A simple but effective approach to speaker tracking in broadcast news

The automatic transcription of broadcast news and meetings involves the segmentation, identification and tracking of speaker turns during each session, which is known as speaker diarization. This paper presents a simple but effective approach to a slightly different task, called speaker tracking, also involving audio segmentation and speaker identification, but with a subset of known speakers, which allows to estimate speaker models and to perform identification on a segment-by-segment basis. The proposed algorithm segments the audio signal in a fully unsupervised way, by locating the most likely change points from an purely acoustic point of view. Then the available speaker data are used to estimate single-Gaussian acoustic models. Finally, speaker models are used to classify the audio segments by choosing the most likely speaker or, alternatively, the Other category, if none of the speakers is likely enough. Despite its simplicity, the proposed approach yielded the best performance in the speaker tracking challenge organized in November 2006 by the Spanish Network on Speech Technology.