Optimization of spectral warping parameters in a speech modification system

Previously the authors proposed an adaptive spectral envelope modification method for the purpose of enhancing vocal tract resonance-disordered speech. This approach is to frequency warp abnormal vowel spectral envelope functions nonlinearly to match vowel spectra from a normal speaker; warping functions for nonvowel input spectra are estimated from spectrally similar vowel warping functions. A discussion is presented of attempts at optimizing the spectral warping accuracy and perceived output signal quality of the algorithm when applied to continuous speech modifications