Head relational transfer function virtualizer

• US 20050147261A1
• Filed: 12/30/2003
• Published: 07/07/2005
• Est. Priority Date: 12/30/2003
• Status: Abandoned Application

• Current Assignee: Alcatel SA (Nokia Corporation)
• Original Assignee: Alcatel SA (Nokia Corporation)
• Inventors: Yeh, Chiang
• Application Number:
  US10/750,471
• Publication Number:
  US 20050147261A1
• Time in Patent Office: Days
• US Class Current: 381/92
• CPC Class Codes: H04M 3/567 Multimedia conference systems
• CPC Class Codes: H04M 3/568 audio processing specific to telephonic conferencing, e.g. spatial distribution, mixing of participants echo suppression in two-way loud-speaking telephone systems H04M9/02; sound field processing per se H04S7/30
• CPC Class Codes: H04R 2201/403 Linear arrays of transducers
• CPC Class Codes: H04R 3/12 for distributing signals to two or more loudspeakers specially adapted for hearing aids H04R25/407
• CPC Class Codes: H04S 2400/01 Multi-channel, i.e. more than two input channels, sound reproduction with two speakers wherein the multi-channel information is substantially preserved
• CPC Class Codes: H04S 2400/11 Positioning of individual sound objects, e.g. moving airplane, within a sound field H04S2420/13 takes precedence
• CPC Class Codes: H04S 2420/01 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 Class Codes: H04S 7/303 Tracking of listener position or orientation

Abstract

Sound and the spatial location of the sound relative to a microphone array are sensed and derived respectively and transmitted to a sound reproducing system that uses the sound as a monaural stream and shapes the monaural stream according to channels using time delays, attenuation, reverberation, and filters that represent head-related transfer functions (HRTFs) where each HRTF has coefficients that are functions of spatial location, particularly one or both angles of incidence. This invention in some embodiments provides for acoustical images of a speaker moving relative to the microphone array and in other embodiments provides for adjustments in a listener'"'"'s HRTF database derived from sounds from the listener.

Claims

1. A method of processing sound data received at one or more microphones, the method comprising the steps of:

receiving a transmission having sound data and an audio source spatial data set relative to the one or more microphones;

determining, in a sound conditioning filter database having filters characterized by a stored set of coefficients wherein each stored set of filter coefficients is a function of at least one element of the audio source spatial data set, two or more stored sets of coefficients proximate to the at least one element of the audio source spatial data set;

interpolating between the determined two or more stored sets of coefficients;

convolving the sound data with a shaping filter having the interpolated filter coefficients; and

transmitting the resulting signal to a sound-producing array.

2. The method of claim 1 wherein the spatial data set comprises an audio source distance setting relative to the one or more microphones.

3. The method of claim 1 wherein the spatial data set comprises a first audio source angle of incidence relative to the one or more microphones.

4. The method of claim 3 wherein the spatial data set comprises an audio source distance setting relative to the one or more microphones.

5. The method of claim 3 wherein the spatial data set further comprises a second audio source angle of incidence relative to the one or more microphones, the second audio source angle of incidence being substantially orthogonal to the first audio source angle of incidence.

6. The method of claim 5 wherein the spatial data set comprises an audio source distance setting relative to the one or more microphones.

7. The method of claim 1 further comprising the step of determining a first audio source angle of incidence relative to the one or more microphones for inclusion in the spatial data set.

8. The method of claim 7 further comprising the steps of:

determining, for a voice-over-Internet Protocol session, a nominal audio source distance set point relative to the one or more microphones; and

determining an audio source distance setting relative to the determined nominal distance set point for inclusion in the spatial data set.

9. The method of claim 7 further comprising the step of determining a second audio source angle of incidence relative to the one or more microphones, the second audio source angle of incidence being substantially orthogonal to the first audio source angle of incidence for inclusion in the spatial data set.

10. The method of claim 9 further comprising the steps of:

determining, for a voice-over-Internet Protocol session, a nominal audio source distance set point relative to the one or more microphones; and

determining an audio source distance setting relative to the determined nominal distance set point for inclusion in the spatial data set.

11. The method of claim 1 further comprising the steps of:

encapsulating the sound data and an audio source spatial data set relative to the one or more microphones into packets;

transmitting via a network the packets; and

receiving and de-encapsulating from the packets the sound data and the audio source spatial data set.

12. The method of claim 1 further comprising the steps of:

encoding the sound data and an audio source spatial data set relative to the one or more microphones into telephone signals;

transmitting via a circuit switched network;

receiving and de-encoding from the telephone signals the sound data and the audio source spatial data set.

13. The method of claim 1 wherein the sound-producing array is comprised of headphones.

14. The method of claim 1 wherein the sound-producing array is comprised of a plurality of audio speakers.

15. A method of spatial filter tuning comprising

transmitting sound waves toward a subject having a torso and a head via a sound-producing array;

receiving the reflected sound waves via one or more microphones;

processing the received sound waves to determine time-relative changes in subject head orientation and subject torso orientation;

translating the determined time-relative changes in subject orientation into changes in an audio source spatial data set;

determining, in a sound conditioning filter database having filters characterized by a stored set of coefficients wherein each stored set of filter coefficients is a function of at least one element of the audio source spatial data set, two or more stored sets of coefficients proximate to the at least one element of the audio source spatial data set;

interpolating between the determined two or more stored sets of coefficients,

convolving the sound data with a shaping filter having the interpolated filter coefficients; and

transmitting the resulting signal to the sound-producing array.

16. The method of claim 15 wherein the spatial data set further comprises an audio source distance setting relative to the one or more microphones.

17. The method of claim 15 wherein the spatial data set comprises a first audio source angle of incidence relative to the one or more microphones.

18. The method of claim 17 wherein the spatial data set comprises an audio source distance setting relative to the one or more microphones.

19. The method of claim 17 wherein the spatial data set further comprises a second audio source angle of incidence relative to the one or more microphones, the second audio source angle of incidence being substantially orthogonal to the first audio source angle of incidence.

20. The method of claim 19 wherein the spatial data set comprises an audio source distance setting relative to the one or more microphones.

21. The method of claim 15 further comprising the step of determining a first audio source angle of incidence relative to the one or more microphones for inclusion in the spatial data set.

22. The method of claim 15 further comprising the steps of:

determining, for a session, a nominal audio source distance set point relative to the one or more microphones; and

determining an audio source distance setting relative to the determined nominal distance set point for inclusion in the spatial data set.

23. The method of claim 15 further comprising the step of determining a second audio source angle of incidence relative to the one or more microphones, the second audio source angle of incidence being substantially orthogonal to the first audio source angle of incidence for inclusion in the spatial data set.

24. The method of claim 15 wherein the sound-producing array is comprised of headphones.

25. The method of claim 15 wherein the sound-producing array is comprised of a plurality of audio speakers.

26. A system for spatial audio source tracking and representation comprising:

one or more microphones;

a microphone processing interface for providing a sound data stream and an audio source spatial data set;

a processor for modifying spatial filters based on the audio source spatial data set and for shaping the sound data stream with modified spatial filters; and

a

sound-producing array.

27. The system of claim 26 wherein the spatial data set comprises an audio source distance setting relative to the one or more microphones.

28. The system of claim 26 wherein the spatial data set comprises a first audio source angle of incidence relative to the one or more microphones.

29. The system of claim 28 wherein the spatial data set comprises an audio source distance setting relative to the one or more microphones.

30. The system of claim 28 wherein the spatial data set further comprises a second audio source angle of incidence relative to the one or more microphones, the second audio source angle of incidence being substantially orthogonal to the first audio source angle of incidence.

31. The system of claim 30 wherein the spatial data set comprises an audio source distance setting relative to the one or more microphones.

32. The system of claim 26 wherein the system further comprises:

a first communication processing interface for encapsulating the sound data and an audio source spatial data set relative to the one or more microphones into packets; and

transmitting via a network the packets; and

a second communication processing interface for receiving the packets and de-encapsulating sound data and the audio source spatial data set.

33. The system of claim 26 wherein the system further comprises:

a first communication processing interface for encoding the sound data and an audio source spatial data set relative to the one or more microphones into telephone signals; and

transmitting via a circuit switched network; and

a second communication processing interface for receiving the telephone signal and de-encoding the sound data and the audio source spatial data set.

34. The system of claim 26 wherein the sound-producing array is comprised of headphones.

35. The system of claim 26 wherein the sound-producing array is comprised of a plurality of audio speakers.