Microphone Array Direction from Phase-Offset Sinusoidal Signals

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Solution Overview

Problem

Existing audio systems struggle to accurately determine the 3D position of sound sources in environments with interference, leading to suboptimal sound reproduction and listener discomfort due to noise sensitivity and environmental distortions.

Innovation Solution

A method using cross-correlations on sound signals received by an array of microphones to create sinusoidal functions with phase offsets, combined with Bartlett's method, to compute azimuth and elevation values, improving accuracy and comfort by using white or pink noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If sinusoidal signals are used for direction determination, then measurement precision is improved, but listener comfort deteriorates due to noise sensitivity and environmental distortions

Engineering Contradiction:

Improvedirection determination accuracyVSAvoidnoise sensitivity and environmental distortions

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the signal type parameter from sinusoidal to white or pink noise. This parameter change resolves the contradiction by providing signals that are less sensitive to environmental distortions while maintaining direction determination accuracy through cross-correlation processing.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent substitutes the traditional sinusoidal signal generation approach with a noise-based signal approach. By using white or pink noise instead of sinusoidal signals, the system replaces a mechanically sensitive measurement method with a more robust noise-based method that maintains precision while reducing harmful environmental effects.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Object-affected harmful factors

If white or pink noise is used instead of sinusoidal signals, then listener comfort is improved, but measurement precision deteriorates due to signal complexity

Engineering Contradiction:

Improvelistener comfortVSAvoiddirection determination accuracy

Core Design Contradiction:

Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The patent introduces cross-correlation processing as an intermediary mechanism between the noise signals and direction determination. This intermediary process extracts precise directional information from the complex noise signals, resolving the contradiction by maintaining measurement precision while using comfortable noise-based signals.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent substitutes traditional sinusoidal signal processing with a noise-based approach enhanced by cross-correlation. This substitution replaces a simple but environmentally sensitive method with a more complex signal type that is compensated for by advanced processing, thereby improving listener comfort while maintaining precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If cross-correlations are computed on received signals, then direction determination robustness is improved, but computational complexity increases

Engineering Contradiction:

Improvedirection determination robustnessVSAvoidcomputational complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies cross-correlation processing as a preliminary step to extract relative times of arrival before final direction determination. This preliminary action prepares the data in a form that enhances robustness while organizing the computational workload, making the overall process more reliable despite increased computational requirements.

Inventive Principle:

Principle #10Preliminary action

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

Accurately determines sound source positions with enhanced precision and listener comfort, allowing for dynamic audio system adjustments and compliance with audio standards.

Implementation Method 1

emitting a sound by way of the at least one sound source and recording the sound signals received by an array of microphones

Methodology Applied

Scientific EffectAcoustic wave propagation: Sound

Implementation Method 2

executing cross-correlations between the received signals in order to deduce the relative times of arrival therefrom

Methodology Applied

Scientific EffectCross-correlation:

Implementation Method 3

creating a sinusoidal function of time having a determined frequency and a phase offset dependent on the relative times of arrival

Methodology Applied

Scientific EffectPhase offset: Phase Modulation

Data Source

PatentUS12407985B2Method for determining a direction of propagation of a sound source by creating sinusoidal signals from sound signals received by microphones

Publication Date: 2025.09.02 IMMERSIVE AUDIO TECH FRANCE

AI summary

A method for determining a direction of at least one sound source using an audio system capturing by an array of microphones sound emitted by the at least one sound source. The method includes: emitting a sound by way of the at least one sound source; recording sound signals received by the array of microphones; executing cross-correlations between the received signals in order to deduce relative times of arrival therefrom; creating a sinusoidal function of time having a determined frequency and a phase offset dependent on the relative times of arrival; and computing to determine a direction value of the sound source in a spatial reference frame defined by the array of microphones, using the values computed from the sinusoidal function of time at input, presenting the direction value.