Method and apparatus for recognizing deformed speech
First Claim
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1. A system for processing a non-deformed speech signal spectrum, the speech signal spectrum having a first and a second frequency which represent a respective formant of said speech signal, the system comprising:
- extraction means responsive to said speech signal to extract therefrom an excitation signal representative of the sound and vibration sources of the speech;
envelope determination means responsive to said speech signal to compute coefficients characteristic of the shape of the spectrum envelope of said speech signal;
interpolation means responsive to said excitation signal to generate an interpolated excitation signal having a waveform that is identical to the waveform of said excitation signal and having a point density that is about two to three times the point density of said excitation signal;
synthesizer means responsive to said interpolated excitation signal and said characteristic coefficients to synthesize a deformed speech signal;
electronic means for linearly increasing the frequencies of the formants of said speech signal by a factor of about 2 to 3.
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Abstract
An apparatus and method for recognizing deformed speech signals outputted from a microphone includes a module for comparing deformed signals with simulated deformed signals that are generated from non-deformed speech signals that have previously been digitized and stored in a memory. Frequencies of the formants of simulated deformed signals are about two-three times the frequencies of the formants of digitized non-deformed signals.
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Citations
8 Claims
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1. A system for processing a non-deformed speech signal spectrum, the speech signal spectrum having a first and a second frequency which represent a respective formant of said speech signal, the system comprising:
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extraction means responsive to said speech signal to extract therefrom an excitation signal representative of the sound and vibration sources of the speech; envelope determination means responsive to said speech signal to compute coefficients characteristic of the shape of the spectrum envelope of said speech signal; interpolation means responsive to said excitation signal to generate an interpolated excitation signal having a waveform that is identical to the waveform of said excitation signal and having a point density that is about two to three times the point density of said excitation signal; synthesizer means responsive to said interpolated excitation signal and said characteristic coefficients to synthesize a deformed speech signal; electronic means for linearly increasing the frequencies of the formants of said speech signal by a factor of about 2 to 3. - View Dependent Claims (2, 3)
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4. A system for recognizing deformed speech signals delivered by a microphone, the system comprising:
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an apparatus for generating speech data representative of simulated deformed signals generated from non-deformed analog speech signals and for storing said data in a memory, said apparatus comprising; a) conversion means for digitizing said analog speech signals into a time sequence of digital values representing a digitized sampled speech signal, said digitized sampled speech signal having high frequency component that represent said formants of speech; b) digital pre-emphasis means for boosting the high frequency components of the digitized sampled speech signal; c) windowing means for weighting a window in application of a curve of predetermined shape; d) extraction means responsive to said speech data representative of said speech signal to extract digital excitation data representative of an excitation signal; e) envelope determination means responsive to said speech data to compute coefficients characteristic of a shape of a spectrum envelope of said digitized speech signal; f) interpolation means responsive to said excitation data to generate interpolated excitation data having a waveform that is identical to a waveform of said excitation data and having a point density that is about two to three times a point density of said excitation data; and g) synthesizer means responsive to said interpolated excitation data and to said characteristic coefficients to synthesize data representative of a simulated deformed speech signal; means for converting said simulated deformed speech data into analog simulated deformed speech signals, wherein the frequencies of the formants of said simulated deformed signal are about two to three times the frequencies of the formants of said digitized non-deformed signals; and a comparator module for comparing the deformed speech signals with said simulated deformed signals.
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5. A method of recognizing deformed speech comprising the steps of:
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digitizing and storing non-deformed speech signals in a memory; generating simulated deformed speech signals from said non-deformed speech signals, the simulated deformed speech signals including frequencies representing formants of speech; increasing the frequencies of the formants of said simulated deformed signals by a factor of about two to three times with respect to the frequencies of the formants of said digitized non-deformed signals; and comparing said deformed signals with said simulated deformed signals. - View Dependent Claims (6, 7, 8)
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Specification