HRTF Synthesis via Timbre Extraction for Personalized Binaural Audio

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Solution Overview

Problem

Existing methods for HRTF synthesis and personalization focus solely on localization features, limiting the level of personalization and the quality of the audio experience.

Innovation Solution

A computer-implemented method for synthesizing an HRTF that involves processing the HRTF to remove localization perception features, calculating the subject's HRTF timbre by subtracting a baseline HRTF, and using the HRTF timbre to synthesize a personalized HRTF.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If HRTF synthesis focuses solely on localization features (spectral notches, ITD, ILD), then localisation accuracy is improved, but the level of personalisation and audio quality is limited

Engineering Contradiction:
Improvelocalisation accuracyVSAvoidlevel of personalisation
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The HRTF is segmented into two distinct components: localization features (spectral notches, ITD, ILD) and timbral features (frequency-dependent magnitude changes). This segmentation allows independent processing and personalization of each component, resolving the contradiction by enabling both accurate localization and high personalization levels simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The timbral component is extracted from the HRTF by removing localization features through spectral notch removal and baseline subtraction. This extraction enables the timbral component to be independently synthesized and applied, allowing personalization beyond what was previously achievable with localization features alone.

Inventive Principle:
Principle #2Taking out (Extraction)

2Device complexity

If HRTF synthesis focuses solely on localization features, then processing complexity is reduced, but the quality of binaural audio experience deteriorates

Engineering Contradiction:
Improveprocessing complexityVSAvoidquality of audio experience
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

By segmenting HRTF into localization and timbral components, the system can apply different processing strategies to each. The localization component uses established low-complexity methods, while the extracted timbral component adds realistic audio quality enhancement without requiring complex full-HRTF personalization.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Extracting the timbral component separates it from the localization features, allowing it to be synthesized and applied independently. This extraction enables quality enhancement through timbre personalization without the computational burden of synthesizing complete personalized HRTFs.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If the timbral component is incorporated into HRTF synthesis, then the realism and fullness of binaural audio is improved, but the complexity of the synthesis method increases

Engineering Contradiction:
Improverealism of audio experienceVSAvoidsynthesis method complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The timbral component is extracted by removing spectral notches and subtracting a baseline HRTF, creating a simplified representation that captures subject-specific variations. This extracted component can be stored and applied directly, adding realism without requiring complex synthesis algorithms.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The synthesis method incorporates the timbral component by adding it to the localized HRTF, effectively changing the frequency response parameters to include subject-specific timbral characteristics. This parameter adjustment enhances audio realism while maintaining the simplicity of the base localization-based synthesis method.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4531439A1Methods and systems for synthesising an hrtf
Publication Date: 2025.04.02 SONY COMP ENTERTAINMENT EURO LTD
  • EP4531439A1 patent drawingFigure 1A~1B
  • EP4531439A1 patent drawingFigure 1C~1D
  • EP4531439A1 patent drawingFigure 1E

AI summary

A computer-implemented method of synthesising an HRTF is disclosed. The method comprising: providing the HRTF of a subject measured at a particular measurement angle; processing the HRTF to remove localisation perception features of the HRTF, where the processing comprises: removing spectral notches from the measured HRTF, the resulting processed HRTF referred to as the HRTF'; and calculating a subject's HRTF timbre by subtracting a baseline HRTF at the measurement angle from the subject's HRTF', the baseline HRTF comprising a generalised response component such that the HRTF timbre comprises subject-specific variations in the HRTF. The method further comprises using the HRTF timbre to synthesise an HRTF. The method allows for generating a personalised timbre component of an HRTF to provide better personalisation of an HRTF, thereby providing improved binaural audio.