Speech Morphing by Progressive Interpolation of Spectra

ICSP1997: International Conference on Speech Processing, August 26-28, 1997, Seoul, Korea.A speech morphing, continuous alternation of speech waveforms of different two speakers, algorithm based on progressive interpolation of spectral envelope and source signal is proposed. The basic scheme of the morphing is 1) find correspondence of unit waveforms of original and target speech. 2) separate speech spectra to envelope and source excitation components, 3) find correspondence of spectral channels of original and target speech for each envelope, 4)interpolate both source signal and envelope, and 5) construct unit waveform and generates morphing speech by PSOLA. In the objective test, proposed method can reduce the spectral distortion by 1.9dB compare to the method based on progressive substitution of spectra, when it is used for interpolating two vowels in real speech. The effectiveness of the method is also confirmed by subjective test in which more than 90% (male to female morphing) or 60% (female to male morphing ) subjects preferred the proposed method