Phoneme Adjustment in Enhanced Speech
Abstract
A system was developed to enhance the quality and intelligibility of speech which had been pre-processed by a Speech Enhancement Unit (SEU) at RADC Griffis AFB. The system processes the speech in the frequency domain. A Hamming window with 50% overlap was applied to the time waveform and a 512-point Discrete Fourier Transform (DFT) was computed. The amplitude spectrum of voiced regions was smoothed in order to reduce the effects of noise. Frequencies above 2.5 KHz were enhanced as they had been attenuated by SEU. Harmonics of the glottal pitch frequency of voiced speech and peaks of unvoiced speech were selected to further reduce the noise effects. The harmonics of the glottal frequency. The two neighboring frequency points were checked and the maximum of those three points was selected instead of the exact glottal harmonic. Speech was reconstructed using amplitude phase, and frequency of the harmonics/peaks selected. The reconstructed speech had much better quality and improved SNR. SPIRE (Speech and phonetics Interactive Research Environment) and ILS (interactive Laboratory System) software packages were used for visual analysis of the amplitude spectrum. The system was implemented in FORTRAN 77 on a VAX 11/ 780 machine. Keywords: Speech processing, Theses.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1989
- Accession Number
- ADA206357
Entities
People
- Nadeem A. Bashir
Organizations
- Air Force Institute of Technology