Generating Acoustic Quiet Zone by Noise Injection Techniques

• US 20120057716A1
• Filed: 01/18/2011
• Published: 03/08/2012
• Est. Priority Date: 09/02/2010
• Status: Active Grant

• Current Assignee: Spatial Digital Systems Inc
• Original Assignee: Spatial Digital Systems Inc
• Inventors: Chang, Donald C. D., Chen, Steve
• Granted Patent: US 9,995,828 B2
• Time in Patent Office: Days
• US Class Current: 381/71.1
• CPC Class Codes: G01S 19/215 issues related to spoofing
• CPC Class Codes: G10K 11/17857 Geometric disposition, e.g. placement of microphones
• CPC Class Codes: G10K 11/34 using electrical steering of transducer arrays, e.g. beam steering constructional aspects B06B1/0607, B06B1/085
• CPC Class Codes: G10K 11/341 Circuits therefor
• CPC Class Codes: G10K 11/348 using amplitude variation
• CPC Class Codes: G10K 2210/12 Rooms, e.g. ANC inside a room, office, concert hall or automobile cabin
• CPC Class Codes: G10K 2210/128 Vehicles
• CPC Class Codes: G10K 2210/3215 Arrays, e.g. for beamforming

Abstract

A quiet zone generation technique for acoustic/audio signals is proposed for mitigation of selected noise or interferences over limited areas in free space by injecting the very acoustic noise, interference, or audio feedback signals via iterative processing, generating quiet zones dynamically. This creates undesired noise-free quiet zones. Optimization loops operating iteratively to electronically process cancellation signals consist of three interconnected functional blocks: (1) an acoustic injection array, consisting of pick-up arrays to obtain the interference signals, beam forming networks for element weighting and/or re-positioning, and array elements for noise injections, (2) a diagnostic network with strategically located probes, and (3) an optimization processor with cost minimization algorithms to calculate element weights for updating.

Claims

1. Architectures and methods of generating acoustic quiet zones by injections of interference for cancellation, comprising

a plurality of auxiliary transmit acoustic arrays comprising

a plurality of input elements,

a plurality of output elements, and

a plurality of acoustic beam forming networks with element weighting functions,

a diagnostic network comprising

a plurality of microphones distributed in various locations in the quiet zone, wherein said microphones measure the combined field strengths from the existing acoustic noises and injected noises from said auxiliary transmit arrays, and

optimization process converting measurements from diagnostic microphones to performance indexes, and performing weight updating for elements of the auxiliary transmit acoustic arrays based on said performance indexes.

2. The input elements of the auxiliary transmit acoustic array of claim 1, wherein the circuit is adapted to pick up acoustic noise signals to be injected by the auxiliary acoustic array.

3. The element weighting functions of claim 1, wherein the circuit or equivalent mechanism is adapted to modify the amplitudes and phases of frequency components of the injected acoustic noise signals.

4. The output elements to the auxiliary transmit acoustic array of claim 1, wherein the elements are adapted to transmit acoustic signals into the quiet zones.

5. The diagnostic network of claim 1, wherein the processing is adapted

to measure the combined field strengths of the selected acoustic noises created by nearby noise sources and injected noises from the auxiliary transmit arrays, and

to convert the measured field strength from said diagnostic microphones into performance indexes or cost functions, where cost functions which must be positive “

definited”

, and

to calculate total cost based on the sum of all the cost functions.

6. The optimization loop of claim 1, wherein the optimization processing is adapted

to measure the gradient of total cost,

to calculate a new set of element weights for next update using cost minimization algorithms, and

to send the new set of element weights to the injection array for next update, wherein the process continues until values meet preset parameters.

7. Architectures and methods of an acoustic injection-for-cancellation system dynamically generating quiet zones for mitigating select acoustic signals from nearby acoustic noise sources, comprising

an auxiliary transmit acoustic array comprising

a plurality of input elements,

a plurality of output elements, and

a plurality of beam forming networks with element weighting functions,

a diagnostic network consisting of

a plurality of microphones distributed at various locations in the quiet zones for measurement of the combined acoustic noise field strength from selected noises and injected noise interference from the auxiliary transmit acoustic arrays, and conversion of said measurement to performance indexes, and

an optimization process for the purpose of performing weight updating for elements of the auxiliary transmit acoustic arrays based on said performance indexes.

8. The input elements to the auxiliary transmit array of claim 7, wherein the circuit is adapted to selectively pick up acoustic noise signals to be injected by the auxiliary transmit acoustic array,

9. The element weighting functions of claim 7, wherein the circuit or equivalent mechanical mechanism is adapted to modify the amplitudes and phases of the frequency components of injected acoustic noise signals for both input and output elements.

10. The output elements to the auxiliary transmit acoustic array of claim 7, wherein the circuit is adapted to inject processed selected noise signals to said quiet zones.

11. The diagnostic network of claim 7, wherein the processing is adapted

to measure the combined acoustic noise field strength from the leakages of nearby noise sources and those injected by the injection array over the quiet zones via the diagnostic microphones,

to convert the acoustic measurements into performance indexes, or cost functions, wherein cost functions which must be positive “

definited”

,

to calculate total cost based on the sum of all the cost functions.

12. The optimization process of claim 7, wherein:

the processing is adapted

to measure the gradient of total cost,

to calculate a new set of element weights for next update using cost minimization algorithms, and

to send the new set of element weights to the injection array for next update.

13. Architectures and methods of an injection-for-cancellation acoustic system dynamically generating quiet zones for mitigating undesired noises from nearby noise sources, comprising

auxiliary transmit acoustic arrays comprising

a plurality of input elements,

a plurality of output elements, and

beam forming networks with element weighting functions,

diagnostic network consisting of microphones distributed at various locations in quiet zones, wherein said microphones measure the combined acoustic noise field strength from selected noises and injected noise interferences from the auxiliary transmit acoustic arrays, and conversion of said measurements to performance indexes, and

an optimization process performing weight updating for elements of the auxiliary transmit acoustic arrays based on performance indexes.

14. The input elements to the auxiliary transmit array of claim 13, wherein said elements are implemented in array fashion, wherein the circuit is adapted to selectively pick up acoustic signals remotely to be injected by the auxiliary transmit acoustic array.

15. The element weighting functions of claim 13, wherein the circuit or equivalent mechanism is adapted to modify the amplitudes and phases of the frequency components of said injected acoustic noise signals for both input and output elements.

16. The multiple output elements of the auxiliary transmit array of claim 13 wherein the circuit is adapted to inject processed selected acoustic signals to the quiet zones, wherein said quiet zones are dynamically selectable by users.

17. The diagnostic network of claim 13, wherein said processing is adapted

to measure the combined acoustic noise field strength of the selected quiet zones created by leakages of nearby noise sources and those injected by the injection array,

to convert said measurements into performance indexes, or cost functions, wherein cost functions which must be positive “

definited”

, and to calculate total cost based on the sum of all the cost functions.

18. The diagnostic microphones of claim 17, wherein said microphones function as a multi-beam acoustic array, with capabilities for focusing on spot acoustic signal pick up in the near field, wherein said near field may be near the user'"'"'s extremeties.

19. The optimization process of claim 13, wherein, the processing is adapted

to measure the gradient of total cost,

to calculate a new set of element weights for next update using cost minimization algorithms, and

to send the new set of element weights to the injection array for next update.

20. Architectures and methods of injection-for-cancellation of an audio quiet zone generation system for mitigation of feedback from speakers to microphones, dynamically generating quiet zones around microphones, comprising

auxiliary transmit arrays comprising

a plurality of remote input elements,

a plurality of output elements, and

an audio beam forming network with element weighting functions, wherein said network dynamically causes destructive interference between the feedback audio signals from main speakers and those injected by the auxiliary transmit arrays over the quiet zone,

diagnostic probes distributed in the quiet zones measuring the combined field strength of audio signals from main speakers and those injected from the auxiliary transmit arrays, and converting the measurement to performance indexes, and

An optimization loop performing weight updating for elements of the auxiliary transmit arrays based on performance indexes.

21. The element weighting functions of claim 20, wherein the circuit or equivalent mechanical mechanism is adapted to modify the amplitude and phase of the frequency components of injected audio signals for both input and output elements.

22. The multiple output elements to the auxiliary transmit array of claim 21, wherein:

the circuit is adapted

to concurrently inject the selected external audio signals after processing to the quiet zones, and

to process external audio signals element by element with proper weightings on associated finite impulse response filters, or equivalently with proper weightings on amplitudes and phases of various frequency components..

23. The optimization loop of claim 20, wherein the processing is adapted

to convert the measured field strength of the probing microphones into performance indexes, or cost functions, wherein cost functions which must be positive definite, and to calculate total cost based on the sum of all the cost functions,

to measure the gradient of total cost and to calculate a new set of element weights for next update using cost minimization algorithms and the gradient of cost function to minimize the total cost.