Wind noise reduction by microphone placement

Patent metadata

Field	Value
Publication number	US-11245982-B2
Application number	US-202016907849-A
Country	US
Kind code	B2
Filing date	Jun 22, 2020
Priority date	Jun 22, 2020
Publication date	Feb 8, 2022
Grant date	Feb 8, 2022

Abstract

An image capture device includes a housing having a lens snout protruding from a front housing surface. A front microphone is mounted below the lens snout. A top microphone is mounted under a top housing surface. The top microphone is positioned to receive direct freestream air flow at a first pitched forward angle. The front microphone is positioned to receive turbulent air flow at a second pitched forward angle. The second pitched forward angle is greater than or equal to the first pitched forward angle. An audio processor receives a first audio signal and a second audio signal from the top microphone and front microphone, respectively. The audio processor generates frequency sub-bands from the first and second audio signals. The audio processor selects the frequency sub-bands with the lowest noise metric and combines them to generate an output audio signal.

First claim

What is claimed is:

1. An image capture device, comprising:
a housing having a top housing surface, a front housing surface, and two side housing surfaces;
a lens snout protruding from the front housing surface;
a front microphone mounted within the housing behind the front housing surface and below the lens snout;
a top microphone mounted within the housing under the top housing surface;
a drainage microphone mounted within the housing behind one of the side housing surfaces, wherein the drainage microphone is positioned less than 30 degrees from the front microphone relative to a horizontal axis of the housing; and
an audio processor comprising a memory that is configured to store instructions that when executed cause the audio processor to generate an output audio signal,
wherein the top microphone is located at a position under the top housing surface to receive direct freestream air flow when the housing is positioned in a pitched forward orientation at a first pitched forward angle relative to a vertical axis, and
wherein the front microphone is located at a position under the front housing surface to receive turbulent air flow from the lens snout when the housing is positioned in the pitched forward orientation at a second pitched forward angle relative to the vertical axis.

2. The image capture device of claim 1 , wherein the second pitched forward angle is greater than or equal to the first pitched forward angle.

3. The image capture device of claim 1 , wherein the front microphone is positioned below the lens snout.

4. The image capture device of claim 1 , wherein the top microphone is biased within the housing under the top housing surface towards the front housing surface.

5. The image capture device of claim 1 ,
wherein the audio processor is configured to execute the instructions stored in the memory so that when the instructions are executed, the audio processor is configured to:
receive a first audio signal from the front microphone;
for frequency sub-bands, generate first frequency sub-band signals from the first audio signal;
receive a second audio signal from the top microphone;
for the frequency sub-bands, generate second frequency sub-band signals from the second audio signal;
receive a third audio signal from the drainage microphone;
for the frequency sub-bands, generate third frequency sub-band signals from the third audio signal;
for the respective frequency sub-bands, select one of the first frequency sub-band signals, the second frequency sub-band signals, or the third frequency sub-band signals having the lowest noise metric; and
combine the selected sub-band signals to generate the output audio signal.

6. The image capture device of claim 1 , wherein when the drainage microphone includes a channel entrance surface area to channel volume ratio that moves audio wave resonance outside of a 500 Hz to 9 kHz frequency range.

7. The image capture device of claim 1 , wherein the memory stores instructions that when executed cause the audio processor to:
perform beamforming on the first frequency sub-band signals and the third frequency sub-band signals to output a stereo audio stream.

8. An image capture device, comprising:
a housing having a first housing surface, a second housing surface orthogonal to the first housing surface, and a third housing surface orthogonal to the first housing surface and the second housing surface;
a protruding feature protruding from the first housing surface;
a first microphone mounted within the housing behind the first housing surface and adjacent to the protruding feature;
a second microphone mounted within the housing under the second housing surface;
a third microphone mounted within the housing behind the third housing surface, wherein the third microphone comprises a drainage microphone that is positioned on a side housing surface of the housing and is biased towards a second housing surface of the housing at an angle of less than 30 degrees from the second microphone relative to a horizontal axis of the housing; and
an audio processor comprising a memory configured to store instructions that when executed cause the audio processor to generate an output audio signal,
wherein the first microphone is located at a position under the first housing surface to receive direct freestream air flow when the housing is positioned in a pitched orientation with a first pitched angle; and
wherein the second microphone is located at a position under the second housing surface to receive turbulent air flow from the protruding feature when the housing is positioned in the pitched orientation with a second pitched angle.

9. The image capture device of claim 8 , wherein the second pitched angle is greater than or equal to the first pitched angle.

10. The image capture device of claim 8 , wherein the second microphone is positioned below the protruding feature.

11. The image capture device of claim 8 , wherein when the first microphone is biased within the housing under the first housing surface towards the second housing surface.

12. The image capture device of claim 8 ,
wherein the memory stores instructions that when executed cause the audio processor to:
receive a third audio signal from the third microphone;
for the frequency sub-bands, generate third frequency sub-band signals from the third audio signal;
for the respective frequency sub-bands, select one of the first frequency sub-band signals, the second frequency sub-band signals, or the third frequency sub-band signals having the lowest noise metric; and
combine the selected sub-band signals to generate the output audio signal.

13. The image capture device of claim 8 , wherein the memory stores instructions that when executed cause the audio processor to perform beamforming on the first frequency sub-band signals and the third frequency sub-band signals to output a stereo audio stream.

14. A method of reducing wind noise in an image capture device, comprising:
receiving, by an audio processor, a first audio signal from a first microphone mounted above a protruding feature extending from a first housing surface of a housing of an image capture device, the first microphone mounted to receive direct freestream air flow when the housing is positioned in a pitched forward orientation at a first pitched forward angle;
receiving, by the audio processor, a second audio signal from a second microphone mounted below the protruding feature, the second microphone mounted to receive turbulent air flow when the housing is positioned in the pitched forward orientation at a second pitched forward angle, the second pitched forward angle being greater than or equal to the first pitched forward angle;
receiving, by the audio processor, a third audio signal from a third microphone that is a drainage microphone mounted within the housing behind one of the side housing surfaces and is positioned less than 30 degrees from the second microphone relative to a horizontal axis of the housing;
generating, by the audio processor, for frequency sub-bands, first frequency sub-band signals from the first audio signal;
generating, by the audio processor, for the frequency sub-bands, second frequency sub-band signals from the second audio signal;
generating, by the audio processor, for the frequency sub-bands, third frequency sub-band signals from the third audio signal;
selecting, by the audio processor, for respective frequency sub-bands, one of the first frequency sub-band signals, the second frequency sub-band signals, or the third sub-band signals having a lowest noise metric; and
combining, by the audio processor, t

Assignees

• Gopro Inc

Inventors

• Tisch Erich
• Dick Timothy
• Penrod Eric

Classifications

• H04R2430/03

  Synergistic effects of band splitting and sub-band processing · CPC title

• H04S2400/15

  Aspects of sound capture and related signal processing for recording or reproduction · CPC title

• H04R1/04

  Structural association of microphone with electric circuitry therefor (in electric hearing aids H04R25/00) · CPC title

• H04R2410/07

  Mechanical or electrical reduction of wind noise generated by wind passing a microphone · CPC title

• H04R2499/11

  Transducers incorporated or for use in hand-held devices, e.g. mobile phones, PDA's, camera's · CPC title