Head-related transfer function determination using base stations

1. A system comprising:

a plurality of base stations, each base station located at a respective distinct static location within a local area and including a speaker configured to emit a test sound in accordance with calibration instructions;

a depth camera assembly configured to determine depth information describing a position of a head-mounted display (HMD) in the local area relative to the locations of the plurality of base stations;

a microphone configured to:

be placed in an ear canal of a user wearing the HMD, and

generate a respective audio sample from the test sound emitted by the speaker of each base station; and

a controller configured to:

determine the relative position of the HMD using the depth information;

generate the calibration instructions based on the relative position of the HMD; and

determine a head related transfer function (HRTF) based on the audio samples.

2. The system of claim 1 , wherein the microphone is coupled to the HMD.

3. The system of claim 1 , wherein the depth camera assembly comprises:

a light projector configured to provide structured light in a direction of the HMD;

an imaging device configured to capture images of the HMD and the plurality of base stations; and

a depth camera controller configured to determine the depth information using the captured images.

4. The system of claim 1 , wherein the determining of the HRTF comprises steps to:

determine a first transfer function based on audio samples generated by the microphone coupled to the HMD;

determine a second transfer function based on audio samples generated by the microphone coupled to the HMD worn by the user; and

compute the HRTF as a difference between the first transfer function and the second transfer function.

5. The system of claim 1 , wherein the test sounds comprise one or more logarithmic chirps.

6. The system of claim 1 , wherein the controller is further configured to:

populate a set of configurations, each configuration comprising the location of at least one base station;

for each configuration, instruct the speaker of the at least one base station to emit the test sound to obtain the audio samples from the microphone for the configuration; and

determine HRTFs based on the audio samples for the set of configurations.

7. The system of claim 6 , wherein the controller is further configured to:

determine an audio characterization configuration based on the HRTFs, the audio characterization configuration being a function to synthesize a binaural sound that seems to come from a particular point in a virtual space; and

synthesizing the binaural sound based on the audio characterization configuration.

8. A head-mounted display (HMD) comprising:

a microphone configured to:

be placed in an ear canal of a user wearing the HMD, and

generate respective audio samples from test sounds received from a plurality of base stations, each base station located at a respective distinct static location within a local area and including a speaker configured to emit a test sound in accordance with calibration instructions; and

a controller configured to:

determine depth information describing a position of the HMD in the local area relative to the locations of the plurality of base stations using images captured by a depth camera assembly,

determine the position of the HMD using the depth information,

generate the calibration instructions based on the relative position of the HMD, and

determine a head-related transfer function (HRTF) based on the audio samples.

9. The HMD of claim 8 , wherein the depth camera assembly comprises:

a light projector configured to provide structured light in a direction of the HMD; and

an imaging device configured to capture the images of the HMD and the plurality of base stations.

10. The HMD of claim 8 , wherein the determining of the HRTF comprises steps to:

determine a first transfer function based on audio samples generated by the microphone;

determine a second transfer function based on audio samples generated by the microphone worn by the user; and

compute the HRTF as a difference between the first transfer function and the second transfer function.

11. The HMD of claim 8 , wherein the test sounds comprise one or more logarithmic chirps.

12. The HMD of claim 8 , wherein the controller is further configured to:

populate a set of configurations, each configuration comprising the location of at least one base station;

for each configuration, instruct the speaker of the at least one base station to emit the test sound to obtain the audio samples from the microphone for the configuration; and

determine HRTFs based on the audio samples for the set of configurations.

13. The HMD of claim 12 , wherein the controller is further configured to:

determine an audio characterization configuration based on the HRTFs, the audio characterization configuration being a function to synthesize a binaural sound that seems to come from a particular point in a virtual space; and

synthesizing the binaural sound based on the audio characterization configuration.

14. A method comprising:

determining depth information describing a position of a head-mounted display (HMD) in a local area relative to a plurality of base stations, each base station located at a respective distinct static location within the local area;

determining the relative position of the HMD using the depth information;

generating calibration instructions based on the relative position of the HMD;

emitting test sounds in accordance with the calibration instructions from speakers of the plurality of base stations;

generating, by a microphone configured to be placed in an ear canal of a user wearing the HMD, respective audio samples from the test sounds emitted by the speakers;

determining a head-related transfer function (HRTF) based on the audio samples.

15. The method of claim 14 , wherein the microphone is coupled to the HMD.

16. The method of claim 14 , wherein the determining of the depth information comprises:

illuminating, by a light projector, the HMD with structured light, wherein the light projector is coupled to a first base station of the plurality of base stations;

capturing, by an imaging device, images of the HMD, wherein the imaging device is coupled to the first base station; and

determining the depth information based in part on the captured images.

17. The method of claim 14 , wherein the determining of the HRTF comprises:

determining a first transfer function based on audio samples generated by the microphone coupled to the HMD;

determining a second transfer function based on audio samples generated by the microphone coupled to the HMD worn by the user; and

computing the HRTF as a difference between the first transfer function and the second transfer function.

18. The method of claim 14 , wherein the test sounds comprise one or more logarithmic chirps.

19. The method of claim 14 , further comprising:

populating a set of configurations, each configuration comprising the location of at least one base station;

for each configuration, instructing the speaker of the at least one base station to emit the test sound to obtain the audio samples from the microphone for the configuration; and

determining HRTFs based on the audio samples for the set of configurations.

20. The method of claim 19 , further comprising:

determining an audio characterization configuration based on the HRTFs, the audio characterization configuration being a function to synthesize a binaural sound that seems to come from a particular point in a virtual space; and

synthesizing the binaural sound based on the audio characterization configuration.

21. The system of claim 1 , wherein the plurality of base stations includes a first base station and a second base station, and a speaker of the first base station and a speaker of the second base station are configured to emit at least one test sound simultaneously.