HEARING ASSISTANCE APPARATUS

• US 20090262969A1
• Filed: 04/22/2008
• Published: 10/22/2009
• Est. Priority Date: 04/22/2008
• Status: Active Grant

• Current Assignee: Bose Corporation
• Original Assignee: Bose Corporation
• Inventors: Walters, Luke C., Short, William R.
• Granted Patent: US 8,611,554 B2
• Time in Patent Office: Days
• US Class Current: 381/370
• 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 2225/43 Signal processing in hearing aids to enhance the speech intelligibility
• CPC Class Codes: H04R 25/407 Circuits for combining signals of a plurality of transducers
• CPC Class Codes: H04R 25/50 Customised settings for obtaining desired overall acoustical characteristics
• CPC Class Codes: H04R 25/505 using digital signal processing
• CPC Class Codes: H04R 25/552 Binaural
• CPC Class Codes: H04R 3/005 for combining the signals of two or more microphones specially adapted for hearing aids H04R25/407
• CPC Class Codes: H04R 3/04 for correcting frequency response
• CPC Class Codes: H04R 5/033 Headphones for stereophonic communication details thereof, e.g. relating to batteries, cables or control elements H04R1/10
• CPC Class Codes: H04S 1/005 For headphones

Abstract

A hearing assistance device includes two transducers which react to a characteristic of an acoustic wave to capture data representative of the characteristic. The device is arranged so that each transducers is located adjacent a respective ear of a person wearing the device. A signal processor processes the data to provide relatively more emphasis of data representing a first sound source the person is facing over data representing a second sound source the person is not facing. At least one speaker utilizes the data to reproduce sounds to the person. An active noise reduction system provides a signal to the speaker for reducing an amount of ambient acoustic noise in the vicinity of the person that is heard by the person.

Claims

1. A hearing assistance device, comprising:

two transducers which react to a characteristic of an acoustic wave to capture data representative of the characteristic, the device being arranged so that each transducers is located adjacent a respective ear of a person wearing the device;

a signal processor for processing said data to provide relatively more emphasis of data representing a first sound source the person is facing over data representing a second sound source the person is not facing;

at least one speaker which utilizes the data to reproduce sounds to the person; and

an active noise reduction system that provides a signal to the speaker for reducing an amount of ambient acoustic noise in the vicinity of the person that is heard by the person.

2. The hearing assistance device of claim 1, further comprising:

a voice activity detector, wherein the output of the voice activity detector is used to alter a characteristic of the signal processor.

3. The hearing assistance device of claim 2, wherein the characteristic of the signal processor is altered based on a likelihood that the voice activity detector has detected a human voice in the first sound source.

4. The hearing assistance device of claim 1, wherein each transducer is a directional transducer.

5. The hearing assistance device of claim 1, wherein the signal processor determines (a) which data represents one or more sound sources located within a zone in front of the user, and (b) which data represents one or more sound sources located outside of the zone, the signal processor being adjustable as a function of at least one of frequency, a user setting, an amount of active noise reduction, a ratio of acoustic energy from sound sources in the zone to sound sources outside the zone, and sound level in a vicinity of the transducers, in order to adjust a size of the zone.

6. The hearing assistance device of claim 1, wherein a gain of substantially 1 is applied to data representing the first sound source, and a gain of substantially less than 1 is applied to data representing the second sound source.

7. A hearing assistance device, comprising:

two transducers, spaced from each other, which react to a characteristic of an acoustic wave to capture data representative of the characteristic;

a signal processor for processing said data to determine (a) which data represents one or more sound sources located within a zone in front of the user, and (b) which data represents one or more sound sources located outside of the zone, the signal processor providing relatively less emphasis of data representing the sound source(s) outside the zone over data representing the sound source(s) inside the zone;

a voice activity detector, a characteristic of the signal processor being adjusted based on whether or not the voice activity detector determines that a human voice is making sound within the zone; and

at least one speaker which utilizes the data to reproduce sounds to the user.

8. The hearing assistance device of claim 7, further comprising:

an active noise reduction system that provides a signal to the speaker for reducing an amount of ambient acoustic noise in the vicinity of the user that is heard by the user.

9. The hearing assistance device of claim 7, wherein the signal processor is adjustable as a function of at least one of frequency, a user setting, an amount of active noise reduction, a ratio of acoustic energy from sound sources in the zone to sound sources outside the zone, and sound level in a vicinity of the transducers, in order to adjust an effective size of the zone.

10. The hearing assistance device of claim 7, wherein the signal processor is adjustable in order to adjust an effective size of the zone.

11. The hearing assistance device of claim 10, wherein the signal processor is manually adjustable.

12. The hearing assistance device of claim 10, wherein the signal processor is automatically adjustable as a function of at least one of frequency, a user setting, an amount of active noise reduction, a ratio of acoustic energy from sound sources in the zone to sound sources outside the zone, and sound level in a vicinity of the transducers.

13. The hearing assistance device of claim 7, wherein each transducer is a directional transducer.

14. A method of providing hearing assistance to a person, comprising the steps of:

transforming data, collected by transducers which react to a characteristic of an acoustic wave, into signals for each transducer location;

separating the signals into a plurality of frequency bands for each location;

for each band determining from the signals whether or not a sound source providing energy to a particular band is substantially facing the person; and

causing a relative gain change between those frequency bands whose signal characteristics indicate that a sound source providing energy to a particular band is substantially facing the person, and those frequency bands whose signal characteristics indicate that a sound source providing energy to a particular band is not substantially facing the person, the signal processor being adjustable as a function of at least one of frequency, a user setting, an amount of active noise reduction, a ratio of acoustic energy from sound sources substantially facing the person to sound sources substantially not facing the person, and sound level in a vicinity of the transducers, in order to adjust an effective size of a zone in which a sound source is considered to be substantially facing the person.

15. The method of claim 14, wherein the separating, determining and causing steps are accomplished by a signal processor, a characteristic of the signal processor being adjusted based on whether or not a voice activity detector determines that the person is facing a human voice.

16. The method of claim 14, wherein each transducer is a directional transducer.

17. A hearing assistance device, comprising:

a voice activity detector into which a gain signal is input, the output of the voice activity detector being indicative of whether or not a voice of interest is present.

18. The hearing assistance device of claim 17, further including a first low pass filter which receives as a first input the output of the voice activity detector.

19. The hearing assistance device of claim 18, wherein the low pass filter receives as a second input the gain signal, the output of the voice activity detector setting the cutoff frequency of the low pass filter.

20. The hearing assistance device of claim 19, wherein when the voice activity detector indicates a presence of a voice signal, the cutoff frequency is set to a relatively higher frequency, and when the voice activity detector indicates an absence of a voice signal, the cutoff frequency is set to a relatively lower frequency.

21. The hearing assistance device of claim 18, further including a variable rate fast attack slow decay (FASD) filter which receives as an input the output of the low pass filter.

22. The hearing assistance device of claim 21, wherein when an average over a period of time of the input to the FASD filter is at a first level, a decay rate of the FASD filter is set to be at a first rate, and when an average over a period of time of the input to the FASD filter is at a second level above the first level, a decay rate of the FASD filter is set to be at a second rate below the first rate.

23. The hearing assistance device of claim 21, further including a second low pass filter which receives as an input the output of the FASD filter, wherein when the input to the second low pass filter is above a threshold this input bypasses the second low pass filter unmodified, and when the input to the second low pass filter is below the threshold this input is low pass filtered by the second low pass filter.

24. The hearing assistance device of claim 23, further including a median filter which receives as an input the output of the second low pass filter.

25. A hearing assistance device, comprising:

two transducers which react to a characteristic of an acoustic wave to capture data representative of the characteristic;

a signal processor for processing said data, wherein the signal processor (a) provides a first level of emphasis to data representing a first sound source that a user of the hearing assistance device is facing, the first sound source being substantially on axis with the user, and (b) provides a second level of emphasis lower than the first level of emphasis to data representing a second sound source off axis with the user, and (c) provides a third level of emphasis lower than the second level of emphasis to data representing a third sound source that is relatively more off axis than the second sound source; and

at least one speaker which utilizes the data to reproduce sounds to the person.

26. The hearing assistance device of claim 25, wherein the signal processor provides a fourth level of emphasis lower than the third level of emphasis to data representing a fourth sound source that is relatively more off axis than the third sound source.

27. A method of providing hearing assistance to a person, comprising the steps of:

transforming data, collected by two transducers which react to a characteristic of an acoustic wave, into signals for each transducer location;

utilizing the signals to determine a magnitude relationship and a phase angle relationship between the two transducers for a plurality of frequency bands at certain points in time;

mapping the magnitude relationship and phase angle relationship for each frequency band onto a two-dimensional plot;

determining an origin of the plot, the origin being where the magnitudes are substantially equal to each other and the phase angles are substantially equal to each other; and

causing a relative gain change between those frequency bands whose mapped magnitude relationship and phase angle relationship is relatively closer to the origin of the plot compared to those frequency bands whose mapped magnitude relationship and phase angle relationship is relatively further from the origin of the plot.

28. An apparatus for providing hearing assistance to a person, comprising:

a pair of transducers which react to a characteristic of an acoustic wave to create signals for each transducer location;

a signal processor that separates the signals into a plurality of frequency bands for each location, the signal processor, for each band, establishing a relationship between the signals, the signal processor applying a gain of substantially 1 to those frequency bands whose signal relationship meets a predetermined criteria, the signal processor applying a gain of substantially less than 1 to those frequency bands whose signal relationship does not meet the predetermined criteria.