Cartilage Conduction HRTF Calibration for Real-Time Spatial Audio

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional methods for determining head-related transfer functions (HRTFs) in artificial reality systems are inefficient in terms of hardware resources and time, requiring complex setups and lengthy processes such as sound dampening chambers and multiple speaker arrays.

Innovation Solution

A method involving cartilage conduction transducers to present test sounds at various positions on the pinna, capturing audio signals, and using a model to determine customized HRTFs based on audio and geometric information, reducing the need for extensive hardware and time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional HRTF measurement methods are used with sound dampening chambers and multiple speaker arrays, then measurement precision is improved, but device complexity and time consumption increase significantly

Engineering Contradiction:
ImproveHRTF measurement precisionVSAvoidhardware complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary computational model that maps simplified audio signals to HRTFs, replacing the need for complex physical measurement systems. This intermediary layer allows accurate HRTF determination without requiring sound dampening chambers or multiple speaker arrays.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a computational copy of the HRTF measurement process through machine learning models trained on conventional measurement data. These models can then predict HRTFs for new users without requiring actual physical measurements, thus reducing hardware complexity while maintaining precision.

Inventive Principle:
Principle #26Copying

2Measurement precision

If conventional HRTF measurement methods are used with sound dampening chambers and multiple speaker arrays, then measurement precision is improved, but time consumption increases significantly

Engineering Contradiction:
ImproveHRTF measurement precisionVSAvoidHRTF determination time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary training of computational models using conventional measurement data in advance. Once trained, these models can rapidly predict HRTFs for individual users without requiring time-consuming physical measurements, thus reducing determination time while maintaining precision through the pre-computed knowledge.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates a computational copy of the HRTF measurement process through machine learning models trained on conventional measurement data. These models can then predict HRTFs for new users without requiring actual physical measurements, thus reducing hardware complexity while maintaining precision.

Inventive Principle:
Principle #26Copying

3Productivity

If cartilage conduction transducers are used to present test sounds at multiple pinna positions, then HRTF calibration efficiency is improved, but measurement complexity increases

Engineering Contradiction:
ImproveHRTF calibration efficiencyVSAvoidmeasurement setup complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent makes the cartilage conduction transducer multi-functional by using it both to present test sounds and to capture the resulting audio signals. This universal use of a single component simplifies the measurement setup while maintaining the ability to collect data from multiple pinna positions efficiently.

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

Solution Approach 2:

The patent merges the sound presentation function and signal capture function into a single integrated measurement process using cartilage conduction transducers. This combining of functions reduces the number of separate components needed while maintaining calibration efficiency through the use of multiple test positions.

Inventive Principle:
Principle #5Merging (Combining)

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

Enables efficient, real-time HRTF calibration and geometric information calibration for audio systems, allowing for high-quality spatialized audio without the need for specialized equipment or lengthy procedures.

Implementation Method 1

an audio signal corresponding to sound at an entrance to an ear canal of the user responsive to a cartilage conduction transducer coupled to a pinna of the user presenting the test sound to the user

Methodology Applied
Scientific EffectCartilage conduction: Conduction (thermal)

Data Source

PatentEP4128819B1Head-related transfer function determination using cartilage conduction
Publication Date: 2025.12.03 META PLATFORMS TECHNOLOGIES LLC
  • EP4128819B1 patent drawingFigure 1A
  • EP4128819B1 patent drawingFigure 1B
  • EP4128819B1 patent drawingFigure 2

AI summary

Embodiments relate to calibrating head-related transfer functions (HRTFs) for a user of an audio system (e.g., as a component of a headset) using cartilage conducted sounds. A test sound is presented to a user using a transducer (e.g., cartilage conduction) and an audio signal is responsively received via a microphone at an entrance to the user's ear canal. The test sound and audio signal combination may be provided to an audio server where a model is used to determine one or more HRTFs for the user. Information describing the one or more HRTFs is provided to the audio system to be used for providing audio to the user. The audio server may also use a model to determine geometric information describing a pinna of the user based on the combination. In one embodiment, the geometric information is used to determine the one or more HRTFs for the user.