Microphone Audio Alignment Using Source-Based Delay Estimation

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Solution Overview

Problem

Existing audio signal processing systems struggle to temporally align audio signals captured by microphones positioned at different locations, leading to delays and jitter that hinder immersive audio experiences in mediated reality applications like virtual and augmented reality.

Innovation Solution

A method and apparatus for processing audio signals that account for spatial separation and transmission jitter by using a microphone array and local microphones positioned close to audio sources, determining delays, and ensuring sufficient signal lengths are available for temporal alignment, allowing for efficient memory usage and immersive audio rendering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If microphones are positioned at different locations to capture spatial audio, then spatial audio quality is improved, but temporal alignment accuracy deteriorates due to propagation delays

Engineering Contradiction:
Improvespatial audio qualityVSAvoidtemporal alignment accuracy
Core Design Contradiction:
Illumination intensityVSMeasurement precision

Solution Approach 1:

The system performs preliminary actions by making audio signals from multiple microphones available for a determined length of time before processing, allowing temporal alignment to compensate for propagation delays. This ensures that signals captured at different locations can be properly synchronized during rendering.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system changes the time parameter by determining appropriate signal lengths based on microphone positions and making signals available for those specific durations. This parameter adjustment enables accurate temporal alignment while maintaining spatial audio quality.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If audio signals are made available for longer durations to enable temporal alignment, then temporal alignment accuracy is improved, but memory usage increases

Engineering Contradiction:
Improvetemporal alignment accuracyVSAvoidmemory usage
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The system optimizes the time parameter by calculating specific signal lengths required for temporal alignment based on microphone positions and audio rendering requirements. This ensures signals are available for precisely the duration needed, avoiding excessive memory allocation while maintaining alignment accuracy.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system applies partial action by making audio signals available for only the necessary length of time required for temporal alignment, rather than storing them indefinitely. This optimized duration balances alignment accuracy with efficient memory resource usage.

Inventive Principle:
Principle #16Partial or excessive action

3Illumination intensity

If multiple microphones are used to capture audio from different locations, then spatial audio immersion is improved, but system complexity increases

Engineering Contradiction:
Improvespatial audio immersionVSAvoidsystem complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The system performs preliminary calculations to determine appropriate signal lengths based on microphone positions before audio rendering. This advance preparation simplifies the real-time processing by pre-establishing the temporal alignment parameters needed for multiple microphone inputs.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements a universal audio processing framework that handles multiple microphones with different positions using a unified approach. The same temporal alignment and signal length determination methods apply regardless of the number or arrangement of microphones, reducing overall system complexity.

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

Data Source

PatentEP3689001B1Processing audio signals
Publication Date: 2025.11.26 NOKIA TECHNOLOGIES OY
  • EP3689001B1 patent drawingFigure 1A~1B
  • EP3689001B1 patent drawingFigure 2A~2B
  • EP3689001B1 patent drawingFigure 3A~3B

AI summary

A method, apparatus (63) and computer program comprising: obtaining (60) a first audio signal from at least a first microphone (1) located at a first distance from an audio source (5A - 5C); obtaining (60) a local audio signal from a local microphone (3A - 3C) wherein the local microphone is located closer to the audio source (5A - 5C) than the first microphone (1); identifying (62) the audio source using the first audio signal and the local audio signal; using the identified audio source to determine (64) a delay between the first audio signal and the local audio signal: and using the determined delay to determine (66) the length of the first audio signal and the local audio signal to be made available for processing so as to enable temporal alignment of at least the first audio signal and the local audio signal.