Robust active noise cancelling at the eardrum
Disclosed herein, among other things, are systems and methods for active noise cancellation (ANC) for hearing device applications. A method includes measuring a receiver-to-inward-facing microphone response during an in-situ calibration stage for the hearing device, estimating a receiver-to-eardrum transfer function using the measured receiver-to-inward-facing microphone response, and measuring an outward-facing microphone to inward-facing microphone transfer function for an external noise sound field during run-time operation of the hearing device. The method also includes estimating an inward-facing microphone to eardrum transformation for the external noise sound field in the inward-facing microphone using the measured outward-facing microphone to inward-facing microphone transfer function, computing an ANC controller using the estimated receiver-to-eardrum transfer function and the estimated inward-facing microphone to eardrum transformation, and cancelling acoustic noise for the hearing device using the ANC controller.
1 . A method for active noise cancellation (ANC) for a hearing device including a receiver, an inward-facing microphone, and an outward-facing microphone, the method comprising:
measuring a receiver-to-inward-facing microphone response during an in-situ calibration stage for the hearing device;
estimating a receiver-to-eardrum transfer function using the measured receiver-to-inward-facing microphone response;
measuring an outward-facing microphone to inward-facing microphone transfer function for an external noise sound field during run-time operation of the hearing device;
estimating an inward-facing microphone to eardrum transformation for the external noise sound field in the inward-facing microphone using the measured outward-facing microphone to inward-facing microphone transfer function;
computing an ANC controller using the estimated receiver-to-eardrum transfer function and the estimated inward-facing microphone to eardrum transformation; and
cancelling acoustic noise for the hearing device using the ANC controller.
2 . The method of claim 1 , wherein computing the ANC controller includes using a computed variability of the estimated receiver-to-eardrum transfer function and the estimated inward-facing microphone to eardrum transformation.
3 . The method of claim 2 , further comprising:
updating internal models of acoustic paths within the hearing device using the computed variability of the estimated receiver-to-eardrum transfer function and the estimated inward-facing microphone to eardrum transformation.
4 . The method of claim 1 , further comprising:
updating internal models of acoustic paths within the hearing device using the estimated receiver-to-eardrum transfer function and the estimated inward-facing microphone to eardrum transformation.
5 . The method of claim 1 , further comprising logging the receiver-to-inward-facing microphone response and the outward-facing microphone to inward-facing microphone transfer function in an external storage location.
6 . The method of claim 5 , wherein the external storage location includes cloud storage.
7 . The method of claim 1 , further comprising wirelessly communicating with an external device to transfer data to or from the external device.
8 . The method of claim 7 , wherein wirelessly communicating with the external device includes using a Bluetooth® or Bluetooth® Low Energy (BLE) transceiver.
9 . The method of claim 7 , wherein wirelessly communicating with the external device includes wirelessly communication with a smart phone.
10 . The method of claim 1 , wherein the hearing device includes a hearing aid.
11 . A hearing device, comprising:
a receiver;
an inward-facing microphone;
an outward-facing microphone;
a memory; and
one or more processors programmed to:
measure a receiver-to-inward-facing microphone response during an in-situ calibration stage for the hearing device;
estimate a receiver-to-eardrum transfer function using the measured receiver-to-inward-facing microphone response;
measure an outward-facing microphone to inward-facing microphone transfer function for an external noise sound field during run-time operation of the hearing device;
estimate an inward-facing microphone to eardrum transformation for the external noise sound field in the inward-facing microphone using the measured outward-facing microphone to inward-facing microphone transfer function;
compute an ANC controller using the estimated receiver-to-eardrum transfer function and the estimated inward-facing microphone to eardrum transformation; and
cancel acoustic noise for the hearing device using the ANC controller.
12 . The hearing device of claim 11 , wherein the receiver-to-inward-facing microphone response and the outward-facing microphone to inward-facing microphone transfer function are logged in an external storage location.
13 . The hearing device of claim 12 , wherein the external storage location includes cloud storage.
14 . The hearing device of claim 11 , further comprising a wireless transceiver configured to communicate with an external device.
15 . The hearing device of claim 14 , wherein the wireless transceiver includes a Bluetooth® or Bluetooth® Low Energy (BLE) transceiver.
16 . The hearing device of claim 14 , wherein the external device includes a smart phone.
17 . The hearing device of claim 11 , wherein the hearing device includes a hearing aid.
18 . The hearing device of claim 11 , wherein, to compute the ANC controller, the one or more processors are programmed to use a computed variability of the estimated receiver-to-eardrum transfer function and the estimated inward-facing microphone to eardrum transformation.
19 . The hearing device of claim 11 , wherein the one or more processors are further programmed to:
update internal models of acoustic paths within the hearing device using the estimated receiver-to-eardrum transfer function and the estimated inward-facing microphone to eardrum transformation.
20 . A hearing device, comprising:
a receiver;
an inward-facing microphone;
an outward-facing microphone:
a memory; and
one or more processors programmed to:
measure a receiver-to-inward-facing microphone response during an in-situ calibration stage for the hearing device;
estimate a receiver-to-eardrum transfer function using the measured receiver-to-inward-facing microphone response;
measure an outward-facing microphone to inward-facing microphone transfer function for an external noise sound field during run-time operation of the hearing device;
estimate an inward-facing microphone to eardrum transformation for the external noise sound field in the inward-facing microphone using the measured outward-facing microphone to inward-facing microphone transfer function;
compute an ANC controller using the estimated receiver-to-eardrum transfer function and the estimated inward-facing microphone to eardrum transformation and a computed variability of the estimated receiver-to-eardrum transfer function and the estimated inward-facing microphone to eardrum transformation;
cancel acoustic noise for the hearing device using the ANC controller; and
update internal models of acoustic paths within the hearing device using the computed variability of the estimated receiver-to-eardrum transfer function and the estimated inward-facing microphone to eardrum transformation.