Variable Microphone Array Orientation Voice Processing

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Solution Overview

Problem

Existing dual microphone voice processing systems in headsets face challenges with variable microphone array orientations relative to the user's mouth, leading to reduced voice quality and increased background noise interference, especially in noisy environments.

Innovation Solution

A method and integrated circuit for an audio device with a variable microphone array that computes normalized cross-correlation functions to determine the optimal orientation of the microphone array, dynamically modifying voice processing parameters to preserve desired speech while reducing interfering sounds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If traditional dual microphone algorithms with fixed array orientation are used, then voice processing is simplified, but voice quality deteriorates when microphone orientation changes relative to user's mouth

Engineering Contradiction:

Improvevoice processing simplicityVSAvoidvoice quality

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent implements dynamic beamforming that adapts to changing microphone array orientations by continuously tracking the direction of arrival of speech signals. The system transitions from static fixed-orientation algorithms to dynamic algorithms that adjust beamforming parameters in real-time based on detected speech direction, thereby maintaining voice quality regardless of headset position or user movement.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system employs feedback mechanisms by analyzing the received audio signals to determine the actual orientation of the microphone array relative to the user's mouth. This feedback information is then used to adjust the beamforming parameters, creating a closed-loop system that automatically compensates for orientation changes and maintains optimal voice capture.

Inventive Principle:

Principle #23Feedback

2Volume of moving object

If microphones are placed close to receiver in earbud to save space, then device size is reduced, but echo-related problems increase

Engineering Contradiction:

Improveheadset sizeVSAvoidecho interference

Core Design Contradiction:

Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent introduces an acoustic echo canceller as an intermediary component that processes the audio signals to remove echo interference. This canceller uses reference signals from the microphones and applies adaptive filtering to subtract the echo components from the received signals, thereby eliminating the harmful echo effect while allowing the microphones to remain in close proximity to the receiver.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If control box position is moved manually close to mouth for increased signal-to-noise ratio, then noise reduction improves, but device adaptability decreases

Engineering Contradiction:

Improvebackground noise levelVSAvoidcontrol box positioning flexibility

Core Design Contradiction:

Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The system performs self-service by automatically determining the direction of arrival of speech signals using beamforming and cross-correlation techniques. This eliminates the need for manual user intervention to position the control box optimally, as the system autonomously identifies and tracks the speech source direction, continuously optimizing noise reduction performance without requiring user action.

Inventive Principle:

Principle #25Self-service

4Object-affected harmful factors

If dual microphone array is used in control box, then noise reduction performance improves, but orientation tracking complexity increases

Engineering Contradiction:

Improvenoise reduction performanceVSAvoidorientation tracking complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent segments the complex orientation tracking problem into simpler sub-tasks by implementing a bank of beamformers, each optimized for a specific directional sector. This segmentation allows the system to process different spatial regions independently, reducing the overall computational complexity while maintaining accurate orientation tracking capability across the full spatial range.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS10297267B2Dual microphone voice processing for headsets with variable microphone array orientation

Publication Date: 2019.05.21 CIRRUS LOGIC INC

AI summary

In accordance with embodiments of the present disclosure, a method for voice processing in an audio device having an array of a plurality of microphones wherein the array is capable of having a plurality of positional orientations relative to a user of the array, is provided. The method may include periodically computing a plurality of normalized cross-correlation functions, each cross-correlation function corresponding to a possible orientation of the array with respect to a desired source of speech, determining an orientation of the array relative to the desired source based on the plurality of normalized cross-correlation functions, detecting changes in the orientation based on the plurality of normalized cross-correlation functions, and responsive to a change in the orientation, dynamically modifying voice processing parameters of the audio device such that speech from the desired source is preserved while reducing interfering sounds.