Speech Classification of Glottal Closure Instants in the Dypsa Algorithm
The Dynamic Programming Projected-Phase Slope Algorithm (DYPSA) detects glottal closure instants (GCI) in speech signals. We present an improvement in the algorithm in which a voiced/unvoiced/silence discrimination measure is applied in order to reduce the spurious Gels detected incorrectly for silence and unvoiced speech. Speech classification is addressed by formulating a decision rule for the glottal closure instant candidates which classifies the candidates as voiced or non-voiced (the ones occurring in silence and unvoiced speech) on the basis of feature measurements extracted from the speech signal alone. The technique of Dynamic Programming is then employed in order to select an optimum set of epochs from the GCI candidates. The algorithm has been tested on the APLA WD speech database with 87.23% improvement achieved in reduction of spurious GCis.