Semi-Supervised Online Speaker Diarization using Vector Quantization with Alternative Codebooks

Speaker diarization systems process audio files by labelling speech segments according to speakers' identities. Many speaker diarization systems work offline and are not suited for online applications. We present a semi-supervised, online, low-complexity system. While, in general, speaker diarization operates in an unsupervised manner, the presented system relies on the enrollment of the participating speakers in the conversation. The diarization system has two main novel aspects. The first one is a proposed online learning strategy that evaluates processed segments according to their usefulness for learning a speaker, i.e. update a speaker model with it. The segment is evaluated using two metrics to determine whether to use the segment to update the system. The second novel aspect is a proposed vector quantization approach that models the score not only depending on the target speaker codebook but also takes an alternative codebook into account. We also present an approach to compute the alternative codebook. Simulation results show that the proposed system outperforms a comparable system without the proposed online learning strategy and shows benefits, especially for short training lengths.