Audio system that uses an optical microphone
An audio system including an optical microphone and an audio controller. The optical microphone includes a light source and a detector. In some embodiments, the light source illuminates skin of a user. Alternatively the optical microphone also includes a membrane, and the light source illuminates a portion of the membrane. Sounds from a local area cause vibrations in the skin (or vibrations in the membrane). The detector may be in an interferometric configuration or a non-interferometric configuration with the light source. The audio controller monitors the vibrations of the skin (or membrane) using signal output from the detector, and measures the sounds using the monitored vibrations.
1 . An audio system comprising:
an optical microphone, the optical microphone comprising:
a light source configured to emit light, the light including a reference beam and a sensing beam, the light source configured to illuminate skin of a user with the sensing beam, the sensing beam being directed to a location on the skin that vibrates in response to a voice of the user conducted through tissue; and
a detector in an interferometric configuration with the light source such that the detector is configured to detect a mixed signal, the mixed signal corresponding to the reference beam that is mixed with a portion of the sensing beam that is reflected by the skin, wherein the mixed signal includes (1) a dynamic high frequency component that changes as a function of a distance between the illuminated skin of the user and the detector, and (2) a modulation component;
an audio controller configured to filter out at least a portion of the dynamic high frequency component corresponding to motion noise and measure sounds corresponding to the voice of the user conducted through tissue using the dynamic high frequency component of the mixed signal;
a second optical microphone comprising a second light source and a second detector, and optically isolated from the optical microphone by an optical block; and
an optical element coupled to the optical microphone, the optical block, and the second optical microphone.
2 . The audio system of claim 1 , wherein the interferometric configuration is such that the light source and the detector form at least one of a self-mixing interferometer, a Michelson interferometer, a low coherence interferometric system, a laser doppler vibrometer, or some other type of interferometric system.
3 . The audio system of claim 1 , wherein the light source abuts the detector, and the audio system further comprises an optical element configured to:
split the light emitted from the light source into the reference beam and the sensing beam; and
direct the sensing beam towards the skin and direct the reference beam towards the detector.
4 . The audio system of claim 1 ,
wherein the second optical microphone is optically isolated from the optical microphone by the optical block, the second optical microphone comprising:
the second light source configured to emit light, the light including a second reference beam and a second sensing beam, the light source configured to illuminate the skin of the user with the sensing beam, and
a second detector in the interferometric configuration with the second light source such that the second detector is configured to detect a second mixed signal, the second mixed signal corresponding to the second reference beam that is mixed with a portion of the second sensing beam that is reflected by the skin; and
wherein the audio system further comprises the optical element coupled to the optical microphone, the optical block, and the second optical microphone, the optical element configured to:
split the light emitted from the light source into the reference beam and the sensing beam and the light emitted from the second light source into the second reference beam and the second sensing beam,
direct the sensing beam and the second sensing beam to the skin,
redirect the reference beam reflected by the skin towards the detector, and redirect the second reference beam reflected by the skin towards the second detector.
5 . The audio system of claim 1 , wherein the detector and the light source are separated from each other by a threshold distance.
6 . The audio system of claim 1 , wherein the optical microphone is on a headset that includes a nose pad, and the optical microphone is integrated into the nose pad and the light source is configured to illuminate the skin of a nose of the user with the sensing beam.
7 . The audio system of claim 1 , wherein the optical microphone is on a headset that includes a frame, and the optical microphone is integrated into the frame and the light source is configured to illuminate the skin on a face of the user with the sensing beam.
8 . The audio system of claim 7 , the audio system further comprising a second optical microphone that is integrated into a different location on the frame than the optical microphone, the second optical microphone configured to Illuminate with a second sensing beam a different portion of the skin on the face of the user than the optical microphone.
9 . The audio system of claim 1 , wherein the optical microphone is on a headset, the audio system further comprising:
a microphone array on the headset, the microphone array configured to detect the sounds from a local area,
wherein the audio controller is further configured to calibrate the optical microphone using the detected sounds.
10 . The audio system of claim 1 , wherein the optical microphone is on a headset, the audio system further comprising:
a microphone array on the headset, the microphone array configured to detect the sounds from a local area,
wherein the audio controller is further configured to enhance the sounds measured using the mixed signal detected by the detector of the optical microphone based in part on the sounds detected by the microphone array.
11 . The audio system of claim 1 , wherein the audio controller is further configured to determine an expression of a face of the user based in part on the measured sounds.
12 . The audio system of claim 1 , wherein the optical microphone is on a headset and the audio controller is further configured to:
identify noise in the measured sounds; generate a sound filter to suppress the identified noise; and
apply the sound filter to modify an audio signal that corresponds to audio content, wherein the audio system further comprises
a transducer array integrated into the headset, the transducer array configured to present the modified audio signal to the user as modified audio content, the modified audio content including the audio content and a suppression component that suppress the noise.
13 . The audio system of claim 1 , wherein the optical microphone is on a headset, the audio system further comprising:
a microphone array on the headset, the microphone array configured to detect the sounds from a local area, the sounds from the local area including a voice of the user of the audio system;
wherein the audio controller is further configured to:
identify the voice of the user in the detected sounds using the measured sounds; and
update a sound filter based on the identified voice of the user,
wherein audio content is modified using the updated sound filter, and the modified audio content is presented by at least one audio system.
14 . The audio system of claim 13 , wherein the updated sound filter enhances the voice of the user, and the audio controller is further configured to:
modify the audio content with the updated sound filter, wherein the modified audio content enhances the voice of the user; and
provide the modified audio content to a second audio system, wherein the second audio system presents the modified audio content.
15 . The audio system of claim 13 , wherein the updated sound filter enhances the voice of the user, and the audio controller is further configured to:
modify the audio content with the updated sound filter, wherein the modified audio content enhances the voice of the user;
determine that the modified audio content includes a command; and
perform an action in accordance with the command.
16 . The audio system of claim 1 , further comprising:
a waveguide structure coupled to the light source and the detector and including an interferometer of the interferometric configuration; and
a grating coupler coupled to the waveguide structure and configured to (1) transmit the sensing beam from the waveguide structure towards the skin of the user and (2) couple the portion of the sensing beam that is reflected by the skin into the waveguide structure and towards the interferometer of the waveguide structure.
17 . The audio system of claim 16 , wherein the waveguide structure includes an optical amplifier.
18 . The audio system of claim 1 , further comprising a vibrational damping structure between the optical microphone and a headset and configured to mitigate an effect on the optical microphone by vibrations from the headset.
19 . The audio system of claim 1 , wherein the audio controller is further configured to reconstruct high frequency content of the sounds that is attenuated by a body part of the user.
20 . An audio system comprising:
an optical microphone comprising:
a membrane configured to vibrate in response to a voice of a user conducted through tissue, the membrane being at least partially reflective;
a light source configured to emit light to illuminate a surface of the membrane, wherein sounds from a local area cause vibrations in at least a portion of skin of the user and the membrane; and
a detector in an interferometric configuration with the light source and configured to generate a measurement signal corresponding to at least a portion of light reflected by the surface of the membrane;
an audio controller configured to measure the sounds using the measurement signal;
a second optical microphone comprising a second light source and a second detector, and optically isolated from the optical microphone by an optical block; and
an optical element coupled to the optical microphone, the optical block, and the second optical microphone.