A novel method for two-speaker segmentation
Rashmi Gangadharaiah, Balakrishnan Narayanaswamy, N. Balakrishnan · 2004
This paper addresses the problem of speaker based audio data segmentation. A novel method that has the advantages of both model and metric based techniques is proposed which creates a model for each speaker from the available data on the fly. This can be viewed as building a Hidden Markov Model (HMM) for the data with speakers abstracted as the hidden states. Each speaker/state is modeled with a Gaussian Mixture Model (GMM). To prevent a large number of spurious change points being detected, the use of the Generalized Likelihood Ratio (GLR) metric for grouping feature vectors is proposed. A clustering technique is described, through which a good initialization of each GMM is achieved, such that each state corresponds to a single speaker and not noise, silence or word classes, something that may happen in conventional unlabelled clustering. Finally, a refinement method, along the lines of Viterbi Training of HMMs is presented. The proposed method does not require prior knowledge of any speaker characteristics. It also does not require any tuning of threshold parameters, so it can be used with confidence over new data sets. The method assumes that the number of speakers is known apriori to be two. The method results in a decrease in the error rate by 84.75% on the files reported in the baseline system. It performs just as well even when the speaker segments are as short as 1s each, which is a large improvement over some previous methods, which require larger segments for accurate detection of speaker change points. 1.