Audio privacy method and system

• US 8,059,828 B2
• Filed: 12/14/2005
• Issued: 11/15/2011
• Est. Priority Date: 12/14/2005
• Status: Active Grant

• Current Assignee: TP Lab, Inc.
• Original Assignee: TP Lab, Inc.
• Inventors: Ho, Chi Fai, Chiu, Shin Cheung Simon
• Primary Examiner(s): Mei, Xu
• Application Number:
  US11/302,913
• Publication Number:
  US 20070135176A1
• Time in Patent Office: 2,162 Days
• Field of Search: 381 711- 7114, 381/104, 381/106, 381/107, 381/110, 381/73.1
• US Class Current: 381/73.1
• CPC Class Codes: H04R 3/00 Circuits for transducers , loudspeakers or microphones

Abstract

Provided is a method and system for audio privacy that includes receiving a first sound signal at a microphone proximal to a user'"'"'s ear, generating a second sound signal based on the first sound signal and a stored filter, the second sound signal interfering with the first sound signal, and emitting the second sound signal from a speaker proximal to the user'"'"'s ear.

Claims

1. An audio privacy system comprising:

a signal sampling module which operates to receive and sample a combined sound signal comprising the voice of a user of the system over a series of sampling time intervals and which operates to generate a sequence of sampled audio objects, wherein each sampled audio object represents the combined sound signal for sampling time interval for the sampled audio object;

a signal interfering module for emitting an interfering sound signal positioned in a direction to emit the interfering sound signal destructively with the voice of the user; and

a signal processing module comprising an audio filter, operatively connected to receive the sampled audio objects from the signal sampling module and to generate and transmit a sequence of interfering audio objects based on a sequence of sampled audio objects it receives to the signal interfering module, wherein for each sampled audio object, the signal processing module computes a recovered audio object which represents an approximation of the combined sound signal by subtracting the sound represented by the audio filter from the sound represented by the sampled audio object, wherein the interfering audio objects comprise an inversion of the recovered audio objects and the audio filter is an audio object approximating the interfering sound signal emitted by the signal interfering module such that the interfering sound signal destructively interferes with the voice of the user.

2. The audio privacy system according to claim 1, the signal sampling module, signal interfering module and signal processing module together comprising an item wearable by a user.

3. The audio privacy system according to claim 1, the signal sampling module, signal interfering module and signal processing module together comprising an item selected from the group consisting of a headset, jewelry and eyeglasses.

4. The audio privacy system according to claim 1, wherein the signal sampling module comprises a microphone, the signal interfering module comprises a speaker and the signal sampling module and signal interfering module are mounted on or in a communication device.

5. The audio privacy system according to claim 1, the signal processing module comprising an application specific integrated circuit.

6. The audio privacy system according to claim 1, in which the signal processing module comprises a microprocessor and associated memory, the microprocessor being configured to perform the signal generating function of the signal processing module.

7. The audio privacy system according to claim 1, the signal sampling module configured to filter out sounds over a predetermined decibel level.

8. The audio privacy system according to claim 1, the predetermined decibel level being 100 decibels.

9. The audio privacy system according to claim 1, wherein a sound represented by the audio filter is filtered from the sampled audio object before inverting the sampled audio object to generate the interfering audio object.

10. The audio privacy system according to claim 1 wherein the signal processing module is operable to replace the audio filter with the interfering audio object so that the interfering audio object is a new audio filter and is operable to employ the new audio filter to process a next sampled audio object.

11. The audio privacy system according to claim 1, wherein the audio filter comprises an audio normalization factor, and the subtract function comprises adjusting the amplitude of the recovered audio objects to an amplitude level indicated by the audio normalization factor.

12. A method of providing a quiet area for a user participating in a telephone conversation using an audio privacy system, comprising:

positioning a signal sampling device in an area proximate a source from which the user'"'"'s voice emanates into a telephone mouthpiece adequate to receive the voice of the user;

receiving, at the signal sampling device and sample a combined sound signal comprising the voice of the user over a series of sampling intervals;

generating a sequence of sampled audio objects, based on the voice of the user, wherein each sampled audio object represents the combined sound signal for a sampling time interval for the sampled audio object;

providing a signal processing module, operatively connected to receive the sampled audio objects from the signal sampling module;

generating and transmitting a sequence of interfering audio objects to a signal interfering module, the interfering audio objects generated based on a sequence of sampled audio objects wherein the audio objects comprise the inverted form of the sampled audio objects,

filtering, using an audio filter which is an audio object approximating an interfering sound signal emitted by the signal interfering module

computing for each sampled audio object a recovered audio object which represents an approximation of the combined sound signal by subtracting the audio object represented by the audio filter from the sound represented by the sampled audio object; and

positioning the signal interfering module for emitting an interfering sound signal in a direction to emit an interfering sound signal destructively with the voice of the user.

13. The method according to claim 12, further comprising replacing, in the signal processing module, the audio filter with the interfering audio object so that the interfering audio object is a new audio filter and

using the new audio filter to process a next sampled audio object.

14. The method according to claim 13, the filtering being filtering out of sound in the frequency range of 120 Hz to 3800 Hz.

15. The method according to claim 13, the filtering being filtering out of sound in the frequency range of human speech.

16. The method according to claim 12 comprising providing the audio filter with an audio normalization factor, and the subtract function comprises adjusting the amplitude of the recovered audio objects to an amplitude level indicated by the audio normalization factor.