Sound Source Direction Detection Using Direct-Sound Metrics

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current techniques for determining sound source direction are limited in their ability to accurately differentiate between direct and indirect sound, leading to inefficiencies in spatial audio processing and sound source localization.

Innovation Solution

An apparatus and method that utilize direct-sound metrics and metadata to determine sound source directions by accumulating values based on the balance between direct and other sound, independent of the audio capture device, allowing for precise sound source localization using low bit-rate streams.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If digital signal processing is used to convert delays between correlated audio events to sound source position, then sound source direction can be determined, but the ability to accurately differentiate between direct and indirect sound is limited

Engineering Contradiction:
Improvesound source direction determination accuracyVSAvoiddirect sound differentiation capability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent segments the audio signal processing into distinct components: direct sound metrics calculation, indirect sound metrics calculation, and their combination. By separating the processing of direct and indirect sound paths, the system can independently evaluate each component's contribution to the overall sound field, thereby improving the reliability of direct sound differentiation while maintaining direction determination accuracy

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces new parameters (direct sound metrics and indirect sound metrics) that change based on the balance between direct and indirect sound. By monitoring these parameter changes over time and comparing them against reference values, the system can dynamically adjust its determination of sound source direction, enhancing both measurement precision and reliability in varying acoustic environments

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If spatial audio processing is performed to determine sound source position, then direction information can be obtained, but the processing efficiency is reduced due to inability to distinguish direct from indirect sound

Engineering Contradiction:
Improvesound source localization accuracyVSAvoidspatial audio processing efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent performs preliminary calculation of direct sound metrics and indirect sound metrics separately before combining them for final sound source localization. This preliminary separation allows the system to pre-process and evaluate different sound paths independently, reducing the computational complexity of the overall processing while maintaining high localization accuracy

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces metrics as intermediary variables that mediate between the raw audio signals and the final sound source position determination. These metrics serve as intermediate representations that capture the essential characteristics of direct and indirect sound, enabling more efficient processing while preserving the accuracy needed for precise localization

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If microphone signals from spatially separated microphones are used for spatial audio processing, then direction parameters can be determined, but the system complexity increases

Engineering Contradiction:
Improvedirection parameter determination accuracyVSAvoidmicrophone array configuration complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent develops a universal processing framework that can handle microphone signals from various spatial configurations. By creating metrics that are independent of the specific audio capture device and working principle, the system can process signals from different microphone array geometries using the same methodology, reducing the apparent complexity despite using multiple spatially separated microphones

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

Data Source

PatentEP3819655B1Determination of sound source direction
Publication Date: 2025.09.24 NOKIA TECHNOLOGIES OY
  • EP3819655B1 patent drawingFigure 1~2B
  • EP3819655B1 patent drawingFigure 3~5
  • EP3819655B1 patent drawingFigure 6~9

AI summary

An apparatus comprising means for: providing a plurality of metrics (10) associated with multiple directions, wherein the metrics are dependent, for the respective multiple directions, on an amount of direct-sound propagated (110); accumulating, for the respective multiple directions, values (20) dependent upon the metrics associated with the respective multiple directions to enable determination of sound source directions (120).