Most multi-pitch algorithms are tested for performance only in voiced regions of speech, and are prone to yield pitch estimates even when the participating speakers are unvoiced. This paper presents a multi-pitch algorithm that detects the voiced and unvoiced regions in a mixture of two speakers, identifies the number of speakers in voiced regions, and yields the pitch estimates of each speaker in those regions. The algorithm relies on the 2-Dimensional AMDF for estimating the periodicity of the signal, and uses the temporal evolution of the 2-D AMDF to estimate the number of speakers present in periodic regions. Evaluation of this algorithm on a frame-wise basis demonstrates accurate voiced / unvoiced decisions and also gives pitch estimation results comparable to the state of the art. The pitch estimation errors are quantitatively analyzed and shown to be resulting partly from speaker domination & pitch matching between speakers.
Bibliographic reference. Vishnubhotla, Srikanth / Espy-Wilson, Carol Y. (2008): "An algorithm for multi-pitch tracking in co-channel speech", In INTERSPEECH-2008, 143-146.