Audio Capture Beamforming Point Source Estimation

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Solution Overview

Problem

Existing audio capture systems face challenges in effectively extracting speech in noisy environments, particularly when the speaker is outside the reverberation radius, leading to speech distortion and suboptimal performance due to difficulties in distinguishing between echoes and diffuse background noise.

Innovation Solution

An audio capture apparatus comprising a microphone array, adaptive beamformers, and a point audio source estimator that generates a point audio source estimate by calculating time frequency tile difference measures between beamformed audio and noise reference signals, allowing for improved detection and estimation of point audio sources even outside the reverberation radius.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If beamforming is used to extract speech in noisy environments, then speech capture performance is improved, but speech distortion occurs when the speaker is outside the reverberation radius

Engineering Contradiction:

Improvespeech capture performanceVSAvoidspeech quality

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The system dynamically changes the beamforming parameters (beam width, direction, and depth) based on the detected presence of point audio sources. When a point source is detected, the beamformer adjusts to focus more narrowly on that source, improving speech quality for distant speakers while maintaining noise rejection capabilities.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The beamforming system transitions from a static configuration to a dynamic one where beam parameters are continuously adapted based on real-time audio analysis. The point audio source detector triggers beamformer reconfiguration, allowing the system to respond to changing acoustic environments and speaker positions.

Inventive Principle:

Principle #15Dynamics

2Object-affected harmful factors

If adaptive beamformers are used to focus on speech sources, then noise suppression is improved, but the system becomes sensitive to diffuse background noise when sources are distant

Engineering Contradiction:

Improvenoise suppressionVSAvoidnoise sensitivity

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The system applies different processing qualities to different spatial regions and frequency ranges. The point audio source detector identifies specific directional sources, and the beamformer then applies localized beamforming parameters specifically targeted at those sources, while diffuse noise from other directions is handled with broader suppression techniques.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The audio processing is segmented into distinct functional blocks: the point audio source detector separately identifies point sources from diffuse noise, and the beamformer then processes these segmented components differently. This segmentation allows independent optimization of point source enhancement and diffuse noise suppression.

Inventive Principle:

Principle #1Segmentation

3Productivity

If the beamformer adapts to audio sources in reverberant environments, then speech extraction is improved, but adaptation becomes suboptimal when speakers are outside the reverberation radius

Engineering Contradiction:

Improvespeech extraction efficiencyVSAvoidsource localization accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The point audio source detector acts as an intermediary between the microphone array and the beamformer. It pre-processes the audio signals to identify and characterize point audio sources, providing enhanced input information to the beamformer that improves its ability to accurately localize and extract speech from distant speakers in reverberant environments.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Device complexity

If fixed beam configurations are used for audio capture, then system complexity is reduced, but the system cannot adapt to different speaker positions and environments

Engineering Contradiction:

Improvesystem complexityVSAvoidenvironmental adaptation

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The beamforming system performs self-adaptation through the point audio source detector that automatically identifies speech sources and triggers beamformer reconfiguration without external control. The system serves itself by detecting its own operational needs and adjusting parameters accordingly, maintaining low complexity while achieving high adaptability.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS10887691B2Audio capture using beamforming

Publication Date: 2021.01.05 KONINKLIJKE PHILIPS NV

AI summary

An audio capture apparatus comprises a microphone array (301) and a beamformer (303) arranged to generate a beamformed audio output signal and a noise reference signal. A first and second transformer (309, 311) generates a first and second frequency domain signal from a frequency transform of the beamformed audio output signal and noise reference signal respectively. A difference processor (313) generates time frequency tile difference measures which for a given frequency is indicative of a difference between a monotonic function of a norm (magnitude) of a time frequency tile value of the first frequency domain signal and a monotonic function of a norm of a time frequency tile value of the second frequency domain signal for the first frequency. An estimator (315) generates an estimate indicative of whether the audio output signal comprises a point audio source in response to a combined difference value for time frequency tile difference measures for frequencies above a frequency threshold.