Meeting segmentation using two-layer cascaded subband filters

Abstract

The extraction of information from recorded meetings is a very important yet challenging task. The problem lies in the inability of speech recognition systems to be directly applied onto meeting speech data, mainly because meeting participants speak concurrently and head-mounted microphones record more than just their wearers' utterances - crosstalk from his neighbours are inevitably recorded as well. As a result, a degree of preprocessing of these recordings is needed. The current work presents an approach to segment meetings into four audio classes: Single speaker, crosstalk, single speaker plus crosstalk and silence. For this purpose, we propose Two-Layer Cascaded Subband Filters, which spread according to the pitch and formant frequency scales. This filters are able to detect the presence or absence of pitch and formants in an audio signal. In addition, the filters can determine how many numbers of pitches and formants are present in an audio signal based on the output subband energies. Experiments conducted on the ICSI meeting corpus, show that although an overall recognition rate of up to 57% was achieved, rates for crosstalk and silence classes are as high as 80%. This indicates the positive effect and potential of this subband feature in meeting segmentation tasks. © 2006 Springer-Verlag Berlin/Heidelberg.