HRTF Interpolation Tool for Spatial Audio Localization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Personalized audio delivery devices such as headphones and earbuds fail to accurately spatially localize sound sources due to the absence of interaction with human anatomy, leading to a lack of audio cues that help in sound source localization.
Innovation Solution
A process of mapping a Head Related Transfer Function (HRTF) from a first spatial location grid to a second spatial location grid using an interpolation method, specifically employing vector-based amplitude panning (VBAP) to determine gain weights for accurate interpolation of Head Related Impulse Responses (HRIRs), allowing for the spatialization of sound output by personalized audio devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If personalized audio delivery devices output sound directly into the ear canal, then sound delivery efficiency is improved, but the ability to spatially localize sound sources deteriorates
Solution Approach 1:
The patent introduces HRTF data as an intermediary element that mediates between the audio delivery device and the user's auditory system. By applying pre-measured HRTF filters (transfer functions) to the audio signal before delivery, the system artificially generates the spectral and temporal cues that would normally result from natural sound interaction with the head and pinna. This allows the device to deliver sound efficiently through the ear canal while simultaneously providing the anatomical interaction cues needed for accurate spatial localization.
Solution Approach 2:
The patent employs preliminary action by pre-measuring and storing HRTF data for various spatial locations before actual audio delivery. The HRTF filters are calculated and stored in advance for different sound source positions, allowing the system to quickly apply the appropriate filter during audio playback without requiring real-time measurement of anatomical interactions. This pre-computation enables efficient real-time spatialization while maintaining accurate localization cues.
2Measurement precision
If HRTF data is measured for many spatial locations to improve localization accuracy, then measurement precision is improved, but measurement time and complexity increase
Solution Approach 1:
The patent transitions from measuring HRTF at discrete spatial locations to representing HRTF as a continuous function of spatial parameters (azimuth and elevation angles). Instead of collecting data points at specific grid locations, the system models HRTF as a smooth surface across the spherical spatial domain. This dimensional transformation allows interpolation to generate HRTF values for any spatial position, providing complete spatial coverage without the need for exhaustive measurements at every possible location.
Solution Approach 2:
The patent uses interpolation to create copies of HRTF data for spatial locations that were not directly measured. By measuring HRTF at a limited set of discrete locations and then interpolating between these measured points, the system generates accurate HRTF estimates for all intermediate spatial positions. This copying approach allows comprehensive spatial coverage while requiring measurements at only a subset of possible locations, significantly reducing measurement time and effort.
Data Source
AI summary
A head related transfer function (HRTF) associated with a first spatial location grid is received. The first spatial location grid defines a plurality of head related impulse responses (HRIRs) and respective indications of where a sound source is physically located. A second spatial location grid is received. Given locations in the first spatial location grid within a predetermined distance from a target location in the second spatial location grid are determined. An acute triangle is formed based on one or more of the given locations in the first spatial location grid, where the target location in the second spatial location grid is within the acute triangle. Gain weights are determined based on the one or more of the given locations and the target location. The gain weights are applied to a respective HRIR associated with the one or more of the given locations to determine an HRIR associated with the target location which is output.