| 摘要 |
A method and apparatus for enhancing the intelligibility of a telephonic speech signal within the available bandwidth and intensity limits of a telephone communication network. The method combines enhancement of both the formant ratio and the consonant/vowel energy ratio to realize a speech signal more intelligible to a hearing impaired user. The invention uses an auditory model of the human ear. A speech signal is put through a filter bank designed to simulate the cochlear filter shapes and filter spacing of a healthy cochlea. The energy output from each of a plurality of filters is computed and used to form an auditory spectrum. The peaks associated with strong first and second formants are identified, and the second formant is enhanced relative to the first formant by attenuating the first formant. Also, consonants in the speech signal are identified as having an energy level below a threshold associated with vowels, but above the threshold associated with silent regions. Consonant regions are amplified. The net effect is to provide more energy in regions of the second formant and the consonants to enhance the intelligibility of the speech signal.
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