Masking Based Gain Control

• US 20100158263A1
• Filed: 12/23/2008
• Published: 06/24/2010
• Est. Priority Date: 12/23/2008
• Status: Active Grant

• Current Assignee: Bose Corporation
• Original Assignee: Bose Corporation
• Inventors: Hartung, Klaus, Katzer, Roman
• Granted Patent: US 8,218,783 B2
• Time in Patent Office: Days
• US Class Current: 381/73.100
• CPC Class Codes: G10K 11/1752 Masking
• CPC Class Codes: H04K 2203/12 for acoustic communication
• CPC Class Codes: H04K 3/224 with countermeasures at transmission and/or reception of the jammed signal, e.g. stopping operation of transmitter or receiver, nulling or enhancing transmitted power in direction of or at frequency of jammer

Abstract

Interfering signals that may be present in a listening environment are masked by reproducing a desired signal in a listening environment, determining a masking threshold associated with the desired signal, identifying an interfering signal that may be present in the environment, comparing the interfering signal to the masking threshold, and adjusting the desired signal over time to raise its masking threshold above the level of the interfering signal.

Claims

1. A method for masking an interfering audio signal comprising:

identifying a first frequency band of a desired signal being provided to a first acoustic zone to adjust a masking threshold associated with a second frequency band of the desired signal; and

,

applying a gain to the first frequency band of the desired signal to raise the masking threshold in the second frequency band above a level of an interfering signal containing energy in the second frequency band.

2. The method of claim 1, wherein identifying the first frequency band of the desired signal includes selecting a band with a maximum level from a group of bands.

3. The method of claim 1, wherein the first and second bands are in a Bark domain.

4. The method of claim 1, wherein adjusting the first portion of the signal includes comparing the masking threshold to the level of the interfering signal.

5. The method of claim 4, wherein the applied gain is slew rate limited.

6. The method of claim 1, wherein the applying the gain include smoothing the gain to preserve a peak gain value.

7. The method of claim 6, wherein preserving the peak value includes extending the peak value.

8. The method of claim 1, wherein the interfering signal includes a signal being provided to a second acoustic zone.

9. The method of claim 1, wherein the interfering signal includes an estimate of a noise signal.

10. A method for masking an interfering audio signal comprising:

reproducing in a first location a first signal having a level, the first signal also having a first frequency range,

determining a masking threshold as a function of frequency associated with the first signal in the first location,

identifying a level of a second signal present in the first location, the second signal having a second frequency range different from the first frequency range,

comparing the level of the second signal present in the first location to the masking threshold, and

adjusting the first signal level to raise the masking threshold above the level of the second signal within the second frequency range.

11. The method of claim 10, wherein the first and second frequency ranges are represented in a Bark domain.

12. The method of claim 10 wherein the adjusted level of the first signal is slew rate limited.

13. The method of claim 10, wherein adjusting the first signal level includes applying a gain.

14. The method of claim 13, wherein applying the gain includes smoothing the gain to preserve a peak gain value.

15. The method of claim 14, wherein preserving the peak value includes extending the peak value.

16. The method of claim 10, wherein the second signal includes a signal being provided to a second location.

17. The method of claim 10, wherein the second signal represents an estimate of a noise signal.

18. The method of claim 10 further comprising,

adjusting the second signal level as a function of frequency to lower the second signal level below the masking threshold over at least a portion of the second frequency range, to reduce audibility of the second signal in the first location.

19. A method for reducing audibility of an interfering signal comprising:

reproducing in a first location a first signal having a level as a function of frequency, the first signal also having a first frequency range,

determining a masking threshold as a function of frequency associated with the first signal in the first location,

identifying a level as a function of frequency of a second signal present in the first location, the second signal having a second frequency range,

comparing the level of the second signal present in the first location to the masking threshold, and

adjusting the second signal level as a function of frequency to lower the second signal level below the masking threshold over at least a portion of the second frequency range, to reduce audibility of the second signal in the first location.

20. The method of claim 19, wherein the first and second frequency ranges are represented in a Bark domain.

21. The method of claim 19, wherein adjusting the second signal level includes reducing a gain.

22. The method of claim 19, wherein the second signal includes a signal being provided to a second location.

23. A method for smoothing data comprising:

receiving a plurality of data points, wherein each of the data points is associated with a value;

defining an averaging window having a window length;

identifying at least one peak value from the data point values;

assigning the identified peak value to data points adjacent to the data point associated with the identified peak value to produce an adjusted plurality of data points, wherein the combined length of the adjacent data points and the data point associated with the identified peak value is equivalent to the window length; and

averaging the adjusted plurality of data points by using the averaging window to produce a smoothed version of the plurality of data points.

24. The method of claim 23, wherein the data point associated with the identified peak value is located at the center of the adjacent data points assigned the peak value.

25. The method of claim 23, wherein the averaging includes stepping the averaging window along the adjusted plurality of data points.