Spectral and prosodic transformations of hearing-impaired Mandarin speech

This paper studies the combined use of spectral and prosodic conversions to enhance the hearing-impaired Mandarin speech. The analysis-synthesis system is based on a sinusoidal representation of the speech production mechanism. By taking advantage of the tone structure in Mandarin speech, pitch contours are orthogonally transformed and applied within the sinusoidal framework to perform pitch modification. Also proposed is a time-scale modification algorithm that finds accurate alignments between hearing-impaired and normal utterances. Using the alignments, spectral conversion is performed on subsyllabic acoustic units by a continuous probabilistic transform based on a Gaussian mixture model. Results of perceptual evaluation indicate that the proposed system greatly improves the intelligibility and the naturalness of hearing-impaired Mandarin speech.