HRTF Personalization via Vertical-Lateral Component Segmentation

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Solution Overview

Problem

Conventional methods for measuring individualized Head-Related Transfer Functions (HRTFs) are costly and time-consuming, often resulting in unnatural sound localization due to the need for extensive measurements, and lack a simple representation of perceptually-relevant features using a small number of parameters.

Innovation Solution

The approach involves a listener-specific component for vertical variations and a general component for lateral variations in HRTFs, using a database of individual-specific vertical variations derived from a plurality of HRTFs, and employing spherical harmonic representations to estimate sectoral coefficients via Bayesian estimation, allowing for efficient modeling and estimation from a limited number of spatial samples.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional methods are used to measure individualized HRTFs with extensive spatial measurements, then measurement precision is improved, but loss of time and cost increase significantly

Engineering Contradiction:
ImproveHRTF measurement accuracyVSAvoidmeasurement collection time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The HRTF measurement process is segmented into two components: listener-specific vertical variations and general lateral variations. This segmentation allows the measurement system to focus on capturing only the essential listener-specific characteristics rather than requiring complete spatial measurements at numerous locations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts and isolates the listener-specific vertical variations from the complete HRTF, separating them from the general lateral variations. This extraction enables the system to use a reduced set of spatial measurements while still achieving accurate individualized HRTF representation.

Inventive Principle:
Principle #2Taking out (Extraction)

2Productivity

If spherical speaker arrays are used to make measurements more rapidly, then productivity is improved, but device complexity and cost increase

Engineering Contradiction:
Improvemeasurement speedVSAvoidspeaker array complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent replaces expensive spherical speaker arrays with simpler, more affordable movable speaker arrays. While the simpler arrays require longer measurement times, the invention compensates by using the segmented HRTF approach that requires fewer measurement points, thus maintaining productivity while reducing device complexity and cost.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Device complexity

If generalized HRTFs are used instead of individualized measurements, then device complexity is reduced, but measurement precision deteriorates due to mislocalization

Engineering Contradiction:
ImproveHRTF system complexityVSAvoidsound localization accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies local quality by making the HRTF system partially individualized through the listener-specific vertical variations component. This selective personalization focuses computational and measurement resources on the specific aspects of HRTF that most affect localization accuracy, while using general components for the remainder.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the parameter representation of HRTF by decomposing it into listener-specific and general components. This parameter transformation allows the system to achieve accurate localization with fewer parameters than a complete individualized HRTF would require.

Inventive Principle:
Principle #35Parameter changes

4Measurement precision

If a priori information about HRTF is used to aid interpolation, then measurement precision is improved with fewer samples, but device complexity increases due to modeling requirements

Engineering Contradiction:
ImproveHRTF estimation accuracyVSAvoidmodeling complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent performs preliminary action by pre-computing and storing the general lateral variations component that can be applied to multiple listeners. This preliminary processing reduces the computational burden during actual measurement and estimation phases, achieving improved precision without proportionally increasing overall system complexity.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS10070239B2Efficient personalization of head-related transfer functions for improved virtual spatial audio
Publication Date: 2018.09.04 THE GOVERNMENT OF THE UNITED STATES AS REPRESENTED BY THE SECRETARY OF THE AIR FORCE
  • US10070239B2 patent drawing
  • US10070239B2 patent drawing
  • US10070239B2 patent drawing

AI summary

A Head-Related Transfer Function. The Head-Related Transfer Function includes listener-specific and general components. The listener-specific component includes listener-specific, vertical variations in the Head-Related Transfer Function. The general component includes non-listener-specific, lateral variations in the Head-Related Transfer Function.