US 2008/0177532 A1 · Apparatus and methods for enhancement of speech

Abstract

A method for improving the intelligibility of an incoming telephone signal, including boosting loudness of at least one band of poorly heard frequencies of the signal within at least one band of intensities of the signal, the band lying below a predetermined intensity level at which telephone standard conformance testing is performed, thereby to generate a differentially boosted telephone signal. Alternatively or in addition, intelligibility of sibilants in a narrow band telephone signal is enhanced, by doubling the sampling rate of the narrow band signal by interpolation, thereby to provide a narrow band interpolated signal, generating a harmonic extrapolation signal by harmonically extrapolating from the narrow band interpolated signal thereby to estimate the missing portions of the telephone signal, the harmonic extrapolation comprising a sequence of pulses located at peaks of the interpolated signal, generating a missing energy estimator measure estimating energy missing at high frequency bands of the telephone signal, continuously modulating the amplitude of the pulses in said sequence of pulses based on said missing energy estimator measure, thereby to generate a modulated signal, passing the modulated signal through a shaping filter thereby to obtain a shaped signal, and summing the shaped signal with the interpolated signal.

Claims26

Dependent claims

Apparatus for improving the intelligibility of an incoming telephone signal, the apparatus comprising:

a frequency band and intensity dependent loudness modifier operative to boost loudness of at least one band of poorly heard frequencies of the incoming telephone signal within at least one band of intensities of the incoming telephone signal, said band lying below a predetermined intensity level at which telephone standard conformance testing is performed, thereby to generate a loudness boosted signal,
wherein said loudness modifier is also operative to boost loudness of at least one band of poorly heard frequencies of the incoming telephone signal at said predetermined intensity level wherein the loudness is boosted at the predetermined intensity level only to the extent allowed by the telephone standard.

A method for enhancing the intelligibility of sibilants in a narrow band telephone signal, the method comprising:

doubling the sampling rate of the narrow band telephone signal by interpolation, thereby to provide a narrow band interpolated signal;
generating a harmonic extrapolation signal by harmonically extrapolating from the narrow band interpolated signal thereby to estimate the missing portions of the telephone signal, the harmonic extrapolation comprising a sequence of pulses located at peaks of the interpolated signal;
generating a missing energy estimator measure estimating energy missing at high frequency bands of the telephone signal;
continuously modulating the amplitude of the pulses in said sequence of pulses based on said missing energy estimator measure, thereby to generate a modulated signal;
passing the modulated signal through a shaping filter thereby to obtain a shaped signal;
and
summing the shaped signal with the interpolated signal.

4 more elements

Dependencies are inferred from the claim text.

Apparatus and methods for enhancement of speech

Life of this patent

Apparatus and methods for enhancement of speech

Life of this patent

Abstract

Claims26