Methods and apparatus for maximizing speech intelligibility in quiet or noisy backgrounds
First Claim
1. A method of enhancing intelligibility of speech contained in an audio signal perceived by a subject via a communications path, where the communications path includes a intelligibility enhancing device having an adjustable gain, comprising generating a candidate frequency-wise gain which, if applied to the intelligibility enhancing device, would maximize an intelligibility metric of the communications path, where the intelligibility metric is a function of the relation:
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AI=v×
e×
f×
h where, AI is the intelligibility metric, V is a measure of audibility of the speech contained in the audio signal and is associated with a speech-to-noise ratio in the audio signal, E is a loudness limit associated the speech contained in the audio signal, F is a measure of spectral balance of the speech contained in the audio signal, H is a measure of any of (i) intermodulation distortion introduced by an ear of the subject, (ii) reverberation in the medium, (iii) frequency-compression in the communications path, (iv) frequency-shifting in the communications path and (v) peak-clipping in the communications path, (vi) amplitude compression in the communications path, (vii) any other noise or distortion in the communications path not otherwise associated with V, E and F.
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Abstract
Methods and apparatus for maximizing speech intelligibility use psycho-acoustic variables of a model of speech perception to control the determination of optimal frequency-band specific gain adjustments. Speech signals (or other audio input) whose intelligibility is to be improved are characterized by parameters which are applied to the model. These include measurements or estimates of speech intensity level, average noise spectrum of the incoming audio signal, and/or the current frequency-gain characteristic of the hearing compensation device. Characterizations of listeners based on hearing test results, for example, may also be applied to the model. Frequency-band specific gain adjustments generated by use of the model can be used for hearing aids, assistive listening devices, telephones, cellular telephones, or other speech delivery systems, personal music delivery systems, public-address systems, sound systems, speech generating systems, or other devices or mediums which project, transfer or assist in the detection or recognition of speech.
50 Citations
36 Claims
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1. A method of enhancing intelligibility of speech contained in an audio signal perceived by a subject via a communications path, where the communications path includes a intelligibility enhancing device having an adjustable gain, comprising
generating a candidate frequency-wise gain which, if applied to the intelligibility enhancing device, would maximize an intelligibility metric of the communications path, where the intelligibility metric is a function of the relation: -
AI=v×
e×
f×
hwhere, AI is the intelligibility metric, V is a measure of audibility of the speech contained in the audio signal and is associated with a speech-to-noise ratio in the audio signal, E is a loudness limit associated the speech contained in the audio signal, F is a measure of spectral balance of the speech contained in the audio signal, H is a measure of any of (i) intermodulation distortion introduced by an ear of the subject, (ii) reverberation in the medium, (iii) frequency-compression in the communications path, (iv) frequency-shifting in the communications path and (v) peak-clipping in the communications path, (vi) amplitude compression in the communications path, (vii) any other noise or distortion in the communications path not otherwise associated with V, E and F. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method of enhancing intelligibility of speech contained in an audio signal perceived by a subject via a communications path, where the communications path includes a intelligibility enhancing device having an adjustable gain, comprising:
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A. generating a candidate frequency-wise gain that mirrors an attenuation-modeled component of an audiogram for said subject, in order to bring a sum of that candidate frequency-wise gain and that attenuation-modeled component toward zero. B. adjusting the broadband gain of the candidate frequency-wise gain so that, if applied to the intelligibility enhancing device, would maximize an intelligibility metric of the communications path without substantially exceeding a loudness limit, E, for said subject, where the intelligibility metric is a function of the relation;
AI=V×
E×
F×
Hwhere, AI is the intelligibility metric, V is a measure of audibility of the speech contained in the audio signal and is associated with a speech-to-noise ratio in the audio signal, E is a loudness limit associated the speech contained in the audio signal, F is a measure of spectral balance of the speech contained in the audio signal, H is a measure of any of (i) intermodulation distortion introduced by an ear of the subject, (ii) reverberation in the medium, (iii) frequency-compression in the communications path, (iv) frequency-shifting in the communications path and (v) peak-clipping in the communications path, (vi) amplitude compression in the communications path, (vii) any other noise or distortion in the communications path not otherwise associated with V, E and F, C. adjusting the frequency-wise gain to compensate for a noise spectrum associated with the communications path, specifically, such that adjustment of the gain of the intelligibility enhancing device in accord with that candidate frequency-wise gain would bring that spectrum to audiogram thresholds, D. adjusting the broadband gain of the candidate frequency-wise gain so that, if applied to the intelligibility enhancing device, would maximize an intelligibility metric of the communications path without substantially exceeding a loudness limit, E, for said subject, E. testing whether adjusting the candidate frequency-wise gain to remove at least some of the adjustments made in step (C) would increase the intelligibility metric of the communications path and, if so, adjusting the candidate frequency-wise gain, F. adjusting the broadband gain of the candidate frequency-wise gain so that, if applied to the intelligibility enhancing device, would maximize an intelligibility metric of the communications path without substantially exceeding a loudness limit, E, for said subject, G. choosing the candidate frequency-wise gain characteristic resulting from steps (B), (D) and (F) associated the highest intelligibility metric, H. choosing between a zero gain and the candidate frequency-wise gain chosen in step (G), depending on which of such gains is associated the highest intelligibility metric, and I. adjusting the gain of the hearing compensation device in accord with the candidate frequency-wise gain characteristic chosen in step (H).
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17. A method of enhancing intelligibility of speech contained in an audio signal perceived by a subject via a communications path, where the communications path includes a intelligibility enhancing device, the method comprising applying to the intelligibility enhancing device a frequency-wise gain (hereinafter, “
- applied frequency-wise gain”
) made by a process that maximizes an intelligibility metric of the communications path, where the intelligibility metric is a function of the relation;
AI=V×
E×
F×
Hwhere, AI is the intelligibility metric, V is a measure of audibility of the speech contained in the audio signal and is associated with a speech-to-noise ratio in the audio signal, E is a loudness limit associated the speech contained in the audio signal, F is a measure of spectral balance of the speech contained in the audio signal, H is a measure of any of (i) intermodulation distortion introduced by an ear of the subject, (ii) reverberation in the medium, (iii) frequency-compression in the communications path, (iv) frequency-shifting in the communications path and (v) peak-clipping in the communications path, (vi) amplitude compression in the communications path, (vii) any other noise or distortion in the communications path not otherwise associated with V, E and F. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
- applied frequency-wise gain”
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30. In a device for enhancing intelligibility of speech contained in an audio signal perceived by a subject via a communications path that includes the device, the improvement wherein the device applies to the audio signal a frequency-wise gain (hereinafter, “
- applied frequency-wise gain”
) made by a process that maximizes an intelligibility metric of the communications path, where the intelligibility metric is a function of the relation;
AI=V×
E×
F×
Hwhere, AI is the intelligibility metric, V is a measure of audibility of the speech contained in the audio signal and is associated with a speech-to-noise ratio in the audio signal, E is a loudness limit associated the speech contained in the audio signal, F is a measure of spectral balance of the speech contained in the audio signal, H is a measure of any of (i) intermodulation distortion introduced by an ear of the subject, (ii) reverberation in the medium, (iii) frequency-compression in the communications path, (iv) frequency-shifting in the communications path and (v) peak-clipping in the communications path, (vi) amplitude compression in the communications path, (vii) any other noise or distortion in the communications path not otherwise associated with V, E and F. - View Dependent Claims (31, 32, 33, 34)
- applied frequency-wise gain”
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35. A method of enhancing intelligibility of sound contained in an audio signal perceived by a subject via a communications path, where the communications path includes a intelligibility enhancing device having an adjustable gain, comprising
generating a candidate frequency-wise gain which, if applied to the intelligibility enhancing device, would maximize an intelligibility metric of the communications path, where the intelligibility metric is a function of the relation: -
AI=V×
E×
F×
Hwhere, AI is the intelligibility metric, V is a measure of audibility of the sound contained in the audio signal and is associated with a sound-to-noise ratio in the audio signal, E is a loudness limit associated the sound contained in the audio signal, F is a measure of spectral balance of the sound contained in the audio signal, H is a measure of any of (i) intermodulation distortion introduced by an ear of the subject, (ii) reverberation in the medium, (iii) frequency-compression in the communications path, (iv) frequency-shifting in the communications path and (v) peak-clipping in the communications path, (vi) amplitude compression in the communications path, (vii) any other noise or distortion in the communications path not otherwise associated with V, E and F.
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36. In a device for enhancing intelligibility of sound contained in an audio signal perceived by a subject via a communications path that includes the device, the improvement wherein the device applies to the audio signal a frequency-wise gain (hereinafter, “
- applied frequency-wise gain”
) made by a process that maximizes an intelligibility metric of the communications path, where the intelligibility metric is a function of the relation;
AI=V×
E×
F×
Hwhere, AI is the intelligibility metric, V is a measure of audibility of the sound contained in the audio signal and is associated with a sound-to-noise ratio in the audio signal, E is a loudness limit associated the sound contained in the audio signal, F is a measure of spectral balance of the sound contained in the audio signal, H is a measure of any of (i) intermodulation distortion introduced by an ear of the subject, (ii) reverberation in the medium, (iii) frequency-compression in the communications path, (iv) frequency-shifting in the communications path and (v) peak-clipping in the communications path, (vi) amplitude compression in the communications path, (vii) any other noise or distortion in the communications path not otherwise associated with V, E and F.
- applied frequency-wise gain”
Specification