Methods, systems, and computer readable media for source and listener directivity for interactive wave-based sound propagation

Patent metadata

Field	Value
Publication number	US-9560439-B2
Application number	US-201414318916-A
Country	US
Kind code	B2
Filing date	Jun 30, 2014
Priority date	Jul 1, 2013
Publication date	Jan 31, 2017
Grant date	Jan 31, 2017

Abstract

Methods, systems, and computer readable media for supporting source or listener directivity in a wave-based sound propagation model are disclosed. According to one method, the method includes computing, prior to run-time, one or more sound fields associated with a source or listener position and modeling, at run-time and using the one or more sound fields and a wave-based sound propagation model, source or listener directivity in an environment.

First claim

What is claimed is:

1. A method for supporting source or listener directivity in a wave-based sound propagation model, the method comprising:
at a sound propagation model (SPM) module comprising executable instructions executable by at least one processor:
computing, prior to run-time, one or more sound fields associated with a source or listener position in a virtual environment; and
modeling, at run-time and using the one or more sound fields and a wave-based sound propagation model, source or listener directivity in the virtual environment, wherein modeling, at run-time and using the one or more sound fields and the wave-based sound propagation model, source or listener directivity in the virtual environment includes:
performing a spherical harmonic (SH) decomposition of the source directivity;
computing one or more SH coefficients corresponding to the SH decomposition; and
computing an acoustic response of the virtual environment, wherein the acoustic response is computed as a summation of the one or more sound fields evaluated at the listener position weighted by the one or more SH coefficients.

2. The method of claim 1 wherein the one or more sound fields are associated with one or more elemental spherical harmonics sources located at the source position.

3. The method of claim 1 wherein the one or more sound fields represent one or more acoustic responses of the environment to any directivity at the source position.

4. The method of claim 1 wherein the wave-based sound propagation model may use a finite element method, a boundary element method, an equivalent source method, a spectral method, or a frequency-domain wave-based sound propagation technique.

5. The method of claim 1 wherein computing, prior to run-time, one or more sound fields associated with a source position includes using a one-point multipole method to represent a sound field radiated by a directional source and capturing directivity using spherical harmonic (SH) expansion.

6. The method of claim 1 wherein modeling, at run-time and using the one or more sound fields and the wave-based sound propagation model, source or listener directivity in the virtual environment includes generating, using the one or more sound fields, an acoustic response to an arbitrary time-varying or rotating directional source.

7. The method of claim 1 wherein computing an acoustic response includes convolving the acoustic response with source audio information to render the sound.

8. The method of claim 1 wherein acoustic responses for both ears are computed using a head-related transfer function (HRTF).

9. The method of claim 1 wherein computing, prior to run-time, one or more sound fields associated with a source or listener position includes computing a pressure field of an entire domain by using pressure and its higher order derivatives at a single point.

10. The method of claim 1 wherein computing, prior to run-time, one or more sound fields associated with a source or listener position includes computing a plane wave decomposition of a sound field around the listener position using pressure derivatives and spherical harmonic (SH) decomposition.

11. The method of claim 10 wherein modeling, at run-time and using the one or more sound fields and the wave-based sound propagation model, source or listener directivity in the virtual environment includes computing, during run-time, spatial sound as a dot product of spherical harmonic (SH) coefficients associated with the sound field around the listener position and a head-related transfer function.

12. A system for supporting source or listener directivity in a wave-based sound propagation model, the system comprising:
at least one processor; and
a sound propagation model (SPM) module comprising executable instructions executable by the at least one processor, the SPM module configured to compute, prior to run-time, one or more sound fields associated with a source or listener position and to render, at run-time and using the one or more sound fields and the wave-based sound propagation model, source or listener directivity in a virtual environment, wherein the SPM module is configured to:
perform a spherical harmonic (SH) decomposition of the source's directivity;
compute SH coefficients corresponding to the SH decomposition; and
compute an acoustic response of the virtual environment to the source, wherein the acoustic response is computed as a linear combination of the one or more sound fields, wherein the one or more sound fields correspond to elementary SH sources weighted by the computed SH coefficients.

13. The system of claim 12 wherein the one or more sound fields are associated with one or more elemental spherical harmonics sources located at the source position.

14. The system of claim 12 wherein the one or more sound fields represent one or more acoustic responses of the virtual environment to any directivity at the source position.

15. The system of claim 12 wherein the wave-based sound propagation model may use a finite element method, a boundary element method, an equivalent source method, a spectral method, or a frequency-domain wave-based sound propagation technique.

16. The system of claim 12 wherein the SPM module is configured to use a one-point multipole method to represent a sound field radiated by a directional source and to capture directivity using spherical harmonic (SH) expansion.

17. The system of claim 12 wherein the SPM module is configured to generate, using the one or more sound fields, an acoustic response to an arbitrary time-varying or rotating directional source.

18. The system of claim 12 wherein the SPM module is configured to convolve the acoustic response with source audio information to render the sound.

19. The system of claim 12 wherein acoustic responses for both ears are computed using a head-related transfer function (HRTF).

20. The system of claim 12 wherein the SPM module is configured to compute a pressure field of an entire domain by using pressure and its higher order derivatives at a single point.

21. The system of claim 12 the SPM module is configured to compute a plane wave decomposition of a sound field around the listener position using pressure derivatives and spherical harmonic (SH) decomposition.

22. The system of claim 21 wherein the SPM module is configured to compute, during run-time, spatial sound as a dot product of spherical harmonic (SH) coefficients associated with the sound field around the listener position and a head-related transfer function.

23. A non-transitory computer readable medium having stored thereon executable instructions that when executed by at least one processor of a computer control the computer to perform steps comprising:
computing, prior to run-time, one or more sound fields associated with a source or listener position in a virtual environment; and
modeling, at run-time and using the one or more sound fields and a wave-based sound propagation model, source or listener directivity in the virtual environment, wherein modeling, at run-time and using the one or more sound fields and the wave-based sound propagation model, source or listener directivity in the virtual environment includes:
performing a spherical harmonic (SH) decomposition of the source directivity;
computing one or more SH coefficients corresponding to the SH decomposition; and
computing an acoustic response of the virtual environment, wherein the acoustic response is computed as

Assignees

• Univ North Carolina Chapel Hill
• The Univ Of North Carolina At Chapel Hills

Inventors

• Mehra Ravish
• Antani Lakulish Shailesh
• Manocha Dinesh

Classifications

• H04R1/20 Primary

  Arrangements for obtaining desired frequency or directional characteristics (for stereophonic purpose H04R5/00) · CPC title

• H04S2420/01

  Enhancing the perception of the sound image or of the spatial distribution using head related transfer functions [HRTF's] or equivalents thereof, e.g. interaural time difference [ITD] or interaural level difference [ILD] · CPC title

• H04S7/304 Primary

  For headphones · CPC title

• H04S2420/11

  Application of ambisonics in stereophonic audio systems · CPC title