-axis.