ACTIVE NOISE CANCELLATION FOR WEARABLE HEAD DEVICE
Examples of the disclosure describe systems and methods for reducing audio effects of fan noise, specifically, for a wearable system. A method wherein operating a fan of a wearable head device: detecting, with a microphone of the wearable head device, noise generated by the fan generating a fan reference signal. wherein the fan reference signal represents at least one of a speed of the fan, a mode of the fan, a power output of the fan, and a phase of the fan; deriving a transfer function based on the fan reference signal and based further on the detected noise of the fan: generating a compensation signal based on the transfer function: and while operating the fan of the wearable head device, outputting, by a speaker of the wearable head device, an anti-noise signal, wherein the anti-noise signal is based on the compensation signal.
1 . A method comprising:
operating a fan of a wearable head device in a first state;
detecting, with a first microphone of the wearable head device, a first noise generated by the fan operating in the first state;
while operating the fan of the wearable head device in the first state, outputting, by a speaker of the wearable head device, a first anti-noise signal to at least partially cancel the first noise;
detecting a change in operation of the fan of the wearable head device from the first state to a second state in which the fan generates a second noise; and
while operating the fan of the wearable head device in the second state, outputting, by the speaker of the wearable head device, a second anti-noise signal, different than the first anti-noise signal to at least partially cancel the second noise.
2 . The method of claim 1 , wherein the method further comprises deriving a first transfer function based on the first noise and generating the first anti-noise signal at least partially based on the first transfer function.
3 . The method of claim 2 , wherein:
the wearable head device comprises an acoustic echo canceller;
deriving the first transfer function is performed via the acoustic echo canceller; and generating the first anti-noise signal is performed via the acoustic echo canceller.
4 . The method of claim 2 , wherein the first transfer function comprises a fan-to-microphone transfer function.
5 . The method of claim 2 , wherein the first transfer function comprises a fan-to-ear transfer function.
6 . The method of claim 1 , wherein:
the second anti-noise signal is an output of a deep neural network (DNN) based subtraction based on a recorded sound; and
the second anti-noise signal is configured to reduce a level of noise associated with the recorded sound.
7 . The method of claim 1 , wherein the first anti-noise signal is at least partially based on a fan reference signal representing at least one of a speed of the fan, a mode of the fan, a power output of the fan, and a phase of the fan.
8 . The method of claim 1 , wherein the first anti-noise signal reduces a level of the first noise received at the first microphone.
9 . The method of claim 1 , wherein the first anti-noise signal reduces a level of the first noise received at an ear canal of a user of the wearable head device.
10 . The method of claim 1 , wherein the second anti-noise signal reduces a level of second noise received at a second microphone.
11 . The method of claim 1 , wherein the second anti-noise signal reduces a level of the second noise received at an ear canal of a user of the wearable head device.
12 . The method of claim 1 , wherein the first noise comprises a frequency in a range of 0 to 4 kHz.
13 . The method of claim 1 , wherein the second noise comprises a frequency in a range of 0 to 4 kHz.
14 . The method of claim 1 , wherein each of the first noise and the second noise comprises a frequency in a range of 0 to 4 kHz.
15 . The method of claim 1 , wherein operating the fan comprises revolving the fan at a rate of 800-5000 revolutions per minute.
16 . The method of claim 1 , wherein the first anti-noise signal comprises a periodic signal.
17 . The method of claim 1 , further comprising:
detecting a speaker feed signal from the speaker; and
in response to detecting the speaker feed signal, reducing a level of the speaker feed signal.
18 . The method of claim 1 , further comprising aligning a phase of the first anti-noise signal with a phase of the first noise generated by the fan.
19 . The method of claim 1 , wherein the first anti-noise signal comprises signals having frequencies below 4 kHz.