High-quality and light-weight voice transformation enabling extrapolation without perceptual and objective breakdown

A voice transformation method that only relies on vowel information is proposed. The method is based on empirical cumulative distributions of perceptually relevant spectral distances, which are used to design mapping functions from distance to proximity. A set of operators are optimized in the design phase to implement on-the-fly compilation of executable transformations used in the transformation phase. Proximity of the current input parameters to the speaker´s own vowel templates is used in this compilation. The proposed method deforms the source speaker´s parameter space using a set of monotonic and continuous mapping functions. This smooth and topology-preserving mapping yields high-quality modification of existing speech resources.