HRTF Interpolation Using Grid Segmentation and Pre-computation

Solution Overview

Problem

Conventional HRTF interpolation methods are inefficient for real-time audio output, particularly when dealing with fast-moving sound images, as they require a large number of calculations, making them unsuitable for applications like virtual reality and gaming.

Innovation Solution

A method that interpolates HRTF data by using altitude and azimuth angle segments to generate HRTF interpolation signals, applying variations in interaural level difference (ILD) data to create a final HRTF signal for accurate sound localization, reducing the computational burden.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional HRTF interpolation methods are used to achieve accurate sound localization, then measurement precision is improved, but calculation complexity increases making it unsuitable for real-time processing

Engineering Contradiction:

Improvesound localization accuracyVSAvoidcalculation complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the spherical coordinate space into discrete latitude and longitude grids, pre-calculating and storing HRTF values at these grid points. During real-time processing, the sound localization point is divided into integer grid coordinates and remainder offsets, allowing the use of pre-computed values for the grid portion and simplified interpolation for the remainder portion.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs HRTF calculations and interpolation in advance for all grid points in the spherical coordinate system, storing these pre-computed values in a database. This preliminary action eliminates the need for complex real-time calculations during actual audio processing, as the system only needs to retrieve and combine pre-computed values based on the current sound position.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If conventional HRTF interpolation methods are used to achieve accurate sound localization, then measurement precision is improved, but processing speed decreases making it unsuitable for fast motion

Engineering Contradiction:

Improvesound localization accuracyVSAvoidprocessing speed

Core Design Contradiction:

Measurement precisionVSSpeed

Solution Approach 1:

The patent segments the spherical coordinate space into discrete latitude and longitude grids, pre-calculating and storing HRTF values at these grid points. During real-time processing, the sound localization point is divided into integer grid coordinates and remainder offsets, allowing the use of pre-computed values for the grid portion and simplified interpolation for the remainder portion.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs HRTF calculations and interpolation in advance for all grid points in the spherical coordinate system, storing these pre-computed values in a database. This preliminary action eliminates the need for complex real-time calculations during actual audio processing, as the system only needs to retrieve and combine pre-computed values based on the current sound position.

Inventive Principle:

Principle #10Preliminary action

3Measurement precision

If conventional HRTF interpolation methods are used to achieve accurate sound localization, then measurement precision is improved, but loss of time increases making it unsuitable for real-time environment

Engineering Contradiction:

Improvesound localization accuracyVSAvoidprocessing time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent segments the spherical coordinate space into discrete latitude and longitude grids, pre-calculating and storing HRTF values at these grid points. During real-time processing, the sound localization point is divided into integer grid coordinates and remainder offsets, allowing the use of pre-computed values for the grid portion and simplified interpolation for the remainder portion.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs HRTF calculations and interpolation in advance for all grid points in the spherical coordinate system, storing these pre-computed values in a database. This preliminary action eliminates the need for complex real-time calculations during actual audio processing, as the system only needs to retrieve and combine pre-computed values based on the current sound position.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS9980077B2Method of interpolating HRTF and audio output apparatus using same

Publication Date: 2018.05.22 LG ELECTRONICS INC

AI summary

A method of interpolating a head-related transfer function (HRTF) and an audio output apparatus using the same are disclosed. The method includes receiving HRTF data corresponding to a point at which an altitude angle and an azimuth angle cross and receiving complementary information about a point at which the HRTF data is present, generating an HRTF interpolation signal corresponding to an altitude angle of a sound localization point, using HRTF data corresponding to two points constituting an altitude angle segment nearest the sound location point, calculating an amount of variation up to an azimuth angle θ of the sound localization point, using complementary information of two points constituting an azimuth angle segment nearest the sound localization point, and generating a final HRTF interpolation signal corresponding to the sound localization point by applying the amount of variation to the HRTF interpolation signal corresponding to the altitude angle of the sound localization point.