ICA-based hierarchical text classification for multi-domain text-to-speech synthesis

In the framework of multi-domain text-to-speech synthesis, it is essential (i) to design a hierarchically structured database for allowing several domains in the same speech corpus and (ii) to include a text classification module that, at run time, assigns the input sentences to a domain or set of domains from the database. We present a hierarchical text classifier based on independent component analysis (ICA), which is capable of (i) organizing the contents of the corpus in a hierarchical manner and (ii) classifying the texts to be synthesized according to the learned structure. The document organization and classification performance of our ICA-based hierarchical classifier are evaluated in several encouraging experiments conducted on a journalistic-style text corpus for speech synthesis in Catalan.