Machine for Enabling and Disabling Noise Reduction (MEDNR) Based on a Threshold

• US 20120084080A1
• Filed: 04/08/2011
• Published: 04/05/2012
• Est. Priority Date: 10/02/2010
• Status: Active Grant

• Current Assignee: Noise Free Wireless Incorporated
• Original Assignee: Alon Konchitsky
• Inventors: Konchitsky, Alon, Berstein, Alberto D, Kulakcherla, Sandeep
• Granted Patent: US 8,775,172 B2
• Time in Patent Office: Days
• US Class Current: 704/210
• CPC Class Codes: G10L 2021/02166 Microphone arrays; Beamforming
• CPC Class Codes: G10L 2025/783 based on threshold decision
• CPC Class Codes: G10L 21/0208 Noise filtering
• CPC Class Codes: H04R 1/1083 Reduction of ambient noise active noise reduction per se G10K11/175; protective devices for the ear, e.g. providing acoustic protection A61F11/06
• CPC Class Codes: H04R 2460/03 Aspects of the reduction of energy consumption in hearing devices

Abstract

The present invention provides a novel system and method for monitoring the audio signals, analyze selected audio signal components, compare the results of analysis with a threshold value, and enable or disable noise reduction capability of a communication device.

Claims

1. A machine to automatically enable and disable noise reduction based on a set threshold.

2. A machine in accordance with claim 1, wherein disabling noise reduction when there is no or less background noise than the set threshold,

3. A machine in accordance with claim 1, wherein disabling noise reduction s

4. A machine in accordance with claim 1, wherein disabling noise reduction when there is no or less background noise than the set threshold, just by-passes the audio signal thereby preserving the voice quality which are altered/modified by noise reduction algorithms.

5. A machine in accordance with claim 1, wherein the threshold can be pre-defined by the user, manufacturer, or set during production of a communication device, beginning of the conversation or set on the fly during a conversation.

6. A machine in accordance with claim 1, wherein the Voice Activity Detector (VAD) decides if the incoming audio signal is speech or non-speech/noise.

7. A machine in accordance with claim 6, wherein the Root Mean Square (RMS) value and/or RMS (dB, decibels) are calculated for non-speech/noise durations;

when VAD is OFF.

8. A machine in accordance with claim 7, wherein the RMS and/or RMS (dB) are compared to the set threshold;

when VAD is OFF. If the RMS and/or RMS (dB) are less than the set threshold, noise reduction is disabled;

if the RMS and/or RMS (dB) are greater than the set threshold, noise reduction is enabled.

9. A machine in accordance with claim 8, wherein the decision to enable or disable noise reduction is done every N seconds;

where N≧

frame size of the communication system/device. For narrowband and wideband communication systems, N≧

20 milli-seconds and N≧

10 milli-seconds respectively.

10. A machine in accordance with claim 9, wherein the noise reduction, initially for a certain time, can be enabled or disabled, irrespective of the RMS level of the background noise present in the operating environment.

11. A machine in accordance with claim 10, wherein the initial time may be independent of the time described in claim 9. For narrowband and wideband communication systems, initial time ≧

20 milli-seconds and Initial time ≧

10 milli-seconds respectively.

12. A machine in accordance with claim 11, wherein the decision to enable or disable noise reduction is stored in a binary format of one or zero or any other machine readable format.

13. A machine in accordance with claim 12, wherein the stored decision is used to either by

pass or process the audio signal with noise reduction when the VAD is ON.

14. A machine in accordance with claim 13, wherein the stored decision is used to either by

pass or process the audio signal with noise reduction when time is not equal to N seconds;

For narrowband and wideband communication systems, N≧

20 milli-seconds and N≧

10 milli-seconds respectively.

15. A system for controlling noise reduction devices, the system comprising:

a) input for two or more microphones;

b) a microprocessor block;

c) a memory block, with external and internal memory;

d) an internal bus in communication with the internal memory and microprocessor block;

e) a voice activity detector (“

VAD”

) in connection with the two or more microphones;

f) the VAD deciding if an incoming signal from a microphone is speech or noise,

i) if the VAD finds an incoming signal to be noise, the VAD is turned off,

ii) if the VAD finds an incoming signal to be speech, the VAD is on, and control goes to an execution block with an instruction to enable the noise reduction system,

iii) if the VAD is turned off, control goes to a decision subsystem, deciding if a noise reduction system is to be enabled or disabled, the decision occurring every N seconds,

g) the decision subsystem comprising;

i) a counter to measure time,

ii) when time does not equal N seconds, the value for time is incremented and the noise reduction system is activated or the noise reduction system is not activated, depending upon the value stored in a storage decision block, with the value in the storage decision block being transmitted to the execution block,

iii) when time does equal N, the microprocessor calculates the root mean square (“

RMS”

) of the input signal;

aa) if the RMS is less than a set threshold level, a decision to disable the noise reduction system is made and stored in the storage decision block, then transmitted to the execution block and the value of time is reset to zero.

bb) if the RMS is greater than a set threshold level, a decision to enable the noise reduction system is made and stored in the storage decision block, transmitted to the execution block and the value of time is reset to zero.

16. The system of claim 15 wherein the threshold value is set by the end user.

17. The system of claim 15 wherein N is between 20 and 200 milli-seconds.