Automatic Classification of Types of Artefacts Arising During the Unit Selection Speech Synthesis

摘要

The paper describes an experiment with automatic classification of the basic types of artefacts in the synthetic speech produced by the Czech text-to-speech system using the unit selection synthesis method. The developed classifier based on the Gaussian mixture models (GMM) is solved finally as the open-set classification task due to a limited database of speech artefacts resulting from incorrectly chosen or exchanged speech units during the synthesis process. The realized experiments prove principal impact of the accuracy of determination of the speech artefact section on the final precision of the artefact type classification. From the auxiliary investigations follows a relatively great influence of the number of mixtures and the type of a covariance matrix on the output artefact classification error rate as well as on the computational complexity.