Adaptive Rectangular Decomposition for Personalized HRTF Generation

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Solution Overview

Problem

Current methods for generating personalized Head-Related Transfer Functions (HRTFs) are expensive and time-consuming, leading to the use of generic HRTFs in 3D audio systems, which result in inaccurate spatialization and unconvincing spatial sound experiences due to variations in individual head and ear geometries.

Innovation Solution

The use of adaptive rectangular decomposition (ARD) with a system comprising a preprocessing engine, ARD simulation engine, and HRTF engine to generate customized HRTFs by simulating sound pressure signals within partitioned domains, leveraging the acoustic reciprocity principle and Kirchhoff surface integral representation to reduce computation time and improve accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If physical measurements in an anechoic chamber are conducted to generate personalized HRTFs, then manufacturing precision of HRTFs is improved, but loss of time and productivity deteriorate

Engineering Contradiction:
ImproveHRTF accuracyVSAvoidmeasurement time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent uses finite-difference time-domain (FDTD) simulation to create virtual copies of physical HRTF measurements. Instead of conducting actual physical measurements in an anechoic chamber, the system simulates sound wave propagation through 3D models of head and ear geometries, producing HRTF data that closely matches physical measurements while eliminating the time-consuming measurement process

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical measurement system (physical anechoic chamber measurements) with a computational simulation system. The FDTD method numerically solves the acoustic wave equation to simulate sound propagation, substituting physical measurement apparatus with algorithmic computation that achieves similar accuracy without the time constraints of physical setups

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If physical measurements in an anechoic chamber are conducted to generate personalized HRTFs, then manufacturing precision of HRTFs is improved, but productivity deteriorates

Engineering Contradiction:
ImproveHRTF accuracyVSAvoidHRTF generation efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent creates virtual HRTF measurements through FDTD simulation, copying the essential acoustic characteristics without requiring actual physical measurement sessions. This allows rapid generation of personalized HRTFs by simply inputting 3D geometric data, dramatically improving productivity while maintaining the precision benefits of personalized measurements

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent substitutes the low-productivity physical measurement process with high-speed computational simulation. The FDTD algorithm can process 3D geometric models and generate HRTF data in minutes rather than hours or days, transforming HRTF generation from a resource-intensive measurement process into an efficient computational task

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If standard datasets or mathematical models are used to generate HRTFs, then productivity is improved, but manufacturing precision deteriorates

Engineering Contradiction:
ImproveHRTF generation efficiencyVSAvoidspatialization accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by using FDTD simulation to generate HRTFs tailored to each individual's specific head and ear geometry. Instead of applying a generic mathematical model to all users, the system processes each person's unique 3D geometric data through the simulation, producing locally optimized HRTFs that accurately reflect individual anatomical variations and deliver precise spatialization

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the key parameter from generic mathematical approximations to individualized 3D geometric data. By using actual measured or scanned head and ear geometries as input to the FDTD simulation, the system transforms HRTF generation from a one-size-fits-all approach to a personalized approach, where each user's unique anatomical parameters drive the simulation results, achieving both high precision and efficiency

Inventive Principle:
Principle #35Parameter changes

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

ARD significantly reduces computation time from hours or days to approximately 20 minutes while maintaining high accuracy, with mean spectral mismatch as low as 3.88 dB for the left-ear HRTF of the Fritz and KEMAR manikins, enabling efficient and personalized HRTF generation for improved spatial sound rendering.

Implementation Method 1

conducting an ARD simulation on the plurality of partitions to generate simulated sound pressure signals within each of the plurality of partitions

Methodology Applied
Scientific EffectSound propagation: Sound

Data Source

PatentUS9906884B2Methods, systems, and computer readable media for utilizing adaptive rectangular decomposition (ARD) to generate head-related transfer functions
Publication Date: 2018.02.27 THE UNIV OF NORTH CAROLINA AT CHAPEL HILL
  • US9906884B2 patent drawing
  • US9906884B2 patent drawing
  • US9906884B2 patent drawing

AI summary

Methods, systems, and computer readable media for utilizing adaptive rectangular decomposition (ARD) to perform head-related transfer function (HRTF) simulations are disclosed herein. According to one method, the method includes obtaining a mesh model representative of head and ear geometry of a listener entity and segmenting a simulation domain of the mesh model into a plurality of partitions. The method further includes conducting an ARD simulation on the plurality of partitions to generate simulated sound pressure signals within each of the plurality of partitions and processing the simulated sound pressure signals to generate at least one HRTF that is customized for the listener entity.