Beamforming Coefficients for Speech Recognition in Noisy Environments

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Solution Overview

Problem

Existing voice-controlled devices face challenges in accurately recognizing speech in noisy home environments due to poor signal-to-noise ratios, as they lack effective methods to selectively focus on user speech while attenuating background noise.

Innovation Solution

The implementation of beamforming techniques that apply pre-calculated or on-demand beamformer coefficients to create beampatterns, which selectively focus on user speech by enhancing specific lobes of the audio signal, improving signal-to-noise ratios and enhancing processing resources for echo cancellation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If beamforming techniques are applied to selectively focus on user speech, then speech recognition accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvespeech recognition accuracyVSAvoidbeamforming processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs preliminary actions by pre-calculating beamformer coefficients for multiple potential user positions before speech occurs. These coefficients are stored and ready for rapid application when speech is detected, avoiding real-time calculation complexity while maintaining beamforming precision for accurate speech recognition.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system applies different beamforming coefficients to different spatial regions (lobes) based on where users are most likely to speak. By tailoring the beamforming characteristics to specific directions and positions, the system achieves high speech recognition accuracy in relevant areas without uniformly complex processing across all directions.

Inventive Principle:
Principle #3Local quality

2Reliability

If processing resources are devoted to enhancing specific lobes of audio signal, then signal-to-noise ratio is improved, but computational load increases

Engineering Contradiction:
Improvesignal-to-noise ratioVSAvoidcomputational energy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system applies enhanced processing only to specific lobes corresponding to directions where users are most likely to speak, rather than uniformly processing the entire audio spectrum. This localized approach improves signal-to-noise ratio for relevant speech while minimizing computational energy consumption in irrelevant directions.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system applies beamforming enhancement to a subset of lobes that are most likely to contain user speech, rather than processing all possible directions equally. This partial action approach achieves sufficient signal-to-noise ratio improvement for practical speech recognition while avoiding the excessive computational load of omnidirectional processing.

Inventive Principle:
Principle #16Partial or excessive action

3Speed

If pre-calculated beamformer coefficients are used, then processing speed is improved, but adaptability to different environments decreases

Engineering Contradiction:
Improvebeamforming processing speedVSAvoidenvironmental adaptability
Core Design Contradiction:
SpeedVSAdaptability or versatility

Solution Approach 1:

The system calculates and stores beamformer coefficients for multiple different environments and user positions in advance. These pre-calculated coefficient sets can be selected and applied based on the current environment, providing both fast processing speed through pre-computation and adaptability to different spatial configurations and acoustic conditions.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach significantly improves the accuracy of speech recognition by selectively amplifying user speech and attenuating background noise, leading to better automatic speech recognition results and more efficient use of processing resources.

Implementation Method 1

Beamforming is the process of applying a set of beamformer coefficients to the signal data to create beampatterns, or effective directions of gain or attenuation

Methodology Applied
Scientific EffectBeamforming: Acoustic Lens

Implementation Method 2

these volumes may be considered to result from constructive and destructive interference between signals from individual microphones in a microphone array

Methodology Applied
Scientific EffectConstructive and destructive interference: Interference

Data Source

PatentUS10249299B1Tailoring beamforming techniques to environments
Publication Date: 2019.04.02 AMAZON TECH INC
  • US10249299B1 patent drawing
  • US10249299B1 patent drawing
  • US10249299B1 patent drawing

AI summary

Techniques for tailoring beamforming techniques to environments such that processing resources may be devoted to a portion of an audio signal corresponding to a lobe of a beampattern that is most likely to contain user speech. The techniques take into account both acoustic characteristics of an environment and heuristics regarding lobes that have previously been found to include user speech.