Microphone Array Reflection Filtering for Accurate Audio Direction
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Solution Overview
Problem
Computing devices with microphone arrays face challenges in accurately distinguishing between direct audio from a user and reflections of that audio, leading to potential misdirection of actions or movements, as existing beamforming techniques may not adequately differentiate between the two based on time and energy differences.
Innovation Solution
The implementation of a system that processes audio data from multiple microphones using techniques such as beamforming, cross-correlation, and power spectral analysis to determine the direction of arrival of audio signals, identifying reflections by comparing arrival times and energy levels, and discarding them to focus on direct user audio for further processing and action.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If beamforming techniques are used to process audio data from multiple microphones, then the device can determine the direction of audio sources, but it cannot adequately differentiate between direct audio and reflections based on time and energy differences
Solution Approach 1:
The patent segments the audio signal processing into distinct stages: initial beamforming to identify potential audio sources, followed by a separate reflection detection stage that analyzes time and energy characteristics. This segmentation allows the system to first locate audio sources and then filter out reflections, resolving the contradiction between direction determination and source differentiation.
Solution Approach 2:
The patent introduces an intermediary reflection detection mechanism that acts as a mediator between the beamforming output and the final audio source identification. This intermediary layer analyzes temporal and energetic properties of audio signals to distinguish direct sounds from reflections, thereby improving reliability without compromising direction determination accuracy.
2Productivity
If the device processes all detected audio signals including reflections, then it can respond to all audio events, but it may misdirect actions or movements due to inaccurate source localization
Solution Approach 1:
The patent applies preliminary action by performing reflection detection and filtering before the device executes directional responses. The system pre-processes audio signals to identify and eliminate reflections, ensuring that subsequent directional actions are based only on direct audio sources, thus maintaining both high response coverage and accurate localization.
Solution Approach 2:
The patent extracts and removes reflection components from the audio signal processing pipeline. By specifically identifying temporal and energy characteristics of reflections and extracting them from the overall audio input, the system maintains comprehensive response coverage while eliminating sources of localization error.
3Device complexity
If existing beamforming techniques are used without reflection detection, then the device complexity is lower, but the interaction efficiency and accuracy deteriorate due to misdirection
Solution Approach 1:
The patent implements dynamic processing by adapting the audio analysis based on detected signal characteristics. The system dynamically adjusts between processing direct audio and processing reflected audio based on temporal and energy analysis, allowing efficient interaction without requiring permanently complex processing for all scenarios.
Solution Approach 2:
The patent changes key parameters such as time thresholds and energy level thresholds to differentiate between direct audio and reflections. By adjusting these parameters dynamically based on environmental conditions, the system achieves high interaction efficiency without requiring permanently complex processing architecture.
Data Source
AI summary
A device capable of autonomous motion may move in response to a user speaking an utterance, such as a command. Before moving, the device processes audio data received from a microphone array to identify different audio signals arriving at the device from different directions. Based on properties of the audio signals, the device determines which of the audio signals are merely reflections of other audio.